diff options
author | Russ Cox <rsc@golang.org> | 2014-09-08 00:08:51 -0400 |
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committer | Russ Cox <rsc@golang.org> | 2014-09-08 00:08:51 -0400 |
commit | 8528da672cc093d4dd06732819abc1f7b6b5a46e (patch) | |
tree | 334be80d4a4c85b77db6f6fdb67cbf0528cba5f5 /src/hash/crc32 | |
parent | 73bcb69f272cbf34ddcc9daa56427a8683b5a95d (diff) | |
download | go-8528da672cc093d4dd06732819abc1f7b6b5a46e.tar.gz |
build: move package sources from src/pkg to src
Preparation was in CL 134570043.
This CL contains only the effect of 'hg mv src/pkg/* src'.
For more about the move, see golang.org/s/go14nopkg.
Diffstat (limited to 'src/hash/crc32')
-rw-r--r-- | src/hash/crc32/crc32.go | 135 | ||||
-rw-r--r-- | src/hash/crc32/crc32_amd64.s | 64 | ||||
-rw-r--r-- | src/hash/crc32/crc32_amd64p32.s | 64 | ||||
-rw-r--r-- | src/hash/crc32/crc32_amd64x.go | 27 | ||||
-rw-r--r-- | src/hash/crc32/crc32_generic.go | 14 | ||||
-rw-r--r-- | src/hash/crc32/crc32_test.go | 99 |
6 files changed, 403 insertions, 0 deletions
diff --git a/src/hash/crc32/crc32.go b/src/hash/crc32/crc32.go new file mode 100644 index 000000000..a2a21a06f --- /dev/null +++ b/src/hash/crc32/crc32.go @@ -0,0 +1,135 @@ +// 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 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" + "sync" +) + +// 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 + +// castagnoliTable points to a lazily initialized Table for the Castagnoli +// polynomial. MakeTable will always return this value when asked to make a +// Castagnoli table so we can compare against it to find when the caller is +// using this polynomial. +var castagnoliTable *Table +var castagnoliOnce sync.Once + +func castagnoliInit() { + castagnoliTable = makeTable(Castagnoli) +} + +// IEEETable is the table for the IEEE polynomial. +var IEEETable = makeTable(IEEE) + +// MakeTable returns the Table constructed from the specified polynomial. +func MakeTable(poly uint32) *Table { + switch poly { + case IEEE: + return IEEETable + case Castagnoli: + castagnoliOnce.Do(castagnoliInit) + return castagnoliTable + } + return makeTable(poly) +} + +// 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 +} + +// 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) BlockSize() int { return 1 } + +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 { + if tab == castagnoliTable { + return updateCastagnoli(crc, p) + } + return update(crc, tab, p) +} + +func (d *digest) Write(p []byte) (n int, err 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(in []byte) []byte { + s := d.Sum32() + return append(in, byte(s>>24), byte(s>>16), byte(s>>8), byte(s)) +} + +// 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/src/hash/crc32/crc32_amd64.s b/src/hash/crc32/crc32_amd64.s new file mode 100644 index 000000000..30b0d0691 --- /dev/null +++ b/src/hash/crc32/crc32_amd64.s @@ -0,0 +1,64 @@ +// Copyright 2011 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. + +#include "textflag.h" + +// func castagnoliSSE42(crc uint32, p []byte) uint32 +TEXT ·castagnoliSSE42(SB),NOSPLIT,$0 + MOVL crc+0(FP), AX // CRC value + MOVQ p+8(FP), SI // data pointer + MOVQ p_len+16(FP), CX // len(p) + + NOTL AX + + /* If there's less than 8 bytes to process, we do it byte-by-byte. */ + CMPQ CX, $8 + JL cleanup + + /* Process individual bytes until the input is 8-byte aligned. */ +startup: + MOVQ SI, BX + ANDQ $7, BX + JZ aligned + + CRC32B (SI), AX + DECQ CX + INCQ SI + JMP startup + +aligned: + /* The input is now 8-byte aligned and we can process 8-byte chunks. */ + CMPQ CX, $8 + JL cleanup + + CRC32Q (SI), AX + ADDQ $8, SI + SUBQ $8, CX + JMP aligned + +cleanup: + /* We may have some bytes left over that we process one at a time. */ + CMPQ CX, $0 + JE done + + CRC32B (SI), AX + INCQ SI + DECQ CX + JMP cleanup + +done: + NOTL AX + MOVL AX, ret+32(FP) + RET + +// func haveSSE42() bool +TEXT ·haveSSE42(SB),NOSPLIT,$0 + XORQ AX, AX + INCL AX + CPUID + SHRQ $20, CX + ANDQ $1, CX + MOVB CX, ret+0(FP) + RET + diff --git a/src/hash/crc32/crc32_amd64p32.s b/src/hash/crc32/crc32_amd64p32.s new file mode 100644 index 000000000..b6770eba3 --- /dev/null +++ b/src/hash/crc32/crc32_amd64p32.s @@ -0,0 +1,64 @@ +// Copyright 2011 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. + +#include "textflag.h" + +// func castagnoliSSE42(crc uint32, p []byte) uint32 +TEXT ·castagnoliSSE42(SB),NOSPLIT,$0 + MOVL crc+0(FP), AX // CRC value + MOVL p+4(FP), SI // data pointer + MOVL p_len+8(FP), CX // len(p) + + NOTL AX + + /* If there's less than 8 bytes to process, we do it byte-by-byte. */ + CMPQ CX, $8 + JL cleanup + + /* Process individual bytes until the input is 8-byte aligned. */ +startup: + MOVQ SI, BX + ANDQ $7, BX + JZ aligned + + CRC32B (SI), AX + DECQ CX + INCQ SI + JMP startup + +aligned: + /* The input is now 8-byte aligned and we can process 8-byte chunks. */ + CMPQ CX, $8 + JL cleanup + + CRC32Q (SI), AX + ADDQ $8, SI + SUBQ $8, CX + JMP aligned + +cleanup: + /* We may have some bytes left over that we process one at a time. */ + CMPQ CX, $0 + JE done + + CRC32B (SI), AX + INCQ SI + DECQ CX + JMP cleanup + +done: + NOTL AX + MOVL AX, ret+16(FP) + RET + +// func haveSSE42() bool +TEXT ·haveSSE42(SB),NOSPLIT,$0 + XORQ AX, AX + INCL AX + CPUID + SHRQ $20, CX + ANDQ $1, CX + MOVB CX, ret+0(FP) + RET + diff --git a/src/hash/crc32/crc32_amd64x.go b/src/hash/crc32/crc32_amd64x.go new file mode 100644 index 000000000..b7e359930 --- /dev/null +++ b/src/hash/crc32/crc32_amd64x.go @@ -0,0 +1,27 @@ +// Copyright 2011 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. + +// +build amd64 amd64p32 + +package crc32 + +// This file contains the code to call the SSE 4.2 version of the Castagnoli +// CRC. + +// haveSSE42 is defined in crc_amd64.s and uses CPUID to test for SSE 4.2 +// support. +func haveSSE42() bool + +// castagnoliSSE42 is defined in crc_amd64.s and uses the SSE4.2 CRC32 +// instruction. +func castagnoliSSE42(crc uint32, p []byte) uint32 + +var sse42 = haveSSE42() + +func updateCastagnoli(crc uint32, p []byte) uint32 { + if sse42 { + return castagnoliSSE42(crc, p) + } + return update(crc, castagnoliTable, p) +} diff --git a/src/hash/crc32/crc32_generic.go b/src/hash/crc32/crc32_generic.go new file mode 100644 index 000000000..c3fdcd685 --- /dev/null +++ b/src/hash/crc32/crc32_generic.go @@ -0,0 +1,14 @@ +// Copyright 2011 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. + +// +build 386 arm + +package crc32 + +// The file contains the generic version of updateCastagnoli which just calls +// the software implementation. + +func updateCastagnoli(crc uint32, p []byte) uint32 { + return update(crc, castagnoliTable, p) +} diff --git a/src/hash/crc32/crc32_test.go b/src/hash/crc32/crc32_test.go new file mode 100644 index 000000000..75dc26e7c --- /dev/null +++ b/src/hash/crc32/crc32_test.go @@ -0,0 +1,99 @@ +// 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 { + ieee, castagnoli uint32 + in string +} + +var golden = []test{ + {0x0, 0x0, ""}, + {0xe8b7be43, 0xc1d04330, "a"}, + {0x9e83486d, 0xe2a22936, "ab"}, + {0x352441c2, 0x364b3fb7, "abc"}, + {0xed82cd11, 0x92c80a31, "abcd"}, + {0x8587d865, 0xc450d697, "abcde"}, + {0x4b8e39ef, 0x53bceff1, "abcdef"}, + {0x312a6aa6, 0xe627f441, "abcdefg"}, + {0xaeef2a50, 0xa9421b7, "abcdefgh"}, + {0x8da988af, 0x2ddc99fc, "abcdefghi"}, + {0x3981703a, 0xe6599437, "abcdefghij"}, + {0x6b9cdfe7, 0xb2cc01fe, "Discard medicine more than two years old."}, + {0xc90ef73f, 0xe28207f, "He who has a shady past knows that nice guys finish last."}, + {0xb902341f, 0xbe93f964, "I wouldn't marry him with a ten foot pole."}, + {0x42080e8, 0x9e3be0c3, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave"}, + {0x154c6d11, 0xf505ef04, "The days of the digital watch are numbered. -Tom Stoppard"}, + {0x4c418325, 0x85d3dc82, "Nepal premier won't resign."}, + {0x33955150, 0xc5142380, "For every action there is an equal and opposite government program."}, + {0x26216a4b, 0x75eb77dd, "His money is twice tainted: 'taint yours and 'taint mine."}, + {0x1abbe45e, 0x91ebe9f7, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977"}, + {0xc89a94f7, 0xf0b1168e, "It's a tiny change to the code and not completely disgusting. - Bob Manchek"}, + {0xab3abe14, 0x572b74e2, "size: a.out: bad magic"}, + {0xbab102b6, 0x8a58a6d5, "The major problem is with sendmail. -Mark Horton"}, + {0x999149d7, 0x9c426c50, "Give me a rock, paper and scissors and I will move the world. CCFestoon"}, + {0x6d52a33c, 0x735400a4, "If the enemy is within range, then so are you."}, + {0x90631e8d, 0xbec49c95, "It's well we cannot hear the screams/That we create in others' dreams."}, + {0x78309130, 0xa95a2079, "You remind me of a TV show, but that's all right: I watch it anyway."}, + {0x7d0a377f, 0xde2e65c5, "C is as portable as Stonehedge!!"}, + {0x8c79fd79, 0x297a88ed, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley"}, + {0xa20b7167, 0x66ed1d8b, "The fugacity of a constituent in a mixture of gases at a given temperature is proportional to its mole fraction. Lewis-Randall Rule"}, + {0x8e0bb443, 0xdcded527, "How can you write a big system without C++? -Paul Glick"}, +} + +func TestGolden(t *testing.T) { + castagnoliTab := MakeTable(Castagnoli) + + for _, g := range golden { + ieee := NewIEEE() + io.WriteString(ieee, g.in) + s := ieee.Sum32() + if s != g.ieee { + t.Errorf("IEEE(%s) = 0x%x want 0x%x", g.in, s, g.ieee) + } + + castagnoli := New(castagnoliTab) + io.WriteString(castagnoli, g.in) + s = castagnoli.Sum32() + if s != g.castagnoli { + t.Errorf("Castagnoli(%s) = 0x%x want 0x%x", g.in, s, g.castagnoli) + } + + if len(g.in) > 0 { + // The SSE4.2 implementation of this has code to deal + // with misaligned data so we ensure that we test that + // too. + castagnoli = New(castagnoliTab) + io.WriteString(castagnoli, g.in[:1]) + io.WriteString(castagnoli, g.in[1:]) + s = castagnoli.Sum32() + if s != g.castagnoli { + t.Errorf("Castagnoli[misaligned](%s) = 0x%x want 0x%x", g.in, s, g.castagnoli) + } + } + } +} + +func BenchmarkCrc32KB(b *testing.B) { + b.SetBytes(1024) + data := make([]byte, 1024) + for i := range data { + data[i] = byte(i) + } + h := NewIEEE() + in := make([]byte, 0, h.Size()) + + b.ResetTimer() + for i := 0; i < b.N; i++ { + h.Reset() + h.Write(data) + h.Sum(in) + } +} |