binary.go

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build darwin || dragonfly || freebsd || netbsd || openbsd
     6  
     7  package route
     8  
     9  // This file contains duplicates of encoding/binary package.
    10  //
    11  // This package is supposed to be used by the net package of standard
    12  // library. Therefore the package set used in the package must be the
    13  // same as net package.
    14  
    15  var (
    16  	littleEndian binaryLittleEndian
    17  	bigEndian    binaryBigEndian
    18  )
    19  
    20  type binaryByteOrder interface {
    21  	Uint16([]byte) uint16
    22  	Uint32([]byte) uint32
    23  	PutUint16([]byte, uint16)
    24  	PutUint32([]byte, uint32)
    25  	Uint64([]byte) uint64
    26  }
    27  
    28  type binaryLittleEndian struct{}
    29  
    30  func (binaryLittleEndian) Uint16(b []byte) uint16 {
    31  	_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
    32  	return uint16(b[0]) | uint16(b[1])<<8
    33  }
    34  
    35  func (binaryLittleEndian) PutUint16(b []byte, v uint16) {
    36  	_ = b[1] // early bounds check to guarantee safety of writes below
    37  	b[0] = byte(v)
    38  	b[1] = byte(v >> 8)
    39  }
    40  
    41  func (binaryLittleEndian) Uint32(b []byte) uint32 {
    42  	_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
    43  	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
    44  }
    45  
    46  func (binaryLittleEndian) PutUint32(b []byte, v uint32) {
    47  	_ = b[3] // early bounds check to guarantee safety of writes below
    48  	b[0] = byte(v)
    49  	b[1] = byte(v >> 8)
    50  	b[2] = byte(v >> 16)
    51  	b[3] = byte(v >> 24)
    52  }
    53  
    54  func (binaryLittleEndian) Uint64(b []byte) uint64 {
    55  	_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
    56  	return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
    57  		uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
    58  }
    59  
    60  type binaryBigEndian struct{}
    61  
    62  func (binaryBigEndian) Uint16(b []byte) uint16 {
    63  	_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
    64  	return uint16(b[1]) | uint16(b[0])<<8
    65  }
    66  
    67  func (binaryBigEndian) PutUint16(b []byte, v uint16) {
    68  	_ = b[1] // early bounds check to guarantee safety of writes below
    69  	b[0] = byte(v >> 8)
    70  	b[1] = byte(v)
    71  }
    72  
    73  func (binaryBigEndian) Uint32(b []byte) uint32 {
    74  	_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
    75  	return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
    76  }
    77  
    78  func (binaryBigEndian) PutUint32(b []byte, v uint32) {
    79  	_ = b[3] // early bounds check to guarantee safety of writes below
    80  	b[0] = byte(v >> 24)
    81  	b[1] = byte(v >> 16)
    82  	b[2] = byte(v >> 8)
    83  	b[3] = byte(v)
    84  }
    85  
    86  func (binaryBigEndian) Uint64(b []byte) uint64 {
    87  	_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
    88  	return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
    89  		uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
    90  }
    91
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