github.com/GeniusesGroup/libgo@v0.0.0-20220929090155-5ff932cb408e/binary/be-in-le-cpu.go (about)

     1  // For license and copyright information please see the LEGAL file in the code repository
     2  
     3  //go:build 386 || amd64 || amd64p32 || arm || arm64 || loong64 || mips64le || mips64p32le || mipsle || ppc64le || riscv || riscv64 || wasm
     4  
     5  package binary
     6  
     7  import "unsafe"
     8  
     9  // BigEndian is the big-endian implementation to get|set from be binary to le cpu
    10  var BigEndian bigEndian
    11  
    12  type bigEndian struct{}
    13  
    14  func (bigEndian) Uint16(b []byte) uint16 {
    15  	_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
    16  	return uint16(b[1]) | uint16(b[0])<<8
    17  }
    18  func (bigEndian) Uint32(b []byte) uint32 {
    19  	_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
    20  	return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
    21  }
    22  
    23  func (bigEndian) Uint64(b []byte) uint64 {
    24  	_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
    25  	return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
    26  		uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
    27  }
    28  
    29  func (bigEndian) PutUint16(b []byte, v uint16) {
    30  	_ = b[1] // early bounds check to guarantee safety of writes below
    31  	b[0] = byte(v >> 8)
    32  	b[1] = byte(v)
    33  }
    34  func (bigEndian) PutUint32(b []byte, v uint32) {
    35  	_ = b[3] // early bounds check to guarantee safety of writes below
    36  	b[0] = byte(v >> 24)
    37  	b[1] = byte(v >> 16)
    38  	b[2] = byte(v >> 8)
    39  	b[3] = byte(v)
    40  }
    41  func (bigEndian) PutUint64(b []byte, v uint64) {
    42  	_ = b[7] // early bounds check to guarantee safety of writes below
    43  	b[0] = byte(v >> 56)
    44  	b[1] = byte(v >> 48)
    45  	b[2] = byte(v >> 40)
    46  	b[3] = byte(v >> 32)
    47  	b[4] = byte(v >> 24)
    48  	b[5] = byte(v >> 16)
    49  	b[6] = byte(v >> 8)
    50  	b[7] = byte(v)
    51  }
    52  
    53  func init() {
    54  	i := uint32(1)
    55  	b := (*[4]byte)(unsafe.Pointer(&i))
    56  	if b[0] != 1 {
    57  		panic("Expect LittleEndian CPU but have BigEndian CPU that cause many problem in other packages")
    58  	}
    59  }