/
bit.go
90 lines (77 loc) · 1.64 KB
/
bit.go
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package drawfcall // import "bwsd.dev/draw/drawfcall"
// Note that these are big-endian, unlike Plan 9 fcalls, which are little-endian.
func gbit8(b []byte) (uint8, []byte) {
return uint8(b[0]), b[1:]
}
func gbit16(b []byte) (uint16, []byte) {
return uint16(b[1]) | uint16(b[0])<<8, b[2:]
}
func gbit32(b []byte) (int, []byte) {
return int(uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24), b[4:]
}
func gbit64(b []byte) (uint64, []byte) {
hi, b := gbit32(b)
lo, b := gbit32(b)
return uint64(hi)<<32 | uint64(lo), b
}
func gstring(b []byte) (string, []byte) {
n, b := gbit32(b)
return string(b[0:n]), b[n:]
}
func gbytes(b []byte) ([]byte, []byte) {
n, b := gbit32(b)
return b[0:n], b[n:]
}
func pbit8(b []byte, x uint8) []byte {
n := len(b)
if n+1 > cap(b) {
nb := make([]byte, n, 100+2*cap(b))
copy(nb, b)
b = nb
}
b = b[0 : n+1]
b[n] = x
return b
}
func pbit16(b []byte, x uint16) []byte {
n := len(b)
if n+2 > cap(b) {
nb := make([]byte, n, 100+2*cap(b))
copy(nb, b)
b = nb
}
b = b[0 : n+2]
b[n] = byte(x >> 8)
b[n+1] = byte(x)
return b
}
func pbit32(b []byte, i int) []byte {
x := uint32(i)
n := len(b)
if n+4 > cap(b) {
nb := make([]byte, n, 100+2*cap(b))
copy(nb, b)
b = nb
}
b = b[0 : n+4]
b[n] = byte(x >> 24)
b[n+1] = byte(x >> 16)
b[n+2] = byte(x >> 8)
b[n+3] = byte(x)
return b
}
func pbit64(b []byte, x uint64) []byte {
b = pbit32(b, int(x>>32))
b = pbit32(b, int(x))
return b
}
func pstring(b []byte, s string) []byte {
b = pbit32(b, len(s))
b = append(b, []byte(s)...)
return b
}
func pbytes(b, s []byte) []byte {
b = pbit32(b, len(s))
b = append(b, s...)
return b
}