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// Copyright © 2020 rsiddharth <s@ricketyspace.net>
// SPDX-License-Identifier: ISC
package lib
const b64_table = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
func HexToBase64(hex string) string {
hb := []byte(hex)
b64 := ""
for i := 0; i <= len(hb)-3; i = i + 3 {
a := (HexCharToDec(hb[i])<<8 |
HexCharToDec(hb[i+1])<<4 |
HexCharToDec(hb[i+2]))
b64 += encode(a >> 6)
b64 += encode(a & 0x3f)
}
return b64
}
func Base64ToBytes(enc string) []byte {
enc = StripSpaceChars(enc)
l := len(enc)
bs := make([]byte, 3*(l/4))
// Base64 decode.
for i, j := 0, 0; i <= l-4; i, j = i+4, j+3 {
// Jam 24 bits together.
a := index(enc[i])<<18 |
index(enc[i+1])<<12 |
index(enc[i+2])<<6 |
index(enc[i+3])
// Get first byte.
bs[j] = byte(a >> 16)
if enc[i+2] == '=' {
return bs[0 : j+1]
}
// Get second byte.
bs[j+1] = byte((a & 0xff00) >> 8)
if enc[i+3] == '=' {
return bs[0 : j+2]
}
// Get third byte.
bs[j+2] = byte(a & 0xff)
}
return bs
}
func encode(b uint16) string {
return string(b64_table[b])
}
// Return the index for a base64 character.
func index(c byte) uint32 {
for i := 0; i < 64; i++ {
if c == b64_table[i] {
return uint32(i)
}
}
return uint32(0)
}
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