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// Copyright 2019 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.
package cpu
import (
"runtime"
)
// byteOrder is a subset of encoding/binary.ByteOrder.
type byteOrder interface {
Uint32([]byte) uint32
Uint64([]byte) uint64
}
type littleEndian struct{}
type bigEndian struct{}
func (littleEndian) Uint32(b []byte) uint32 {
_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
}
func (littleEndian) Uint64(b []byte) uint64 {
_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
}
func (bigEndian) Uint32(b []byte) uint32 {
_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
}
func (bigEndian) Uint64(b []byte) uint64 {
_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
}
// hostByteOrder returns littleEndian on little-endian machines and
// bigEndian on big-endian machines.
func hostByteOrder() byteOrder {
switch runtime.GOARCH {
case "386", "amd64", "amd64p32",
"alpha",
"arm", "arm64",
"mipsle", "mips64le", "mips64p32le",
"nios2",
"ppc64le",
"riscv", "riscv64",
"sh":
return littleEndian{}
case "armbe", "arm64be",
"m68k",
"mips", "mips64", "mips64p32",
"ppc", "ppc64",
"s390", "s390x",
"shbe",
"sparc", "sparc64":
return bigEndian{}
}
panic("unknown architecture")
}
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