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authorrsiddharth <s@ricketyspace.net>2020-09-05 16:40:10 -0400
committerrsiddharth <s@ricketyspace.net>2020-09-05 16:40:10 -0400
commite57a76620a5de1f627a50ab63635f6f1cae39c8c (patch)
tree1c0ee2838efb926740f73676d8cbbe611f81193d
parent9cbdd560c0d397f02138ef2d28a414d599a0c91d (diff)
lib: add Base64ToBytes
* lib/b64.go (Base64ToBytes): New function. lib/b64.go
-rw-r--r--lib/b64.go32
1 files changed, 32 insertions, 0 deletions
diff --git a/lib/b64.go b/lib/b64.go
index 1fb45dd..f566b14 100644
--- a/lib/b64.go
+++ b/lib/b64.go
@@ -19,6 +19,38 @@ func HexToBase64(hex string) string {
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])
}