github.com/geniusesgroup/libgo@v0.0.0-20220713101832-828057a9d3d4/binary/le-in-le-cpu.go (about)

     1  // For license and copyright information please see LEGAL file in 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 (
     8  	"unsafe"
     9  )
    10  
    11  // LittleEndian is the little-endian implementation to get|set from le binary to le cpu
    12  var LittleEndian littleEndian
    13  
    14  type littleEndian struct{}
    15  
    16  func (littleEndian) Uint16(b []byte) uint16 { return uint16(b[0]) | uint16(b[1])<<8 }
    17  func (littleEndian) Uint32(b []byte) uint32 {
    18  	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
    19  }
    20  func (littleEndian) Uint64(b []byte) uint64 {
    21  	return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
    22  		uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
    23  }
    24  
    25  func (littleEndian) PutUint16(b []byte, v uint16) {
    26  	b[0] = byte(v)
    27  	b[1] = byte(v >> 8)
    28  }
    29  func (littleEndian) PutUint32(b []byte, v uint32) {
    30  	b[0] = byte(v)
    31  	b[1] = byte(v >> 8)
    32  	b[2] = byte(v >> 16)
    33  	b[3] = byte(v >> 24)
    34  }
    35  func (littleEndian) PutUint64(b []byte, v uint64) {
    36  	b[0] = byte(v)
    37  	b[1] = byte(v >> 8)
    38  	b[2] = byte(v >> 16)
    39  	b[3] = byte(v >> 24)
    40  	b[4] = byte(v >> 32)
    41  	b[5] = byte(v >> 40)
    42  	b[6] = byte(v >> 48)
    43  	b[7] = byte(v >> 56)
    44  }
    45  
    46  // *data = math.Float32frombits(order.Uint32(bs))
    47  // *data = math.Float64frombits(order.Uint64(bs))
    48  
    49  func init() {
    50  	i := uint32(1)
    51  	b := (*[4]byte)(unsafe.Pointer(&i))
    52  	if b[0] != 1 {
    53  		panic("Expect LittleEndian CPU but have BigEndian CPU that cause many problem in other packages")
    54  	}
    55  }