mirror of https://github.com/go-gitea/gitea.git
53 lines
1.6 KiB
Go
53 lines
1.6 KiB
Go
// Copyright 2019 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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// +build ppc64le,!gccgo,!appengine
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package chacha20
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import "encoding/binary"
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const (
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bufSize = 256
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haveAsm = true
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)
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//go:noescape
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func chaCha20_ctr32_vmx(out, inp *byte, len int, key *[8]uint32, counter *uint32)
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func (c *Cipher) xorKeyStreamAsm(dst, src []byte) {
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if len(src) >= bufSize {
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chaCha20_ctr32_vmx(&dst[0], &src[0], len(src)-len(src)%bufSize, &c.key, &c.counter)
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}
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if len(src)%bufSize != 0 {
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chaCha20_ctr32_vmx(&c.buf[0], &c.buf[0], bufSize, &c.key, &c.counter)
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start := len(src) - len(src)%bufSize
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ts, td, tb := src[start:], dst[start:], c.buf[:]
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// Unroll loop to XOR 32 bytes per iteration.
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for i := 0; i < len(ts)-32; i += 32 {
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td, tb = td[:len(ts)], tb[:len(ts)] // bounds check elimination
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s0 := binary.LittleEndian.Uint64(ts[0:8])
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s1 := binary.LittleEndian.Uint64(ts[8:16])
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s2 := binary.LittleEndian.Uint64(ts[16:24])
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s3 := binary.LittleEndian.Uint64(ts[24:32])
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b0 := binary.LittleEndian.Uint64(tb[0:8])
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b1 := binary.LittleEndian.Uint64(tb[8:16])
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b2 := binary.LittleEndian.Uint64(tb[16:24])
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b3 := binary.LittleEndian.Uint64(tb[24:32])
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binary.LittleEndian.PutUint64(td[0:8], s0^b0)
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binary.LittleEndian.PutUint64(td[8:16], s1^b1)
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binary.LittleEndian.PutUint64(td[16:24], s2^b2)
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binary.LittleEndian.PutUint64(td[24:32], s3^b3)
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ts, td, tb = ts[32:], td[32:], tb[32:]
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}
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td, tb = td[:len(ts)], tb[:len(ts)] // bounds check elimination
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for i, v := range ts {
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td[i] = tb[i] ^ v
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}
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c.len = bufSize - (len(src) % bufSize)
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}
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}
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