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-rw-r--r--libgo/go/encoding/base64/base64.go329
-rw-r--r--libgo/go/encoding/base64/base64_test.go196
2 files changed, 525 insertions, 0 deletions
diff --git a/libgo/go/encoding/base64/base64.go b/libgo/go/encoding/base64/base64.go
new file mode 100644
index 000000000..496129798
--- /dev/null
+++ b/libgo/go/encoding/base64/base64.go
@@ -0,0 +1,329 @@
+// 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 base64 implements base64 encoding as specified by RFC 4648.
+package base64
+
+import (
+ "io"
+ "os"
+ "strconv"
+)
+
+/*
+ * Encodings
+ */
+
+// An Encoding is a radix 64 encoding/decoding scheme, defined by a
+// 64-character alphabet. The most common encoding is the "base64"
+// encoding defined in RFC 4648 and used in MIME (RFC 2045) and PEM
+// (RFC 1421). RFC 4648 also defines an alternate encoding, which is
+// the standard encoding with - and _ substituted for + and /.
+type Encoding struct {
+ encode string
+ decodeMap [256]byte
+}
+
+const encodeStd = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
+const encodeURL = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_"
+
+// NewEncoding returns a new Encoding defined by the given alphabet,
+// which must be a 64-byte string.
+func NewEncoding(encoder string) *Encoding {
+ e := new(Encoding)
+ e.encode = encoder
+ for i := 0; i < len(e.decodeMap); i++ {
+ e.decodeMap[i] = 0xFF
+ }
+ for i := 0; i < len(encoder); i++ {
+ e.decodeMap[encoder[i]] = byte(i)
+ }
+ return e
+}
+
+// StdEncoding is the standard base64 encoding, as defined in
+// RFC 4648.
+var StdEncoding = NewEncoding(encodeStd)
+
+// URLEncoding is the alternate base64 encoding defined in RFC 4648.
+// It is typically used in URLs and file names.
+var URLEncoding = NewEncoding(encodeURL)
+
+/*
+ * Encoder
+ */
+
+// Encode encodes src using the encoding enc, writing
+// EncodedLen(len(src)) bytes to dst.
+//
+// The encoding pads the output to a multiple of 4 bytes,
+// so Encode is not appropriate for use on individual blocks
+// of a large data stream. Use NewEncoder() instead.
+func (enc *Encoding) Encode(dst, src []byte) {
+ if len(src) == 0 {
+ return
+ }
+
+ for len(src) > 0 {
+ dst[0] = 0
+ dst[1] = 0
+ dst[2] = 0
+ dst[3] = 0
+
+ // Unpack 4x 6-bit source blocks into a 4 byte
+ // destination quantum
+ switch len(src) {
+ default:
+ dst[3] |= src[2] & 0x3F
+ dst[2] |= src[2] >> 6
+ fallthrough
+ case 2:
+ dst[2] |= (src[1] << 2) & 0x3F
+ dst[1] |= src[1] >> 4
+ fallthrough
+ case 1:
+ dst[1] |= (src[0] << 4) & 0x3F
+ dst[0] |= src[0] >> 2
+ }
+
+ // Encode 6-bit blocks using the base64 alphabet
+ for j := 0; j < 4; j++ {
+ dst[j] = enc.encode[dst[j]]
+ }
+
+ // Pad the final quantum
+ if len(src) < 3 {
+ dst[3] = '='
+ if len(src) < 2 {
+ dst[2] = '='
+ }
+ break
+ }
+
+ src = src[3:]
+ dst = dst[4:]
+ }
+}
+
+type encoder struct {
+ err os.Error
+ enc *Encoding
+ w io.Writer
+ buf [3]byte // buffered data waiting to be encoded
+ nbuf int // number of bytes in buf
+ out [1024]byte // output buffer
+}
+
+func (e *encoder) Write(p []byte) (n int, err os.Error) {
+ if e.err != nil {
+ return 0, e.err
+ }
+
+ // Leading fringe.
+ if e.nbuf > 0 {
+ var i int
+ for i = 0; i < len(p) && e.nbuf < 3; i++ {
+ e.buf[e.nbuf] = p[i]
+ e.nbuf++
+ }
+ n += i
+ p = p[i:]
+ if e.nbuf < 3 {
+ return
+ }
+ e.enc.Encode(e.out[0:], e.buf[0:])
+ if _, e.err = e.w.Write(e.out[0:4]); e.err != nil {
+ return n, e.err
+ }
+ e.nbuf = 0
+ }
+
+ // Large interior chunks.
+ for len(p) >= 3 {
+ nn := len(e.out) / 4 * 3
+ if nn > len(p) {
+ nn = len(p)
+ }
+ nn -= nn % 3
+ if nn > 0 {
+ e.enc.Encode(e.out[0:], p[0:nn])
+ if _, e.err = e.w.Write(e.out[0 : nn/3*4]); e.err != nil {
+ return n, e.err
+ }
+ }
+ n += nn
+ p = p[nn:]
+ }
+
+ // Trailing fringe.
+ for i := 0; i < len(p); i++ {
+ e.buf[i] = p[i]
+ }
+ e.nbuf = len(p)
+ n += len(p)
+ return
+}
+
+// Close flushes any pending output from the encoder.
+// It is an error to call Write after calling Close.
+func (e *encoder) Close() os.Error {
+ // If there's anything left in the buffer, flush it out
+ if e.err == nil && e.nbuf > 0 {
+ e.enc.Encode(e.out[0:], e.buf[0:e.nbuf])
+ e.nbuf = 0
+ _, e.err = e.w.Write(e.out[0:4])
+ }
+ return e.err
+}
+
+// NewEncoder returns a new base64 stream encoder. Data written to
+// the returned writer will be encoded using enc and then written to w.
+// Base64 encodings operate in 4-byte blocks; when finished
+// writing, the caller must Close the returned encoder to flush any
+// partially written blocks.
+func NewEncoder(enc *Encoding, w io.Writer) io.WriteCloser {
+ return &encoder{enc: enc, w: w}
+}
+
+// EncodedLen returns the length in bytes of the base64 encoding
+// of an input buffer of length n.
+func (enc *Encoding) EncodedLen(n int) int { return (n + 2) / 3 * 4 }
+
+/*
+ * Decoder
+ */
+
+type CorruptInputError int64
+
+func (e CorruptInputError) String() string {
+ return "illegal base64 data at input byte " + strconv.Itoa64(int64(e))
+}
+
+// decode is like Decode but returns an additional 'end' value, which
+// indicates if end-of-message padding was encountered and thus any
+// additional data is an error. decode also assumes len(src)%4==0,
+// since it is meant for internal use.
+func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err os.Error) {
+ for i := 0; i < len(src)/4 && !end; i++ {
+ // Decode quantum using the base64 alphabet
+ var dbuf [4]byte
+ dlen := 4
+
+ dbufloop:
+ for j := 0; j < 4; j++ {
+ in := src[i*4+j]
+ if in == '=' && j >= 2 && i == len(src)/4-1 {
+ // We've reached the end and there's
+ // padding
+ if src[i*4+3] != '=' {
+ return n, false, CorruptInputError(i*4 + 2)
+ }
+ dlen = j
+ end = true
+ break dbufloop
+ }
+ dbuf[j] = enc.decodeMap[in]
+ if dbuf[j] == 0xFF {
+ return n, false, CorruptInputError(i*4 + j)
+ }
+ }
+
+ // Pack 4x 6-bit source blocks into 3 byte destination
+ // quantum
+ switch dlen {
+ case 4:
+ dst[i*3+2] = dbuf[2]<<6 | dbuf[3]
+ fallthrough
+ case 3:
+ dst[i*3+1] = dbuf[1]<<4 | dbuf[2]>>2
+ fallthrough
+ case 2:
+ dst[i*3+0] = dbuf[0]<<2 | dbuf[1]>>4
+ }
+ n += dlen - 1
+ }
+
+ return n, end, nil
+}
+
+// Decode decodes src using the encoding enc. It writes at most
+// DecodedLen(len(src)) bytes to dst and returns the number of bytes
+// written. If src contains invalid base64 data, it will return the
+// number of bytes successfully written and CorruptInputError.
+func (enc *Encoding) Decode(dst, src []byte) (n int, err os.Error) {
+ if len(src)%4 != 0 {
+ return 0, CorruptInputError(len(src) / 4 * 4)
+ }
+
+ n, _, err = enc.decode(dst, src)
+ return
+}
+
+type decoder struct {
+ err os.Error
+ enc *Encoding
+ r io.Reader
+ end bool // saw end of message
+ buf [1024]byte // leftover input
+ nbuf int
+ out []byte // leftover decoded output
+ outbuf [1024 / 4 * 3]byte
+}
+
+func (d *decoder) Read(p []byte) (n int, err os.Error) {
+ if d.err != nil {
+ return 0, d.err
+ }
+
+ // Use leftover decoded output from last read.
+ if len(d.out) > 0 {
+ n = copy(p, d.out)
+ d.out = d.out[n:]
+ return n, nil
+ }
+
+ // Read a chunk.
+ nn := len(p) / 3 * 4
+ if nn < 4 {
+ nn = 4
+ }
+ if nn > len(d.buf) {
+ nn = len(d.buf)
+ }
+ nn, d.err = io.ReadAtLeast(d.r, d.buf[d.nbuf:nn], 4-d.nbuf)
+ d.nbuf += nn
+ if d.nbuf < 4 {
+ return 0, d.err
+ }
+
+ // Decode chunk into p, or d.out and then p if p is too small.
+ nr := d.nbuf / 4 * 4
+ nw := d.nbuf / 4 * 3
+ if nw > len(p) {
+ nw, d.end, d.err = d.enc.decode(d.outbuf[0:], d.buf[0:nr])
+ d.out = d.outbuf[0:nw]
+ n = copy(p, d.out)
+ d.out = d.out[n:]
+ } else {
+ n, d.end, d.err = d.enc.decode(p, d.buf[0:nr])
+ }
+ d.nbuf -= nr
+ for i := 0; i < d.nbuf; i++ {
+ d.buf[i] = d.buf[i+nr]
+ }
+
+ if d.err == nil {
+ d.err = err
+ }
+ return n, d.err
+}
+
+// NewDecoder constructs a new base64 stream decoder.
+func NewDecoder(enc *Encoding, r io.Reader) io.Reader {
+ return &decoder{enc: enc, r: r}
+}
+
+// DecodedLen returns the maximum length in bytes of the decoded data
+// corresponding to n bytes of base64-encoded data.
+func (enc *Encoding) DecodedLen(n int) int { return n / 4 * 3 }
diff --git a/libgo/go/encoding/base64/base64_test.go b/libgo/go/encoding/base64/base64_test.go
new file mode 100644
index 000000000..de41e704b
--- /dev/null
+++ b/libgo/go/encoding/base64/base64_test.go
@@ -0,0 +1,196 @@
+// 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 base64
+
+import (
+ "bytes"
+ "io/ioutil"
+ "os"
+ "testing"
+)
+
+type testpair struct {
+ decoded, encoded string
+}
+
+var pairs = []testpair{
+ // RFC 3548 examples
+ {"\x14\xfb\x9c\x03\xd9\x7e", "FPucA9l+"},
+ {"\x14\xfb\x9c\x03\xd9", "FPucA9k="},
+ {"\x14\xfb\x9c\x03", "FPucAw=="},
+
+ // RFC 4648 examples
+ {"", ""},
+ {"f", "Zg=="},
+ {"fo", "Zm8="},
+ {"foo", "Zm9v"},
+ {"foob", "Zm9vYg=="},
+ {"fooba", "Zm9vYmE="},
+ {"foobar", "Zm9vYmFy"},
+
+ // Wikipedia examples
+ {"sure.", "c3VyZS4="},
+ {"sure", "c3VyZQ=="},
+ {"sur", "c3Vy"},
+ {"su", "c3U="},
+ {"leasure.", "bGVhc3VyZS4="},
+ {"easure.", "ZWFzdXJlLg=="},
+ {"asure.", "YXN1cmUu"},
+ {"sure.", "c3VyZS4="},
+}
+
+var bigtest = testpair{
+ "Twas brillig, and the slithy toves",
+ "VHdhcyBicmlsbGlnLCBhbmQgdGhlIHNsaXRoeSB0b3Zlcw==",
+}
+
+func testEqual(t *testing.T, msg string, args ...interface{}) bool {
+ if args[len(args)-2] != args[len(args)-1] {
+ t.Errorf(msg, args...)
+ return false
+ }
+ return true
+}
+
+func TestEncode(t *testing.T) {
+ for _, p := range pairs {
+ buf := make([]byte, StdEncoding.EncodedLen(len(p.decoded)))
+ StdEncoding.Encode(buf, []byte(p.decoded))
+ testEqual(t, "Encode(%q) = %q, want %q", p.decoded, string(buf), p.encoded)
+ }
+}
+
+func TestEncoder(t *testing.T) {
+ for _, p := range pairs {
+ bb := &bytes.Buffer{}
+ encoder := NewEncoder(StdEncoding, bb)
+ encoder.Write([]byte(p.decoded))
+ encoder.Close()
+ testEqual(t, "Encode(%q) = %q, want %q", p.decoded, bb.String(), p.encoded)
+ }
+}
+
+func TestEncoderBuffering(t *testing.T) {
+ input := []byte(bigtest.decoded)
+ for bs := 1; bs <= 12; bs++ {
+ bb := &bytes.Buffer{}
+ encoder := NewEncoder(StdEncoding, bb)
+ for pos := 0; pos < len(input); pos += bs {
+ end := pos + bs
+ if end > len(input) {
+ end = len(input)
+ }
+ n, err := encoder.Write(input[pos:end])
+ testEqual(t, "Write(%q) gave error %v, want %v", input[pos:end], err, os.Error(nil))
+ testEqual(t, "Write(%q) gave length %v, want %v", input[pos:end], n, end-pos)
+ }
+ err := encoder.Close()
+ testEqual(t, "Close gave error %v, want %v", err, os.Error(nil))
+ testEqual(t, "Encoding/%d of %q = %q, want %q", bs, bigtest.decoded, bb.String(), bigtest.encoded)
+ }
+}
+
+func TestDecode(t *testing.T) {
+ for _, p := range pairs {
+ dbuf := make([]byte, StdEncoding.DecodedLen(len(p.encoded)))
+ count, end, err := StdEncoding.decode(dbuf, []byte(p.encoded))
+ testEqual(t, "Decode(%q) = error %v, want %v", p.encoded, err, os.Error(nil))
+ testEqual(t, "Decode(%q) = length %v, want %v", p.encoded, count, len(p.decoded))
+ if len(p.encoded) > 0 {
+ testEqual(t, "Decode(%q) = end %v, want %v", p.encoded, end, (p.encoded[len(p.encoded)-1] == '='))
+ }
+ testEqual(t, "Decode(%q) = %q, want %q", p.encoded, string(dbuf[0:count]), p.decoded)
+ }
+}
+
+func TestDecoder(t *testing.T) {
+ for _, p := range pairs {
+ decoder := NewDecoder(StdEncoding, bytes.NewBufferString(p.encoded))
+ dbuf := make([]byte, StdEncoding.DecodedLen(len(p.encoded)))
+ count, err := decoder.Read(dbuf)
+ if err != nil && err != os.EOF {
+ t.Fatal("Read failed", err)
+ }
+ testEqual(t, "Read from %q = length %v, want %v", p.encoded, count, len(p.decoded))
+ testEqual(t, "Decoding of %q = %q, want %q", p.encoded, string(dbuf[0:count]), p.decoded)
+ if err != os.EOF {
+ count, err = decoder.Read(dbuf)
+ }
+ testEqual(t, "Read from %q = %v, want %v", p.encoded, err, os.EOF)
+ }
+}
+
+func TestDecoderBuffering(t *testing.T) {
+ for bs := 1; bs <= 12; bs++ {
+ decoder := NewDecoder(StdEncoding, bytes.NewBufferString(bigtest.encoded))
+ buf := make([]byte, len(bigtest.decoded)+12)
+ var total int
+ for total = 0; total < len(bigtest.decoded); {
+ n, err := decoder.Read(buf[total : total+bs])
+ testEqual(t, "Read from %q at pos %d = %d, %v, want _, %v", bigtest.encoded, total, n, err, os.Error(nil))
+ total += n
+ }
+ testEqual(t, "Decoding/%d of %q = %q, want %q", bs, bigtest.encoded, string(buf[0:total]), bigtest.decoded)
+ }
+}
+
+func TestDecodeCorrupt(t *testing.T) {
+ type corrupt struct {
+ e string
+ p int
+ }
+ examples := []corrupt{
+ {"!!!!", 0},
+ {"x===", 1},
+ {"AA=A", 2},
+ {"AAA=AAAA", 3},
+ {"AAAAA", 4},
+ {"AAAAAA", 4},
+ }
+
+ for _, e := range examples {
+ dbuf := make([]byte, StdEncoding.DecodedLen(len(e.e)))
+ _, err := StdEncoding.Decode(dbuf, []byte(e.e))
+ switch err := err.(type) {
+ case CorruptInputError:
+ testEqual(t, "Corruption in %q at offset %v, want %v", e.e, int(err), e.p)
+ default:
+ t.Error("Decoder failed to detect corruption in", e)
+ }
+ }
+}
+
+func TestBig(t *testing.T) {
+ n := 3*1000 + 1
+ raw := make([]byte, n)
+ const alpha = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ for i := 0; i < n; i++ {
+ raw[i] = alpha[i%len(alpha)]
+ }
+ encoded := new(bytes.Buffer)
+ w := NewEncoder(StdEncoding, encoded)
+ nn, err := w.Write(raw)
+ if nn != n || err != nil {
+ t.Fatalf("Encoder.Write(raw) = %d, %v want %d, nil", nn, err, n)
+ }
+ err = w.Close()
+ if err != nil {
+ t.Fatalf("Encoder.Close() = %v want nil", err)
+ }
+ decoded, err := ioutil.ReadAll(NewDecoder(StdEncoding, encoded))
+ if err != nil {
+ t.Fatalf("ioutil.ReadAll(NewDecoder(...)): %v", err)
+ }
+
+ if !bytes.Equal(raw, decoded) {
+ var i int
+ for i = 0; i < len(decoded) && i < len(raw); i++ {
+ if decoded[i] != raw[i] {
+ break
+ }
+ }
+ t.Errorf("Decode(Encode(%d-byte string)) failed at offset %d", n, i)
+ }
+}
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