src/internal/byteorder/byteorder.go

// Copyright 2024 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 byteorder provides functions for decoding and encoding
// little and big endian integer types from/to byte slices.
package byteorder

func LEUint16(b []byte) uint16 {
	_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
	return uint16(b[0]) | uint16(b[1])<<8
}

func LEPutUint16(b []byte, v uint16) {
	_ = b[1] // early bounds check to guarantee safety of writes below
	b[0] = byte(v)
	b[1] = byte(v >> 8)
}

func LEAppendUint16(b []byte, v uint16) []byte {
	return append(b,
		byte(v),
		byte(v>>8),
	)
}

func LEUint32(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 LEPutUint32(b []byte, v uint32) {
	_ = b[3] // early bounds check to guarantee safety of writes below
	b[0] = byte(v)
	b[1] = byte(v >> 8)
	b[2] = byte(v >> 16)
	b[3] = byte(v >> 24)
}

func LEAppendUint32(b []byte, v uint32) []byte {
	return append(b,
		byte(v),
		byte(v>>8),
		byte(v>>16),
		byte(v>>24),
	)
}

func LEUint64(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 LEPutUint64(b []byte, v uint64) {
	_ = b[7] // early bounds check to guarantee safety of writes below
	b[0] = byte(v)
	b[1] = byte(v >> 8)
	b[2] = byte(v >> 16)
	b[3] = byte(v >> 24)
	b[4] = byte(v >> 32)
	b[5] = byte(v >> 40)
	b[6] = byte(v >> 48)
	b[7] = byte(v >> 56)
}

func LEAppendUint64(b []byte, v uint64) []byte {
	return append(b,
		byte(v),
		byte(v>>8),
		byte(v>>16),
		byte(v>>24),
		byte(v>>32),
		byte(v>>40),
		byte(v>>48),
		byte(v>>56),
	)
}

func BEUint16(b []byte) uint16 {
	_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
	return uint16(b[1]) | uint16(b[0])<<8
}

func BEPutUint16(b []byte, v uint16) {
	_ = b[1] // early bounds check to guarantee safety of writes below
	b[0] = byte(v >> 8)
	b[1] = byte(v)
}

func BEAppendUint16(b []byte, v uint16) []byte {
	return append(b,
		byte(v>>8),
		byte(v),
	)
}

func BEUint32(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 BEPutUint32(b []byte, v uint32) {
	_ = b[3] // early bounds check to guarantee safety of writes below
	b[0] = byte(v >> 24)
	b[1] = byte(v >> 16)
	b[2] = byte(v >> 8)
	b[3] = byte(v)
}

func BEAppendUint32(b []byte, v uint32) []byte {
	return append(b,
		byte(v>>24),
		byte(v>>16),
		byte(v>>8),
		byte(v),
	)
}

func BEUint64(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
}

func BEPutUint64(b []byte, v uint64) {
	_ = b[7] // early bounds check to guarantee safety of writes below
	b[0] = byte(v >> 56)
	b[1] = byte(v >> 48)
	b[2] = byte(v >> 40)
	b[3] = byte(v >> 32)
	b[4] = byte(v >> 24)
	b[5] = byte(v >> 16)
	b[6] = byte(v >> 8)
	b[7] = byte(v)
}

func BEAppendUint64(b []byte, v uint64) []byte {
	return append(b,
		byte(v>>56),
		byte(v>>48),
		byte(v>>40),
		byte(v>>32),
		byte(v>>24),
		byte(v>>16),
		byte(v>>8),
		byte(v),
	)
}