You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
95 lines
2.2 KiB
Go
95 lines
2.2 KiB
Go
// Copyright 2016 Tom Thorogood. All rights reserved.
|
|
// Use of this source code is governed by a
|
|
// Modified BSD License license that can be found in
|
|
// the LICENSE file.
|
|
|
|
// +build amd64,!gccgo,!appengine
|
|
|
|
package hex
|
|
|
|
import "golang.org/x/sys/cpu"
|
|
|
|
// RawEncode encodes src into EncodedLen(len(src))
|
|
// bytes of dst. As a convenience, it returns the number
|
|
// of bytes written to dst, but this value is always EncodedLen(len(src)).
|
|
// RawEncode implements hexadecimal encoding for a given alphabet.
|
|
func RawEncode(dst, src, alpha []byte) int {
|
|
if len(alpha) != 16 {
|
|
panic("invalid alphabet")
|
|
}
|
|
|
|
if len(dst) < len(src)*2 {
|
|
panic("dst buffer is too small")
|
|
}
|
|
|
|
if len(src) == 0 {
|
|
return 0
|
|
}
|
|
|
|
switch {
|
|
case cpu.X86.HasAVX:
|
|
encodeAVX(&dst[0], &src[0], uint64(len(src)), &alpha[0])
|
|
case cpu.X86.HasSSE41:
|
|
encodeSSE(&dst[0], &src[0], uint64(len(src)), &alpha[0])
|
|
default:
|
|
encodeGeneric(dst, src, alpha)
|
|
}
|
|
|
|
return len(src) * 2
|
|
}
|
|
|
|
// Decode decodes src into DecodedLen(len(src)) bytes, returning the actual
|
|
// number of bytes written to dst.
|
|
//
|
|
// If Decode encounters invalid input, it returns an error describing the failure.
|
|
func Decode(dst, src []byte) (int, error) {
|
|
if len(src)%2 != 0 {
|
|
return 0, errLength
|
|
}
|
|
|
|
if len(dst) < len(src)/2 {
|
|
panic("dst buffer is too small")
|
|
}
|
|
|
|
if len(src) == 0 {
|
|
return 0, nil
|
|
}
|
|
|
|
var (
|
|
n uint64
|
|
ok bool
|
|
)
|
|
switch {
|
|
case cpu.X86.HasAVX:
|
|
n, ok = decodeAVX(&dst[0], &src[0], uint64(len(src)))
|
|
case cpu.X86.HasSSE41:
|
|
n, ok = decodeSSE(&dst[0], &src[0], uint64(len(src)))
|
|
default:
|
|
n, ok = decodeGeneric(dst, src)
|
|
}
|
|
|
|
if !ok {
|
|
return 0, InvalidByteError(src[n])
|
|
}
|
|
|
|
return len(src) / 2, nil
|
|
}
|
|
|
|
//go:generate go run asm_gen.go
|
|
|
|
// This function is implemented in hex_encode_amd64.s
|
|
//go:noescape
|
|
func encodeAVX(dst *byte, src *byte, len uint64, alpha *byte)
|
|
|
|
// This function is implemented in hex_encode_amd64.s
|
|
//go:noescape
|
|
func encodeSSE(dst *byte, src *byte, len uint64, alpha *byte)
|
|
|
|
// This function is implemented in hex_decode_amd64.s
|
|
//go:noescape
|
|
func decodeAVX(dst *byte, src *byte, len uint64) (n uint64, ok bool)
|
|
|
|
// This function is implemented in hex_decode_amd64.s
|
|
//go:noescape
|
|
func decodeSSE(dst *byte, src *byte, len uint64) (n uint64, ok bool)
|