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fq/pkg/bitio/bitstring.go
Mattias Wadman 970465996c Init
2021-09-12 13:08:42 +02:00

40 lines
781 B
Go

package bitio
import (
"fmt"
"strings"
)
// BytesFromBitString []byte from bit string, ex: "0101" -> ([]byte{0x50}, 4)
func BytesFromBitString(s string) ([]byte, int) {
r := len(s) % 8
bufLen := len(s) / 8
if r > 0 {
bufLen++
}
buf := make([]byte, bufLen)
for i := 0; i < len(s); i++ {
d := s[i] - '0'
if d != 0 && d != 1 {
panic(fmt.Sprintf("invalid bit string %q at index %d %q", s, i, s[i]))
}
buf[i/8] |= d << (7 - i%8)
}
return buf, len(s)
}
// BitStringFromBytes string from []byte], ex: ([]byte{0x50}, 4) -> "0101"
func BitStringFromBytes(buf []byte, nBits int) string {
sb := &strings.Builder{}
for i := 0; i < nBits; i++ {
if buf[i/8]&(1<<(7-i%8)) > 0 {
sb.WriteString("1")
} else {
sb.WriteString("0")
}
}
return sb.String()
}