diff options
Diffstat (limited to 'libgo/go/hash')
-rw-r--r-- | libgo/go/hash/adler32/adler32.go | 88 | ||||
-rw-r--r-- | libgo/go/hash/adler32/adler32_test.go | 63 | ||||
-rw-r--r-- | libgo/go/hash/crc32/crc32.go | 111 | ||||
-rw-r--r-- | libgo/go/hash/crc32/crc32_test.go | 76 | ||||
-rw-r--r-- | libgo/go/hash/crc64/crc64.go | 96 | ||||
-rw-r--r-- | libgo/go/hash/crc64/crc64_test.go | 78 | ||||
-rw-r--r-- | libgo/go/hash/hash.go | 36 |
7 files changed, 548 insertions, 0 deletions
diff --git a/libgo/go/hash/adler32/adler32.go b/libgo/go/hash/adler32/adler32.go new file mode 100644 index 000000000..cd0c2599a --- /dev/null +++ b/libgo/go/hash/adler32/adler32.go @@ -0,0 +1,88 @@ +// 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 package implements the Adler-32 checksum. +// Defined in RFC 1950: +// Adler-32 is composed of two sums accumulated per byte: s1 is +// the sum of all bytes, s2 is the sum of all s1 values. Both sums +// are done modulo 65521. s1 is initialized to 1, s2 to zero. The +// Adler-32 checksum is stored as s2*65536 + s1 in most- +// significant-byte first (network) order. +package adler32 + +import ( + "hash" + "os" +) + +const ( + mod = 65521 +) + +// The size of an Adler-32 checksum in bytes. +const Size = 4 + +// digest represents the partial evaluation of a checksum. +type digest struct { + // invariant: (a < mod && b < mod) || a <= b + // invariant: a + b + 255 <= 0xffffffff + a, b uint32 +} + +func (d *digest) Reset() { d.a, d.b = 1, 0 } + +// New returns a new hash.Hash32 computing the Adler-32 checksum. +func New() hash.Hash32 { + d := new(digest) + d.Reset() + return d +} + +func (d *digest) Size() int { return Size } + +// Add p to the running checksum a, b. +func update(a, b uint32, p []byte) (aa, bb uint32) { + for i := 0; i < len(p); i++ { + a += uint32(p[i]) + b += a + // invariant: a <= b + if b > (0xffffffff-255)/2 { + a %= mod + b %= mod + // invariant: a < mod && b < mod + } else { + // invariant: a + b + 255 <= 2 * b + 255 <= 0xffffffff + } + } + return a, b +} + +// Return the 32-bit checksum corresponding to a, b. +func finish(a, b uint32) uint32 { + if b >= mod { + a %= mod + b %= mod + } + return b<<16 | a +} + +func (d *digest) Write(p []byte) (nn int, err os.Error) { + d.a, d.b = update(d.a, d.b, p) + return len(p), nil +} + +func (d *digest) Sum32() uint32 { return finish(d.a, d.b) } + +func (d *digest) Sum() []byte { + p := make([]byte, 4) + s := d.Sum32() + p[0] = byte(s >> 24) + p[1] = byte(s >> 16) + p[2] = byte(s >> 8) + p[3] = byte(s) + return p +} + +// Checksum returns the Adler-32 checksum of data. +func Checksum(data []byte) uint32 { return finish(update(1, 0, data)) } diff --git a/libgo/go/hash/adler32/adler32_test.go b/libgo/go/hash/adler32/adler32_test.go new file mode 100644 index 000000000..ffa5569bc --- /dev/null +++ b/libgo/go/hash/adler32/adler32_test.go @@ -0,0 +1,63 @@ +// 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 adler32 + +import ( + "io" + "testing" +) + +type _Adler32Test struct { + out uint32 + in string +} + +var golden = []_Adler32Test{ + {0x1, ""}, + {0x620062, "a"}, + {0x12600c4, "ab"}, + {0x24d0127, "abc"}, + {0x3d8018b, "abcd"}, + {0x5c801f0, "abcde"}, + {0x81e0256, "abcdef"}, + {0xadb02bd, "abcdefg"}, + {0xe000325, "abcdefgh"}, + {0x118e038e, "abcdefghi"}, + {0x158603f8, "abcdefghij"}, + {0x3f090f02, "Discard medicine more than two years old."}, + {0x46d81477, "He who has a shady past knows that nice guys finish last."}, + {0x40ee0ee1, "I wouldn't marry him with a ten foot pole."}, + {0x16661315, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave"}, + {0x5b2e1480, "The days of the digital watch are numbered. -Tom Stoppard"}, + {0x8c3c09ea, "Nepal premier won't resign."}, + {0x45ac18fd, "For every action there is an equal and opposite government program."}, + {0x53c61462, "His money is twice tainted: 'taint yours and 'taint mine."}, + {0x7e511e63, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977"}, + {0xe4801a6a, "It's a tiny change to the code and not completely disgusting. - Bob Manchek"}, + {0x61b507df, "size: a.out: bad magic"}, + {0xb8631171, "The major problem is with sendmail. -Mark Horton"}, + {0x8b5e1904, "Give me a rock, paper and scissors and I will move the world. CCFestoon"}, + {0x7cc6102b, "If the enemy is within range, then so are you."}, + {0x700318e7, "It's well we cannot hear the screams/That we create in others' dreams."}, + {0x1e601747, "You remind me of a TV show, but that's all right: I watch it anyway."}, + {0xb55b0b09, "C is as portable as Stonehedge!!"}, + {0x39111dd0, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley"}, + {0x91dd304f, "The fugacity of a constituent in a mixture of gases at a given temperature is proportional to its mole fraction. Lewis-Randall Rule"}, + {0x2e5d1316, "How can you write a big system without C++? -Paul Glick"}, + {0xd0201df6, "'Invariant assertions' is the most elegant programming technique! -Tom Szymanski"}, +} + +func TestGolden(t *testing.T) { + for i := 0; i < len(golden); i++ { + g := golden[i] + c := New() + io.WriteString(c, g.in) + s := c.Sum32() + if s != g.out { + t.Errorf("adler32(%s) = 0x%x want 0x%x", g.in, s, g.out) + t.FailNow() + } + } +} diff --git a/libgo/go/hash/crc32/crc32.go b/libgo/go/hash/crc32/crc32.go new file mode 100644 index 000000000..2ab0c5491 --- /dev/null +++ b/libgo/go/hash/crc32/crc32.go @@ -0,0 +1,111 @@ +// 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 package implements the 32-bit cyclic redundancy check, or CRC-32, checksum. +// See http://en.wikipedia.org/wiki/Cyclic_redundancy_check for information. +package crc32 + +import ( + "hash" + "os" +) + +// The size of a CRC-32 checksum in bytes. +const Size = 4 + +// Predefined polynomials. +const ( + // Far and away the most common CRC-32 polynomial. + // Used by ethernet (IEEE 802.3), v.42, fddi, gzip, zip, png, mpeg-2, ... + IEEE = 0xedb88320 + + // Castagnoli's polynomial, used in iSCSI. + // Has better error detection characteristics than IEEE. + // http://dx.doi.org/10.1109/26.231911 + Castagnoli = 0x82f63b78 + + // Koopman's polynomial. + // Also has better error detection characteristics than IEEE. + // http://dx.doi.org/10.1109/DSN.2002.1028931 + Koopman = 0xeb31d82e +) + +// Table is a 256-word table representing the polynomial for efficient processing. +type Table [256]uint32 + +// MakeTable returns the Table constructed from the specified polynomial. +func MakeTable(poly uint32) *Table { + t := new(Table) + for i := 0; i < 256; i++ { + crc := uint32(i) + for j := 0; j < 8; j++ { + if crc&1 == 1 { + crc = (crc >> 1) ^ poly + } else { + crc >>= 1 + } + } + t[i] = crc + } + return t +} + +// IEEETable is the table for the IEEE polynomial. +var IEEETable = MakeTable(IEEE) + +// digest represents the partial evaluation of a checksum. +type digest struct { + crc uint32 + tab *Table +} + +// New creates a new hash.Hash32 computing the CRC-32 checksum +// using the polynomial represented by the Table. +func New(tab *Table) hash.Hash32 { return &digest{0, tab} } + +// NewIEEE creates a new hash.Hash32 computing the CRC-32 checksum +// using the IEEE polynomial. +func NewIEEE() hash.Hash32 { return New(IEEETable) } + +func (d *digest) Size() int { return Size } + +func (d *digest) Reset() { d.crc = 0 } + +func update(crc uint32, tab *Table, p []byte) uint32 { + crc = ^crc + for _, v := range p { + crc = tab[byte(crc)^v] ^ (crc >> 8) + } + return ^crc +} + +// Update returns the result of adding the bytes in p to the crc. +func Update(crc uint32, tab *Table, p []byte) uint32 { + return update(crc, tab, p) +} + +func (d *digest) Write(p []byte) (n int, err os.Error) { + d.crc = update(d.crc, d.tab, p) + return len(p), nil +} + +func (d *digest) Sum32() uint32 { return d.crc } + +func (d *digest) Sum() []byte { + p := make([]byte, 4) + s := d.Sum32() + p[0] = byte(s >> 24) + p[1] = byte(s >> 16) + p[2] = byte(s >> 8) + p[3] = byte(s) + return p +} + +// Checksum returns the CRC-32 checksum of data +// using the polynomial represented by the Table. +func Checksum(data []byte, tab *Table) uint32 { return update(0, tab, data) } + +// ChecksumIEEE returns the CRC-32 checksum of data +// using the IEEE polynomial. +func ChecksumIEEE(data []byte) uint32 { return update(0, IEEETable, data) } diff --git a/libgo/go/hash/crc32/crc32_test.go b/libgo/go/hash/crc32/crc32_test.go new file mode 100644 index 000000000..cf5743c99 --- /dev/null +++ b/libgo/go/hash/crc32/crc32_test.go @@ -0,0 +1,76 @@ +// 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 crc32 + +import ( + "io" + "testing" +) + +type test struct { + out uint32 + in string +} + +var golden = []test{ + {0x0, ""}, + {0xe8b7be43, "a"}, + {0x9e83486d, "ab"}, + {0x352441c2, "abc"}, + {0xed82cd11, "abcd"}, + {0x8587d865, "abcde"}, + {0x4b8e39ef, "abcdef"}, + {0x312a6aa6, "abcdefg"}, + {0xaeef2a50, "abcdefgh"}, + {0x8da988af, "abcdefghi"}, + {0x3981703a, "abcdefghij"}, + {0x6b9cdfe7, "Discard medicine more than two years old."}, + {0xc90ef73f, "He who has a shady past knows that nice guys finish last."}, + {0xb902341f, "I wouldn't marry him with a ten foot pole."}, + {0x42080e8, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave"}, + {0x154c6d11, "The days of the digital watch are numbered. -Tom Stoppard"}, + {0x4c418325, "Nepal premier won't resign."}, + {0x33955150, "For every action there is an equal and opposite government program."}, + {0x26216a4b, "His money is twice tainted: 'taint yours and 'taint mine."}, + {0x1abbe45e, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977"}, + {0xc89a94f7, "It's a tiny change to the code and not completely disgusting. - Bob Manchek"}, + {0xab3abe14, "size: a.out: bad magic"}, + {0xbab102b6, "The major problem is with sendmail. -Mark Horton"}, + {0x999149d7, "Give me a rock, paper and scissors and I will move the world. CCFestoon"}, + {0x6d52a33c, "If the enemy is within range, then so are you."}, + {0x90631e8d, "It's well we cannot hear the screams/That we create in others' dreams."}, + {0x78309130, "You remind me of a TV show, but that's all right: I watch it anyway."}, + {0x7d0a377f, "C is as portable as Stonehedge!!"}, + {0x8c79fd79, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley"}, + {0xa20b7167, "The fugacity of a constituent in a mixture of gases at a given temperature is proportional to its mole fraction. Lewis-Randall Rule"}, + {0x8e0bb443, "How can you write a big system without C++? -Paul Glick"}, +} + +func TestGolden(t *testing.T) { + for i := 0; i < len(golden); i++ { + g := golden[i] + c := NewIEEE() + io.WriteString(c, g.in) + s := c.Sum32() + if s != g.out { + t.Errorf("crc32(%s) = 0x%x want 0x%x", g.in, s, g.out) + t.FailNow() + } + } +} + +func BenchmarkCrc32KB(b *testing.B) { + b.StopTimer() + data := make([]uint8, 1024) + for i := 0; i < 1024; i++ { + data[i] = uint8(i) + } + c := NewIEEE() + b.StartTimer() + + for i := 0; i < b.N; i++ { + c.Write(data) + } +} diff --git a/libgo/go/hash/crc64/crc64.go b/libgo/go/hash/crc64/crc64.go new file mode 100644 index 000000000..844386564 --- /dev/null +++ b/libgo/go/hash/crc64/crc64.go @@ -0,0 +1,96 @@ +// 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 package implements the 64-bit cyclic redundancy check, or CRC-64, checksum. +// See http://en.wikipedia.org/wiki/Cyclic_redundancy_check for information. +package crc64 + +import ( + "hash" + "os" +) + +// The size of a CRC-64 checksum in bytes. +const Size = 8 + +// Predefined polynomials. +const ( + // The ISO polynomial, defined in ISO 3309 and used in HDLC. + ISO = 0xD800000000000000 + + // The ECMA polynomial, defined in ECMA 182. + ECMA = 0xC96C5795D7870F42 +) + +// Table is a 256-word table representing the polynomial for efficient processing. +type Table [256]uint64 + +// MakeTable returns the Table constructed from the specified polynomial. +func MakeTable(poly uint64) *Table { + t := new(Table) + for i := 0; i < 256; i++ { + crc := uint64(i) + for j := 0; j < 8; j++ { + if crc&1 == 1 { + crc = (crc >> 1) ^ poly + } else { + crc >>= 1 + } + } + t[i] = crc + } + return t +} + +// digest represents the partial evaluation of a checksum. +type digest struct { + crc uint64 + tab *Table +} + +// New creates a new hash.Hash64 computing the CRC-64 checksum +// using the polynomial represented by the Table. +func New(tab *Table) hash.Hash64 { return &digest{0, tab} } + +func (d *digest) Size() int { return Size } + +func (d *digest) Reset() { d.crc = 0 } + +func update(crc uint64, tab *Table, p []byte) uint64 { + crc = ^crc + for _, v := range p { + crc = tab[byte(crc)^v] ^ (crc >> 8) + } + return ^crc +} + +// Update returns the result of adding the bytes in p to the crc. +func Update(crc uint64, tab *Table, p []byte) uint64 { + return update(crc, tab, p) +} + +func (d *digest) Write(p []byte) (n int, err os.Error) { + d.crc = update(d.crc, d.tab, p) + return len(p), nil +} + +func (d *digest) Sum64() uint64 { return d.crc } + +func (d *digest) Sum() []byte { + p := make([]byte, 8) + s := d.Sum64() + p[0] = byte(s >> 56) + p[1] = byte(s >> 48) + p[2] = byte(s >> 40) + p[3] = byte(s >> 32) + p[4] = byte(s >> 24) + p[5] = byte(s >> 16) + p[6] = byte(s >> 8) + p[7] = byte(s) + return p +} + +// Checksum returns the CRC-64 checksum of data +// using the polynomial represented by the Table. +func Checksum(data []byte, tab *Table) uint64 { return update(0, tab, data) } diff --git a/libgo/go/hash/crc64/crc64_test.go b/libgo/go/hash/crc64/crc64_test.go new file mode 100644 index 000000000..e932524e0 --- /dev/null +++ b/libgo/go/hash/crc64/crc64_test.go @@ -0,0 +1,78 @@ +// 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 crc64 + +import ( + "io" + "testing" +) + +type test struct { + out uint64 + in string +} + +var golden = []test{ + {0x0, ""}, + {0x3420000000000000, "a"}, + {0x36c4200000000000, "ab"}, + {0x3776c42000000000, "abc"}, + {0x336776c420000000, "abcd"}, + {0x32d36776c4200000, "abcde"}, + {0x3002d36776c42000, "abcdef"}, + {0x31b002d36776c420, "abcdefg"}, + {0xe21b002d36776c4, "abcdefgh"}, + {0x8b6e21b002d36776, "abcdefghi"}, + {0x7f5b6e21b002d367, "abcdefghij"}, + {0x8ec0e7c835bf9cdf, "Discard medicine more than two years old."}, + {0xc7db1759e2be5ab4, "He who has a shady past knows that nice guys finish last."}, + {0xfbf9d9603a6fa020, "I wouldn't marry him with a ten foot pole."}, + {0xeafc4211a6daa0ef, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave"}, + {0x3e05b21c7a4dc4da, "The days of the digital watch are numbered. -Tom Stoppard"}, + {0x5255866ad6ef28a6, "Nepal premier won't resign."}, + {0x8a79895be1e9c361, "For every action there is an equal and opposite government program."}, + {0x8878963a649d4916, "His money is twice tainted: 'taint yours and 'taint mine."}, + {0xa7b9d53ea87eb82f, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977"}, + {0xdb6805c0966a2f9c, "It's a tiny change to the code and not completely disgusting. - Bob Manchek"}, + {0xf3553c65dacdadd2, "size: a.out: bad magic"}, + {0x9d5e034087a676b9, "The major problem is with sendmail. -Mark Horton"}, + {0xa6db2d7f8da96417, "Give me a rock, paper and scissors and I will move the world. CCFestoon"}, + {0x325e00cd2fe819f9, "If the enemy is within range, then so are you."}, + {0x88c6600ce58ae4c6, "It's well we cannot hear the screams/That we create in others' dreams."}, + {0x28c4a3f3b769e078, "You remind me of a TV show, but that's all right: I watch it anyway."}, + {0xa698a34c9d9f1dca, "C is as portable as Stonehedge!!"}, + {0xf6c1e2a8c26c5cfc, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley"}, + {0xd402559dfe9b70c, "The fugacity of a constituent in a mixture of gases at a given temperature is proportional to its mole fraction. Lewis-Randall Rule"}, + {0xdb6efff26aa94946, "How can you write a big system without C++? -Paul Glick"}, +} + +var tab = MakeTable(ISO) + +func TestGolden(t *testing.T) { + for i := 0; i < len(golden); i++ { + g := golden[i] + c := New(tab) + io.WriteString(c, g.in) + s := c.Sum64() + if s != g.out { + t.Errorf("crc64(%s) = 0x%x want 0x%x", g.in, s, g.out) + t.FailNow() + } + } +} + +func BenchmarkCrc64KB(b *testing.B) { + b.StopTimer() + data := make([]uint8, 1024) + for i := 0; i < 1024; i++ { + data[i] = uint8(i) + } + c := New(tab) + b.StartTimer() + + for i := 0; i < b.N; i++ { + c.Write(data) + } +} diff --git a/libgo/go/hash/hash.go b/libgo/go/hash/hash.go new file mode 100644 index 000000000..56ac259db --- /dev/null +++ b/libgo/go/hash/hash.go @@ -0,0 +1,36 @@ +// 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 hash + +import "io" + +// Hash is the common interface implemented by all hash functions. +type Hash interface { + // Write adds more data to the running hash. + // It never returns an error. + io.Writer + + // Sum returns the current hash, without changing the + // underlying hash state. + Sum() []byte + + // Reset resets the hash to one with zero bytes written. + Reset() + + // Size returns the number of bytes Sum will return. + Size() int +} + +// Hash32 is the common interface implemented by all 32-bit hash functions. +type Hash32 interface { + Hash + Sum32() uint32 +} + +// Hash64 is the common interface implemented by all 64-bit hash functions. +type Hash64 interface { + Hash + Sum64() uint64 +} |