7a9389330e
gcc/: * gcc.c (default_compilers): Add entry for ".go". * common.opt: Add -static-libgo as a driver option. * doc/install.texi (Configuration): Mention libgo as an option for --enable-shared. Mention go as an option for --enable-languages. * doc/invoke.texi (Overall Options): Mention .go as a file name suffix. Mention go as a -x option. * doc/frontends.texi (G++ and GCC): Mention Go as a supported language. * doc/sourcebuild.texi (Top Level): Mention libgo. * doc/standards.texi (Standards): Add section on Go language. Move references for other languages into their own section. * doc/contrib.texi (Contributors): Mention that I contributed the Go frontend. gcc/testsuite/: * lib/go.exp: New file. * lib/go-dg.exp: New file. * lib/go-torture.exp: New file. * lib/target-supports.exp (check_compile): Match // Go. From-SVN: r167407
97 lines
2.2 KiB
Go
97 lines
2.2 KiB
Go
// 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 >> 54)
|
|
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) }
|