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
58 lines
1.5 KiB
Go
58 lines
1.5 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// This package implements functions that are often useful in cryptographic
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// code but require careful thought to use correctly.
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package subtle
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// ConstantTimeCompare returns 1 iff the two equal length slices, x
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// and y, have equal contents. The time taken is a function of the length of
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// the slices and is independent of the contents.
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func ConstantTimeCompare(x, y []byte) int {
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var v byte
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for i := 0; i < len(x); i++ {
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v |= x[i] ^ y[i]
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}
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return ConstantTimeByteEq(v, 0)
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}
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// ConstantTimeSelect returns x if v is 1 and y if v is 0.
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// Its behavior is undefined if v takes any other value.
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func ConstantTimeSelect(v, x, y int) int { return ^(v-1)&x | (v-1)&y }
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// ConstantTimeByteEq returns 1 if x == y and 0 otherwise.
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func ConstantTimeByteEq(x, y uint8) int {
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z := ^(x ^ y)
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z &= z >> 4
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z &= z >> 2
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z &= z >> 1
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return int(z)
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}
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// ConstantTimeEq returns 1 if x == y and 0 otherwise.
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func ConstantTimeEq(x, y int32) int {
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z := ^(x ^ y)
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z &= z >> 16
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z &= z >> 8
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z &= z >> 4
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z &= z >> 2
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z &= z >> 1
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return int(z & 1)
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}
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// ConstantTimeCopy copies the contents of y into x iff v == 1. If v == 0, x is left unchanged.
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// Its behavior is undefined if v takes any other value.
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func ConstantTimeCopy(v int, x, y []byte) {
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xmask := byte(v - 1)
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ymask := byte(^(v - 1))
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for i := 0; i < len(x); i++ {
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x[i] = x[i]&xmask | y[i]&ymask
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}
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return
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}
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