obtained gcc-4.6.4.tar.bz2 from upstream website;upstream

verified gcc-4.6.4.tar.bz2.sig;
imported gcc-4.6.4 source tree from verified upstream tarball.

downloading a git-generated archive based on the 'upstream' tag
should provide you with a source tree that is binary identical
to the one extracted from the above tarball.

if you have obtained the source via the command 'git clone',
however, do note that line-endings of files in your working
directory might differ from line-endings of the respective
files in the upstream repository.

44 files changed, 4269 insertions, 0 deletions

diff --git a/libgo/go/image/color.go b/libgo/go/image/color.go
new file mode 100644
index 000000000..c1345c025
--- /dev/null
+++ b/libgo/go/image/color.go
@@ -0,0 +1,251 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package image
+
+// All Colors can convert themselves, with a possible loss of precision,
+// to 64-bit alpha-premultiplied RGBA. Each channel value ranges within
+// [0, 0xFFFF].
+type Color interface {
+	RGBA() (r, g, b, a uint32)
+}
+
+// An RGBAColor represents a traditional 32-bit alpha-premultiplied color,
+// having 8 bits for each of red, green, blue and alpha.
+type RGBAColor struct {
+	R, G, B, A uint8
+}
+
+func (c RGBAColor) RGBA() (r, g, b, a uint32) {
+	r = uint32(c.R)
+	r |= r << 8
+	g = uint32(c.G)
+	g |= g << 8
+	b = uint32(c.B)
+	b |= b << 8
+	a = uint32(c.A)
+	a |= a << 8
+	return
+}
+
+// An RGBA64Color represents a 64-bit alpha-premultiplied color,
+// having 16 bits for each of red, green, blue and alpha.
+type RGBA64Color struct {
+	R, G, B, A uint16
+}
+
+func (c RGBA64Color) RGBA() (r, g, b, a uint32) {
+	return uint32(c.R), uint32(c.G), uint32(c.B), uint32(c.A)
+}
+
+// An NRGBAColor represents a non-alpha-premultiplied 32-bit color.
+type NRGBAColor struct {
+	R, G, B, A uint8
+}
+
+func (c NRGBAColor) RGBA() (r, g, b, a uint32) {
+	r = uint32(c.R)
+	r |= r << 8
+	r *= uint32(c.A)
+	r /= 0xff
+	g = uint32(c.G)
+	g |= g << 8
+	g *= uint32(c.A)
+	g /= 0xff
+	b = uint32(c.B)
+	b |= b << 8
+	b *= uint32(c.A)
+	b /= 0xff
+	a = uint32(c.A)
+	a |= a << 8
+	return
+}
+
+// An NRGBA64Color represents a non-alpha-premultiplied 64-bit color,
+// having 16 bits for each of red, green, blue and alpha.
+type NRGBA64Color struct {
+	R, G, B, A uint16
+}
+
+func (c NRGBA64Color) RGBA() (r, g, b, a uint32) {
+	r = uint32(c.R)
+	r *= uint32(c.A)
+	r /= 0xffff
+	g = uint32(c.G)
+	g *= uint32(c.A)
+	g /= 0xffff
+	b = uint32(c.B)
+	b *= uint32(c.A)
+	b /= 0xffff
+	a = uint32(c.A)
+	return
+}
+
+// An AlphaColor represents an 8-bit alpha.
+type AlphaColor struct {
+	A uint8
+}
+
+func (c AlphaColor) RGBA() (r, g, b, a uint32) {
+	a = uint32(c.A)
+	a |= a << 8
+	return a, a, a, a
+}
+
+// An Alpha16Color represents a 16-bit alpha.
+type Alpha16Color struct {
+	A uint16
+}
+
+func (c Alpha16Color) RGBA() (r, g, b, a uint32) {
+	a = uint32(c.A)
+	return a, a, a, a
+}
+
+// A GrayColor represents an 8-bit grayscale color.
+type GrayColor struct {
+	Y uint8
+}
+
+func (c GrayColor) RGBA() (r, g, b, a uint32) {
+	y := uint32(c.Y)
+	y |= y << 8
+	return y, y, y, 0xffff
+}
+
+// A Gray16Color represents a 16-bit grayscale color.
+type Gray16Color struct {
+	Y uint16
+}
+
+func (c Gray16Color) RGBA() (r, g, b, a uint32) {
+	y := uint32(c.Y)
+	return y, y, y, 0xffff
+}
+
+// A ColorModel can convert foreign Colors, with a possible loss of precision,
+// to a Color from its own color model.
+type ColorModel interface {
+	Convert(c Color) Color
+}
+
+// The ColorModelFunc type is an adapter to allow the use of an ordinary
+// color conversion function as a ColorModel.  If f is such a function,
+// ColorModelFunc(f) is a ColorModel object that invokes f to implement
+// the conversion.
+type ColorModelFunc func(Color) Color
+
+func (f ColorModelFunc) Convert(c Color) Color {
+	return f(c)
+}
+
+func toRGBAColor(c Color) Color {
+	if _, ok := c.(RGBAColor); ok {
+		return c
+	}
+	r, g, b, a := c.RGBA()
+	return RGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
+}
+
+func toRGBA64Color(c Color) Color {
+	if _, ok := c.(RGBA64Color); ok {
+		return c
+	}
+	r, g, b, a := c.RGBA()
+	return RGBA64Color{uint16(r), uint16(g), uint16(b), uint16(a)}
+}
+
+func toNRGBAColor(c Color) Color {
+	if _, ok := c.(NRGBAColor); ok {
+		return c
+	}
+	r, g, b, a := c.RGBA()
+	if a == 0xffff {
+		return NRGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), 0xff}
+	}
+	if a == 0 {
+		return NRGBAColor{0, 0, 0, 0}
+	}
+	// Since Color.RGBA returns a alpha-premultiplied color, we should have r <= a && g <= a && b <= a.
+	r = (r * 0xffff) / a
+	g = (g * 0xffff) / a
+	b = (b * 0xffff) / a
+	return NRGBAColor{uint8(r >> 8), uint8(g >> 8), uint8(b >> 8), uint8(a >> 8)}
+}
+
+func toNRGBA64Color(c Color) Color {
+	if _, ok := c.(NRGBA64Color); ok {
+		return c
+	}
+	r, g, b, a := c.RGBA()
+	if a == 0xffff {
+		return NRGBA64Color{uint16(r), uint16(g), uint16(b), 0xffff}
+	}
+	if a == 0 {
+		return NRGBA64Color{0, 0, 0, 0}
+	}
+	// Since Color.RGBA returns a alpha-premultiplied color, we should have r <= a && g <= a && b <= a.
+	r = (r * 0xffff) / a
+	g = (g * 0xffff) / a
+	b = (b * 0xffff) / a
+	return NRGBA64Color{uint16(r), uint16(g), uint16(b), uint16(a)}
+}
+
+func toAlphaColor(c Color) Color {
+	if _, ok := c.(AlphaColor); ok {
+		return c
+	}
+	_, _, _, a := c.RGBA()
+	return AlphaColor{uint8(a >> 8)}
+}
+
+func toAlpha16Color(c Color) Color {
+	if _, ok := c.(Alpha16Color); ok {
+		return c
+	}
+	_, _, _, a := c.RGBA()
+	return Alpha16Color{uint16(a)}
+}
+
+func toGrayColor(c Color) Color {
+	if _, ok := c.(GrayColor); ok {
+		return c
+	}
+	r, g, b, _ := c.RGBA()
+	y := (299*r + 587*g + 114*b + 500) / 1000
+	return GrayColor{uint8(y >> 8)}
+}
+
+func toGray16Color(c Color) Color {
+	if _, ok := c.(Gray16Color); ok {
+		return c
+	}
+	r, g, b, _ := c.RGBA()
+	y := (299*r + 587*g + 114*b + 500) / 1000
+	return Gray16Color{uint16(y)}
+}
+
+// The ColorModel associated with RGBAColor.
+var RGBAColorModel ColorModel = ColorModelFunc(toRGBAColor)
+
+// The ColorModel associated with RGBA64Color.
+var RGBA64ColorModel ColorModel = ColorModelFunc(toRGBA64Color)
+
+// The ColorModel associated with NRGBAColor.
+var NRGBAColorModel ColorModel = ColorModelFunc(toNRGBAColor)
+
+// The ColorModel associated with NRGBA64Color.
+var NRGBA64ColorModel ColorModel = ColorModelFunc(toNRGBA64Color)
+
+// The ColorModel associated with AlphaColor.
+var AlphaColorModel ColorModel = ColorModelFunc(toAlphaColor)
+
+// The ColorModel associated with Alpha16Color.
+var Alpha16ColorModel ColorModel = ColorModelFunc(toAlpha16Color)
+
+// The ColorModel associated with GrayColor.
+var GrayColorModel ColorModel = ColorModelFunc(toGrayColor)
+
+// The ColorModel associated with Gray16Color.
+var Gray16ColorModel ColorModel = ColorModelFunc(toGray16Color)
diff --git a/libgo/go/image/format.go b/libgo/go/image/format.go
new file mode 100644
index 000000000..1d541b094
--- /dev/null
+++ b/libgo/go/image/format.go
@@ -0,0 +1,86 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package image
+
+import (
+	"bufio"
+	"io"
+	"os"
+)
+
+// An UnknownFormatErr indicates that decoding encountered an unknown format.
+var UnknownFormatErr = os.NewError("image: unknown format")
+
+// A format holds an image format's name, magic header and how to decode it.
+type format struct {
+	name, magic  string
+	decode       func(io.Reader) (Image, os.Error)
+	decodeConfig func(io.Reader) (Config, os.Error)
+}
+
+// Formats is the list of registered formats.
+var formats []format
+
+// RegisterFormat registers an image format for use by Decode.
+// Name is the name of the format, like "jpeg" or "png".
+// Magic is the magic prefix that identifies the format's encoding.
+// Decode is the function that decodes the encoded image.
+// DecodeConfig is the function that decodes just its configuration.
+func RegisterFormat(name, magic string, decode func(io.Reader) (Image, os.Error), decodeConfig func(io.Reader) (Config, os.Error)) {
+	formats = append(formats, format{name, magic, decode, decodeConfig})
+}
+
+// A reader is an io.Reader that can also peek ahead.
+type reader interface {
+	io.Reader
+	Peek(int) ([]byte, os.Error)
+}
+
+// AsReader converts an io.Reader to a reader.
+func asReader(r io.Reader) reader {
+	if rr, ok := r.(reader); ok {
+		return rr
+	}
+	return bufio.NewReader(r)
+}
+
+// sniff determines the format of r's data.
+func sniff(r reader) format {
+	for _, f := range formats {
+		s, err := r.Peek(len(f.magic))
+		if err == nil && string(s) == f.magic {
+			return f
+		}
+	}
+	return format{}
+}
+
+// Decode decodes an image that has been encoded in a registered format.
+// The string returned is the format name used during format registration.
+// Format registration is typically done by the init method of the codec-
+// specific package.
+func Decode(r io.Reader) (Image, string, os.Error) {
+	rr := asReader(r)
+	f := sniff(rr)
+	if f.decode == nil {
+		return nil, "", UnknownFormatErr
+	}
+	m, err := f.decode(rr)
+	return m, f.name, err
+}
+
+// DecodeConfig decodes the color model and dimensions of an image that has
+// been encoded in a registered format. The string returned is the format name
+// used during format registration. Format registration is typically done by
+// the init method of the codec-specific package.
+func DecodeConfig(r io.Reader) (Config, string, os.Error) {
+	rr := asReader(r)
+	f := sniff(rr)
+	if f.decodeConfig == nil {
+		return Config{}, "", UnknownFormatErr
+	}
+	c, err := f.decodeConfig(rr)
+	return c, f.name, err
+}
diff --git a/libgo/go/image/geom.go b/libgo/go/image/geom.go
new file mode 100644
index 000000000..ccfe9cdb0
--- /dev/null
+++ b/libgo/go/image/geom.go
@@ -0,0 +1,223 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package image
+
+import (
+	"strconv"
+)
+
+// A Point is an X, Y coordinate pair. The axes increase right and down.
+type Point struct {
+	X, Y int
+}
+
+// String returns a string representation of p like "(3,4)".
+func (p Point) String() string {
+	return "(" + strconv.Itoa(p.X) + "," + strconv.Itoa(p.Y) + ")"
+}
+
+// Add returns the vector p+q.
+func (p Point) Add(q Point) Point {
+	return Point{p.X + q.X, p.Y + q.Y}
+}
+
+// Sub returns the vector p-q.
+func (p Point) Sub(q Point) Point {
+	return Point{p.X - q.X, p.Y - q.Y}
+}
+
+// Mul returns the vector p*k.
+func (p Point) Mul(k int) Point {
+	return Point{p.X * k, p.Y * k}
+}
+
+// Div returns the vector p/k.
+func (p Point) Div(k int) Point {
+	return Point{p.X / k, p.Y / k}
+}
+
+// Mod returns the point q in r such that p.X-q.X is a multiple of r's width
+// and p.Y-q.Y is a multiple of r's height.
+func (p Point) Mod(r Rectangle) Point {
+	w, h := r.Dx(), r.Dy()
+	p = p.Sub(r.Min)
+	p.X = p.X % w
+	if p.X < 0 {
+		p.X += w
+	}
+	p.Y = p.Y % h
+	if p.Y < 0 {
+		p.Y += h
+	}
+	return p.Add(r.Min)
+}
+
+// Eq returns whether p and q are equal.
+func (p Point) Eq(q Point) bool {
+	return p.X == q.X && p.Y == q.Y
+}
+
+// ZP is the zero Point.
+var ZP Point
+
+// Pt is shorthand for Point{X, Y}.
+func Pt(X, Y int) Point {
+	return Point{X, Y}
+}
+
+// A Rectangle contains the points with Min.X <= X < Max.X, Min.Y <= Y < Max.Y.
+// It is well-formed if Min.X <= Max.X and likewise for Y. Points are always
+// well-formed. A rectangle's methods always return well-formed outputs for
+// well-formed inputs.
+type Rectangle struct {
+	Min, Max Point
+}
+
+// String returns a string representation of r like "(3,4)-(6,5)".
+func (r Rectangle) String() string {
+	return r.Min.String() + "-" + r.Max.String()
+}
+
+// Dx returns r's width.
+func (r Rectangle) Dx() int {
+	return r.Max.X - r.Min.X
+}
+
+// Dy returns r's height.
+func (r Rectangle) Dy() int {
+	return r.Max.Y - r.Min.Y
+}
+
+// Size returns r's width and height.
+func (r Rectangle) Size() Point {
+	return Point{
+		r.Max.X - r.Min.X,
+		r.Max.Y - r.Min.Y,
+	}
+}
+
+// Add returns the rectangle r translated by p.
+func (r Rectangle) Add(p Point) Rectangle {
+	return Rectangle{
+		Point{r.Min.X + p.X, r.Min.Y + p.Y},
+		Point{r.Max.X + p.X, r.Max.Y + p.Y},
+	}
+}
+
+// Add returns the rectangle r translated by -p.
+func (r Rectangle) Sub(p Point) Rectangle {
+	return Rectangle{
+		Point{r.Min.X - p.X, r.Min.Y - p.Y},
+		Point{r.Max.X - p.X, r.Max.Y - p.Y},
+	}
+}
+
+// Inset returns the rectangle r inset by n, which may be negative. If either
+// of r's dimensions is less than 2*n then an empty rectangle near the center
+// of r will be returned.
+func (r Rectangle) Inset(n int) Rectangle {
+	if r.Dx() < 2*n {
+		r.Min.X = (r.Min.X + r.Max.X) / 2
+		r.Max.X = r.Min.X
+	} else {
+		r.Min.X += n
+		r.Max.X -= n
+	}
+	if r.Dy() < 2*n {
+		r.Min.Y = (r.Min.Y + r.Max.Y) / 2
+		r.Max.Y = r.Min.Y
+	} else {
+		r.Min.Y += n
+		r.Max.Y -= n
+	}
+	return r
+}
+
+// Intersect returns the largest rectangle contained by both r and s. If the
+// two rectangles do not overlap then the zero rectangle will be returned.
+func (r Rectangle) Intersect(s Rectangle) Rectangle {
+	if r.Min.X < s.Min.X {
+		r.Min.X = s.Min.X
+	}
+	if r.Min.Y < s.Min.Y {
+		r.Min.Y = s.Min.Y
+	}
+	if r.Max.X > s.Max.X {
+		r.Max.X = s.Max.X
+	}
+	if r.Max.Y > s.Max.Y {
+		r.Max.Y = s.Max.Y
+	}
+	if r.Min.X > r.Max.X || r.Min.Y > r.Max.Y {
+		return ZR
+	}
+	return r
+}
+
+// Union returns the smallest rectangle that contains both r and s.
+func (r Rectangle) Union(s Rectangle) Rectangle {
+	if r.Min.X > s.Min.X {
+		r.Min.X = s.Min.X
+	}
+	if r.Min.Y > s.Min.Y {
+		r.Min.Y = s.Min.Y
+	}
+	if r.Max.X < s.Max.X {
+		r.Max.X = s.Max.X
+	}
+	if r.Max.Y < s.Max.Y {
+		r.Max.Y = s.Max.Y
+	}
+	return r
+}
+
+// Empty returns whether the rectangle contains no points.
+func (r Rectangle) Empty() bool {
+	return r.Min.X >= r.Max.X || r.Min.Y >= r.Max.Y
+}
+
+// Eq returns whether r and s are equal.
+func (r Rectangle) Eq(s Rectangle) bool {
+	return r.Min.X == s.Min.X && r.Min.Y == s.Min.Y &&
+		r.Max.X == s.Max.X && r.Max.Y == s.Max.Y
+}
+
+// Overlaps returns whether r and s have a non-empty intersection.
+func (r Rectangle) Overlaps(s Rectangle) bool {
+	return r.Min.X < s.Max.X && s.Min.X < r.Max.X &&
+		r.Min.Y < s.Max.Y && s.Min.Y < r.Max.Y
+}
+
+// Contains returns whether r contains p.
+func (r Rectangle) Contains(p Point) bool {
+	return p.X >= r.Min.X && p.X < r.Max.X &&
+		p.Y >= r.Min.Y && p.Y < r.Max.Y
+}
+
+// Canon returns the canonical version of r. The returned rectangle has minimum
+// and maximum coordinates swapped if necessary so that it is well-formed.
+func (r Rectangle) Canon() Rectangle {
+	if r.Max.X < r.Min.X {
+		r.Min.X, r.Max.X = r.Max.X, r.Min.X
+	}
+	if r.Max.Y < r.Min.Y {
+		r.Min.Y, r.Max.Y = r.Max.Y, r.Min.Y
+	}
+	return r
+}
+
+// ZR is the zero Rectangle.
+var ZR Rectangle
+
+// Rect is shorthand for Rectangle{Pt(x0, y0), Pt(x1, y1)}.
+func Rect(x0, y0, x1, y1 int) Rectangle {
+	if x0 > x1 {
+		x0, x1 = x1, x0
+	}
+	if y0 > y1 {
+		y0, y1 = y1, y0
+	}
+	return Rectangle{Point{x0, y0}, Point{x1, y1}}
+}
diff --git a/libgo/go/image/image.go b/libgo/go/image/image.go
new file mode 100644
index 000000000..c0e96e1f7
--- /dev/null
+++ b/libgo/go/image/image.go
@@ -0,0 +1,506 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The image package implements a basic 2-D image library.
+package image
+
+// A Config consists of an image's color model and dimensions.
+type Config struct {
+	ColorModel    ColorModel
+	Width, Height int
+}
+
+// An Image is a finite rectangular grid of Colors drawn from a ColorModel.
+type Image interface {
+	// ColorModel returns the Image's ColorModel.
+	ColorModel() ColorModel
+	// Bounds returns the domain for which At can return non-zero color.
+	// The bounds do not necessarily contain the point (0, 0).
+	Bounds() Rectangle
+	// At returns the color of the pixel at (x, y).
+	// At(Bounds().Min.X, Bounds().Min.Y) returns the upper-left pixel of the grid.
+	// At(Bounds().Max.X-1, Bounds().Max.Y-1) returns the lower-right one.
+	At(x, y int) Color
+}
+
+// An RGBA is an in-memory image of RGBAColor values.
+type RGBA struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []RGBAColor
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *RGBA) ColorModel() ColorModel { return RGBAColorModel }
+
+func (p *RGBA) Bounds() Rectangle { return p.Rect }
+
+func (p *RGBA) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return RGBAColor{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *RGBA) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toRGBAColor(c).(RGBAColor)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *RGBA) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewRGBA returns a new RGBA with the given width and height.
+func NewRGBA(w, h int) *RGBA {
+	buf := make([]RGBAColor, w*h)
+	return &RGBA{buf, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An RGBA64 is an in-memory image of RGBA64Color values.
+type RGBA64 struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []RGBA64Color
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *RGBA64) ColorModel() ColorModel { return RGBA64ColorModel }
+
+func (p *RGBA64) Bounds() Rectangle { return p.Rect }
+
+func (p *RGBA64) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return RGBA64Color{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *RGBA64) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toRGBA64Color(c).(RGBA64Color)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *RGBA64) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xffff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewRGBA64 returns a new RGBA64 with the given width and height.
+func NewRGBA64(w, h int) *RGBA64 {
+	pix := make([]RGBA64Color, w*h)
+	return &RGBA64{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An NRGBA is an in-memory image of NRGBAColor values.
+type NRGBA struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []NRGBAColor
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *NRGBA) ColorModel() ColorModel { return NRGBAColorModel }
+
+func (p *NRGBA) Bounds() Rectangle { return p.Rect }
+
+func (p *NRGBA) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return NRGBAColor{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *NRGBA) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toNRGBAColor(c).(NRGBAColor)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *NRGBA) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewNRGBA returns a new NRGBA with the given width and height.
+func NewNRGBA(w, h int) *NRGBA {
+	pix := make([]NRGBAColor, w*h)
+	return &NRGBA{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An NRGBA64 is an in-memory image of NRGBA64Color values.
+type NRGBA64 struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []NRGBA64Color
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *NRGBA64) ColorModel() ColorModel { return NRGBA64ColorModel }
+
+func (p *NRGBA64) Bounds() Rectangle { return p.Rect }
+
+func (p *NRGBA64) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return NRGBA64Color{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *NRGBA64) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toNRGBA64Color(c).(NRGBA64Color)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *NRGBA64) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xffff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewNRGBA64 returns a new NRGBA64 with the given width and height.
+func NewNRGBA64(w, h int) *NRGBA64 {
+	pix := make([]NRGBA64Color, w*h)
+	return &NRGBA64{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An Alpha is an in-memory image of AlphaColor values.
+type Alpha struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []AlphaColor
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *Alpha) ColorModel() ColorModel { return AlphaColorModel }
+
+func (p *Alpha) Bounds() Rectangle { return p.Rect }
+
+func (p *Alpha) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return AlphaColor{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Alpha) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toAlphaColor(c).(AlphaColor)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Alpha) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewAlpha returns a new Alpha with the given width and height.
+func NewAlpha(w, h int) *Alpha {
+	pix := make([]AlphaColor, w*h)
+	return &Alpha{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// An Alpha16 is an in-memory image of Alpha16Color values.
+type Alpha16 struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []Alpha16Color
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *Alpha16) ColorModel() ColorModel { return Alpha16ColorModel }
+
+func (p *Alpha16) Bounds() Rectangle { return p.Rect }
+
+func (p *Alpha16) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return Alpha16Color{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Alpha16) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toAlpha16Color(c).(Alpha16Color)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Alpha16) Opaque() bool {
+	if p.Rect.Empty() {
+		return true
+	}
+	base := p.Rect.Min.Y * p.Stride
+	i0, i1 := base+p.Rect.Min.X, base+p.Rect.Max.X
+	for y := p.Rect.Min.Y; y < p.Rect.Max.Y; y++ {
+		for _, c := range p.Pix[i0:i1] {
+			if c.A != 0xffff {
+				return false
+			}
+		}
+		i0 += p.Stride
+		i1 += p.Stride
+	}
+	return true
+}
+
+// NewAlpha16 returns a new Alpha16 with the given width and height.
+func NewAlpha16(w, h int) *Alpha16 {
+	pix := make([]Alpha16Color, w*h)
+	return &Alpha16{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// A Gray is an in-memory image of GrayColor values.
+type Gray struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []GrayColor
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *Gray) ColorModel() ColorModel { return GrayColorModel }
+
+func (p *Gray) Bounds() Rectangle { return p.Rect }
+
+func (p *Gray) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return GrayColor{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Gray) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toGrayColor(c).(GrayColor)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Gray) Opaque() bool {
+	return true
+}
+
+// NewGray returns a new Gray with the given width and height.
+func NewGray(w, h int) *Gray {
+	pix := make([]GrayColor, w*h)
+	return &Gray{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// A Gray16 is an in-memory image of Gray16Color values.
+type Gray16 struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []Gray16Color
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+}
+
+func (p *Gray16) ColorModel() ColorModel { return Gray16ColorModel }
+
+func (p *Gray16) Bounds() Rectangle { return p.Rect }
+
+func (p *Gray16) At(x, y int) Color {
+	if !p.Rect.Contains(Point{x, y}) {
+		return Gray16Color{}
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Gray16) Set(x, y int, c Color) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = toGray16Color(c).(Gray16Color)
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Gray16) Opaque() bool {
+	return true
+}
+
+// NewGray16 returns a new Gray16 with the given width and height.
+func NewGray16(w, h int) *Gray16 {
+	pix := make([]Gray16Color, w*h)
+	return &Gray16{pix, w, Rectangle{ZP, Point{w, h}}}
+}
+
+// A PalettedColorModel represents a fixed palette of colors.
+type PalettedColorModel []Color
+
+func diff(a, b uint32) uint32 {
+	if a > b {
+		return a - b
+	}
+	return b - a
+}
+
+// Convert returns the palette color closest to c in Euclidean R,G,B space.
+func (p PalettedColorModel) Convert(c Color) Color {
+	if len(p) == 0 {
+		return nil
+	}
+	cr, cg, cb, _ := c.RGBA()
+	// Shift by 1 bit to avoid potential uint32 overflow in sum-squared-difference.
+	cr >>= 1
+	cg >>= 1
+	cb >>= 1
+	result := Color(nil)
+	bestSSD := uint32(1<<32 - 1)
+	for _, v := range p {
+		vr, vg, vb, _ := v.RGBA()
+		vr >>= 1
+		vg >>= 1
+		vb >>= 1
+		dr, dg, db := diff(cr, vr), diff(cg, vg), diff(cb, vb)
+		ssd := (dr * dr) + (dg * dg) + (db * db)
+		if ssd < bestSSD {
+			bestSSD = ssd
+			result = v
+		}
+	}
+	return result
+}
+
+// A Paletted is an in-memory image backed by a 2-D slice of uint8 values and a PalettedColorModel.
+type Paletted struct {
+	// Pix holds the image's pixels. The pixel at (x, y) is Pix[y*Stride+x].
+	Pix    []uint8
+	Stride int
+	// Rect is the image's bounds.
+	Rect Rectangle
+	// Palette is the image's palette.
+	Palette PalettedColorModel
+}
+
+func (p *Paletted) ColorModel() ColorModel { return p.Palette }
+
+func (p *Paletted) Bounds() Rectangle { return p.Rect }
+
+func (p *Paletted) At(x, y int) Color {
+	if len(p.Palette) == 0 {
+		return nil
+	}
+	if !p.Rect.Contains(Point{x, y}) {
+		return p.Palette[0]
+	}
+	return p.Palette[p.Pix[y*p.Stride+x]]
+}
+
+func (p *Paletted) ColorIndexAt(x, y int) uint8 {
+	if !p.Rect.Contains(Point{x, y}) {
+		return 0
+	}
+	return p.Pix[y*p.Stride+x]
+}
+
+func (p *Paletted) SetColorIndex(x, y int, index uint8) {
+	if !p.Rect.Contains(Point{x, y}) {
+		return
+	}
+	p.Pix[y*p.Stride+x] = index
+}
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (p *Paletted) Opaque() bool {
+	for _, c := range p.Palette {
+		_, _, _, a := c.RGBA()
+		if a != 0xffff {
+			return false
+		}
+	}
+	return true
+}
+
+// NewPaletted returns a new Paletted with the given width, height and palette.
+func NewPaletted(w, h int, m PalettedColorModel) *Paletted {
+	pix := make([]uint8, w*h)
+	return &Paletted{pix, w, Rectangle{ZP, Point{w, h}}, m}
+}
diff --git a/libgo/go/image/jpeg/huffman.go b/libgo/go/image/jpeg/huffman.go
new file mode 100644
index 000000000..0d03a7317
--- /dev/null
+++ b/libgo/go/image/jpeg/huffman.go
@@ -0,0 +1,190 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package jpeg
+
+import (
+	"io"
+	"os"
+)
+
+// Each code is at most 16 bits long.
+const maxCodeLength = 16
+
+// Each decoded value is a uint8, so there are at most 256 such values.
+const maxNumValues = 256
+
+// Bit stream for the Huffman decoder.
+// The n least significant bits of a form the unread bits, to be read in MSB to LSB order.
+type bits struct {
+	a int // accumulator.
+	n int // the number of unread bits in a.
+	m int // mask. m==1<<(n-1) when n>0, with m==0 when n==0.
+}
+
+// Huffman table decoder, specified in section C.
+type huffman struct {
+	l        [maxCodeLength]int
+	length   int                 // sum of l[i].
+	val      [maxNumValues]uint8 // the decoded values, as sorted by their encoding.
+	size     [maxNumValues]int   // size[i] is the number of bits to encode val[i].
+	code     [maxNumValues]int   // code[i] is the encoding of val[i].
+	minCode  [maxCodeLength]int  // min codes of length i, or -1 if no codes of that length.
+	maxCode  [maxCodeLength]int  // max codes of length i, or -1 if no codes of that length.
+	valIndex [maxCodeLength]int  // index into val of minCode[i].
+}
+
+// Reads bytes from the io.Reader to ensure that bits.n is at least n.
+func (d *decoder) ensureNBits(n int) os.Error {
+	for d.b.n < n {
+		c, err := d.r.ReadByte()
+		if err != nil {
+			return err
+		}
+		d.b.a = d.b.a<<8 | int(c)
+		d.b.n += 8
+		if d.b.m == 0 {
+			d.b.m = 1 << 7
+		} else {
+			d.b.m <<= 8
+		}
+		// Byte stuffing, specified in section F.1.2.3.
+		if c == 0xff {
+			c, err = d.r.ReadByte()
+			if err != nil {
+				return err
+			}
+			if c != 0x00 {
+				return FormatError("missing 0xff00 sequence")
+			}
+		}
+	}
+	return nil
+}
+
+// The composition of RECEIVE and EXTEND, specified in section F.2.2.1.
+func (d *decoder) receiveExtend(t uint8) (int, os.Error) {
+	err := d.ensureNBits(int(t))
+	if err != nil {
+		return 0, err
+	}
+	d.b.n -= int(t)
+	d.b.m >>= t
+	s := 1 << t
+	x := (d.b.a >> uint8(d.b.n)) & (s - 1)
+	if x < s>>1 {
+		x += ((-1) << t) + 1
+	}
+	return x, nil
+}
+
+// Processes a Define Huffman Table marker, and initializes a huffman struct from its contents.
+// Specified in section B.2.4.2.
+func (d *decoder) processDHT(n int) os.Error {
+	for n > 0 {
+		if n < 17 {
+			return FormatError("DHT has wrong length")
+		}
+		_, err := io.ReadFull(d.r, d.tmp[0:17])
+		if err != nil {
+			return err
+		}
+		tc := d.tmp[0] >> 4
+		if tc > maxTc {
+			return FormatError("bad Tc value")
+		}
+		th := d.tmp[0] & 0x0f
+		const isBaseline = true // Progressive mode is not yet supported.
+		if th > maxTh || isBaseline && th > 1 {
+			return FormatError("bad Th value")
+		}
+		h := &d.huff[tc][th]
+
+		// Read l and val (and derive length).
+		h.length = 0
+		for i := 0; i < maxCodeLength; i++ {
+			h.l[i] = int(d.tmp[i+1])
+			h.length += h.l[i]
+		}
+		if h.length == 0 {
+			return FormatError("Huffman table has zero length")
+		}
+		if h.length > maxNumValues {
+			return FormatError("Huffman table has excessive length")
+		}
+		n -= h.length + 17
+		if n < 0 {
+			return FormatError("DHT has wrong length")
+		}
+		_, err = io.ReadFull(d.r, h.val[0:h.length])
+		if err != nil {
+			return err
+		}
+
+		// Derive size.
+		k := 0
+		for i := 0; i < maxCodeLength; i++ {
+			for j := 0; j < h.l[i]; j++ {
+				h.size[k] = i + 1
+				k++
+			}
+		}
+
+		// Derive code.
+		code := 0
+		size := h.size[0]
+		for i := 0; i < h.length; i++ {
+			if size != h.size[i] {
+				code <<= uint8(h.size[i] - size)
+				size = h.size[i]
+			}
+			h.code[i] = code
+			code++
+		}
+
+		// Derive minCode, maxCode, and valIndex.
+		k = 0
+		index := 0
+		for i := 0; i < maxCodeLength; i++ {
+			if h.l[i] == 0 {
+				h.minCode[i] = -1
+				h.maxCode[i] = -1
+				h.valIndex[i] = -1
+			} else {
+				h.minCode[i] = k
+				h.maxCode[i] = k + h.l[i] - 1
+				h.valIndex[i] = index
+				k += h.l[i]
+				index += h.l[i]
+			}
+			k <<= 1
+		}
+	}
+	return nil
+}
+
+// Returns the next Huffman-coded value from the bit stream, decoded according to h.
+// TODO(nigeltao): This decoding algorithm is simple, but slow. A lookahead table, instead of always
+// peeling off only 1 bit at at time, ought to be faster.
+func (d *decoder) decodeHuffman(h *huffman) (uint8, os.Error) {
+	if h.length == 0 {
+		return 0, FormatError("uninitialized Huffman table")
+	}
+	for i, code := 0, 0; i < maxCodeLength; i++ {
+		err := d.ensureNBits(1)
+		if err != nil {
+			return 0, err
+		}
+		if d.b.a&d.b.m != 0 {
+			code |= 1
+		}
+		d.b.n--
+		d.b.m >>= 1
+		if code <= h.maxCode[i] {
+			return h.val[h.valIndex[i]+code-h.minCode[i]], nil
+		}
+		code <<= 1
+	}
+	return 0, FormatError("bad Huffman code")
+}
diff --git a/libgo/go/image/jpeg/idct.go b/libgo/go/image/jpeg/idct.go
new file mode 100644
index 000000000..518993110
--- /dev/null
+++ b/libgo/go/image/jpeg/idct.go
@@ -0,0 +1,190 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This is a Go translation of idct.c from
+//
+// http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_IEC_13818-4_2004_Conformance_Testing/Video/verifier/mpeg2decode_960109.tar.gz
+//
+// which carries the following notice:
+
+/* Copyright (C) 1996, MPEG Software Simulation Group. All Rights Reserved. */
+
+/*
+ * Disclaimer of Warranty
+ *
+ * These software programs are available to the user without any license fee or
+ * royalty on an "as is" basis.  The MPEG Software Simulation Group disclaims
+ * any and all warranties, whether express, implied, or statuary, including any
+ * implied warranties or merchantability or of fitness for a particular
+ * purpose.  In no event shall the copyright-holder be liable for any
+ * incidental, punitive, or consequential damages of any kind whatsoever
+ * arising from the use of these programs.
+ *
+ * This disclaimer of warranty extends to the user of these programs and user's
+ * customers, employees, agents, transferees, successors, and assigns.
+ *
+ * The MPEG Software Simulation Group does not represent or warrant that the
+ * programs furnished hereunder are free of infringement of any third-party
+ * patents.
+ *
+ * Commercial implementations of MPEG-1 and MPEG-2 video, including shareware,
+ * are subject to royalty fees to patent holders.  Many of these patents are
+ * general enough such that they are unavoidable regardless of implementation
+ * design.
+ *
+ */
+
+package jpeg
+
+const (
+	w1 = 2841 // 2048*sqrt(2)*cos(1*pi/16)
+	w2 = 2676 // 2048*sqrt(2)*cos(2*pi/16)
+	w3 = 2408 // 2048*sqrt(2)*cos(3*pi/16)
+	w5 = 1609 // 2048*sqrt(2)*cos(5*pi/16)
+	w6 = 1108 // 2048*sqrt(2)*cos(6*pi/16)
+	w7 = 565  // 2048*sqrt(2)*cos(7*pi/16)
+
+	w1pw7 = w1 + w7
+	w1mw7 = w1 - w7
+	w2pw6 = w2 + w6
+	w2mw6 = w2 - w6
+	w3pw5 = w3 + w5
+	w3mw5 = w3 - w5
+
+	r2 = 181 // 256/sqrt(2)
+)
+
+// 2-D Inverse Discrete Cosine Transformation, followed by a +128 level shift.
+//
+// The input coefficients should already have been multiplied by the appropriate quantization table.
+// We use fixed-point computation, with the number of bits for the fractional component varying over the
+// intermediate stages. The final values are expected to range within [0, 255], after a +128 level shift.
+//
+// For more on the actual algorithm, see Z. Wang, "Fast algorithms for the discrete W transform and
+// for the discrete Fourier transform", IEEE Trans. on ASSP, Vol. ASSP- 32, pp. 803-816, Aug. 1984.
+func idct(b *[blockSize]int) {
+	// Horizontal 1-D IDCT.
+	for y := 0; y < 8; y++ {
+		// If all the AC components are zero, then the IDCT is trivial.
+		if b[y*8+1] == 0 && b[y*8+2] == 0 && b[y*8+3] == 0 &&
+			b[y*8+4] == 0 && b[y*8+5] == 0 && b[y*8+6] == 0 && b[y*8+7] == 0 {
+			dc := b[y*8+0] << 3
+			b[y*8+0] = dc
+			b[y*8+1] = dc
+			b[y*8+2] = dc
+			b[y*8+3] = dc
+			b[y*8+4] = dc
+			b[y*8+5] = dc
+			b[y*8+6] = dc
+			b[y*8+7] = dc
+			continue
+		}
+
+		// Prescale.
+		x0 := (b[y*8+0] << 11) + 128
+		x1 := b[y*8+4] << 11
+		x2 := b[y*8+6]
+		x3 := b[y*8+2]
+		x4 := b[y*8+1]
+		x5 := b[y*8+7]
+		x6 := b[y*8+5]
+		x7 := b[y*8+3]
+
+		// Stage 1.
+		x8 := w7 * (x4 + x5)
+		x4 = x8 + w1mw7*x4
+		x5 = x8 - w1pw7*x5
+		x8 = w3 * (x6 + x7)
+		x6 = x8 - w3mw5*x6
+		x7 = x8 - w3pw5*x7
+
+		// Stage 2.
+		x8 = x0 + x1
+		x0 -= x1
+		x1 = w6 * (x3 + x2)
+		x2 = x1 - w2pw6*x2
+		x3 = x1 + w2mw6*x3
+		x1 = x4 + x6
+		x4 -= x6
+		x6 = x5 + x7
+		x5 -= x7
+
+		// Stage 3.
+		x7 = x8 + x3
+		x8 -= x3
+		x3 = x0 + x2
+		x0 -= x2
+		x2 = (r2*(x4+x5) + 128) >> 8
+		x4 = (r2*(x4-x5) + 128) >> 8
+
+		// Stage 4.
+		b[8*y+0] = (x7 + x1) >> 8
+		b[8*y+1] = (x3 + x2) >> 8
+		b[8*y+2] = (x0 + x4) >> 8
+		b[8*y+3] = (x8 + x6) >> 8
+		b[8*y+4] = (x8 - x6) >> 8
+		b[8*y+5] = (x0 - x4) >> 8
+		b[8*y+6] = (x3 - x2) >> 8
+		b[8*y+7] = (x7 - x1) >> 8
+	}
+
+	// Vertical 1-D IDCT.
+	for x := 0; x < 8; x++ {
+		// Similar to the horizontal 1-D IDCT case, if all the AC components are zero, then the IDCT is trivial.
+		// However, after performing the horizontal 1-D IDCT, there are typically non-zero AC components, so
+		// we do not bother to check for the all-zero case.
+
+		// Prescale.
+		y0 := (b[8*0+x] << 8) + 8192
+		y1 := b[8*4+x] << 8
+		y2 := b[8*6+x]
+		y3 := b[8*2+x]
+		y4 := b[8*1+x]
+		y5 := b[8*7+x]
+		y6 := b[8*5+x]
+		y7 := b[8*3+x]
+
+		// Stage 1.
+		y8 := w7*(y4+y5) + 4
+		y4 = (y8 + w1mw7*y4) >> 3
+		y5 = (y8 - w1pw7*y5) >> 3
+		y8 = w3*(y6+y7) + 4
+		y6 = (y8 - w3mw5*y6) >> 3
+		y7 = (y8 - w3pw5*y7) >> 3
+
+		// Stage 2.
+		y8 = y0 + y1
+		y0 -= y1
+		y1 = w6*(y3+y2) + 4
+		y2 = (y1 - w2pw6*y2) >> 3
+		y3 = (y1 + w2mw6*y3) >> 3
+		y1 = y4 + y6
+		y4 -= y6
+		y6 = y5 + y7
+		y5 -= y7
+
+		// Stage 3.
+		y7 = y8 + y3
+		y8 -= y3
+		y3 = y0 + y2
+		y0 -= y2
+		y2 = (r2*(y4+y5) + 128) >> 8
+		y4 = (r2*(y4-y5) + 128) >> 8
+
+		// Stage 4.
+		b[8*0+x] = (y7 + y1) >> 14
+		b[8*1+x] = (y3 + y2) >> 14
+		b[8*2+x] = (y0 + y4) >> 14
+		b[8*3+x] = (y8 + y6) >> 14
+		b[8*4+x] = (y8 - y6) >> 14
+		b[8*5+x] = (y0 - y4) >> 14
+		b[8*6+x] = (y3 - y2) >> 14
+		b[8*7+x] = (y7 - y1) >> 14
+	}
+
+	// Level shift.
+	for i := range *b {
+		b[i] += 128
+	}
+}
diff --git a/libgo/go/image/jpeg/reader.go b/libgo/go/image/jpeg/reader.go
new file mode 100644
index 000000000..fb9cb11bb
--- /dev/null
+++ b/libgo/go/image/jpeg/reader.go
@@ -0,0 +1,455 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The jpeg package implements a decoder for JPEG images, as defined in ITU-T T.81.
+package jpeg
+
+// See http://www.w3.org/Graphics/JPEG/itu-t81.pdf
+
+import (
+	"bufio"
+	"image"
+	"io"
+	"os"
+)
+
+// A FormatError reports that the input is not a valid JPEG.
+type FormatError string
+
+func (e FormatError) String() string { return "invalid JPEG format: " + string(e) }
+
+// An UnsupportedError reports that the input uses a valid but unimplemented JPEG feature.
+type UnsupportedError string
+
+func (e UnsupportedError) String() string { return "unsupported JPEG feature: " + string(e) }
+
+// Component specification, specified in section B.2.2.
+type component struct {
+	c  uint8 // Component identifier.
+	h  uint8 // Horizontal sampling factor.
+	v  uint8 // Vertical sampling factor.
+	tq uint8 // Quantization table destination selector.
+}
+
+const (
+	blockSize = 64 // A DCT block is 8x8.
+
+	dcTableClass = 0
+	acTableClass = 1
+	maxTc        = 1
+	maxTh        = 3
+	maxTq        = 3
+
+	// We only support 4:4:4, 4:2:2 and 4:2:0 downsampling, and assume that the components are Y, Cb, Cr.
+	nComponent = 3
+	maxH       = 2
+	maxV       = 2
+)
+
+const (
+	soiMarker   = 0xd8 // Start Of Image.
+	eoiMarker   = 0xd9 // End Of Image.
+	sof0Marker  = 0xc0 // Start Of Frame (Baseline).
+	sof2Marker  = 0xc2 // Start Of Frame (Progressive).
+	dhtMarker   = 0xc4 // Define Huffman Table.
+	dqtMarker   = 0xdb // Define Quantization Table.
+	sosMarker   = 0xda // Start Of Scan.
+	driMarker   = 0xdd // Define Restart Interval.
+	rst0Marker  = 0xd0 // ReSTart (0).
+	rst7Marker  = 0xd7 // ReSTart (7).
+	app0Marker  = 0xe0 // APPlication specific (0).
+	app15Marker = 0xef // APPlication specific (15).
+	comMarker   = 0xfe // COMment.
+)
+
+// Maps from the zig-zag ordering to the natural ordering.
+var unzig = [blockSize]int{
+	0, 1, 8, 16, 9, 2, 3, 10,
+	17, 24, 32, 25, 18, 11, 4, 5,
+	12, 19, 26, 33, 40, 48, 41, 34,
+	27, 20, 13, 6, 7, 14, 21, 28,
+	35, 42, 49, 56, 57, 50, 43, 36,
+	29, 22, 15, 23, 30, 37, 44, 51,
+	58, 59, 52, 45, 38, 31, 39, 46,
+	53, 60, 61, 54, 47, 55, 62, 63,
+}
+
+// If the passed in io.Reader does not also have ReadByte, then Decode will introduce its own buffering.
+type Reader interface {
+	io.Reader
+	ReadByte() (c byte, err os.Error)
+}
+
+type decoder struct {
+	r             Reader
+	width, height int
+	image         *image.RGBA
+	ri            int // Restart Interval.
+	comps         [nComponent]component
+	huff          [maxTc + 1][maxTh + 1]huffman
+	quant         [maxTq + 1][blockSize]int
+	b             bits
+	blocks        [nComponent][maxH * maxV][blockSize]int
+	tmp           [1024]byte
+}
+
+// Reads and ignores the next n bytes.
+func (d *decoder) ignore(n int) os.Error {
+	for n > 0 {
+		m := len(d.tmp)
+		if m > n {
+			m = n
+		}
+		_, err := io.ReadFull(d.r, d.tmp[0:m])
+		if err != nil {
+			return err
+		}
+		n -= m
+	}
+	return nil
+}
+
+// Specified in section B.2.2.
+func (d *decoder) processSOF(n int) os.Error {
+	if n != 6+3*nComponent {
+		return UnsupportedError("SOF has wrong length")
+	}
+	_, err := io.ReadFull(d.r, d.tmp[0:6+3*nComponent])
+	if err != nil {
+		return err
+	}
+	// We only support 8-bit precision.
+	if d.tmp[0] != 8 {
+		return UnsupportedError("precision")
+	}
+	d.height = int(d.tmp[1])<<8 + int(d.tmp[2])
+	d.width = int(d.tmp[3])<<8 + int(d.tmp[4])
+	if d.tmp[5] != nComponent {
+		return UnsupportedError("SOF has wrong number of image components")
+	}
+	for i := 0; i < nComponent; i++ {
+		hv := d.tmp[7+3*i]
+		d.comps[i].c = d.tmp[6+3*i]
+		d.comps[i].h = hv >> 4
+		d.comps[i].v = hv & 0x0f
+		d.comps[i].tq = d.tmp[8+3*i]
+		// We only support YCbCr images, and 4:4:4, 4:2:2 or 4:2:0 chroma downsampling ratios. This implies that
+		// the (h, v) values for the Y component are either (1, 1), (2, 1) or (2, 2), and the
+		// (h, v) values for the Cr and Cb components must be (1, 1).
+		if i == 0 {
+			if hv != 0x11 && hv != 0x21 && hv != 0x22 {
+				return UnsupportedError("luma downsample ratio")
+			}
+		} else {
+			if hv != 0x11 {
+				return UnsupportedError("chroma downsample ratio")
+			}
+		}
+	}
+	return nil
+}
+
+// Specified in section B.2.4.1.
+func (d *decoder) processDQT(n int) os.Error {
+	const qtLength = 1 + blockSize
+	for ; n >= qtLength; n -= qtLength {
+		_, err := io.ReadFull(d.r, d.tmp[0:qtLength])
+		if err != nil {
+			return err
+		}
+		pq := d.tmp[0] >> 4
+		if pq != 0 {
+			return UnsupportedError("bad Pq value")
+		}
+		tq := d.tmp[0] & 0x0f
+		if tq > maxTq {
+			return FormatError("bad Tq value")
+		}
+		for i := range d.quant[tq] {
+			d.quant[tq][i] = int(d.tmp[i+1])
+		}
+	}
+	if n != 0 {
+		return FormatError("DQT has wrong length")
+	}
+	return nil
+}
+
+// Set the Pixel (px, py)'s RGB value, based on its YCbCr value.
+func (d *decoder) calcPixel(px, py, lumaBlock, lumaIndex, chromaIndex int) {
+	y, cb, cr := d.blocks[0][lumaBlock][lumaIndex], d.blocks[1][0][chromaIndex], d.blocks[2][0][chromaIndex]
+	// The JFIF specification (http://www.w3.org/Graphics/JPEG/jfif3.pdf, page 3) gives the formula
+	// for translating YCbCr to RGB as:
+	//   R = Y + 1.402 (Cr-128)
+	//   G = Y - 0.34414 (Cb-128) - 0.71414 (Cr-128)
+	//   B = Y + 1.772 (Cb-128)
+	yPlusHalf := 100000*y + 50000
+	cb -= 128
+	cr -= 128
+	r := (yPlusHalf + 140200*cr) / 100000
+	g := (yPlusHalf - 34414*cb - 71414*cr) / 100000
+	b := (yPlusHalf + 177200*cb) / 100000
+	if r < 0 {
+		r = 0
+	} else if r > 255 {
+		r = 255
+	}
+	if g < 0 {
+		g = 0
+	} else if g > 255 {
+		g = 255
+	}
+	if b < 0 {
+		b = 0
+	} else if b > 255 {
+		b = 255
+	}
+	d.image.Pix[py*d.image.Stride+px] = image.RGBAColor{uint8(r), uint8(g), uint8(b), 0xff}
+}
+
+// Convert the MCU from YCbCr to RGB.
+func (d *decoder) convertMCU(mx, my, h0, v0 int) {
+	lumaBlock := 0
+	for v := 0; v < v0; v++ {
+		for h := 0; h < h0; h++ {
+			chromaBase := 8*4*v + 4*h
+			py := 8 * (v0*my + v)
+			for y := 0; y < 8 && py < d.height; y++ {
+				px := 8 * (h0*mx + h)
+				lumaIndex := 8 * y
+				chromaIndex := chromaBase + 8*(y/v0)
+				for x := 0; x < 8 && px < d.width; x++ {
+					d.calcPixel(px, py, lumaBlock, lumaIndex, chromaIndex)
+					if h0 == 1 {
+						chromaIndex += 1
+					} else {
+						chromaIndex += x % 2
+					}
+					lumaIndex++
+					px++
+				}
+				py++
+			}
+			lumaBlock++
+		}
+	}
+}
+
+// Specified in section B.2.3.
+func (d *decoder) processSOS(n int) os.Error {
+	if d.image == nil {
+		d.image = image.NewRGBA(d.width, d.height)
+	}
+	if n != 4+2*nComponent {
+		return UnsupportedError("SOS has wrong length")
+	}
+	_, err := io.ReadFull(d.r, d.tmp[0:4+2*nComponent])
+	if err != nil {
+		return err
+	}
+	if d.tmp[0] != nComponent {
+		return UnsupportedError("SOS has wrong number of image components")
+	}
+	var scanComps [nComponent]struct {
+		td uint8 // DC table selector.
+		ta uint8 // AC table selector.
+	}
+	h0, v0 := int(d.comps[0].h), int(d.comps[0].v) // The h and v values from the Y components.
+	for i := 0; i < nComponent; i++ {
+		cs := d.tmp[1+2*i] // Component selector.
+		if cs != d.comps[i].c {
+			return UnsupportedError("scan components out of order")
+		}
+		scanComps[i].td = d.tmp[2+2*i] >> 4
+		scanComps[i].ta = d.tmp[2+2*i] & 0x0f
+	}
+	// mxx and myy are the number of MCUs (Minimum Coded Units) in the image.
+	mxx := (d.width + 8*int(h0) - 1) / (8 * int(h0))
+	myy := (d.height + 8*int(v0) - 1) / (8 * int(v0))
+
+	mcu, expectedRST := 0, uint8(rst0Marker)
+	var allZeroes [blockSize]int
+	var dc [nComponent]int
+	for my := 0; my < myy; my++ {
+		for mx := 0; mx < mxx; mx++ {
+			for i := 0; i < nComponent; i++ {
+				qt := &d.quant[d.comps[i].tq]
+				for j := 0; j < int(d.comps[i].h*d.comps[i].v); j++ {
+					d.blocks[i][j] = allZeroes
+
+					// Decode the DC coefficient, as specified in section F.2.2.1.
+					value, err := d.decodeHuffman(&d.huff[dcTableClass][scanComps[i].td])
+					if err != nil {
+						return err
+					}
+					if value > 16 {
+						return UnsupportedError("excessive DC component")
+					}
+					dcDelta, err := d.receiveExtend(value)
+					if err != nil {
+						return err
+					}
+					dc[i] += dcDelta
+					d.blocks[i][j][0] = dc[i] * qt[0]
+
+					// Decode the AC coefficients, as specified in section F.2.2.2.
+					for k := 1; k < blockSize; k++ {
+						value, err := d.decodeHuffman(&d.huff[acTableClass][scanComps[i].ta])
+						if err != nil {
+							return err
+						}
+						v0 := value >> 4
+						v1 := value & 0x0f
+						if v1 != 0 {
+							k += int(v0)
+							if k > blockSize {
+								return FormatError("bad DCT index")
+							}
+							ac, err := d.receiveExtend(v1)
+							if err != nil {
+								return err
+							}
+							d.blocks[i][j][unzig[k]] = ac * qt[k]
+						} else {
+							if v0 != 0x0f {
+								break
+							}
+							k += 0x0f
+						}
+					}
+
+					idct(&d.blocks[i][j])
+				} // for j
+			} // for i
+			d.convertMCU(mx, my, int(d.comps[0].h), int(d.comps[0].v))
+			mcu++
+			if d.ri > 0 && mcu%d.ri == 0 && mcu < mxx*myy {
+				// A more sophisticated decoder could use RST[0-7] markers to resynchronize from corrupt input,
+				// but this one assumes well-formed input, and hence the restart marker follows immediately.
+				_, err := io.ReadFull(d.r, d.tmp[0:2])
+				if err != nil {
+					return err
+				}
+				if d.tmp[0] != 0xff || d.tmp[1] != expectedRST {
+					return FormatError("bad RST marker")
+				}
+				expectedRST++
+				if expectedRST == rst7Marker+1 {
+					expectedRST = rst0Marker
+				}
+				// Reset the Huffman decoder.
+				d.b = bits{}
+				// Reset the DC components, as per section F.2.1.3.1.
+				for i := 0; i < nComponent; i++ {
+					dc[i] = 0
+				}
+			}
+		} // for mx
+	} // for my
+
+	return nil
+}
+
+// Specified in section B.2.4.4.
+func (d *decoder) processDRI(n int) os.Error {
+	if n != 2 {
+		return FormatError("DRI has wrong length")
+	}
+	_, err := io.ReadFull(d.r, d.tmp[0:2])
+	if err != nil {
+		return err
+	}
+	d.ri = int(d.tmp[0])<<8 + int(d.tmp[1])
+	return nil
+}
+
+// decode reads a JPEG image from r and returns it as an image.Image.
+func (d *decoder) decode(r io.Reader, configOnly bool) (image.Image, os.Error) {
+	if rr, ok := r.(Reader); ok {
+		d.r = rr
+	} else {
+		d.r = bufio.NewReader(r)
+	}
+
+	// Check for the Start Of Image marker.
+	_, err := io.ReadFull(d.r, d.tmp[0:2])
+	if err != nil {
+		return nil, err
+	}
+	if d.tmp[0] != 0xff || d.tmp[1] != soiMarker {
+		return nil, FormatError("missing SOI marker")
+	}
+
+	// Process the remaining segments until the End Of Image marker.
+	for {
+		_, err := io.ReadFull(d.r, d.tmp[0:2])
+		if err != nil {
+			return nil, err
+		}
+		if d.tmp[0] != 0xff {
+			return nil, FormatError("missing 0xff marker start")
+		}
+		marker := d.tmp[1]
+		if marker == eoiMarker { // End Of Image.
+			break
+		}
+
+		// Read the 16-bit length of the segment. The value includes the 2 bytes for the
+		// length itself, so we subtract 2 to get the number of remaining bytes.
+		_, err = io.ReadFull(d.r, d.tmp[0:2])
+		if err != nil {
+			return nil, err
+		}
+		n := int(d.tmp[0])<<8 + int(d.tmp[1]) - 2
+		if n < 0 {
+			return nil, FormatError("short segment length")
+		}
+
+		switch {
+		case marker == sof0Marker: // Start Of Frame (Baseline).
+			err = d.processSOF(n)
+			if configOnly {
+				return nil, err
+			}
+		case marker == sof2Marker: // Start Of Frame (Progressive).
+			err = UnsupportedError("progressive mode")
+		case marker == dhtMarker: // Define Huffman Table.
+			err = d.processDHT(n)
+		case marker == dqtMarker: // Define Quantization Table.
+			err = d.processDQT(n)
+		case marker == sosMarker: // Start Of Scan.
+			err = d.processSOS(n)
+		case marker == driMarker: // Define Restart Interval.
+			err = d.processDRI(n)
+		case marker >= app0Marker && marker <= app15Marker || marker == comMarker: // APPlication specific, or COMment.
+			err = d.ignore(n)
+		default:
+			err = UnsupportedError("unknown marker")
+		}
+		if err != nil {
+			return nil, err
+		}
+	}
+	return d.image, nil
+}
+
+// Decode reads a JPEG image from r and returns it as an image.Image.
+func Decode(r io.Reader) (image.Image, os.Error) {
+	var d decoder
+	return d.decode(r, false)
+}
+
+// DecodeConfig returns the color model and dimensions of a JPEG image without
+// decoding the entire image.
+func DecodeConfig(r io.Reader) (image.Config, os.Error) {
+	var d decoder
+	if _, err := d.decode(r, true); err != nil {
+		return image.Config{}, err
+	}
+	return image.Config{image.RGBAColorModel, d.width, d.height}, nil
+}
+
+func init() {
+	image.RegisterFormat("jpeg", "\xff\xd8", Decode, DecodeConfig)
+}
diff --git a/libgo/go/image/names.go b/libgo/go/image/names.go
new file mode 100644
index 000000000..c309684ce
--- /dev/null
+++ b/libgo/go/image/names.go
@@ -0,0 +1,67 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package image
+
+var (
+	// Black is an opaque black ColorImage.
+	Black = NewColorImage(Gray16Color{0})
+	// White is an opaque white ColorImage.
+	White = NewColorImage(Gray16Color{0xffff})
+	// Transparent is a fully transparent ColorImage.
+	Transparent = NewColorImage(Alpha16Color{0})
+	// Opaque is a fully opaque ColorImage.
+	Opaque = NewColorImage(Alpha16Color{0xffff})
+)
+
+// A ColorImage is an infinite-sized Image of uniform Color.
+// It implements both the Color and Image interfaces.
+type ColorImage struct {
+	C Color
+}
+
+func (c *ColorImage) RGBA() (r, g, b, a uint32) {
+	return c.C.RGBA()
+}
+
+func (c *ColorImage) ColorModel() ColorModel {
+	return ColorModelFunc(func(Color) Color { return c.C })
+}
+
+func (c *ColorImage) Bounds() Rectangle { return Rectangle{Point{-1e9, -1e9}, Point{1e9, 1e9}} }
+
+func (c *ColorImage) At(x, y int) Color { return c.C }
+
+// Opaque scans the entire image and returns whether or not it is fully opaque.
+func (c *ColorImage) Opaque() bool {
+	_, _, _, a := c.C.RGBA()
+	return a == 0xffff
+}
+
+func NewColorImage(c Color) *ColorImage {
+	return &ColorImage{c}
+}
+
+// A Tiled is an infinite-sized Image that repeats another Image in both
+// directions. Tiled{i, p}.At(x, y) will equal i.At(x+p.X, y+p.Y) for all
+// points {x+p.X, y+p.Y} within i's Bounds.
+type Tiled struct {
+	I      Image
+	Offset Point
+}
+
+func (t *Tiled) ColorModel() ColorModel {
+	return t.I.ColorModel()
+}
+
+func (t *Tiled) Bounds() Rectangle { return Rectangle{Point{-1e9, -1e9}, Point{1e9, 1e9}} }
+
+func (t *Tiled) At(x, y int) Color {
+	p := Point{x, y}.Add(t.Offset).Mod(t.I.Bounds())
+	return t.I.At(p.X, p.Y)
+}
+
+func NewTiled(i Image, offset Point) *Tiled {
+	return &Tiled{i, offset}
+}
diff --git a/libgo/go/image/png/reader.go b/libgo/go/image/png/reader.go
new file mode 100644
index 000000000..e2d679bb4
--- /dev/null
+++ b/libgo/go/image/png/reader.go
@@ -0,0 +1,588 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// The png package implements a PNG image decoder and encoder.
+//
+// The PNG specification is at http://www.libpng.org/pub/png/spec/1.2/PNG-Contents.html
+package png
+
+import (
+	"compress/zlib"
+	"fmt"
+	"hash"
+	"hash/crc32"
+	"image"
+	"io"
+	"os"
+)
+
+// Color type, as per the PNG spec.
+const (
+	ctGrayscale      = 0
+	ctTrueColor      = 2
+	ctPaletted       = 3
+	ctGrayscaleAlpha = 4
+	ctTrueColorAlpha = 6
+)
+
+// A cb is a combination of color type and bit depth.
+const (
+	cbInvalid = iota
+	cbG8
+	cbTC8
+	cbP8
+	cbTCA8
+	cbG16
+	cbTC16
+	cbTCA16
+)
+
+// Filter type, as per the PNG spec.
+const (
+	ftNone    = 0
+	ftSub     = 1
+	ftUp      = 2
+	ftAverage = 3
+	ftPaeth   = 4
+	nFilter   = 5
+)
+
+// Decoding stage.
+// The PNG specification says that the IHDR, PLTE (if present), IDAT and IEND
+// chunks must appear in that order. There may be multiple IDAT chunks, and
+// IDAT chunks must be sequential (i.e. they may not have any other chunks
+// between them).
+const (
+	dsStart = iota
+	dsSeenIHDR
+	dsSeenPLTE
+	dsSeenIDAT
+	dsSeenIEND
+)
+
+const pngHeader = "\x89PNG\r\n\x1a\n"
+
+type imgOrErr struct {
+	img image.Image
+	err os.Error
+}
+
+type decoder struct {
+	width, height int
+	palette       image.PalettedColorModel
+	cb            int
+	stage         int
+	idatWriter    io.WriteCloser
+	idatDone      chan imgOrErr
+	tmp           [3 * 256]byte
+}
+
+// A FormatError reports that the input is not a valid PNG.
+type FormatError string
+
+func (e FormatError) String() string { return "png: invalid format: " + string(e) }
+
+var chunkOrderError = FormatError("chunk out of order")
+
+// An IDATDecodingError wraps an inner error (such as a ZLIB decoding error) encountered while processing an IDAT chunk.
+type IDATDecodingError struct {
+	Err os.Error
+}
+
+func (e IDATDecodingError) String() string { return "png: IDAT decoding error: " + e.Err.String() }
+
+// An UnsupportedError reports that the input uses a valid but unimplemented PNG feature.
+type UnsupportedError string
+
+func (e UnsupportedError) String() string { return "png: unsupported feature: " + string(e) }
+
+// Big-endian.
+func parseUint32(b []uint8) uint32 {
+	return uint32(b[0])<<24 | uint32(b[1])<<16 | uint32(b[2])<<8 | uint32(b[3])
+}
+
+func abs(x int) int {
+	if x < 0 {
+		return -x
+	}
+	return x
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func (d *decoder) parseIHDR(r io.Reader, crc hash.Hash32, length uint32) os.Error {
+	if length != 13 {
+		return FormatError("bad IHDR length")
+	}
+	_, err := io.ReadFull(r, d.tmp[0:13])
+	if err != nil {
+		return err
+	}
+	crc.Write(d.tmp[0:13])
+	if d.tmp[10] != 0 || d.tmp[11] != 0 || d.tmp[12] != 0 {
+		return UnsupportedError("compression, filter or interlace method")
+	}
+	w := int32(parseUint32(d.tmp[0:4]))
+	h := int32(parseUint32(d.tmp[4:8]))
+	if w < 0 || h < 0 {
+		return FormatError("negative dimension")
+	}
+	nPixels := int64(w) * int64(h)
+	if nPixels != int64(int(nPixels)) {
+		return UnsupportedError("dimension overflow")
+	}
+	d.cb = cbInvalid
+	switch d.tmp[8] {
+	case 8:
+		switch d.tmp[9] {
+		case ctGrayscale:
+			d.cb = cbG8
+		case ctTrueColor:
+			d.cb = cbTC8
+		case ctPaletted:
+			d.cb = cbP8
+		case ctTrueColorAlpha:
+			d.cb = cbTCA8
+		}
+	case 16:
+		switch d.tmp[9] {
+		case ctGrayscale:
+			d.cb = cbG16
+		case ctTrueColor:
+			d.cb = cbTC16
+		case ctTrueColorAlpha:
+			d.cb = cbTCA16
+		}
+	}
+	if d.cb == cbInvalid {
+		return UnsupportedError(fmt.Sprintf("bit depth %d, color type %d", d.tmp[8], d.tmp[9]))
+	}
+	d.width, d.height = int(w), int(h)
+	return nil
+}
+
+func (d *decoder) parsePLTE(r io.Reader, crc hash.Hash32, length uint32) os.Error {
+	np := int(length / 3) // The number of palette entries.
+	if length%3 != 0 || np <= 0 || np > 256 {
+		return FormatError("bad PLTE length")
+	}
+	n, err := io.ReadFull(r, d.tmp[0:3*np])
+	if err != nil {
+		return err
+	}
+	crc.Write(d.tmp[0:n])
+	switch d.cb {
+	case cbP8:
+		d.palette = image.PalettedColorModel(make([]image.Color, np))
+		for i := 0; i < np; i++ {
+			d.palette[i] = image.RGBAColor{d.tmp[3*i+0], d.tmp[3*i+1], d.tmp[3*i+2], 0xff}
+		}
+	case cbTC8, cbTCA8, cbTC16, cbTCA16:
+		// As per the PNG spec, a PLTE chunk is optional (and for practical purposes,
+		// ignorable) for the ctTrueColor and ctTrueColorAlpha color types (section 4.1.2).
+	default:
+		return FormatError("PLTE, color type mismatch")
+	}
+	return nil
+}
+
+func (d *decoder) parsetRNS(r io.Reader, crc hash.Hash32, length uint32) os.Error {
+	if length > 256 {
+		return FormatError("bad tRNS length")
+	}
+	n, err := io.ReadFull(r, d.tmp[0:length])
+	if err != nil {
+		return err
+	}
+	crc.Write(d.tmp[0:n])
+	switch d.cb {
+	case cbG8, cbG16:
+		return UnsupportedError("grayscale transparency")
+	case cbTC8, cbTC16:
+		return UnsupportedError("truecolor transparency")
+	case cbP8:
+		if n > len(d.palette) {
+			return FormatError("bad tRNS length")
+		}
+		for i := 0; i < n; i++ {
+			rgba := d.palette[i].(image.RGBAColor)
+			d.palette[i] = image.RGBAColor{rgba.R, rgba.G, rgba.B, d.tmp[i]}
+		}
+	case cbTCA8, cbTCA16:
+		return FormatError("tRNS, color type mismatch")
+	}
+	return nil
+}
+
+// The Paeth filter function, as per the PNG specification.
+func paeth(a, b, c uint8) uint8 {
+	p := int(a) + int(b) - int(c)
+	pa := abs(p - int(a))
+	pb := abs(p - int(b))
+	pc := abs(p - int(c))
+	if pa <= pb && pa <= pc {
+		return a
+	} else if pb <= pc {
+		return b
+	}
+	return c
+}
+
+func (d *decoder) idatReader(idat io.Reader) (image.Image, os.Error) {
+	r, err := zlib.NewReader(idat)
+	if err != nil {
+		return nil, err
+	}
+	defer r.Close()
+	bpp := 0 // Bytes per pixel.
+	maxPalette := uint8(0)
+	var (
+		gray     *image.Gray
+		rgba     *image.RGBA
+		paletted *image.Paletted
+		nrgba    *image.NRGBA
+		gray16   *image.Gray16
+		rgba64   *image.RGBA64
+		nrgba64  *image.NRGBA64
+		img      image.Image
+	)
+	switch d.cb {
+	case cbG8:
+		bpp = 1
+		gray = image.NewGray(d.width, d.height)
+		img = gray
+	case cbTC8:
+		bpp = 3
+		rgba = image.NewRGBA(d.width, d.height)
+		img = rgba
+	case cbP8:
+		bpp = 1
+		paletted = image.NewPaletted(d.width, d.height, d.palette)
+		img = paletted
+		maxPalette = uint8(len(d.palette) - 1)
+	case cbTCA8:
+		bpp = 4
+		nrgba = image.NewNRGBA(d.width, d.height)
+		img = nrgba
+	case cbG16:
+		bpp = 2
+		gray16 = image.NewGray16(d.width, d.height)
+		img = gray16
+	case cbTC16:
+		bpp = 6
+		rgba64 = image.NewRGBA64(d.width, d.height)
+		img = rgba64
+	case cbTCA16:
+		bpp = 8
+		nrgba64 = image.NewNRGBA64(d.width, d.height)
+		img = nrgba64
+	}
+	// cr and pr are the bytes for the current and previous row.
+	// The +1 is for the per-row filter type, which is at cr[0].
+	cr := make([]uint8, 1+bpp*d.width)
+	pr := make([]uint8, 1+bpp*d.width)
+
+	for y := 0; y < d.height; y++ {
+		// Read the decompressed bytes.
+		_, err := io.ReadFull(r, cr)
+		if err != nil {
+			return nil, err
+		}
+
+		// Apply the filter.
+		cdat := cr[1:]
+		pdat := pr[1:]
+		switch cr[0] {
+		case ftNone:
+			// No-op.
+		case ftSub:
+			for i := bpp; i < len(cdat); i++ {
+				cdat[i] += cdat[i-bpp]
+			}
+		case ftUp:
+			for i := 0; i < len(cdat); i++ {
+				cdat[i] += pdat[i]
+			}
+		case ftAverage:
+			for i := 0; i < bpp; i++ {
+				cdat[i] += pdat[i] / 2
+			}
+			for i := bpp; i < len(cdat); i++ {
+				cdat[i] += uint8((int(cdat[i-bpp]) + int(pdat[i])) / 2)
+			}
+		case ftPaeth:
+			for i := 0; i < bpp; i++ {
+				cdat[i] += paeth(0, pdat[i], 0)
+			}
+			for i := bpp; i < len(cdat); i++ {
+				cdat[i] += paeth(cdat[i-bpp], pdat[i], pdat[i-bpp])
+			}
+		default:
+			return nil, FormatError("bad filter type")
+		}
+
+		// Convert from bytes to colors.
+		switch d.cb {
+		case cbG8:
+			for x := 0; x < d.width; x++ {
+				gray.Set(x, y, image.GrayColor{cdat[x]})
+			}
+		case cbTC8:
+			for x := 0; x < d.width; x++ {
+				rgba.Set(x, y, image.RGBAColor{cdat[3*x+0], cdat[3*x+1], cdat[3*x+2], 0xff})
+			}
+		case cbP8:
+			for x := 0; x < d.width; x++ {
+				if cdat[x] > maxPalette {
+					return nil, FormatError("palette index out of range")
+				}
+				paletted.SetColorIndex(x, y, cdat[x])
+			}
+		case cbTCA8:
+			for x := 0; x < d.width; x++ {
+				nrgba.Set(x, y, image.NRGBAColor{cdat[4*x+0], cdat[4*x+1], cdat[4*x+2], cdat[4*x+3]})
+			}
+		case cbG16:
+			for x := 0; x < d.width; x++ {
+				ycol := uint16(cdat[2*x+0])<<8 | uint16(cdat[2*x+1])
+				gray16.Set(x, y, image.Gray16Color{ycol})
+			}
+		case cbTC16:
+			for x := 0; x < d.width; x++ {
+				rcol := uint16(cdat[6*x+0])<<8 | uint16(cdat[6*x+1])
+				gcol := uint16(cdat[6*x+2])<<8 | uint16(cdat[6*x+3])
+				bcol := uint16(cdat[6*x+4])<<8 | uint16(cdat[6*x+5])
+				rgba64.Set(x, y, image.RGBA64Color{rcol, gcol, bcol, 0xffff})
+			}
+		case cbTCA16:
+			for x := 0; x < d.width; x++ {
+				rcol := uint16(cdat[8*x+0])<<8 | uint16(cdat[8*x+1])
+				gcol := uint16(cdat[8*x+2])<<8 | uint16(cdat[8*x+3])
+				bcol := uint16(cdat[8*x+4])<<8 | uint16(cdat[8*x+5])
+				acol := uint16(cdat[8*x+6])<<8 | uint16(cdat[8*x+7])
+				nrgba64.Set(x, y, image.NRGBA64Color{rcol, gcol, bcol, acol})
+			}
+		}
+
+		// The current row for y is the previous row for y+1.
+		pr, cr = cr, pr
+	}
+	return img, nil
+}
+
+func (d *decoder) parseIDAT(r io.Reader, crc hash.Hash32, length uint32) os.Error {
+	// There may be more than one IDAT chunk, but their contents must be
+	// treated as if it was one continuous stream (to the zlib decoder).
+	// We bring up an io.Pipe and write the IDAT chunks into the pipe as
+	// we see them, and decode the stream in a separate go-routine, which
+	// signals its completion (successful or not) via a channel.
+	if d.idatWriter == nil {
+		pr, pw := io.Pipe()
+		d.idatWriter = pw
+		d.idatDone = make(chan imgOrErr)
+		go func() {
+			img, err := d.idatReader(pr)
+			if err == os.EOF {
+				err = FormatError("too little IDAT")
+			}
+			pr.CloseWithError(FormatError("too much IDAT"))
+			d.idatDone <- imgOrErr{img, err}
+		}()
+	}
+	var buf [4096]byte
+	for length > 0 {
+		n, err1 := r.Read(buf[0:min(len(buf), int(length))])
+		// We delay checking err1. It is possible to get n bytes and an error,
+		// but if the n bytes themselves contain a FormatError, for example, we
+		// want to report that error, and not the one that made the Read stop.
+		n, err2 := d.idatWriter.Write(buf[0:n])
+		if err2 != nil {
+			return err2
+		}
+		if err1 != nil {
+			return err1
+		}
+		crc.Write(buf[0:n])
+		length -= uint32(n)
+	}
+	return nil
+}
+
+func (d *decoder) parseIEND(r io.Reader, crc hash.Hash32, length uint32) os.Error {
+	if length != 0 {
+		return FormatError("bad IEND length")
+	}
+	return nil
+}
+
+func (d *decoder) parseChunk(r io.Reader) os.Error {
+	// Read the length.
+	n, err := io.ReadFull(r, d.tmp[0:4])
+	if err == os.EOF {
+		return io.ErrUnexpectedEOF
+	}
+	if err != nil {
+		return err
+	}
+	length := parseUint32(d.tmp[0:4])
+
+	// Read the chunk type.
+	n, err = io.ReadFull(r, d.tmp[0:4])
+	if err == os.EOF {
+		return io.ErrUnexpectedEOF
+	}
+	if err != nil {
+		return err
+	}
+	crc := crc32.NewIEEE()
+	crc.Write(d.tmp[0:4])
+
+	// Read the chunk data.
+	switch string(d.tmp[0:4]) {
+	case "IHDR":
+		if d.stage != dsStart {
+			return chunkOrderError
+		}
+		d.stage = dsSeenIHDR
+		err = d.parseIHDR(r, crc, length)
+	case "PLTE":
+		if d.stage != dsSeenIHDR {
+			return chunkOrderError
+		}
+		d.stage = dsSeenPLTE
+		err = d.parsePLTE(r, crc, length)
+	case "tRNS":
+		if d.stage != dsSeenPLTE {
+			return chunkOrderError
+		}
+		err = d.parsetRNS(r, crc, length)
+	case "IDAT":
+		if d.stage < dsSeenIHDR || d.stage > dsSeenIDAT || (d.cb == cbP8 && d.stage == dsSeenIHDR) {
+			return chunkOrderError
+		}
+		d.stage = dsSeenIDAT
+		err = d.parseIDAT(r, crc, length)
+	case "IEND":
+		if d.stage != dsSeenIDAT {
+			return chunkOrderError
+		}
+		d.stage = dsSeenIEND
+		err = d.parseIEND(r, crc, length)
+	default:
+		// Ignore this chunk (of a known length).
+		var ignored [4096]byte
+		for length > 0 {
+			n, err = io.ReadFull(r, ignored[0:min(len(ignored), int(length))])
+			if err != nil {
+				return err
+			}
+			crc.Write(ignored[0:n])
+			length -= uint32(n)
+		}
+	}
+	if err != nil {
+		return err
+	}
+
+	// Read the checksum.
+	n, err = io.ReadFull(r, d.tmp[0:4])
+	if err == os.EOF {
+		return io.ErrUnexpectedEOF
+	}
+	if err != nil {
+		return err
+	}
+	if parseUint32(d.tmp[0:4]) != crc.Sum32() {
+		return FormatError("invalid checksum")
+	}
+	return nil
+}
+
+func (d *decoder) checkHeader(r io.Reader) os.Error {
+	_, err := io.ReadFull(r, d.tmp[0:8])
+	if err != nil {
+		return err
+	}
+	if string(d.tmp[0:8]) != pngHeader {
+		return FormatError("not a PNG file")
+	}
+	return nil
+}
+
+// Decode reads a PNG image from r and returns it as an image.Image.
+// The type of Image returned depends on the PNG contents.
+func Decode(r io.Reader) (image.Image, os.Error) {
+	var d decoder
+	err := d.checkHeader(r)
+	if err != nil {
+		return nil, err
+	}
+	for d.stage != dsSeenIEND {
+		err = d.parseChunk(r)
+		if err != nil {
+			break
+		}
+	}
+	var img image.Image
+	if d.idatWriter != nil {
+		d.idatWriter.Close()
+		ie := <-d.idatDone
+		if err == nil {
+			img, err = ie.img, ie.err
+		}
+	}
+	if err != nil {
+		return nil, err
+	}
+	return img, nil
+}
+
+// DecodeConfig returns the color model and dimensions of a PNG image without
+// decoding the entire image.
+func DecodeConfig(r io.Reader) (image.Config, os.Error) {
+	var d decoder
+	err := d.checkHeader(r)
+	if err != nil {
+		return image.Config{}, err
+	}
+	for {
+		err = d.parseChunk(r)
+		if err != nil {
+			return image.Config{}, err
+		}
+		if d.stage == dsSeenIHDR && d.cb != cbP8 {
+			break
+		}
+		if d.stage == dsSeenPLTE && d.cb == cbP8 {
+			break
+		}
+	}
+	var cm image.ColorModel
+	switch d.cb {
+	case cbG8:
+		cm = image.GrayColorModel
+	case cbTC8:
+		cm = image.RGBAColorModel
+	case cbP8:
+		cm = d.palette
+	case cbTCA8:
+		cm = image.NRGBAColorModel
+	case cbG16:
+		cm = image.Gray16ColorModel
+	case cbTC16:
+		cm = image.RGBA64ColorModel
+	case cbTCA16:
+		cm = image.NRGBA64ColorModel
+	}
+	return image.Config{cm, d.width, d.height}, nil
+}
+
+func init() {
+	image.RegisterFormat("png", pngHeader, Decode, DecodeConfig)
+}
diff --git a/libgo/go/image/png/reader_test.go b/libgo/go/image/png/reader_test.go
new file mode 100644
index 000000000..fefceee3a
--- /dev/null
+++ b/libgo/go/image/png/reader_test.go
@@ -0,0 +1,190 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package png
+
+import (
+	"bufio"
+	"fmt"
+	"image"
+	"io"
+	"os"
+	"testing"
+)
+
+// The go PNG library currently supports only a subset of the full PNG specification.
+// In particular, bit depths other than 8 or 16 are not supported, nor are grayscale-
+// alpha images.
+var filenames = []string{
+	//"basn0g01",	// bit depth is not 8 or 16
+	//"basn0g02",	// bit depth is not 8 or 16
+	//"basn0g04",	// bit depth is not 8 or 16
+	"basn0g08",
+	"basn0g16",
+	"basn2c08",
+	"basn2c16",
+	//"basn3p01",	// bit depth is not 8 or 16
+	//"basn3p02",	// bit depth is not 8 or 16
+	//"basn3p04",	// bit depth is not 8 or 16
+	"basn3p08",
+	//"basn4a08",	// grayscale-alpha color model
+	//"basn4a16",	// grayscale-alpha color model
+	"basn6a08",
+	"basn6a16",
+}
+
+func readPng(filename string) (image.Image, os.Error) {
+	f, err := os.Open(filename, os.O_RDONLY, 0444)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	return Decode(f)
+}
+
+// An approximation of the sng command-line tool.
+func sng(w io.WriteCloser, filename string, png image.Image) {
+	defer w.Close()
+	bounds := png.Bounds()
+	cm := png.ColorModel()
+	var bitdepth int
+	switch cm {
+	case image.RGBAColorModel, image.NRGBAColorModel, image.AlphaColorModel, image.GrayColorModel:
+		bitdepth = 8
+	default:
+		bitdepth = 16
+	}
+	cpm, _ := cm.(image.PalettedColorModel)
+	var paletted *image.Paletted
+	if cpm != nil {
+		bitdepth = 8
+		paletted = png.(*image.Paletted)
+	}
+
+	// Write the filename and IHDR.
+	io.WriteString(w, "#SNG: from "+filename+".png\nIHDR {\n")
+	fmt.Fprintf(w, "    width: %d; height: %d; bitdepth: %d;\n", bounds.Dx(), bounds.Dy(), bitdepth)
+	switch {
+	case cm == image.RGBAColorModel, cm == image.RGBA64ColorModel:
+		io.WriteString(w, "    using color;\n")
+	case cm == image.NRGBAColorModel, cm == image.NRGBA64ColorModel:
+		io.WriteString(w, "    using color alpha;\n")
+	case cm == image.GrayColorModel, cm == image.Gray16ColorModel:
+		io.WriteString(w, "    using grayscale;\n")
+	case cpm != nil:
+		io.WriteString(w, "    using color palette;\n")
+	default:
+		io.WriteString(w, "unknown PNG decoder color model\n")
+	}
+	io.WriteString(w, "}\n")
+
+	// We fake a gAMA output. The test files have a gAMA chunk but the go PNG parser ignores it
+	// (the PNG spec section 11.3 says "Ancillary chunks may be ignored by a decoder").
+	io.WriteString(w, "gAMA {1.0000}\n")
+
+	// Write the PLTE (if applicable).
+	if cpm != nil {
+		io.WriteString(w, "PLTE {\n")
+		for i := 0; i < len(cpm); i++ {
+			r, g, b, _ := cpm[i].RGBA()
+			r >>= 8
+			g >>= 8
+			b >>= 8
+			fmt.Fprintf(w, "    (%3d,%3d,%3d)     # rgb = (0x%02x,0x%02x,0x%02x)\n", r, g, b, r, g, b)
+		}
+		io.WriteString(w, "}\n")
+	}
+
+	// Write the IMAGE.
+	io.WriteString(w, "IMAGE {\n    pixels hex\n")
+	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+		switch {
+		case cm == image.GrayColorModel:
+			for x := bounds.Min.X; x < bounds.Max.X; x++ {
+				gray := png.At(x, y).(image.GrayColor)
+				fmt.Fprintf(w, "%02x", gray.Y)
+			}
+		case cm == image.Gray16ColorModel:
+			for x := bounds.Min.X; x < bounds.Max.X; x++ {
+				gray16 := png.At(x, y).(image.Gray16Color)
+				fmt.Fprintf(w, "%04x ", gray16.Y)
+			}
+		case cm == image.RGBAColorModel:
+			for x := bounds.Min.X; x < bounds.Max.X; x++ {
+				rgba := png.At(x, y).(image.RGBAColor)
+				fmt.Fprintf(w, "%02x%02x%02x ", rgba.R, rgba.G, rgba.B)
+			}
+		case cm == image.RGBA64ColorModel:
+			for x := bounds.Min.X; x < bounds.Max.X; x++ {
+				rgba64 := png.At(x, y).(image.RGBA64Color)
+				fmt.Fprintf(w, "%04x%04x%04x ", rgba64.R, rgba64.G, rgba64.B)
+			}
+		case cm == image.NRGBAColorModel:
+			for x := bounds.Min.X; x < bounds.Max.X; x++ {
+				nrgba := png.At(x, y).(image.NRGBAColor)
+				fmt.Fprintf(w, "%02x%02x%02x%02x ", nrgba.R, nrgba.G, nrgba.B, nrgba.A)
+			}
+		case cm == image.NRGBA64ColorModel:
+			for x := bounds.Min.X; x < bounds.Max.X; x++ {
+				nrgba64 := png.At(x, y).(image.NRGBA64Color)
+				fmt.Fprintf(w, "%04x%04x%04x%04x ", nrgba64.R, nrgba64.G, nrgba64.B, nrgba64.A)
+			}
+		case cpm != nil:
+			for x := bounds.Min.X; x < bounds.Max.X; x++ {
+				fmt.Fprintf(w, "%02x", paletted.ColorIndexAt(x, y))
+			}
+		}
+		io.WriteString(w, "\n")
+	}
+	io.WriteString(w, "}\n")
+}
+
+func TestReader(t *testing.T) {
+	for _, fn := range filenames {
+		// Read the .png file.
+		image, err := readPng("testdata/pngsuite/" + fn + ".png")
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+		piper, pipew := io.Pipe()
+		pb := bufio.NewReader(piper)
+		go sng(pipew, fn, image)
+		defer piper.Close()
+
+		// Read the .sng file.
+		sf, err := os.Open("testdata/pngsuite/"+fn+".sng", os.O_RDONLY, 0444)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+		defer sf.Close()
+		sb := bufio.NewReader(sf)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+
+		// Compare the two, in SNG format, line by line.
+		for {
+			ps, perr := pb.ReadString('\n')
+			ss, serr := sb.ReadString('\n')
+			if perr == os.EOF && serr == os.EOF {
+				break
+			}
+			if perr != nil {
+				t.Error(fn, perr)
+				break
+			}
+			if serr != nil {
+				t.Error(fn, serr)
+				break
+			}
+			if ps != ss {
+				t.Errorf("%s: Mismatch\n%sversus\n%s\n", fn, ps, ss)
+				break
+			}
+		}
+	}
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/README b/libgo/go/image/png/testdata/pngsuite/README
new file mode 100644
index 000000000..27e7c6558
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/README
@@ -0,0 +1,9 @@
+The *.png and README.original files in this directory are copied from
+libpng.org, specifically contrib/pngsuite/* in libpng-1.2.40.tar.gz.
+README.original gives the following license for those files:
+
+	Permission to use, copy, and distribute these images for any purpose
+	and without fee is hereby granted.
+
+The *.sng files in this directory were generated from the *.png files
+by the sng command-line tool.
diff --git a/libgo/go/image/png/testdata/pngsuite/README.original b/libgo/go/image/png/testdata/pngsuite/README.original
new file mode 100644
index 000000000..714d12c64
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/README.original
@@ -0,0 +1,85 @@
+
+pngsuite
+--------
+(c) Willem van Schaik, 1999
+
+Permission to use, copy, and distribute these images for any purpose and
+without fee is hereby granted.
+
+These 15 images are part of the much larger PngSuite test-set of 
+images, available for developers of PNG supporting software. The 
+complete set, available at http:/www.schaik.com/pngsuite/, contains 
+a variety of images to test interlacing, gamma settings, ancillary
+chunks, etc.
+
+The images in this directory represent the basic PNG color-types:
+grayscale (1-16 bit deep), full color (8 or 16 bit), paletted
+(1-8 bit) and grayscale or color images with alpha channel. You
+can use them to test the proper functioning of PNG software.
+
+    filename      depth type
+    ------------ ------ --------------
+    basn0g01.png  1-bit grayscale
+    basn0g02.png  2-bit grayscale
+    basn0g04.png  4-bit grayscale
+    basn0g08.png  8-bit grayscale
+    basn0g16.png 16-bit grayscale
+    basn2c08.png  8-bit truecolor
+    basn2c16.png 16-bit truecolor
+    basn3p01.png  1-bit paletted
+    basn3p02.png  2-bit paletted
+    basn3p04.png  4-bit paletted
+    basn3p08.png  8-bit paletted
+    basn4a08.png  8-bit gray with alpha
+    basn4a16.png 16-bit gray with alpha
+    basn6a08.png  8-bit RGBA
+    basn6a16.png 16-bit RGBA
+
+Here is the correct result of typing "pngtest -m *.png" in
+this directory:
+
+Testing basn0g01.png: PASS (524 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g02.png: PASS (448 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g04.png: PASS (520 zero samples)
+ Filter 0 was used 32 times
+Testing basn0g08.png: PASS (3 zero samples)
+ Filter 1 was used 9 times
+ Filter 4 was used 23 times
+Testing basn0g16.png: PASS (1 zero samples)
+ Filter 1 was used 1 times
+ Filter 2 was used 31 times
+Testing basn2c08.png: PASS (6 zero samples)
+ Filter 1 was used 5 times
+ Filter 4 was used 27 times
+Testing basn2c16.png: PASS (592 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn3p01.png: PASS (512 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p02.png: PASS (448 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p04.png: PASS (544 zero samples)
+ Filter 0 was used 32 times
+Testing basn3p08.png: PASS (4 zero samples)
+ Filter 0 was used 32 times
+Testing basn4a08.png: PASS (32 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn4a16.png: PASS (64 zero samples)
+ Filter 0 was used 1 times
+ Filter 1 was used 2 times
+ Filter 2 was used 1 times
+ Filter 4 was used 28 times
+Testing basn6a08.png: PASS (160 zero samples)
+ Filter 1 was used 1 times
+ Filter 4 was used 31 times
+Testing basn6a16.png: PASS (1072 zero samples)
+ Filter 1 was used 4 times
+ Filter 4 was used 28 times
+libpng passes test
+
+Willem van Schaik
+<willem@schaik.com>
+October 1999
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g01.png b/libgo/go/image/png/testdata/pngsuite/basn0g01.png
new file mode 100644
index 000000000..e31e1c7a6
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g01.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g01.sng b/libgo/go/image/png/testdata/pngsuite/basn0g01.sng
new file mode 100644
index 000000000..e712d8ec6
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g01.sng
@@ -0,0 +1,41 @@
+#SNG: from basn0g01.png
+IHDR {
+    width: 32; height: 32; bitdepth: 1;
+    using grayscale;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
+fffffffe
+fffffffc
+fffffff8
+fffffff0
+f3f3ffe0
+f3f3ffc0
+f3f3ff80
+f333ff00
+f333fe00
+f333fc00
+f807f800
+f807f000
+fccfe000
+fccfc000
+ffff8000
+ffff0000
+fffe0000
+fffc0000
+fff80fe0
+fff00fe0
+ffe00c30
+ffc00c30
+ff800fe0
+ff000fe0
+fe000c30
+fc000c30
+f8000fe0
+f0000fe0
+e0000000
+c0000000
+80000000
+00000000
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g02.png b/libgo/go/image/png/testdata/pngsuite/basn0g02.png
new file mode 100644
index 000000000..68809dd8f
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g02.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g02.sng b/libgo/go/image/png/testdata/pngsuite/basn0g02.sng
new file mode 100644
index 000000000..e7f2d7ea9
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g02.sng
@@ -0,0 +1,41 @@
+#SNG: from basn0g02.png
+IHDR {
+    width: 32; height: 32; bitdepth: 2;
+    using grayscale;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
+0055aaff0055aaff
+0055aaff0055aaff
+0055aaff0055aaff
+0055aaff0055aaff
+55aaff0055aaff00
+55aaff0055aaff00
+55aaff0055aaff00
+55aaff0055aaff00
+aaff0055aaff0055
+aaff0055aaff0055
+aaff0055aaff0055
+aaff0055aaff0055
+ff0055aaff0055aa
+ff0055aaff0055aa
+ff0055aaff0055aa
+ff0055aaff0055aa
+0055aaff0055aaff
+0055aaff0055aaff
+0055aaff0055aaff
+0055aaff0055aaff
+55aaff0055aaff00
+55aaff0055aaff00
+55aaff0055aaff00
+55aaff0055aaff00
+aaff0055aaff0055
+aaff0055aaff0055
+aaff0055aaff0055
+aaff0055aaff0055
+ff0055aaff0055aa
+ff0055aaff0055aa
+ff0055aaff0055aa
+ff0055aaff0055aa
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g04.png b/libgo/go/image/png/testdata/pngsuite/basn0g04.png
new file mode 100644
index 000000000..6fa089cb8
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g04.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g04.sng b/libgo/go/image/png/testdata/pngsuite/basn0g04.sng
new file mode 100644
index 000000000..396c508b2
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g04.sng
@@ -0,0 +1,41 @@
+#SNG: from basn0g04.png
+IHDR {
+    width: 32; height: 32; bitdepth: 4;
+    using grayscale;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
+00001111222233334444555566667777
+00001111222233334444555566667777
+00001111222233334444555566667777
+00001111222233334444555566667777
+11112222333344445555666677778888
+11112222333344445555666677778888
+11112222333344445555666677778888
+11112222333344445555666677778888
+22223333444455556666777788889999
+22223333444455556666777788889999
+22223333444455556666777788889999
+22223333444455556666777788889999
+3333444455556666777788889999aaaa
+3333444455556666777788889999aaaa
+3333444455556666777788889999aaaa
+3333444455556666777788889999aaaa
+444455556666777788889999aaaabbbb
+444455556666777788889999aaaabbbb
+444455556666777788889999aaaabbbb
+444455556666777788889999aaaabbbb
+55556666777788889999aaaabbbbcccc
+55556666777788889999aaaabbbbcccc
+55556666777788889999aaaabbbbcccc
+55556666777788889999aaaabbbbcccc
+6666777788889999aaaabbbbccccdddd
+6666777788889999aaaabbbbccccdddd
+6666777788889999aaaabbbbccccdddd
+6666777788889999aaaabbbbccccdddd
+777788889999aaaabbbbccccddddeeee
+777788889999aaaabbbbccccddddeeee
+777788889999aaaabbbbccccddddeeee
+777788889999aaaabbbbccccddddeeee
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g08.png b/libgo/go/image/png/testdata/pngsuite/basn0g08.png
new file mode 100644
index 000000000..bf522eef0
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g08.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g08.sng b/libgo/go/image/png/testdata/pngsuite/basn0g08.sng
new file mode 100644
index 000000000..7389eb774
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g08.sng
@@ -0,0 +1,41 @@
+#SNG: from basn0g08.png
+IHDR {
+    width: 32; height: 32; bitdepth: 8;
+    using grayscale;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
+000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f
+202122232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f
+404142434445464748494a4b4c4d4e4f505152535455565758595a5b5c5d5e5f
+606162636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f
+808182838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9f
+a0a1a2a3a4a5a6a7a8a9aaabacadaeafb0b1b2b3b4b5b6b7b8b9babbbcbdbebf
+c0c1c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedf
+e0e1e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfeff
+fefdfcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0df
+dedddcdbdad9d8d7d6d5d4d3d2d1d0cfcecdcccbcac9c8c7c6c5c4c3c2c1c0bf
+bebdbcbbbab9b8b7b6b5b4b3b2b1b0afaeadacabaaa9a8a7a6a5a4a3a2a1a09f
+9e9d9c9b9a999897969594939291908f8e8d8c8b8a898887868584838281807f
+7e7d7c7b7a797877767574737271706f6e6d6c6b6a696867666564636261605f
+5e5d5c5b5a595857565554535251504f4e4d4c4b4a494847464544434241403f
+3e3d3c3b3a393837363534333231302f2e2d2c2b2a292827262524232221201f
+1e1d1c1b1a191817161514131211100f0e0d0c0b0a0908070605040302010001
+02030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f2021
+22232425262728292a2b2c2d2e2f303132333435363738393a3b3c3d3e3f4041
+42434445464748494a4b4c4d4e4f505152535455565758595a5b5c5d5e5f6061
+62636465666768696a6b6c6d6e6f707172737475767778797a7b7c7d7e7f8081
+82838485868788898a8b8c8d8e8f909192939495969798999a9b9c9d9e9fa0a1
+a2a3a4a5a6a7a8a9aaabacadaeafb0b1b2b3b4b5b6b7b8b9babbbcbdbebfc0c1
+c2c3c4c5c6c7c8c9cacbcccdcecfd0d1d2d3d4d5d6d7d8d9dadbdcdddedfe0e1
+e2e3e4e5e6e7e8e9eaebecedeeeff0f1f2f3f4f5f6f7f8f9fafbfcfdfefffefd
+fcfbfaf9f8f7f6f5f4f3f2f1f0efeeedecebeae9e8e7e6e5e4e3e2e1e0dfdedd
+dcdbdad9d8d7d6d5d4d3d2d1d0cfcecdcccbcac9c8c7c6c5c4c3c2c1c0bfbebd
+bcbbbab9b8b7b6b5b4b3b2b1b0afaeadacabaaa9a8a7a6a5a4a3a2a1a09f9e9d
+9c9b9a999897969594939291908f8e8d8c8b8a898887868584838281807f7e7d
+7c7b7a797877767574737271706f6e6d6c6b6a696867666564636261605f5e5d
+5c5b5a595857565554535251504f4e4d4c4b4a494847464544434241403f3e3d
+3c3b3a393837363534333231302f2e2d2c2b2a292827262524232221201f1e1d
+1c1b1a191817161514131211100f0e0d0c0b0a09080706050403020100010203
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g16.png b/libgo/go/image/png/testdata/pngsuite/basn0g16.png
new file mode 100644
index 000000000..318ebcadf
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g16.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn0g16.sng b/libgo/go/image/png/testdata/pngsuite/basn0g16.sng
new file mode 100644
index 000000000..922391a9e
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn0g16.sng
@@ -0,0 +1,41 @@
+#SNG: from basn0g16.png
+IHDR {
+    width: 32; height: 32; bitdepth: 16;
+    using grayscale;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
+0000 0900 1200 1b00 2400 2d00 3600 3f00 4800 5100 5a00 6300 6c00 7500 7e00 8700 9000 9900 a200 ab00 b400 bd00 c600 cf00 d800 e100 ea00 f300 fc00 f0ff d5ff baff 
+0200 0b00 1400 1d00 2600 2f00 3800 4100 4a00 5300 5c00 6500 6e00 7700 8000 8900 9200 9b00 a400 ad00 b600 bf00 c800 d100 da00 e300 ec00 f500 fe00 eaff cfff b4ff 
+0400 0d00 1600 1f00 2800 3100 3a00 4300 4c00 5500 5e00 6700 7000 7900 8200 8b00 9400 9d00 a600 af00 b800 c100 ca00 d300 dc00 e500 ee00 f700 ffff e4ff c9ff aeff 
+0600 0f00 1800 2100 2a00 3300 3c00 4500 4e00 5700 6000 6900 7200 7b00 8400 8d00 9600 9f00 a800 b100 ba00 c300 cc00 d500 de00 e700 f000 f900 f9ff deff c3ff a8ff 
+0800 1100 1a00 2300 2c00 3500 3e00 4700 5000 5900 6200 6b00 7400 7d00 8600 8f00 9800 a100 aa00 b300 bc00 c500 ce00 d700 e000 e900 f200 fb00 f3ff d8ff bdff a2ff 
+0a00 1300 1c00 2500 2e00 3700 4000 4900 5200 5b00 6400 6d00 7600 7f00 8800 9100 9a00 a300 ac00 b500 be00 c700 d000 d900 e200 eb00 f400 fd00 edff d2ff b7ff 9cff 
+0c00 1500 1e00 2700 3000 3900 4200 4b00 5400 5d00 6600 6f00 7800 8100 8a00 9300 9c00 a500 ae00 b700 c000 c900 d200 db00 e400 ed00 f600 ff00 e7ff ccff b1ff 96ff 
+0e00 1700 2000 2900 3200 3b00 4400 4d00 5600 5f00 6800 7100 7a00 8300 8c00 9500 9e00 a700 b000 b900 c200 cb00 d400 dd00 e600 ef00 f800 fcff e1ff c6ff abff 90ff 
+1000 1900 2200 2b00 3400 3d00 4600 4f00 5800 6100 6a00 7300 7c00 8500 8e00 9700 a000 a900 b200 bb00 c400 cd00 d600 df00 e800 f100 fa00 f6ff dbff c0ff a5ff 8aff 
+1200 1b00 2400 2d00 3600 3f00 4800 5100 5a00 6300 6c00 7500 7e00 8700 9000 9900 a200 ab00 b400 bd00 c600 cf00 d800 e100 ea00 f300 fc00 f0ff d5ff baff 9fff 84ff 
+1400 1d00 2600 2f00 3800 4100 4a00 5300 5c00 6500 6e00 7700 8000 8900 9200 9b00 a400 ad00 b600 bf00 c800 d100 da00 e300 ec00 f500 fe00 eaff cfff b4ff 99ff 7eff 
+1600 1f00 2800 3100 3a00 4300 4c00 5500 5e00 6700 7000 7900 8200 8b00 9400 9d00 a600 af00 b800 c100 ca00 d300 dc00 e500 ee00 f700 ffff e4ff c9ff aeff 93ff 78ff 
+1800 2100 2a00 3300 3c00 4500 4e00 5700 6000 6900 7200 7b00 8400 8d00 9600 9f00 a800 b100 ba00 c300 cc00 d500 de00 e700 f000 f900 f9ff deff c3ff a8ff 8dff 72ff 
+1a00 2300 2c00 3500 3e00 4700 5000 5900 6200 6b00 7400 7d00 8600 8f00 9800 a100 aa00 b300 bc00 c500 ce00 d700 e000 e900 f200 fb00 f3ff d8ff bdff a2ff 87ff 6cff 
+1c00 2500 2e00 3700 4000 4900 5200 5b00 6400 6d00 7600 7f00 8800 9100 9a00 a300 ac00 b500 be00 c700 d000 d900 e200 eb00 f400 fd00 edff d2ff b7ff 9cff 81ff 66ff 
+1e00 2700 3000 3900 4200 4b00 5400 5d00 6600 6f00 7800 8100 8a00 9300 9c00 a500 ae00 b700 c000 c900 d200 db00 e400 ed00 f600 ff00 e7ff ccff b1ff 96ff 7bff 60ff 
+2000 2900 3200 3b00 4400 4d00 5600 5f00 6800 7100 7a00 8300 8c00 9500 9e00 a700 b000 b900 c200 cb00 d400 dd00 e600 ef00 f800 fcff e1ff c6ff abff 90ff 75ff 5aff 
+2200 2b00 3400 3d00 4600 4f00 5800 6100 6a00 7300 7c00 8500 8e00 9700 a000 a900 b200 bb00 c400 cd00 d600 df00 e800 f100 fa00 f6ff dbff c0ff a5ff 8aff 6fff 54ff 
+2400 2d00 3600 3f00 4800 5100 5a00 6300 6c00 7500 7e00 8700 9000 9900 a200 ab00 b400 bd00 c600 cf00 d800 e100 ea00 f300 fc00 f0ff d5ff baff 9fff 84ff 69ff 4eff 
+2600 2f00 3800 4100 4a00 5300 5c00 6500 6e00 7700 8000 8900 9200 9b00 a400 ad00 b600 bf00 c800 d100 da00 e300 ec00 f500 fe00 eaff cfff b4ff 99ff 7eff 63ff 48ff 
+2800 3100 3a00 4300 4c00 5500 5e00 6700 7000 7900 8200 8b00 9400 9d00 a600 af00 b800 c100 ca00 d300 dc00 e500 ee00 f700 ffff e4ff c9ff aeff 93ff 78ff 5dff 42ff 
+2a00 3300 3c00 4500 4e00 5700 6000 6900 7200 7b00 8400 8d00 9600 9f00 a800 b100 ba00 c300 cc00 d500 de00 e700 f000 f900 f9ff deff c3ff a8ff 8dff 72ff 57ff 3cff 
+2c00 3500 3e00 4700 5000 5900 6200 6b00 7400 7d00 8600 8f00 9800 a100 aa00 b300 bc00 c500 ce00 d700 e000 e900 f200 fb00 f3ff d8ff bdff a2ff 87ff 6cff 51ff 36ff 
+2e00 3700 4000 4900 5200 5b00 6400 6d00 7600 7f00 8800 9100 9a00 a300 ac00 b500 be00 c700 d000 d900 e200 eb00 f400 fd00 edff d2ff b7ff 9cff 81ff 66ff 4bff 30ff 
+3000 3900 4200 4b00 5400 5d00 6600 6f00 7800 8100 8a00 9300 9c00 a500 ae00 b700 c000 c900 d200 db00 e400 ed00 f600 ff00 e7ff ccff b1ff 96ff 7bff 60ff 45ff 2aff 
+3200 3b00 4400 4d00 5600 5f00 6800 7100 7a00 8300 8c00 9500 9e00 a700 b000 b900 c200 cb00 d400 dd00 e600 ef00 f800 fcff e1ff c6ff abff 90ff 75ff 5aff 3fff 24ff 
+3400 3d00 4600 4f00 5800 6100 6a00 7300 7c00 8500 8e00 9700 a000 a900 b200 bb00 c400 cd00 d600 df00 e800 f100 fa00 f6ff dbff c0ff a5ff 8aff 6fff 54ff 39ff 1eff 
+3600 3f00 4800 5100 5a00 6300 6c00 7500 7e00 8700 9000 9900 a200 ab00 b400 bd00 c600 cf00 d800 e100 ea00 f300 fc00 f0ff d5ff baff 9fff 84ff 69ff 4eff 33ff 18ff 
+3800 4100 4a00 5300 5c00 6500 6e00 7700 8000 8900 9200 9b00 a400 ad00 b600 bf00 c800 d100 da00 e300 ec00 f500 fe00 eaff cfff b4ff 99ff 7eff 63ff 48ff 2dff 12ff 
+3a00 4300 4c00 5500 5e00 6700 7000 7900 8200 8b00 9400 9d00 a600 af00 b800 c100 ca00 d300 dc00 e500 ee00 f700 ffff e4ff c9ff aeff 93ff 78ff 5dff 42ff 27ff 0cff 
+3c00 4500 4e00 5700 6000 6900 7200 7b00 8400 8d00 9600 9f00 a800 b100 ba00 c300 cc00 d500 de00 e700 f000 f900 f9ff deff c3ff a8ff 8dff 72ff 57ff 3cff 21ff 06ff 
+3e00 4700 5000 5900 6200 6b00 7400 7d00 8600 8f00 9800 a100 aa00 b300 bc00 c500 ce00 d700 e000 e900 f200 fb00 f3ff d8ff bdff a2ff 87ff 6cff 51ff 36ff 1bff 00ff 
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn2c08.png b/libgo/go/image/png/testdata/pngsuite/basn2c08.png
new file mode 100644
index 000000000..21d2f91a8
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn2c08.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn2c08.sng b/libgo/go/image/png/testdata/pngsuite/basn2c08.sng
new file mode 100644
index 000000000..09a61317b
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn2c08.sng
@@ -0,0 +1,41 @@
+#SNG: from basn2c08.png
+IHDR {
+    width: 32; height: 32; bitdepth: 8;
+    using color;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
+ffffff fffffe fffffd fffffc fffffb fffffa fffff9 fffff8 fffff7 fffff6 fffff5 fffff4 fffff3 fffff2 fffff1 fffff0 ffffef ffffee ffffed ffffec ffffeb ffffea ffffe9 ffffe8 ffffe7 ffffe6 ffffe5 ffffe4 ffffe3 ffffe2 ffffe1 ffffe0 
+ffffdf ffffde ffffdd ffffdc ffffdb ffffda ffffd9 ffffd8 ffffd7 ffffd6 ffffd5 ffffd4 ffffd3 ffffd2 ffffd1 ffffd0 ffffcf ffffce ffffcd ffffcc ffffcb ffffca ffffc9 ffffc8 ffffc7 ffffc6 ffffc5 ffffc4 ffffc3 ffffc2 ffffc1 ffffc0 
+ffffbf ffffbe ffffbd ffffbc ffffbb ffffba ffffb9 ffffb8 ffffb7 ffffb6 ffffb5 ffffb4 ffffb3 ffffb2 ffffb1 ffffb0 ffffaf ffffae ffffad ffffac ffffab ffffaa ffffa9 ffffa8 ffffa7 ffffa6 ffffa5 ffffa4 ffffa3 ffffa2 ffffa1 ffffa0 
+ffff9f ffff9e ffff9d ffff9c ffff9b ffff9a ffff99 ffff98 ffff97 ffff96 ffff95 ffff94 ffff93 ffff92 ffff91 ffff90 ffff8f ffff8e ffff8d ffff8c ffff8b ffff8a ffff89 ffff88 ffff87 ffff86 ffff85 ffff84 ffff83 ffff82 ffff81 ffff80 
+ffff7f ffff7e ffff7d ffff7c ffff7b ffff7a ffff79 ffff78 ffff77 ffff76 ffff75 ffff74 ffff73 ffff72 ffff71 ffff70 ffff6f ffff6e ffff6d ffff6c ffff6b ffff6a ffff69 ffff68 ffff67 ffff66 ffff65 ffff64 ffff63 ffff62 ffff61 ffff60 
+ffff5f ffff5e ffff5d ffff5c ffff5b ffff5a ffff59 ffff58 ffff57 ffff56 ffff55 ffff54 ffff53 ffff52 ffff51 ffff50 ffff4f ffff4e ffff4d ffff4c ffff4b ffff4a ffff49 ffff48 ffff47 ffff46 ffff45 ffff44 ffff43 ffff42 ffff41 ffff40 
+ffff3f ffff3e ffff3d ffff3c ffff3b ffff3a ffff39 ffff38 ffff37 ffff36 ffff35 ffff34 ffff33 ffff32 ffff31 ffff30 ffff2f ffff2e ffff2d ffff2c ffff2b ffff2a ffff29 ffff28 ffff27 ffff26 ffff25 ffff24 ffff23 ffff22 ffff21 ffff20 
+ffff1f ffff1e ffff1d ffff1c ffff1b ffff1a ffff19 ffff18 ffff17 ffff16 ffff15 ffff14 ffff13 ffff12 ffff11 ffff10 ffff0f ffff0e ffff0d ffff0c ffff0b ffff0a ffff09 ffff08 ffff07 ffff06 ffff05 ffff04 ffff03 ffff02 ffff01 ffff00 
+ffffff fffeff fffdff fffcff fffbff fffaff fff9ff fff8ff fff7ff fff6ff fff5ff fff4ff fff3ff fff2ff fff1ff fff0ff ffefff ffeeff ffedff ffecff ffebff ffeaff ffe9ff ffe8ff ffe7ff ffe6ff ffe5ff ffe4ff ffe3ff ffe2ff ffe1ff ffe0ff 
+ffdfff ffdeff ffddff ffdcff ffdbff ffdaff ffd9ff ffd8ff ffd7ff ffd6ff ffd5ff ffd4ff ffd3ff ffd2ff ffd1ff ffd0ff ffcfff ffceff ffcdff ffccff ffcbff ffcaff ffc9ff ffc8ff ffc7ff ffc6ff ffc5ff ffc4ff ffc3ff ffc2ff ffc1ff ffc0ff 
+ffbfff ffbeff ffbdff ffbcff ffbbff ffbaff ffb9ff ffb8ff ffb7ff ffb6ff ffb5ff ffb4ff ffb3ff ffb2ff ffb1ff ffb0ff ffafff ffaeff ffadff ffacff ffabff ffaaff ffa9ff ffa8ff ffa7ff ffa6ff ffa5ff ffa4ff ffa3ff ffa2ff ffa1ff ffa0ff 
+ff9fff ff9eff ff9dff ff9cff ff9bff ff9aff ff99ff ff98ff ff97ff ff96ff ff95ff ff94ff ff93ff ff92ff ff91ff ff90ff ff8fff ff8eff ff8dff ff8cff ff8bff ff8aff ff89ff ff88ff ff87ff ff86ff ff85ff ff84ff ff83ff ff82ff ff81ff ff80ff 
+ff7fff ff7eff ff7dff ff7cff ff7bff ff7aff ff79ff ff78ff ff77ff ff76ff ff75ff ff74ff ff73ff ff72ff ff71ff ff70ff ff6fff ff6eff ff6dff ff6cff ff6bff ff6aff ff69ff ff68ff ff67ff ff66ff ff65ff ff64ff ff63ff ff62ff ff61ff ff60ff 
+ff5fff ff5eff ff5dff ff5cff ff5bff ff5aff ff59ff ff58ff ff57ff ff56ff ff55ff ff54ff ff53ff ff52ff ff51ff ff50ff ff4fff ff4eff ff4dff ff4cff ff4bff ff4aff ff49ff ff48ff ff47ff ff46ff ff45ff ff44ff ff43ff ff42ff ff41ff ff40ff 
+ff3fff ff3eff ff3dff ff3cff ff3bff ff3aff ff39ff ff38ff ff37ff ff36ff ff35ff ff34ff ff33ff ff32ff ff31ff ff30ff ff2fff ff2eff ff2dff ff2cff ff2bff ff2aff ff29ff ff28ff ff27ff ff26ff ff25ff ff24ff ff23ff ff22ff ff21ff ff20ff 
+ff1fff ff1eff ff1dff ff1cff ff1bff ff1aff ff19ff ff18ff ff17ff ff16ff ff15ff ff14ff ff13ff ff12ff ff11ff ff10ff ff0fff ff0eff ff0dff ff0cff ff0bff ff0aff ff09ff ff08ff ff07ff ff06ff ff05ff ff04ff ff03ff ff02ff ff01ff ff00ff 
+ffffff feffff fdffff fcffff fbffff faffff f9ffff f8ffff f7ffff f6ffff f5ffff f4ffff f3ffff f2ffff f1ffff f0ffff efffff eeffff edffff ecffff ebffff eaffff e9ffff e8ffff e7ffff e6ffff e5ffff e4ffff e3ffff e2ffff e1ffff e0ffff 
+dfffff deffff ddffff dcffff dbffff daffff d9ffff d8ffff d7ffff d6ffff d5ffff d4ffff d3ffff d2ffff d1ffff d0ffff cfffff ceffff cdffff ccffff cbffff caffff c9ffff c8ffff c7ffff c6ffff c5ffff c4ffff c3ffff c2ffff c1ffff c0ffff 
+bfffff beffff bdffff bcffff bbffff baffff b9ffff b8ffff b7ffff b6ffff b5ffff b4ffff b3ffff b2ffff b1ffff b0ffff afffff aeffff adffff acffff abffff aaffff a9ffff a8ffff a7ffff a6ffff a5ffff a4ffff a3ffff a2ffff a1ffff a0ffff 
+9fffff 9effff 9dffff 9cffff 9bffff 9affff 99ffff 98ffff 97ffff 96ffff 95ffff 94ffff 93ffff 92ffff 91ffff 90ffff 8fffff 8effff 8dffff 8cffff 8bffff 8affff 89ffff 88ffff 87ffff 86ffff 85ffff 84ffff 83ffff 82ffff 81ffff 80ffff 
+7fffff 7effff 7dffff 7cffff 7bffff 7affff 79ffff 78ffff 77ffff 76ffff 75ffff 74ffff 73ffff 72ffff 71ffff 70ffff 6fffff 6effff 6dffff 6cffff 6bffff 6affff 69ffff 68ffff 67ffff 66ffff 65ffff 64ffff 63ffff 62ffff 61ffff 60ffff 
+5fffff 5effff 5dffff 5cffff 5bffff 5affff 59ffff 58ffff 57ffff 56ffff 55ffff 54ffff 53ffff 52ffff 51ffff 50ffff 4fffff 4effff 4dffff 4cffff 4bffff 4affff 49ffff 48ffff 47ffff 46ffff 45ffff 44ffff 43ffff 42ffff 41ffff 40ffff 
+3fffff 3effff 3dffff 3cffff 3bffff 3affff 39ffff 38ffff 37ffff 36ffff 35ffff 34ffff 33ffff 32ffff 31ffff 30ffff 2fffff 2effff 2dffff 2cffff 2bffff 2affff 29ffff 28ffff 27ffff 26ffff 25ffff 24ffff 23ffff 22ffff 21ffff 20ffff 
+1fffff 1effff 1dffff 1cffff 1bffff 1affff 19ffff 18ffff 17ffff 16ffff 15ffff 14ffff 13ffff 12ffff 11ffff 10ffff 0fffff 0effff 0dffff 0cffff 0bffff 0affff 09ffff 08ffff 07ffff 06ffff 05ffff 04ffff 03ffff 02ffff 01ffff 00ffff 
+ffffff fefefe fdfdfd fcfcfc fbfbfb fafafa f9f9f9 f8f8f8 f7f7f7 f6f6f6 f5f5f5 f4f4f4 f3f3f3 f2f2f2 f1f1f1 f0f0f0 efefef eeeeee ededed ececec ebebeb eaeaea e9e9e9 e8e8e8 e7e7e7 e6e6e6 e5e5e5 e4e4e4 e3e3e3 e2e2e2 e1e1e1 e0e0e0 
+dfdfdf dedede dddddd dcdcdc dbdbdb dadada d9d9d9 d8d8d8 d7d7d7 d6d6d6 d5d5d5 d4d4d4 d3d3d3 d2d2d2 d1d1d1 d0d0d0 cfcfcf cecece cdcdcd cccccc cbcbcb cacaca c9c9c9 c8c8c8 c7c7c7 c6c6c6 c5c5c5 c4c4c4 c3c3c3 c2c2c2 c1c1c1 c0c0c0 
+bfbfbf bebebe bdbdbd bcbcbc bbbbbb bababa b9b9b9 b8b8b8 b7b7b7 b6b6b6 b5b5b5 b4b4b4 b3b3b3 b2b2b2 b1b1b1 b0b0b0 afafaf aeaeae adadad acacac ababab aaaaaa a9a9a9 a8a8a8 a7a7a7 a6a6a6 a5a5a5 a4a4a4 a3a3a3 a2a2a2 a1a1a1 a0a0a0 
+9f9f9f 9e9e9e 9d9d9d 9c9c9c 9b9b9b 9a9a9a 999999 989898 979797 969696 959595 949494 939393 929292 919191 909090 8f8f8f 8e8e8e 8d8d8d 8c8c8c 8b8b8b 8a8a8a 898989 888888 878787 868686 858585 848484 838383 828282 818181 808080 
+7f7f7f 7e7e7e 7d7d7d 7c7c7c 7b7b7b 7a7a7a 797979 787878 777777 767676 757575 747474 737373 727272 717171 707070 6f6f6f 6e6e6e 6d6d6d 6c6c6c 6b6b6b 6a6a6a 696969 686868 676767 666666 656565 646464 636363 626262 616161 606060 
+5f5f5f 5e5e5e 5d5d5d 5c5c5c 5b5b5b 5a5a5a 595959 585858 575757 565656 555555 545454 535353 525252 515151 505050 4f4f4f 4e4e4e 4d4d4d 4c4c4c 4b4b4b 4a4a4a 494949 484848 474747 464646 454545 444444 434343 424242 414141 404040 
+3f3f3f 3e3e3e 3d3d3d 3c3c3c 3b3b3b 3a3a3a 393939 383838 373737 363636 353535 343434 333333 323232 313131 303030 2f2f2f 2e2e2e 2d2d2d 2c2c2c 2b2b2b 2a2a2a 292929 282828 272727 262626 252525 242424 232323 222222 212121 202020 
+1f1f1f 1e1e1e 1d1d1d 1c1c1c 1b1b1b 1a1a1a 191919 181818 171717 161616 151515 141414 131313 121212 111111 101010 0f0f0f 0e0e0e 0d0d0d 0c0c0c 0b0b0b 0a0a0a 090909 080808 070707 060606 050505 040404 030303 020202 010101 000000 
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn2c16.png b/libgo/go/image/png/testdata/pngsuite/basn2c16.png
new file mode 100644
index 000000000..1bd4a4d0e
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn2c16.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn2c16.sng b/libgo/go/image/png/testdata/pngsuite/basn2c16.sng
new file mode 100644
index 000000000..bac7c9d91
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn2c16.sng
@@ -0,0 +1,41 @@
+#SNG: from basn2c16.png
+IHDR {
+    width: 32; height: 32; bitdepth: 16;
+    using color;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
+ffffffff0000 f7bdffff0000 ef7bffff0000 e739ffff0000 def7ffff0000 d6b5ffff0000 ce73ffff0000 c631ffff0000 bdefffff0000 b5adffff0000 ad6bffff0000 a529ffff0000 9ce7ffff0000 94a5ffff0000 8c63ffff0000 8421ffff0000 7bdeffff0000 739cffff0000 6b5affff0000 6318ffff0000 5ad6ffff0000 5294ffff0000 4a52ffff0000 4210ffff0000 39ceffff0000 318cffff0000 294affff0000 2108ffff0000 18c6ffff0000 1084ffff0000 0842ffff0000 0000ffff0000 
+fffff7bd0000 f7bdf7bd0000 ef7bf7bd0000 e739f7bd0000 def7f7bd0000 d6b5f7bd0000 ce73f7bd0000 c631f7bd0000 bdeff7bd0000 b5adf7bd0000 ad6bf7bd0000 a529f7bd0000 9ce7f7bd0000 94a5f7bd0000 8c63f7bd0000 8421f7bd0000 7bdef7bd0000 739cf7bd0000 6b5af7bd0000 6318f7bd0000 5ad6f7bd0000 5294f7bd0000 4a52f7bd0000 4210f7bd0000 39cef7bd0000 318cf7bd0000 294af7bd0000 2108f7bd0000 18c6f7bd0000 1084f7bd0000 0842f7bd0000 0000f7bd0842 
+ffffef7b0000 f7bdef7b0000 ef7bef7b0000 e739ef7b0000 def7ef7b0000 d6b5ef7b0000 ce73ef7b0000 c631ef7b0000 bdefef7b0000 b5adef7b0000 ad6bef7b0000 a529ef7b0000 9ce7ef7b0000 94a5ef7b0000 8c63ef7b0000 8421ef7b0000 7bdeef7b0000 739cef7b0000 6b5aef7b0000 6318ef7b0000 5ad6ef7b0000 5294ef7b0000 4a52ef7b0000 4210ef7b0000 39ceef7b0000 318cef7b0000 294aef7b0000 2108ef7b0000 18c6ef7b0000 1084ef7b0000 0842ef7b0842 0000ef7b1084 
+ffffe7390000 f7bde7390000 ef7be7390000 e739e7390000 def7e7390000 d6b5e7390000 ce73e7390000 c631e7390000 bdefe7390000 b5ade7390000 ad6be7390000 a529e7390000 9ce7e7390000 94a5e7390000 8c63e7390000 8421e7390000 7bdee7390000 739ce7390000 6b5ae7390000 6318e7390000 5ad6e7390000 5294e7390000 4a52e7390000 4210e7390000 39cee7390000 318ce7390000 294ae7390000 2108e7390000 18c6e7390000 1084e7390842 0842e7391084 0000e73918c6 
+ffffdef70000 f7bddef70000 ef7bdef70000 e739def70000 def7def70000 d6b5def70000 ce73def70000 c631def70000 bdefdef70000 b5addef70000 ad6bdef70000 a529def70000 9ce7def70000 94a5def70000 8c63def70000 8421def70000 7bdedef70000 739cdef70000 6b5adef70000 6318def70000 5ad6def70000 5294def70000 4a52def70000 4210def70000 39cedef70000 318cdef70000 294adef70000 2108def70000 18c6def70842 1084def71084 0842def718c6 0000def72108 
+ffffd6b50000 f7bdd6b50000 ef7bd6b50000 e739d6b50000 def7d6b50000 d6b5d6b50000 ce73d6b50000 c631d6b50000 bdefd6b50000 b5add6b50000 ad6bd6b50000 a529d6b50000 9ce7d6b50000 94a5d6b50000 8c63d6b50000 8421d6b50000 7bded6b50000 739cd6b50000 6b5ad6b50000 6318d6b50000 5ad6d6b50000 5294d6b50000 4a52d6b50000 4210d6b50000 39ced6b50000 318cd6b50000 294ad6b50000 2108d6b50842 18c6d6b51084 1084d6b518c6 0842d6b52108 0000d6b5294a 
+ffffce730000 f7bdce730000 ef7bce730000 e739ce730000 def7ce730000 d6b5ce730000 ce73ce730000 c631ce730000 bdefce730000 b5adce730000 ad6bce730000 a529ce730000 9ce7ce730000 94a5ce730000 8c63ce730000 8421ce730000 7bdece730000 739cce730000 6b5ace730000 6318ce730000 5ad6ce730000 5294ce730000 4a52ce730000 4210ce730000 39cece730000 318cce730000 294ace730842 2108ce731084 18c6ce7318c6 1084ce732108 0842ce73294a 0000ce73318c 
+ffffc6310000 f7bdc6310000 ef7bc6310000 e739c6310000 def7c6310000 d6b5c6310000 ce73c6310000 c631c6310000 bdefc6310000 b5adc6310000 ad6bc6310000 a529c6310000 9ce7c6310000 94a5c6310000 8c63c6310000 8421c6310000 7bdec6310000 739cc6310000 6b5ac6310000 6318c6310000 5ad6c6310000 5294c6310000 4a52c6310000 4210c6310000 39cec6310000 318cc6310842 294ac6311084 2108c63118c6 18c6c6312108 1084c631294a 0842c631318c 0000c63139ce 
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+ffff9ce70000 f7bd9ce70000 ef7b9ce70000 e7399ce70000 def79ce70000 d6b59ce70000 ce739ce70000 c6319ce70000 bdef9ce70000 b5ad9ce70000 ad6b9ce70000 a5299ce70000 9ce79ce70000 94a59ce70000 8c639ce70000 84219ce70000 7bde9ce70000 739c9ce70000 6b5a9ce70000 63189ce70000 5ad69ce70842 52949ce71084 4a529ce718c6 42109ce72108 39ce9ce7294a 318c9ce7318c 294a9ce739ce 21089ce74210 18c69ce74a52 10849ce75294 08429ce75ad6 00009ce76318 
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+ffff8c630000 f7bd8c630000 ef7b8c630000 e7398c630000 def78c630000 d6b58c630000 ce738c630000 c6318c630000 bdef8c630000 b5ad8c630000 ad6b8c630000 a5298c630000 9ce78c630000 94a58c630000 8c638c630000 84218c630000 7bde8c630000 739c8c630000 6b5a8c630842 63188c631084 5ad68c6318c6 52948c632108 4a528c63294a 42108c63318c 39ce8c6339ce 318c8c634210 294a8c634a52 21088c635294 18c68c635ad6 10848c636318 08428c636b5a 00008c63739c 
+ffff84210000 f7bd84210000 ef7b84210000 e73984210000 def784210000 d6b584210000 ce7384210000 c63184210000 bdef84210000 b5ad84210000 ad6b84210000 a52984210000 9ce784210000 94a584210000 8c6384210000 842184210000 7bde84210000 739c84210842 6b5a84211084 6318842118c6 5ad684212108 52948421294a 4a528421318c 4210842139ce 39ce84214210 318c84214a52 294a84215294 210884215ad6 18c684216318 108484216b5a 08428421739c 000084217bde 
+ffff7bde0000 f7bd7bde0000 ef7b7bde0000 e7397bde0000 def77bde0000 d6b57bde0000 ce737bde0000 c6317bde0000 bdef7bde0000 b5ad7bde0000 ad6b7bde0000 a5297bde0000 9ce77bde0000 94a57bde0000 8c637bde0000 84217bde0000 7bde7bde0842 739c7bde1084 6b5a7bde18c6 63187bde2108 5ad67bde294a 52947bde318c 4a527bde39ce 42107bde4210 39ce7bde4a52 318c7bde5294 294a7bde5ad6 21087bde6318 18c67bde6b5a 10847bde739c 08427bde7bde 00007bde8421 
+ffff739c0000 f7bd739c0000 ef7b739c0000 e739739c0000 def7739c0000 d6b5739c0000 ce73739c0000 c631739c0000 bdef739c0000 b5ad739c0000 ad6b739c0000 a529739c0000 9ce7739c0000 94a5739c0000 8c63739c0000 8421739c0842 7bde739c1084 739c739c18c6 6b5a739c2108 6318739c294a 5ad6739c318c 5294739c39ce 4a52739c4210 4210739c4a52 39ce739c5294 318c739c5ad6 294a739c6318 2108739c6b5a 18c6739c739c 1084739c7bde 0842739c8421 0000739c8c63 
+ffff6b5a0000 f7bd6b5a0000 ef7b6b5a0000 e7396b5a0000 def76b5a0000 d6b56b5a0000 ce736b5a0000 c6316b5a0000 bdef6b5a0000 b5ad6b5a0000 ad6b6b5a0000 a5296b5a0000 9ce76b5a0000 94a56b5a0000 8c636b5a0842 84216b5a1084 7bde6b5a18c6 739c6b5a2108 6b5a6b5a294a 63186b5a318c 5ad66b5a39ce 52946b5a4210 4a526b5a4a52 42106b5a5294 39ce6b5a5ad6 318c6b5a6318 294a6b5a6b5a 21086b5a739c 18c66b5a7bde 10846b5a8421 08426b5a8c63 00006b5a94a5 
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+ffff5ad60000 f7bd5ad60000 ef7b5ad60000 e7395ad60000 def75ad60000 d6b55ad60000 ce735ad60000 c6315ad60000 bdef5ad60000 b5ad5ad60000 ad6b5ad60000 a5295ad60000 9ce75ad60842 94a55ad61084 8c635ad618c6 84215ad62108 7bde5ad6294a 739c5ad6318c 6b5a5ad639ce 63185ad64210 5ad65ad64a52 52945ad65294 4a525ad65ad6 42105ad66318 39ce5ad66b5a 318c5ad6739c 294a5ad67bde 21085ad68421 18c65ad68c63 10845ad694a5 08425ad69ce7 00005ad6a529 
+ffff52940000 f7bd52940000 ef7b52940000 e73952940000 def752940000 d6b552940000 ce7352940000 c63152940000 bdef52940000 b5ad52940000 ad6b52940000 a52952940842 9ce752941084 94a5529418c6 8c6352942108 84215294294a 7bde5294318c 739c529439ce 6b5a52944210 631852944a52 5ad652945294 529452945ad6 4a5252946318 421052946b5a 39ce5294739c 318c52947bde 294a52948421 210852948c63 18c6529494a5 108452949ce7 08425294a529 00005294ad6b 
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+ffff42100000 f7bd42100000 ef7b42100000 e73942100000 def742100000 d6b542100000 ce7342100000 c63142100000 bdef42100000 b5ad42100842 ad6b42101084 a529421018c6 9ce742102108 94a54210294a 8c634210318c 8421421039ce 7bde42104210 739c42104a52 6b5a42105294 631842105ad6 5ad642106318 529442106b5a 4a524210739c 421042107bde 39ce42108421 318c42108c63 294a421094a5 210842109ce7 18c64210a529 10844210ad6b 08424210b5ad 00004210bdef 
+ffff39ce0000 f7bd39ce0000 ef7b39ce0000 e73939ce0000 def739ce0000 d6b539ce0000 ce7339ce0000 c63139ce0000 bdef39ce0842 b5ad39ce1084 ad6b39ce18c6 a52939ce2108 9ce739ce294a 94a539ce318c 8c6339ce39ce 842139ce4210 7bde39ce4a52 739c39ce5294 6b5a39ce5ad6 631839ce6318 5ad639ce6b5a 529439ce739c 4a5239ce7bde 421039ce8421 39ce39ce8c63 318c39ce94a5 294a39ce9ce7 210839cea529 18c639cead6b 108439ceb5ad 084239cebdef 000039cec631 
+ffff318c0000 f7bd318c0000 ef7b318c0000 e739318c0000 def7318c0000 d6b5318c0000 ce73318c0000 c631318c0842 bdef318c1084 b5ad318c18c6 ad6b318c2108 a529318c294a 9ce7318c318c 94a5318c39ce 8c63318c4210 8421318c4a52 7bde318c5294 739c318c5ad6 6b5a318c6318 6318318c6b5a 5ad6318c739c 5294318c7bde 4a52318c8421 4210318c8c63 39ce318c94a5 318c318c9ce7 294a318ca529 2108318cad6b 18c6318cb5ad 1084318cbdef 0842318cc631 0000318cce73 
+ffff294a0000 f7bd294a0000 ef7b294a0000 e739294a0000 def7294a0000 d6b5294a0000 ce73294a0842 c631294a1084 bdef294a18c6 b5ad294a2108 ad6b294a294a a529294a318c 9ce7294a39ce 94a5294a4210 8c63294a4a52 8421294a5294 7bde294a5ad6 739c294a6318 6b5a294a6b5a 6318294a739c 5ad6294a7bde 5294294a8421 4a52294a8c63 4210294a94a5 39ce294a9ce7 318c294aa529 294a294aad6b 2108294ab5ad 18c6294abdef 1084294ac631 0842294ace73 0000294ad6b5 
+ffff21080000 f7bd21080000 ef7b21080000 e73921080000 def721080000 d6b521080842 ce7321081084 c631210818c6 bdef21082108 b5ad2108294a ad6b2108318c a529210839ce 9ce721084210 94a521084a52 8c6321085294 842121085ad6 7bde21086318 739c21086b5a 6b5a2108739c 631821087bde 5ad621088421 529421088c63 4a52210894a5 421021089ce7 39ce2108a529 318c2108ad6b 294a2108b5ad 21082108bdef 18c62108c631 10842108ce73 08422108d6b5 00002108def7 
+ffff18c60000 f7bd18c60000 ef7b18c60000 e73918c60000 def718c60842 d6b518c61084 ce7318c618c6 c63118c62108 bdef18c6294a b5ad18c6318c ad6b18c639ce a52918c64210 9ce718c64a52 94a518c65294 8c6318c65ad6 842118c66318 7bde18c66b5a 739c18c6739c 6b5a18c67bde 631818c68421 5ad618c68c63 529418c694a5 4a5218c69ce7 421018c6a529 39ce18c6ad6b 318c18c6b5ad 294a18c6bdef 210818c6c631 18c618c6ce73 108418c6d6b5 084218c6def7 000018c6e739 
+ffff10840000 f7bd10840000 ef7b10840000 e73910840842 def710841084 d6b5108418c6 ce7310842108 c6311084294a bdef1084318c b5ad108439ce ad6b10844210 a52910844a52 9ce710845294 94a510845ad6 8c6310846318 842110846b5a 7bde1084739c 739c10847bde 6b5a10848421 631810848c63 5ad6108494a5 529410849ce7 4a521084a529 42101084ad6b 39ce1084b5ad 318c1084bdef 294a1084c631 21081084ce73 18c61084d6b5 10841084def7 08421084e739 00001084ef7b 
+ffff08420000 f7bd08420000 ef7b08420842 e73908421084 def7084218c6 d6b508422108 ce730842294a c6310842318c bdef084239ce b5ad08424210 ad6b08424a52 a52908425294 9ce708425ad6 94a508426318 8c6308426b5a 84210842739c 7bde08427bde 739c08428421 6b5a08428c63 6318084294a5 5ad608429ce7 52940842a529 4a520842ad6b 42100842b5ad 39ce0842bdef 318c0842c631 294a0842ce73 21080842d6b5 18c60842def7 10840842e739 08420842ef7b 00000842f7bd 
+ffff00000000 f7bd00000842 ef7b00001084 e739000018c6 def700002108 d6b50000294a ce730000318c c631000039ce bdef00004210 b5ad00004a52 ad6b00005294 a52900005ad6 9ce700006318 94a500006b5a 8c630000739c 842100007bde 7bde00008421 739c00008c63 6b5a000094a5 631800009ce7 5ad60000a529 52940000ad6b 4a520000b5ad 42100000bdef 39ce0000c631 318c0000ce73 294a0000d6b5 21080000def7 18c60000e739 10840000ef7b 08420000f7bd 00000000ffff 
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn3p01.png b/libgo/go/image/png/testdata/pngsuite/basn3p01.png
new file mode 100644
index 000000000..a21db5977
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn3p01.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn3p01.sng b/libgo/go/image/png/testdata/pngsuite/basn3p01.sng
new file mode 100644
index 000000000..a8b3ce878
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn3p01.sng
@@ -0,0 +1,45 @@
+#SNG: from basn3p01.png
+IHDR {
+    width: 32; height: 32; bitdepth: 1;
+    using color palette;
+}
+gAMA {1.0000}
+PLTE {
+    (238,255, 34)     # rgb = (0xee,0xff,0x22)
+    ( 34,102,255)     # rgb = (0x22,0x66,0xff)
+}
+IMAGE {
+    pixels hex
+0f0f0f0f
+0f0f0f0f
+0f0f0f0f
+0f0f0f0f
+f0f0f0f0
+f0f0f0f0
+f0f0f0f0
+f0f0f0f0
+0f0f0f0f
+0f0f0f0f
+0f0f0f0f
+0f0f0f0f
+f0f0f0f0
+f0f0f0f0
+f0f0f0f0
+f0f0f0f0
+0f0f0f0f
+0f0f0f0f
+0f0f0f0f
+0f0f0f0f
+f0f0f0f0
+f0f0f0f0
+f0f0f0f0
+f0f0f0f0
+0f0f0f0f
+0f0f0f0f
+0f0f0f0f
+0f0f0f0f
+f0f0f0f0
+f0f0f0f0
+f0f0f0f0
+f0f0f0f0
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn3p02.png b/libgo/go/image/png/testdata/pngsuite/basn3p02.png
new file mode 100644
index 000000000..1d0ab6197
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn3p02.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn3p02.sng b/libgo/go/image/png/testdata/pngsuite/basn3p02.sng
new file mode 100644
index 000000000..f2321aa3d
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn3p02.sng
@@ -0,0 +1,50 @@
+#SNG: from basn3p02.png
+IHDR {
+    width: 32; height: 32; bitdepth: 2;
+    using color palette;
+}
+gAMA {1.0000}
+sBIT {
+    red: 1; green: 1; blue: 1;
+}
+PLTE {
+    (  0,255,  0)     # rgb = (0x00,0xff,0x00) green1
+    (255,  0,  0)     # rgb = (0xff,0x00,0x00) red1
+    (255,255,  0)     # rgb = (0xff,0xff,0x00) yellow1
+    (  0,  0,255)     # rgb = (0x00,0x00,0xff) blue1
+}
+IMAGE {
+    pixels hex
+ff55aa00ff55aa00
+ff55aa00ff55aa00
+ff55aa00ff55aa00
+ff55aa00ff55aa00
+00ff55aa00ff55aa
+00ff55aa00ff55aa
+00ff55aa00ff55aa
+00ff55aa00ff55aa
+aa00ff55aa00ff55
+aa00ff55aa00ff55
+aa00ff55aa00ff55
+aa00ff55aa00ff55
+55aa00ff55aa00ff
+55aa00ff55aa00ff
+55aa00ff55aa00ff
+55aa00ff55aa00ff
+ff55aa00ff55aa00
+ff55aa00ff55aa00
+ff55aa00ff55aa00
+ff55aa00ff55aa00
+00ff55aa00ff55aa
+00ff55aa00ff55aa
+00ff55aa00ff55aa
+00ff55aa00ff55aa
+aa00ff55aa00ff55
+aa00ff55aa00ff55
+aa00ff55aa00ff55
+aa00ff55aa00ff55
+55aa00ff55aa00ff
+55aa00ff55aa00ff
+55aa00ff55aa00ff
+55aa00ff55aa00ff
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn3p04.png b/libgo/go/image/png/testdata/pngsuite/basn3p04.png
new file mode 100644
index 000000000..6dc6eac83
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn3p04.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn3p04.sng b/libgo/go/image/png/testdata/pngsuite/basn3p04.sng
new file mode 100644
index 000000000..e52885dba
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn3p04.sng
@@ -0,0 +1,61 @@
+#SNG: from basn3p04.png
+IHDR {
+    width: 32; height: 32; bitdepth: 4;
+    using color palette;
+}
+gAMA {1.0000}
+sBIT {
+    red: 4; green: 4; blue: 4;
+}
+PLTE {
+    ( 34,  0,255)     # rgb = (0x22,0x00,0xff)
+    (  0,255,255)     # rgb = (0x00,0xff,0xff) cyan1
+    (136,  0,255)     # rgb = (0x88,0x00,0xff)
+    ( 34,255,  0)     # rgb = (0x22,0xff,0x00)
+    (  0,153,255)     # rgb = (0x00,0x99,0xff)
+    (255,102,  0)     # rgb = (0xff,0x66,0x00)
+    (221,  0,255)     # rgb = (0xdd,0x00,0xff)
+    (119,255,  0)     # rgb = (0x77,0xff,0x00)
+    (255,  0,  0)     # rgb = (0xff,0x00,0x00) red1
+    (  0,255,153)     # rgb = (0x00,0xff,0x99)
+    (221,255,  0)     # rgb = (0xdd,0xff,0x00)
+    (255,  0,187)     # rgb = (0xff,0x00,0xbb)
+    (255,187,  0)     # rgb = (0xff,0xbb,0x00)
+    (  0, 68,255)     # rgb = (0x00,0x44,0xff)
+    (  0,255, 68)     # rgb = (0x00,0xff,0x44)
+}
+IMAGE {
+    pixels hex
+88885555ccccaaaa77773333eeee9999
+88885555ccccaaaa77773333eeee9999
+88885555ccccaaaa77773333eeee9999
+88885555ccccaaaa77773333eeee9999
+5555ccccaaaa77773333eeee99991111
+5555ccccaaaa77773333eeee99991111
+5555ccccaaaa77773333eeee99991111
+5555ccccaaaa77773333eeee99991111
+ccccaaaa77773333eeee999911114444
+ccccaaaa77773333eeee999911114444
+ccccaaaa77773333eeee999911114444
+ccccaaaa77773333eeee999911114444
+aaaa77773333eeee999911114444dddd
+aaaa77773333eeee999911114444dddd
+aaaa77773333eeee999911114444dddd
+aaaa77773333eeee999911114444dddd
+77773333eeee999911114444dddd0000
+77773333eeee999911114444dddd0000
+77773333eeee999911114444dddd0000
+77773333eeee999911114444dddd0000
+3333eeee999911114444dddd00002222
+3333eeee999911114444dddd00002222
+3333eeee999911114444dddd00002222
+3333eeee999911114444dddd00002222
+eeee999911114444dddd000022226666
+eeee999911114444dddd000022226666
+eeee999911114444dddd000022226666
+eeee999911114444dddd000022226666
+999911114444dddd000022226666bbbb
+999911114444dddd000022226666bbbb
+999911114444dddd000022226666bbbb
+999911114444dddd000022226666bbbb
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn3p08.png b/libgo/go/image/png/testdata/pngsuite/basn3p08.png
new file mode 100644
index 000000000..0e07f483c
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn3p08.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn3p08.sng b/libgo/go/image/png/testdata/pngsuite/basn3p08.sng
new file mode 100644
index 000000000..0423bb21e
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn3p08.sng
@@ -0,0 +1,299 @@
+#SNG: from basn3p08.png
+IHDR {
+    width: 32; height: 32; bitdepth: 8;
+    using color palette;
+}
+gAMA {1.0000}
+PLTE {
+    ( 34, 68,  0)     # rgb = (0x22,0x44,0x00)
+    (245,255,237)     # rgb = (0xf5,0xff,0xed)
+    (119,255,119)     # rgb = (0x77,0xff,0x77)
+    (203,255,255)     # rgb = (0xcb,0xff,0xff)
+    ( 17, 10,  0)     # rgb = (0x11,0x0a,0x00)
+    ( 58,119,  0)     # rgb = (0x3a,0x77,0x00)
+    ( 34, 34,255)     # rgb = (0x22,0x22,0xff)
+    (255, 17,255)     # rgb = (0xff,0x11,0xff)
+    ( 17,  0,  0)     # rgb = (0x11,0x00,0x00)
+    ( 34, 34,  0)     # rgb = (0x22,0x22,0x00)
+    (255,172, 85)     # rgb = (0xff,0xac,0x55)
+    (102,255,102)     # rgb = (0x66,0xff,0x66)
+    (255,102,102)     # rgb = (0xff,0x66,0x66)
+    (255,  1,255)     # rgb = (0xff,0x01,0xff)
+    ( 34, 18,  0)     # rgb = (0x22,0x12,0x00)
+    (220,255,255)     # rgb = (0xdc,0xff,0xff)
+    (204,255,153)     # rgb = (0xcc,0xff,0x99)
+    ( 68, 68,255)     # rgb = (0x44,0x44,0xff)
+    (  0, 85, 85)     # rgb = (0x00,0x55,0x55)
+    ( 34,  0,  0)     # rgb = (0x22,0x00,0x00)
+    (203,203,255)     # rgb = (0xcb,0xcb,0xff)
+    ( 68, 68,  0)     # rgb = (0x44,0x44,0x00)
+    ( 85,255, 85)     # rgb = (0x55,0xff,0x55)
+    (203,203,  0)     # rgb = (0xcb,0xcb,0x00)
+    ( 51, 26,  0)     # rgb = (0x33,0x1a,0x00)
+    (255,236,220)     # rgb = (0xff,0xec,0xdc)
+    (237,255,255)     # rgb = (0xed,0xff,0xff)
+    (228,255,203)     # rgb = (0xe4,0xff,0xcb)
+    (255,220,220)     # rgb = (0xff,0xdc,0xdc)
+    ( 68,255, 68)     # rgb = (0x44,0xff,0x44)
+    (102,102,255)     # rgb = (0x66,0x66,0xff)
+    ( 51,  0,  0)     # rgb = (0x33,0x00,0x00)
+    ( 68, 34,  0)     # rgb = (0x44,0x22,0x00)
+    (237,237,255)     # rgb = (0xed,0xed,0xff)
+    (102,102,  0)     # rgb = (0x66,0x66,0x00)
+    (255,164, 68)     # rgb = (0xff,0xa4,0x44)
+    (255,255,170)     # rgb = (0xff,0xff,0xaa)
+    (237,237,  0)     # rgb = (0xed,0xed,0x00)
+    (  0,203,203)     # rgb = (0x00,0xcb,0xcb)
+    (254,255,255)     # rgb = (0xfe,0xff,0xff)
+    (253,255,254)     # rgb = (0xfd,0xff,0xfe)
+    (255,255,  1)     # rgb = (0xff,0xff,0x01)
+    ( 51,255, 51)     # rgb = (0x33,0xff,0x33)
+    ( 85, 42,  0)     # rgb = (0x55,0x2a,0x00)
+    (  1,  1,255)     # rgb = (0x01,0x01,0xff)
+    (136,136,255)     # rgb = (0x88,0x88,0xff)
+    (  0,170,170)     # rgb = (0x00,0xaa,0xaa)
+    (  1,  1,  0)     # rgb = (0x01,0x01,0x00)
+    ( 68,  0,  0)     # rgb = (0x44,0x00,0x00)
+    (136,136,  0)     # rgb = (0x88,0x88,0x00)
+    (255,228,203)     # rgb = (0xff,0xe4,0xcb)
+    (186, 91,  0)     # rgb = (0xba,0x5b,0x00)
+    ( 34,255, 34)     # rgb = (0x22,0xff,0x22)
+    (102, 50,  0)     # rgb = (0x66,0x32,0x00)
+    (255,255,153)     # rgb = (0xff,0xff,0x99)
+    (170,170,255)     # rgb = (0xaa,0xaa,0xff)
+    ( 85,  0,  0)     # rgb = (0x55,0x00,0x00)
+    (170,170,  0)     # rgb = (0xaa,0xaa,0x00)
+    (203, 99,  0)     # rgb = (0xcb,0x63,0x00)
+    ( 17,255, 17)     # rgb = (0x11,0xff,0x11)
+    (212,255,170)     # rgb = (0xd4,0xff,0xaa)
+    (119, 58,  0)     # rgb = (0x77,0x3a,0x00)
+    (255, 68, 68)     # rgb = (0xff,0x44,0x44)
+    (220,107,  0)     # rgb = (0xdc,0x6b,0x00)
+    (102,  0,  0)     # rgb = (0x66,0x00,0x00)
+    (  1,255,  1)     # rgb = (0x01,0xff,0x01)
+    (136, 66,  0)     # rgb = (0x88,0x42,0x00)
+    (236,255,220)     # rgb = (0xec,0xff,0xdc)
+    (107,220,  0)     # rgb = (0x6b,0xdc,0x00)
+    (255,220,186)     # rgb = (0xff,0xdc,0xba)
+    (  0, 51, 51)     # rgb = (0x00,0x33,0x33)
+    (  0,237,  0)     # rgb = (0x00,0xed,0x00)
+    (237,115,  0)     # rgb = (0xed,0x73,0x00)
+    (255,255,136)     # rgb = (0xff,0xff,0x88)
+    (153, 74,  0)     # rgb = (0x99,0x4a,0x00)
+    ( 17,255,255)     # rgb = (0x11,0xff,0xff)
+    (119,  0,  0)     # rgb = (0x77,0x00,0x00)
+    (255,131,  1)     # rgb = (0xff,0x83,0x01)
+    (255,186,186)     # rgb = (0xff,0xba,0xba)
+    (254,123,  0)     # rgb = (0xfe,0x7b,0x00)
+    (255,254,255)     # rgb = (0xff,0xfe,0xff)
+    (  0,203,  0)     # rgb = (0x00,0xcb,0x00)
+    (255,153,153)     # rgb = (0xff,0x99,0x99)
+    ( 34,255,255)     # rgb = (0x22,0xff,0xff)
+    (136,  0,  0)     # rgb = (0x88,0x00,0x00)
+    (255,255,119)     # rgb = (0xff,0xff,0x77)
+    (  0,136,136)     # rgb = (0x00,0x88,0x88)
+    (255,220,255)     # rgb = (0xff,0xdc,0xff)
+    ( 26, 51,  0)     # rgb = (0x1a,0x33,0x00)
+    (  0,  0,170)     # rgb = (0x00,0x00,0xaa)
+    ( 51,255,255)     # rgb = (0x33,0xff,0xff)
+    (  0,153,  0)     # rgb = (0x00,0x99,0x00)
+    (153,  0,  0)     # rgb = (0x99,0x00,0x00)
+    (  0,  0,  1)     # rgb = (0x00,0x00,0x01)
+    ( 50,102,  0)     # rgb = (0x32,0x66,0x00)
+    (255,186,255)     # rgb = (0xff,0xba,0xff)
+    ( 68,255,255)     # rgb = (0x44,0xff,0xff)
+    (255,170,255)     # rgb = (0xff,0xaa,0xff)
+    (  0,119,  0)     # rgb = (0x00,0x77,0x00)
+    (  0,254,254)     # rgb = (0x00,0xfe,0xfe)
+    (170,  0,  0)     # rgb = (0xaa,0x00,0x00)
+    ( 74,153,  0)     # rgb = (0x4a,0x99,0x00)
+    (255,255,102)     # rgb = (0xff,0xff,0x66)
+    (255, 34, 34)     # rgb = (0xff,0x22,0x22)
+    (  0,  0,153)     # rgb = (0x00,0x00,0x99)
+    (139,255, 17)     # rgb = (0x8b,0xff,0x11)
+    ( 85,255,255)     # rgb = (0x55,0xff,0xff)
+    (255,  1,  1)     # rgb = (0xff,0x01,0x01)
+    (255,136,255)     # rgb = (0xff,0x88,0xff)
+    (  0, 85,  0)     # rgb = (0x00,0x55,0x00)
+    (  0, 17, 17)     # rgb = (0x00,0x11,0x11)
+    (255,255,254)     # rgb = (0xff,0xff,0xfe)
+    (255,253,254)     # rgb = (0xff,0xfd,0xfe)
+    (164,255, 68)     # rgb = (0xa4,0xff,0x44)
+    (102,255,255)     # rgb = (0x66,0xff,0xff)
+    (255,102,255)     # rgb = (0xff,0x66,0xff)
+    (  0, 51,  0)     # rgb = (0x00,0x33,0x00)
+    (255,255, 85)     # rgb = (0xff,0xff,0x55)
+    (255,119,119)     # rgb = (0xff,0x77,0x77)
+    (  0,  0,136)     # rgb = (0x00,0x00,0x88)
+    (255, 68,255)     # rgb = (0xff,0x44,0xff)
+    (  0, 17,  0)     # rgb = (0x00,0x11,0x00)
+    (119,255,255)     # rgb = (0x77,0xff,0xff)
+    (  0,102,102)     # rgb = (0x00,0x66,0x66)
+    (255,255,237)     # rgb = (0xff,0xff,0xed)
+    (  0,  1,  0)     # rgb = (0x00,0x01,0x00)
+    (255,245,237)     # rgb = (0xff,0xf5,0xed)
+    ( 17, 17,255)     # rgb = (0x11,0x11,0xff)
+    (255,255, 68)     # rgb = (0xff,0xff,0x44)
+    (255, 34,255)     # rgb = (0xff,0x22,0xff)
+    (255,237,237)     # rgb = (0xff,0xed,0xed)
+    ( 17, 17,  0)     # rgb = (0x11,0x11,0x00)
+    (136,255,255)     # rgb = (0x88,0xff,0xff)
+    (  0,  0,119)     # rgb = (0x00,0x00,0x77)
+    (147,255, 34)     # rgb = (0x93,0xff,0x22)
+    (  0,220,220)     # rgb = (0x00,0xdc,0xdc)
+    ( 51, 51,255)     # rgb = (0x33,0x33,0xff)
+    (254,  0,254)     # rgb = (0xfe,0x00,0xfe)
+    (186,186,255)     # rgb = (0xba,0xba,0xff)
+    (153,255,255)     # rgb = (0x99,0xff,0xff)
+    ( 51, 51,  0)     # rgb = (0x33,0x33,0x00)
+    ( 99,203,  0)     # rgb = (0x63,0xcb,0x00)
+    (186,186,  0)     # rgb = (0xba,0xba,0x00)
+    (172,255, 85)     # rgb = (0xac,0xff,0x55)
+    (255,255,220)     # rgb = (0xff,0xff,0xdc)
+    (255,255, 51)     # rgb = (0xff,0xff,0x33)
+    (123,254,  0)     # rgb = (0x7b,0xfe,0x00)
+    (237,  0,237)     # rgb = (0xed,0x00,0xed)
+    ( 85, 85,255)     # rgb = (0x55,0x55,0xff)
+    (170,255,255)     # rgb = (0xaa,0xff,0xff)
+    (220,220,255)     # rgb = (0xdc,0xdc,0xff)
+    ( 85, 85,  0)     # rgb = (0x55,0x55,0x00)
+    (  0,  0,102)     # rgb = (0x00,0x00,0x66)
+    (220,220,  0)     # rgb = (0xdc,0xdc,0x00)
+    (220,  0,220)     # rgb = (0xdc,0x00,0xdc)
+    (131,255,  1)     # rgb = (0x83,0xff,0x01)
+    (119,119,255)     # rgb = (0x77,0x77,0xff)
+    (254,254,255)     # rgb = (0xfe,0xfe,0xff)
+    (255,255,203)     # rgb = (0xff,0xff,0xcb)
+    (255, 85, 85)     # rgb = (0xff,0x55,0x55)
+    (119,119,  0)     # rgb = (0x77,0x77,0x00)
+    (254,254,  0)     # rgb = (0xfe,0xfe,0x00)
+    (203,  0,203)     # rgb = (0xcb,0x00,0xcb)
+    (  0,  0,254)     # rgb = (0x00,0x00,0xfe)
+    (  1,  2,  0)     # rgb = (0x01,0x02,0x00)
+    (  1,  0,  0)     # rgb = (0x01,0x00,0x00)
+    ( 18, 34,  0)     # rgb = (0x12,0x22,0x00)
+    (255,255, 34)     # rgb = (0xff,0xff,0x22)
+    (  0, 68, 68)     # rgb = (0x00,0x44,0x44)
+    (155,255, 51)     # rgb = (0x9b,0xff,0x33)
+    (255,212,170)     # rgb = (0xff,0xd4,0xaa)
+    (  0,  0, 85)     # rgb = (0x00,0x00,0x55)
+    (153,153,255)     # rgb = (0x99,0x99,0xff)
+    (153,153,  0)     # rgb = (0x99,0x99,0x00)
+    (186,  0,186)     # rgb = (0xba,0x00,0xba)
+    ( 42, 85,  0)     # rgb = (0x2a,0x55,0x00)
+    (255,203,203)     # rgb = (0xff,0xcb,0xcb)
+    (180,255,102)     # rgb = (0xb4,0xff,0x66)
+    (255,155, 51)     # rgb = (0xff,0x9b,0x33)
+    (255,255,186)     # rgb = (0xff,0xff,0xba)
+    (170,  0,170)     # rgb = (0xaa,0x00,0xaa)
+    ( 66,136,  0)     # rgb = (0x42,0x88,0x00)
+    ( 83,170,  0)     # rgb = (0x53,0xaa,0x00)
+    (255,170,170)     # rgb = (0xff,0xaa,0xaa)
+    (  0,  0,237)     # rgb = (0x00,0x00,0xed)
+    (  0,186,186)     # rgb = (0x00,0xba,0xba)
+    (255,255, 17)     # rgb = (0xff,0xff,0x11)
+    (  0,254,  0)     # rgb = (0x00,0xfe,0x00)
+    (  0,  0, 68)     # rgb = (0x00,0x00,0x44)
+    (  0,153,153)     # rgb = (0x00,0x99,0x99)
+    (153,  0,153)     # rgb = (0x99,0x00,0x99)
+    (255,204,153)     # rgb = (0xff,0xcc,0x99)
+    (186,  0,  0)     # rgb = (0xba,0x00,0x00)
+    (136,  0,136)     # rgb = (0x88,0x00,0x88)
+    (  0,220,  0)     # rgb = (0x00,0xdc,0x00)
+    (255,147, 34)     # rgb = (0xff,0x93,0x22)
+    (  0,  0,220)     # rgb = (0x00,0x00,0xdc)
+    (254,255,254)     # rgb = (0xfe,0xff,0xfe)
+    (170, 83,  0)     # rgb = (0xaa,0x53,0x00)
+    (119,  0,119)     # rgb = (0x77,0x00,0x77)
+    (  2,  1,  0)     # rgb = (0x02,0x01,0x00)
+    (203,  0,  0)     # rgb = (0xcb,0x00,0x00)
+    (  0,  0, 51)     # rgb = (0x00,0x00,0x33)
+    (255,237,255)     # rgb = (0xff,0xed,0xff)
+    (  0,186,  0)     # rgb = (0x00,0xba,0x00)
+    (255, 51, 51)     # rgb = (0xff,0x33,0x33)
+    (237,255,237)     # rgb = (0xed,0xff,0xed)
+    (255,196,136)     # rgb = (0xff,0xc4,0x88)
+    (188,255,119)     # rgb = (0xbc,0xff,0x77)
+    (  0,170,  0)     # rgb = (0x00,0xaa,0x00)
+    (102,  0,102)     # rgb = (0x66,0x00,0x66)
+    (  0, 34, 34)     # rgb = (0x00,0x22,0x22)
+    (220,  0,  0)     # rgb = (0xdc,0x00,0x00)
+    (255,203,255)     # rgb = (0xff,0xcb,0xff)
+    (220,255,220)     # rgb = (0xdc,0xff,0xdc)
+    (255,139, 17)     # rgb = (0xff,0x8b,0x11)
+    (  0,  0,203)     # rgb = (0x00,0x00,0xcb)
+    (  0,  1,  1)     # rgb = (0x00,0x01,0x01)
+    ( 85,  0, 85)     # rgb = (0x55,0x00,0x55)
+    (  0,136,  0)     # rgb = (0x00,0x88,0x00)
+    (  0,  0, 34)     # rgb = (0x00,0x00,0x22)
+    (  1,255,255)     # rgb = (0x01,0xff,0xff)
+    (203,255,203)     # rgb = (0xcb,0xff,0xcb)
+    (237,  0,  0)     # rgb = (0xed,0x00,0x00)
+    (255,136,136)     # rgb = (0xff,0x88,0x88)
+    ( 68,  0, 68)     # rgb = (0x44,0x00,0x44)
+    ( 91,186,  0)     # rgb = (0x5b,0xba,0x00)
+    (255,188,119)     # rgb = (0xff,0xbc,0x77)
+    (255,153,255)     # rgb = (0xff,0x99,0xff)
+    (  0,102,  0)     # rgb = (0x00,0x66,0x00)
+    (186,255,186)     # rgb = (0xba,0xff,0xba)
+    (  0,119,119)     # rgb = (0x00,0x77,0x77)
+    (115,237,  0)     # rgb = (0x73,0xed,0x00)
+    (254,  0,  0)     # rgb = (0xfe,0x00,0x00)
+    ( 51,  0, 51)     # rgb = (0x33,0x00,0x33)
+    (  0,  0,186)     # rgb = (0x00,0x00,0xba)
+    (255,119,255)     # rgb = (0xff,0x77,0xff)
+    (  0, 68,  0)     # rgb = (0x00,0x44,0x00)
+    (170,255,170)     # rgb = (0xaa,0xff,0xaa)
+    (255,254,254)     # rgb = (0xff,0xfe,0xfe)
+    (  0,  0, 17)     # rgb = (0x00,0x00,0x11)
+    ( 34,  0, 34)     # rgb = (0x22,0x00,0x22)
+    (196,255,136)     # rgb = (0xc4,0xff,0x88)
+    (  0,237,237)     # rgb = (0x00,0xed,0xed)
+    (153,255,153)     # rgb = (0x99,0xff,0x99)
+    (255, 85,255)     # rgb = (0xff,0x55,0xff)
+    (  0, 34,  0)     # rgb = (0x00,0x22,0x00)
+    (255,180,102)     # rgb = (0xff,0xb4,0x66)
+    ( 17,  0, 17)     # rgb = (0x11,0x00,0x11)
+    ( 10, 17,  0)     # rgb = (0x0a,0x11,0x00)
+    (255, 17, 17)     # rgb = (0xff,0x11,0x11)
+    (220,255,186)     # rgb = (0xdc,0xff,0xba)
+    (186,255,255)     # rgb = (0xba,0xff,0xff)
+    (136,255,136)     # rgb = (0x88,0xff,0x88)
+    (  1,  0,  1)     # rgb = (0x01,0x00,0x01)
+    (255, 51,255)     # rgb = (0xff,0x33,0xff)
+}
+IMAGE {
+    pixels hex
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+64646464c6c6c6c639393939b6b6b6b6d1d1d1d12e2e2e2e59595959b4b4b4b4
+c0c0c0c0333333338e8e8e8ee2e2e2e2ccccccccb9b9b9b9ebebebebaeaeaeae
+c9c9c9c93a3a3a3a171717178d8d8d8d5151515126262626d8d8d8d8a2a2a2a2
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+efefefef707070706f6f6f6f28282828c5c5c5c5272727279d9d9d9d50505050
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn4a08.png b/libgo/go/image/png/testdata/pngsuite/basn4a08.png
new file mode 100644
index 000000000..3bb0dd06b
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn4a08.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn4a08.sng b/libgo/go/image/png/testdata/pngsuite/basn4a08.sng
new file mode 100644
index 000000000..b760382a0
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn4a08.sng
@@ -0,0 +1,41 @@
+#SNG: from basn4a08.png
+IHDR {
+    width: 32; height: 32; bitdepth: 8;
+    using grayscale alpha;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
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+0000 0008 0010 0018 0020 0029 0031 0039 0041 004a 0052 005a 0062 006a 0073 007b 0083 008b 0094 009c 00a4 00ac 00b4 00bd 00c5 00cd 00d5 00de 00e6 00ee 00f6 00ff 
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn4a16.png b/libgo/go/image/png/testdata/pngsuite/basn4a16.png
new file mode 100644
index 000000000..6dbee9fbd
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn4a16.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn4a16.sng b/libgo/go/image/png/testdata/pngsuite/basn4a16.sng
new file mode 100644
index 000000000..d3b9b4722
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn4a16.sng
@@ -0,0 +1,41 @@
+#SNG: from basn4a16.png
+IHDR {
+    width: 32; height: 32; bitdepth: 16;
+    using grayscale alpha;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
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+63180000 58461085 4bd92109 3d70318d 2c854211 18615295 00006319 1af26319 35e46319 50d76319 6bc96319 86bc6319 a1ae6319 bca06319 d7936319 f2856319 f2856319 d7936319 bca06319 a1ae6319 86bc6319 6bc96319 50d76319 35e46319 1af26319 00006319 18615295 2c854211 3d70318d 4bd92109 58461085 63180000 
+52940000 469e1085 38e32109 28f5318d 16424211 00005295 18615295 30c25295 49245295 61855295 79e75295 92485295 aaa95295 c30b5295 db6c5295 f3ce5295 f3ce5295 db6c5295 c30b5295 aaa95295 92485295 79e75295 61855295 49245295 30c25295 18615295 00005295 16424211 28f5318d 38e32109 469e1085 52940000 
+42100000 34f61085 25ec2109 147a318d 00004211 16424211 2c854211 42c84211 590a4211 6f4d4211 85904211 9bd24211 b2154211 c8584211 de9a4211 f4dd4211 f4dd4211 de9a4211 c8584211 b2154211 9bd24211 85904211 6f4d4211 590a4211 42c84211 2c854211 16424211 00004211 147a318d 25ec2109 34f61085 42100000 
+318c0000 234f1085 12f62109 0000318d 147a318d 28f5318d 3d70318d 51eb318d 6665318d 7ae0318d 8f5b318d a3d6318d b851318d cccb318d e146318d f5c1318d f5c1318d e146318d cccb318d b851318d a3d6318d 8f5b318d 7ae0318d 6665318d 51eb318d 3d70318d 28f5318d 147a318d 0000318d 12f62109 234f1085 318c0000 
+21080000 11a71085 00002109 12f62109 25ec2109 38e32109 4bd92109 5ed02109 71c62109 84bd2109 97b32109 aaa92109 bda02109 d0962109 e38d2109 f6832109 f6832109 e38d2109 d0962109 bda02109 aaa92109 97b32109 84bd2109 71c62109 5ed02109 4bd92109 38e32109 25ec2109 12f62109 00002109 11a71085 21080000 
+10840000 00001085 11a71085 234f1085 34f61085 469e1085 58461085 69ed1085 7b951085 8d3d1085 9ee41085 b08c1085 c2341085 d3db1085 e5831085 f72b1085 f72b1085 e5831085 d3db1085 c2341085 b08c1085 9ee41085 8d3d1085 7b951085 69ed1085 58461085 469e1085 34f61085 234f1085 11a71085 00001085 10840000 
+00000000 10840000 21080000 318c0000 42100000 52940000 63180000 739c0000 84200000 94a40000 a5280000 b5ac0000 c6300000 d6b40000 e7380000 f7bc0000 f7bc0000 e7380000 d6b40000 c6300000 b5ac0000 a5280000 94a40000 84200000 739c0000 63180000 52940000 42100000 318c0000 21080000 10840000 00000000 
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn6a08.png b/libgo/go/image/png/testdata/pngsuite/basn6a08.png
new file mode 100644
index 000000000..610623085
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn6a08.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn6a08.sng b/libgo/go/image/png/testdata/pngsuite/basn6a08.sng
new file mode 100644
index 000000000..c1e0bf475
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn6a08.sng
@@ -0,0 +1,41 @@
+#SNG: from basn6a08.png
+IHDR {
+    width: 32; height: 32; bitdepth: 8;
+    using color alpha;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
+ff000800 ff000808 ff000810 ff000818 ff000820 ff000829 ff000831 ff000839 ff000841 ff00084a ff000852 ff00085a ff000862 ff00086a ff000873 ff00087b ff000883 ff00088b ff000894 ff00089c ff0008a4 ff0008ac ff0008b4 ff0008bd ff0008c5 ff0008cd ff0008d5 ff0008de ff0008e6 ff0008ee ff0008f6 ff0008ff 
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+a0ff0500 a0ff0508 a0ff0510 a0ff0518 a0ff0520 a0ff0529 a0ff0531 a0ff0539 a0ff0541 a0ff054a a0ff0552 a0ff055a a0ff0562 a0ff056a a0ff0573 a0ff057b a0ff0583 a0ff058b a0ff0594 a0ff059c a0ff05a4 a0ff05ac a0ff05b4 a0ff05bd a0ff05c5 a0ff05cd a0ff05d5 a0ff05de a0ff05e6 a0ff05ee a0ff05f6 a0ff05ff 
+80ff0500 80ff0508 80ff0510 80ff0518 80ff0520 80ff0529 80ff0531 80ff0539 80ff0541 80ff054a 80ff0552 80ff055a 80ff0562 80ff056a 80ff0573 80ff057b 80ff0583 80ff058b 80ff0594 80ff059c 80ff05a4 80ff05ac 80ff05b4 80ff05bd 80ff05c5 80ff05cd 80ff05d5 80ff05de 80ff05e6 80ff05ee 80ff05f6 80ff05ff 
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+03ff7f00 03ff7f08 03ff7f10 03ff7f18 03ff7f20 03ff7f29 03ff7f31 03ff7f39 03ff7f41 03ff7f4a 03ff7f52 03ff7f5a 03ff7f62 03ff7f6a 03ff7f73 03ff7f7b 03ff7f83 03ff7f8b 03ff7f94 03ff7f9c 03ff7fa4 03ff7fac 03ff7fb4 03ff7fbd 03ff7fc5 03ff7fcd 03ff7fd5 03ff7fde 03ff7fe6 03ff7fee 03ff7ff6 03ff7fff 
+03ff9f00 03ff9f08 03ff9f10 03ff9f18 03ff9f20 03ff9f29 03ff9f31 03ff9f39 03ff9f41 03ff9f4a 03ff9f52 03ff9f5a 03ff9f62 03ff9f6a 03ff9f73 03ff9f7b 03ff9f83 03ff9f8b 03ff9f94 03ff9f9c 03ff9fa4 03ff9fac 03ff9fb4 03ff9fbd 03ff9fc5 03ff9fcd 03ff9fd5 03ff9fde 03ff9fe6 03ff9fee 03ff9ff6 03ff9fff 
+02ffbf00 02ffbf08 02ffbf10 02ffbf18 02ffbf20 02ffbf29 02ffbf31 02ffbf39 02ffbf41 02ffbf4a 02ffbf52 02ffbf5a 02ffbf62 02ffbf6a 02ffbf73 02ffbf7b 02ffbf83 02ffbf8b 02ffbf94 02ffbf9c 02ffbfa4 02ffbfac 02ffbfb4 02ffbfbd 02ffbfc5 02ffbfcd 02ffbfd5 02ffbfde 02ffbfe6 02ffbfee 02ffbff6 02ffbfff 
+02ffdf00 02ffdf08 02ffdf10 02ffdf18 02ffdf20 02ffdf29 02ffdf31 02ffdf39 02ffdf41 02ffdf4a 02ffdf52 02ffdf5a 02ffdf62 02ffdf6a 02ffdf73 02ffdf7b 02ffdf83 02ffdf8b 02ffdf94 02ffdf9c 02ffdfa4 02ffdfac 02ffdfb4 02ffdfbd 02ffdfc5 02ffdfcd 02ffdfd5 02ffdfde 02ffdfe6 02ffdfee 02ffdff6 02ffdfff 
+02ffff00 02ffff08 02ffff10 02ffff18 02ffff20 02ffff29 02ffff31 02ffff39 02ffff41 02ffff4a 02ffff52 02ffff5a 02ffff62 02ffff6a 02ffff73 02ffff7b 02ffff83 02ffff8b 02ffff94 02ffff9c 02ffffa4 02ffffac 02ffffb4 02ffffbd 02ffffc5 02ffffcd 02ffffd5 02ffffde 02ffffe6 02ffffee 02fffff6 02ffffff 
+01e0ff00 01e0ff08 01e0ff10 01e0ff18 01e0ff20 01e0ff29 01e0ff31 01e0ff39 01e0ff41 01e0ff4a 01e0ff52 01e0ff5a 01e0ff62 01e0ff6a 01e0ff73 01e0ff7b 01e0ff83 01e0ff8b 01e0ff94 01e0ff9c 01e0ffa4 01e0ffac 01e0ffb4 01e0ffbd 01e0ffc5 01e0ffcd 01e0ffd5 01e0ffde 01e0ffe6 01e0ffee 01e0fff6 01e0ffff 
+01c0ff00 01c0ff08 01c0ff10 01c0ff18 01c0ff20 01c0ff29 01c0ff31 01c0ff39 01c0ff41 01c0ff4a 01c0ff52 01c0ff5a 01c0ff62 01c0ff6a 01c0ff73 01c0ff7b 01c0ff83 01c0ff8b 01c0ff94 01c0ff9c 01c0ffa4 01c0ffac 01c0ffb4 01c0ffbd 01c0ffc5 01c0ffcd 01c0ffd5 01c0ffde 01c0ffe6 01c0ffee 01c0fff6 01c0ffff 
+01a0ff00 01a0ff08 01a0ff10 01a0ff18 01a0ff20 01a0ff29 01a0ff31 01a0ff39 01a0ff41 01a0ff4a 01a0ff52 01a0ff5a 01a0ff62 01a0ff6a 01a0ff73 01a0ff7b 01a0ff83 01a0ff8b 01a0ff94 01a0ff9c 01a0ffa4 01a0ffac 01a0ffb4 01a0ffbd 01a0ffc5 01a0ffcd 01a0ffd5 01a0ffde 01a0ffe6 01a0ffee 01a0fff6 01a0ffff 
+0180ff00 0180ff08 0180ff10 0180ff18 0180ff20 0180ff29 0180ff31 0180ff39 0180ff41 0180ff4a 0180ff52 0180ff5a 0180ff62 0180ff6a 0180ff73 0180ff7b 0180ff83 0180ff8b 0180ff94 0180ff9c 0180ffa4 0180ffac 0180ffb4 0180ffbd 0180ffc5 0180ffcd 0180ffd5 0180ffde 0180ffe6 0180ffee 0180fff6 0180ffff 
+0060ff00 0060ff08 0060ff10 0060ff18 0060ff20 0060ff29 0060ff31 0060ff39 0060ff41 0060ff4a 0060ff52 0060ff5a 0060ff62 0060ff6a 0060ff73 0060ff7b 0060ff83 0060ff8b 0060ff94 0060ff9c 0060ffa4 0060ffac 0060ffb4 0060ffbd 0060ffc5 0060ffcd 0060ffd5 0060ffde 0060ffe6 0060ffee 0060fff6 0060ffff 
+0040ff00 0040ff08 0040ff10 0040ff18 0040ff20 0040ff29 0040ff31 0040ff39 0040ff41 0040ff4a 0040ff52 0040ff5a 0040ff62 0040ff6a 0040ff73 0040ff7b 0040ff83 0040ff8b 0040ff94 0040ff9c 0040ffa4 0040ffac 0040ffb4 0040ffbd 0040ffc5 0040ffcd 0040ffd5 0040ffde 0040ffe6 0040ffee 0040fff6 0040ffff 
+0020ff00 0020ff08 0020ff10 0020ff18 0020ff20 0020ff29 0020ff31 0020ff39 0020ff41 0020ff4a 0020ff52 0020ff5a 0020ff62 0020ff6a 0020ff73 0020ff7b 0020ff83 0020ff8b 0020ff94 0020ff9c 0020ffa4 0020ffac 0020ffb4 0020ffbd 0020ffc5 0020ffcd 0020ffd5 0020ffde 0020ffe6 0020ffee 0020fff6 0020ffff 
+}
diff --git a/libgo/go/image/png/testdata/pngsuite/basn6a16.png b/libgo/go/image/png/testdata/pngsuite/basn6a16.png
new file mode 100644
index 000000000..a9bf3cb46
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn6a16.png
diff --git a/libgo/go/image/png/testdata/pngsuite/basn6a16.sng b/libgo/go/image/png/testdata/pngsuite/basn6a16.sng
new file mode 100644
index 000000000..13c70a4d5
--- /dev/null
+++ b/libgo/go/image/png/testdata/pngsuite/basn6a16.sng
@@ -0,0 +1,41 @@
+#SNG: from basn6a16.png
+IHDR {
+    width: 32; height: 32; bitdepth: 16;
+    using color alpha;
+}
+gAMA {1.0000}
+IMAGE {
+    pixels hex
+ffffffff00000000 f7bcffff00000000 ef7affff00000000 e738ffff00000000 def6ffff00000000 d6b4ffff00000000 ce72ffff00000000 c630ffff00000000 bdeeffff00000000 b5acffff00000000 ad6affff00000000 a528ffff00000000 9ce6ffff00000000 94a4ffff00000000 8c62ffff00000000 8420ffff00000000 7bdeffff00000000 739cffff00000000 6b5affff00000000 6318ffff00000000 5ad6ffff00000000 5294ffff00000000 4a52ffff00000000 4210ffff00000000 39ceffff00000000 318cffff00000000 294affff00000000 2108ffff00000000 18c6ffff00000000 1084ffff00000000 0842ffff00000000 0000ffff00000000 
+fffff7bc00000000 ffffffff00001085 f72bffff00001085 ee57ffff00001085 e583ffff00001085 dcafffff00001085 d3dbffff00001085 cb08ffff00001085 c234ffff00001085 b960ffff00001085 b08cffff00001085 a7b8ffff00001085 9ee4ffff00001085 9611ffff00001085 8d3dffff00001085 8469ffff00001085 7b95ffff00001085 72c1ffff00001085 69edffff00001085 611affff00001085 5846ffff00001085 4f72ffff00001085 469effff00001085 3dcaffff00001085 34f6ffff00001085 2c23ffff00001085 234fffff00001085 1a7bffff00001085 11a7ffff00001085 08d3ffff00001085 0000ffff00001085 0000f7bc08420000 
+ffffef7a00000000 fffff72b00001085 ffffffff00002109 f683ffff00002109 ed08ffff00002109 e38dffff00002109 da12ffff00002109 d096ffff00002109 c71bffff00002109 bda0ffff00002109 b425ffff00002109 aaa9ffff00002109 a12effff00002109 97b3ffff00002109 8e38ffff00002109 84bdffff00002109 7b41ffff00002109 71c6ffff00002109 684bffff00002109 5ed0ffff00002109 5554ffff00002109 4bd9ffff00002109 425effff00002109 38e3ffff00002109 2f68ffff00002109 25ecffff00002109 1c71ffff00002109 12f6ffff00002109 097bffff00002109 0000ffff00002109 0000f72b08d31085 0000ef7a10840000 
+ffffe73800000000 ffffee5700001085 fffff68300002109 ffffffff0000318d f5c1ffff0000318d eb84ffff0000318d e146ffff0000318d d709ffff0000318d ccccffff0000318d c28effff0000318d b851ffff0000318d ae13ffff0000318d a3d6ffff0000318d 9998ffff0000318d 8f5bffff0000318d 851effff0000318d 7ae0ffff0000318d 70a3ffff0000318d 6665ffff0000318d 5c28ffff0000318d 51ebffff0000318d 47adffff0000318d 3d70ffff0000318d 3332ffff0000318d 28f5ffff0000318d 1eb8ffff0000318d 147affff0000318d 0a3dffff0000318d 0000ffff0000318d 0000f683097b2109 0000ee5711a71085 0000e73818c60000 
+ffffdef600000000 ffffe58300001085 ffffed0800002109 fffff5c10000318d ffffffff00004211 f4ddffff00004211 e9bcffff00004211 de9affff00004211 d379ffff00004211 c858ffff00004211 bd36ffff00004211 b215ffff00004211 a6f4ffff00004211 9bd2ffff00004211 90b1ffff00004211 8590ffff00004211 7a6effff00004211 6f4dffff00004211 642cffff00004211 590affff00004211 4de9ffff00004211 42c8ffff00004211 37a6ffff00004211 2c85ffff00004211 2164ffff00004211 1642ffff00004211 0b21ffff00004211 0000ffff00004211 0000f5c10a3d318d 0000ed0812f62109 0000e5831a7b1085 0000def621080000 
+ffffd6b400000000 ffffdcaf00001085 ffffe38d00002109 ffffeb840000318d fffff4dd00004211 ffffffff00005295 f3ceffff00005295 e79dffff00005295 db6cffff00005295 cf3cffff00005295 c30bffff00005295 b6daffff00005295 aaa9ffff00005295 9e79ffff00005295 9248ffff00005295 8617ffff00005295 79e7ffff00005295 6db6ffff00005295 6185ffff00005295 5554ffff00005295 4924ffff00005295 3cf3ffff00005295 30c2ffff00005295 2492ffff00005295 1861ffff00005295 0c30ffff00005295 0000ffff00005295 0000f4dd0b214211 0000eb84147a318d 0000e38d1c712109 0000dcaf234f1085 0000d6b4294a0000 
+ffffce7200000000 ffffd3db00001085 ffffda1200002109 ffffe1460000318d ffffe9bc00004211 fffff3ce00005295 ffffffff00006319 f285ffff00006319 e50cffff00006319 d793ffff00006319 ca1affff00006319 bca0ffff00006319 af27ffff00006319 a1aeffff00006319 9435ffff00006319 86bcffff00006319 7942ffff00006319 6bc9ffff00006319 5e50ffff00006319 50d7ffff00006319 435effff00006319 35e4ffff00006319 286bffff00006319 1af2ffff00006319 0d79ffff00006319 0000ffff00006319 0000f3ce0c305295 0000e9bc16424211 0000e1461eb8318d 0000da1225ec2109 0000d3db2c231085 0000ce72318c0000 
+ffffc63000000000 ffffcb0800001085 ffffd09600002109 ffffd7090000318d ffffde9a00004211 ffffe79d00005295 fffff28500006319 ffffffff0000739d f0f0ffff0000739d e1e1ffff0000739d d2d2ffff0000739d c3c3ffff0000739d b4b3ffff0000739d a5a4ffff0000739d 9695ffff0000739d 8786ffff0000739d 7877ffff0000739d 6968ffff0000739d 5a59ffff0000739d 4b4affff0000739d 3c3bffff0000739d 2d2cffff0000739d 1e1dffff0000739d 0f0effff0000739d 0000ffff0000739d 0000f2850d796319 0000e79d18615295 0000de9a21644211 0000d70928f5318d 0000d0962f682109 0000cb0834f61085 0000c63039ce0000 
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+}
diff --git a/libgo/go/image/png/writer.go b/libgo/go/image/png/writer.go
new file mode 100644
index 000000000..081d06bf5
--- /dev/null
+++ b/libgo/go/image/png/writer.go
@@ -0,0 +1,437 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package png
+
+import (
+	"bufio"
+	"compress/zlib"
+	"hash/crc32"
+	"image"
+	"io"
+	"os"
+	"strconv"
+)
+
+type encoder struct {
+	w      io.Writer
+	m      image.Image
+	cb     int
+	err    os.Error
+	header [8]byte
+	footer [4]byte
+	tmp    [3 * 256]byte
+}
+
+// Big-endian.
+func writeUint32(b []uint8, u uint32) {
+	b[0] = uint8(u >> 24)
+	b[1] = uint8(u >> 16)
+	b[2] = uint8(u >> 8)
+	b[3] = uint8(u >> 0)
+}
+
+type opaquer interface {
+	Opaque() bool
+}
+
+// Returns whether or not the image is fully opaque.
+func opaque(m image.Image) bool {
+	if o, ok := m.(opaquer); ok {
+		return o.Opaque()
+	}
+	b := m.Bounds()
+	for y := b.Min.Y; y < b.Max.Y; y++ {
+		for x := b.Min.X; x < b.Max.X; x++ {
+			_, _, _, a := m.At(x, y).RGBA()
+			if a != 0xffff {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// The absolute value of a byte interpreted as a signed int8.
+func abs8(d uint8) int {
+	if d < 128 {
+		return int(d)
+	}
+	return 256 - int(d)
+}
+
+func (e *encoder) writeChunk(b []byte, name string) {
+	if e.err != nil {
+		return
+	}
+	n := uint32(len(b))
+	if int(n) != len(b) {
+		e.err = UnsupportedError(name + " chunk is too large: " + strconv.Itoa(len(b)))
+		return
+	}
+	writeUint32(e.header[0:4], n)
+	e.header[4] = name[0]
+	e.header[5] = name[1]
+	e.header[6] = name[2]
+	e.header[7] = name[3]
+	crc := crc32.NewIEEE()
+	crc.Write(e.header[4:8])
+	crc.Write(b)
+	writeUint32(e.footer[0:4], crc.Sum32())
+
+	_, e.err = e.w.Write(e.header[0:8])
+	if e.err != nil {
+		return
+	}
+	_, e.err = e.w.Write(b)
+	if e.err != nil {
+		return
+	}
+	_, e.err = e.w.Write(e.footer[0:4])
+}
+
+func (e *encoder) writeIHDR() {
+	b := e.m.Bounds()
+	writeUint32(e.tmp[0:4], uint32(b.Dx()))
+	writeUint32(e.tmp[4:8], uint32(b.Dy()))
+	// Set bit depth and color type.
+	switch e.cb {
+	case cbG8:
+		e.tmp[8] = 8
+		e.tmp[9] = ctGrayscale
+	case cbTC8:
+		e.tmp[8] = 8
+		e.tmp[9] = ctTrueColor
+	case cbP8:
+		e.tmp[8] = 8
+		e.tmp[9] = ctPaletted
+	case cbTCA8:
+		e.tmp[8] = 8
+		e.tmp[9] = ctTrueColorAlpha
+	case cbG16:
+		e.tmp[8] = 16
+		e.tmp[9] = ctGrayscale
+	case cbTC16:
+		e.tmp[8] = 16
+		e.tmp[9] = ctTrueColor
+	case cbTCA16:
+		e.tmp[8] = 16
+		e.tmp[9] = ctTrueColorAlpha
+	}
+	e.tmp[10] = 0 // default compression method
+	e.tmp[11] = 0 // default filter method
+	e.tmp[12] = 0 // non-interlaced
+	e.writeChunk(e.tmp[0:13], "IHDR")
+}
+
+func (e *encoder) writePLTE(p image.PalettedColorModel) {
+	if len(p) < 1 || len(p) > 256 {
+		e.err = FormatError("bad palette length: " + strconv.Itoa(len(p)))
+		return
+	}
+	for i := 0; i < len(p); i++ {
+		r, g, b, a := p[i].RGBA()
+		if a != 0xffff {
+			e.err = UnsupportedError("non-opaque palette color")
+			return
+		}
+		e.tmp[3*i+0] = uint8(r >> 8)
+		e.tmp[3*i+1] = uint8(g >> 8)
+		e.tmp[3*i+2] = uint8(b >> 8)
+	}
+	e.writeChunk(e.tmp[0:3*len(p)], "PLTE")
+}
+
+// An encoder is an io.Writer that satisfies writes by writing PNG IDAT chunks,
+// including an 8-byte header and 4-byte CRC checksum per Write call. Such calls
+// should be relatively infrequent, since writeIDATs uses a bufio.Writer.
+//
+// This method should only be called from writeIDATs (via writeImage).
+// No other code should treat an encoder as an io.Writer.
+//
+// Note that, because the zlib Reader may involve an io.Pipe, e.Write calls may
+// occur on a separate go-routine than the e.writeIDATs call, and care should be
+// taken that e's state (such as its tmp buffer) is not modified concurrently.
+func (e *encoder) Write(b []byte) (int, os.Error) {
+	e.writeChunk(b, "IDAT")
+	if e.err != nil {
+		return 0, e.err
+	}
+	return len(b), nil
+}
+
+// Chooses the filter to use for encoding the current row, and applies it.
+// The return value is the index of the filter and also of the row in cr that has had it applied.
+func filter(cr [][]byte, pr []byte, bpp int) int {
+	// We try all five filter types, and pick the one that minimizes the sum of absolute differences.
+	// This is the same heuristic that libpng uses, although the filters are attempted in order of
+	// estimated most likely to be minimal (ftUp, ftPaeth, ftNone, ftSub, ftAverage), rather than
+	// in their enumeration order (ftNone, ftSub, ftUp, ftAverage, ftPaeth).
+	cdat0 := cr[0][1:]
+	cdat1 := cr[1][1:]
+	cdat2 := cr[2][1:]
+	cdat3 := cr[3][1:]
+	cdat4 := cr[4][1:]
+	pdat := pr[1:]
+	n := len(cdat0)
+
+	// The up filter.
+	sum := 0
+	for i := 0; i < n; i++ {
+		cdat2[i] = cdat0[i] - pdat[i]
+		sum += abs8(cdat2[i])
+	}
+	best := sum
+	filter := ftUp
+
+	// The Paeth filter.
+	sum = 0
+	for i := 0; i < bpp; i++ {
+		cdat4[i] = cdat0[i] - paeth(0, pdat[i], 0)
+		sum += abs8(cdat4[i])
+	}
+	for i := bpp; i < n; i++ {
+		cdat4[i] = cdat0[i] - paeth(cdat0[i-bpp], pdat[i], pdat[i-bpp])
+		sum += abs8(cdat4[i])
+		if sum >= best {
+			break
+		}
+	}
+	if sum < best {
+		best = sum
+		filter = ftPaeth
+	}
+
+	// The none filter.
+	sum = 0
+	for i := 0; i < n; i++ {
+		sum += abs8(cdat0[i])
+		if sum >= best {
+			break
+		}
+	}
+	if sum < best {
+		best = sum
+		filter = ftNone
+	}
+
+	// The sub filter.
+	sum = 0
+	for i := 0; i < bpp; i++ {
+		cdat1[i] = cdat0[i]
+		sum += abs8(cdat1[i])
+	}
+	for i := bpp; i < n; i++ {
+		cdat1[i] = cdat0[i] - cdat0[i-bpp]
+		sum += abs8(cdat1[i])
+		if sum >= best {
+			break
+		}
+	}
+	if sum < best {
+		best = sum
+		filter = ftSub
+	}
+
+	// The average filter.
+	sum = 0
+	for i := 0; i < bpp; i++ {
+		cdat3[i] = cdat0[i] - pdat[i]/2
+		sum += abs8(cdat3[i])
+	}
+	for i := bpp; i < n; i++ {
+		cdat3[i] = cdat0[i] - uint8((int(cdat0[i-bpp])+int(pdat[i]))/2)
+		sum += abs8(cdat3[i])
+		if sum >= best {
+			break
+		}
+	}
+	if sum < best {
+		best = sum
+		filter = ftAverage
+	}
+
+	return filter
+}
+
+func writeImage(w io.Writer, m image.Image, cb int) os.Error {
+	zw, err := zlib.NewWriter(w)
+	if err != nil {
+		return err
+	}
+	defer zw.Close()
+
+	bpp := 0 // Bytes per pixel.
+	var paletted *image.Paletted
+	switch cb {
+	case cbG8:
+		bpp = 1
+	case cbTC8:
+		bpp = 3
+	case cbP8:
+		bpp = 1
+		paletted = m.(*image.Paletted)
+	case cbTCA8:
+		bpp = 4
+	case cbTC16:
+		bpp = 6
+	case cbTCA16:
+		bpp = 8
+	case cbG16:
+		bpp = 2
+	}
+	// cr[*] and pr are the bytes for the current and previous row.
+	// cr[0] is unfiltered (or equivalently, filtered with the ftNone filter).
+	// cr[ft], for non-zero filter types ft, are buffers for transforming cr[0] under the
+	// other PNG filter types. These buffers are allocated once and re-used for each row.
+	// The +1 is for the per-row filter type, which is at cr[*][0].
+	b := m.Bounds()
+	var cr [nFilter][]uint8
+	for i := 0; i < len(cr); i++ {
+		cr[i] = make([]uint8, 1+bpp*b.Dx())
+		cr[i][0] = uint8(i)
+	}
+	pr := make([]uint8, 1+bpp*b.Dx())
+
+	for y := b.Min.Y; y < b.Max.Y; y++ {
+		// Convert from colors to bytes.
+		switch cb {
+		case cbG8:
+			for x := b.Min.X; x < b.Max.X; x++ {
+				c := image.GrayColorModel.Convert(m.At(x, y)).(image.GrayColor)
+				cr[0][x+1] = c.Y
+			}
+		case cbTC8:
+			for x := b.Min.X; x < b.Max.X; x++ {
+				// We have previously verified that the alpha value is fully opaque.
+				r, g, b, _ := m.At(x, y).RGBA()
+				cr[0][3*x+1] = uint8(r >> 8)
+				cr[0][3*x+2] = uint8(g >> 8)
+				cr[0][3*x+3] = uint8(b >> 8)
+			}
+		case cbP8:
+			rowOffset := y * paletted.Stride
+			copy(cr[0][b.Min.X+1:], paletted.Pix[rowOffset+b.Min.X:rowOffset+b.Max.X])
+		case cbTCA8:
+			// Convert from image.Image (which is alpha-premultiplied) to PNG's non-alpha-premultiplied.
+			for x := b.Min.X; x < b.Max.X; x++ {
+				c := image.NRGBAColorModel.Convert(m.At(x, y)).(image.NRGBAColor)
+				cr[0][4*x+1] = c.R
+				cr[0][4*x+2] = c.G
+				cr[0][4*x+3] = c.B
+				cr[0][4*x+4] = c.A
+			}
+		case cbG16:
+			for x := b.Min.X; x < b.Max.X; x++ {
+				c := image.Gray16ColorModel.Convert(m.At(x, y)).(image.Gray16Color)
+				cr[0][2*x+1] = uint8(c.Y >> 8)
+				cr[0][2*x+2] = uint8(c.Y)
+			}
+		case cbTC16:
+			for x := b.Min.X; x < b.Max.X; x++ {
+				// We have previously verified that the alpha value is fully opaque.
+				r, g, b, _ := m.At(x, y).RGBA()
+				cr[0][6*x+1] = uint8(r >> 8)
+				cr[0][6*x+2] = uint8(r)
+				cr[0][6*x+3] = uint8(g >> 8)
+				cr[0][6*x+4] = uint8(g)
+				cr[0][6*x+5] = uint8(b >> 8)
+				cr[0][6*x+6] = uint8(b)
+			}
+		case cbTCA16:
+			// Convert from image.Image (which is alpha-premultiplied) to PNG's non-alpha-premultiplied.
+			for x := b.Min.X; x < b.Max.X; x++ {
+				c := image.NRGBA64ColorModel.Convert(m.At(x, y)).(image.NRGBA64Color)
+				cr[0][8*x+1] = uint8(c.R >> 8)
+				cr[0][8*x+2] = uint8(c.R)
+				cr[0][8*x+3] = uint8(c.G >> 8)
+				cr[0][8*x+4] = uint8(c.G)
+				cr[0][8*x+5] = uint8(c.B >> 8)
+				cr[0][8*x+6] = uint8(c.B)
+				cr[0][8*x+7] = uint8(c.A >> 8)
+				cr[0][8*x+8] = uint8(c.A)
+			}
+		}
+
+		// Apply the filter.
+		f := filter(cr[0:nFilter], pr, bpp)
+
+		// Write the compressed bytes.
+		_, err = zw.Write(cr[f])
+		if err != nil {
+			return err
+		}
+
+		// The current row for y is the previous row for y+1.
+		pr, cr[0] = cr[0], pr
+	}
+	return nil
+}
+
+// Write the actual image data to one or more IDAT chunks.
+func (e *encoder) writeIDATs() {
+	if e.err != nil {
+		return
+	}
+	var bw *bufio.Writer
+	bw, e.err = bufio.NewWriterSize(e, 1<<15)
+	if e.err != nil {
+		return
+	}
+	e.err = writeImage(bw, e.m, e.cb)
+	if e.err != nil {
+		return
+	}
+	e.err = bw.Flush()
+}
+
+func (e *encoder) writeIEND() { e.writeChunk(e.tmp[0:0], "IEND") }
+
+// Encode writes the Image m to w in PNG format. Any Image may be encoded, but
+// images that are not image.NRGBA might be encoded lossily.
+func Encode(w io.Writer, m image.Image) os.Error {
+	// Obviously, negative widths and heights are invalid. Furthermore, the PNG
+	// spec section 11.2.2 says that zero is invalid. Excessively large images are
+	// also rejected.
+	mw, mh := int64(m.Bounds().Dx()), int64(m.Bounds().Dy())
+	if mw <= 0 || mh <= 0 || mw >= 1<<32 || mh >= 1<<32 {
+		return FormatError("invalid image size: " + strconv.Itoa64(mw) + "x" + strconv.Itoa64(mw))
+	}
+
+	var e encoder
+	e.w = w
+	e.m = m
+	pal, _ := m.(*image.Paletted)
+	if pal != nil {
+		e.cb = cbP8
+	} else {
+		switch m.ColorModel() {
+		case image.GrayColorModel:
+			e.cb = cbG8
+		case image.Gray16ColorModel:
+			e.cb = cbG16
+		case image.RGBAColorModel, image.NRGBAColorModel, image.AlphaColorModel:
+			if opaque(m) {
+				e.cb = cbTC8
+			} else {
+				e.cb = cbTCA8
+			}
+		default:
+			if opaque(m) {
+				e.cb = cbTC16
+			} else {
+				e.cb = cbTCA16
+			}
+		}
+	}
+
+	_, e.err = io.WriteString(w, pngHeader)
+	e.writeIHDR()
+	if pal != nil {
+		e.writePLTE(pal.Palette)
+	}
+	e.writeIDATs()
+	e.writeIEND()
+	return e.err
+}
diff --git a/libgo/go/image/png/writer_test.go b/libgo/go/image/png/writer_test.go
new file mode 100644
index 000000000..f218a5564
--- /dev/null
+++ b/libgo/go/image/png/writer_test.go
@@ -0,0 +1,86 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package png
+
+import (
+	"bytes"
+	"fmt"
+	"image"
+	"io"
+	"os"
+	"testing"
+)
+
+func diff(m0, m1 image.Image) os.Error {
+	b0, b1 := m0.Bounds(), m1.Bounds()
+	if !b0.Eq(b1) {
+		return fmt.Errorf("dimensions differ: %v vs %v", b0, b1)
+	}
+	for y := b0.Min.Y; y < b0.Max.Y; y++ {
+		for x := b0.Min.X; x < b0.Max.X; x++ {
+			r0, g0, b0, a0 := m0.At(x, y).RGBA()
+			r1, g1, b1, a1 := m1.At(x, y).RGBA()
+			if r0 != r1 || g0 != g1 || b0 != b1 || a0 != a1 {
+				return fmt.Errorf("colors differ at (%d, %d): %v vs %v", x, y, m0.At(x, y), m1.At(x, y))
+			}
+		}
+	}
+	return nil
+}
+
+func TestWriter(t *testing.T) {
+	// The filenames variable is declared in reader_test.go.
+	for _, fn := range filenames {
+		qfn := "testdata/pngsuite/" + fn + ".png"
+		// Read the image.
+		m0, err := readPng(qfn)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+		// Read the image again, and push it through a pipe that encodes at the write end, and decodes at the read end.
+		pr, pw := io.Pipe()
+		defer pr.Close()
+		go func() {
+			defer pw.Close()
+			m1, err := readPng(qfn)
+			if err != nil {
+				t.Error(fn, err)
+				return
+			}
+			err = Encode(pw, m1)
+			if err != nil {
+				t.Error(fn, err)
+				return
+			}
+		}()
+		m2, err := Decode(pr)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+		// Compare the two.
+		err = diff(m0, m2)
+		if err != nil {
+			t.Error(fn, err)
+			continue
+		}
+	}
+}
+
+func BenchmarkEncodePaletted(b *testing.B) {
+	b.StopTimer()
+	img := image.NewPaletted(640, 480,
+		[]image.Color{
+			image.RGBAColor{0, 0, 0, 255},
+			image.RGBAColor{255, 255, 255, 255},
+		})
+	b.StartTimer()
+	buffer := new(bytes.Buffer)
+	for i := 0; i < b.N; i++ {
+		buffer.Reset()
+		Encode(buffer, img)
+	}
+}