57 lines
1.2 KiB
Go
57 lines
1.2 KiB
Go
package multibase
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import (
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"fmt"
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"math"
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"strconv"
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"strings"
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)
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// binaryEncodeToString takes an array of bytes and returns
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// multibase binary representation
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func binaryEncodeToString(src []byte) string {
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dst := make([]byte, len(src)*8)
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encodeBinary(dst, src)
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return string(dst)
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}
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// encodeBinary takes the src and dst bytes and converts each
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// byte to their binary rep using power reduction method
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func encodeBinary(dst []byte, src []byte) {
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for i := 0; i < len(src); i++ {
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t := src[i]
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for j := i << 3; j < (i<<3)+8; j++ {
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higherPower := math.Pow(2, float64(7-(j&7)))
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if t >= byte(higherPower) {
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dst[j] = '1'
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t = t - byte(higherPower)
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} else {
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dst[j] = '0'
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}
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}
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}
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}
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// decodeBinaryString takes multibase binary representation
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// and returns a byte array
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func decodeBinaryString(s string) ([]byte, error) {
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if len(s)&7 != 0 {
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// prepend the padding
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s = strings.Repeat("0", 8-len(s)&7) + s
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}
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data := make([]byte, len(s)>>3)
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for i, dstIndex := 0, 0; i < len(s); i = i + 8 {
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value, err := strconv.ParseInt(s[i:i+8], 2, 0)
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if err != nil {
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return nil, fmt.Errorf("error while conversion: %s", err)
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}
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data[dstIndex] = byte(value)
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dstIndex++
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}
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return data, nil
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}
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