435c0d9fc8
This PR switches the Nomad repository from using govendor to Go modules for managing dependencies. Aspects of the Nomad workflow remain pretty much the same. The usual Makefile targets should continue to work as they always did. The API submodule simply defers to the parent Nomad version on the repository, keeping the semantics of API versioning that currently exists.
43 lines
1.2 KiB
Go
43 lines
1.2 KiB
Go
// Copyright 2018 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 src the LICENSE file.
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package chacha20
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import "runtime"
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// Platforms that have fast unaligned 32-bit little endian accesses.
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const unaligned = runtime.GOARCH == "386" ||
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runtime.GOARCH == "amd64" ||
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runtime.GOARCH == "arm64" ||
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runtime.GOARCH == "ppc64le" ||
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runtime.GOARCH == "s390x"
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// addXor reads a little endian uint32 from src, XORs it with (a + b) and
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// places the result in little endian byte order in dst.
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func addXor(dst, src []byte, a, b uint32) {
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_, _ = src[3], dst[3] // bounds check elimination hint
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if unaligned {
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// The compiler should optimize this code into
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// 32-bit unaligned little endian loads and stores.
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// TODO: delete once the compiler does a reliably
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// good job with the generic code below.
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// See issue #25111 for more details.
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v := uint32(src[0])
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v |= uint32(src[1]) << 8
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v |= uint32(src[2]) << 16
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v |= uint32(src[3]) << 24
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v ^= a + b
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dst[0] = byte(v)
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dst[1] = byte(v >> 8)
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dst[2] = byte(v >> 16)
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dst[3] = byte(v >> 24)
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} else {
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a += b
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dst[0] = src[0] ^ byte(a)
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dst[1] = src[1] ^ byte(a>>8)
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dst[2] = src[2] ^ byte(a>>16)
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dst[3] = src[3] ^ byte(a>>24)
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}
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}
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