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-rw-r--r--lib/b64.go24
-rw-r--r--lib/hex.go26
-rw-r--r--lib/xor.go22
3 files changed, 72 insertions, 0 deletions
diff --git a/lib/b64.go b/lib/b64.go
new file mode 100644
index 0000000..d37f710
--- /dev/null
+++ b/lib/b64.go
@@ -0,0 +1,24 @@
+// 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 & 0b111111)
+ }
+ return b64
+}
+
+func encode(b uint16) string {
+ return string(b64_table[b])
+}
diff --git a/lib/hex.go b/lib/hex.go
new file mode 100644
index 0000000..bf539bc
--- /dev/null
+++ b/lib/hex.go
@@ -0,0 +1,26 @@
+// Copyright © 2020 rsiddharth <s@ricketyspace.net>
+// SPDX-License-Identifier: ISC
+
+package lib
+
+// Adapted from
+// https://go.googlesource.com/go/+/refs/tags/go1.15/src/encoding/hex/hex.go#83
+func HexCharToDec(c byte) uint16 {
+ switch {
+ case '0' <= c && c <= '9':
+ return uint16(c - '0')
+ case 'a' <= c && c <= 'f':
+ return uint16(c - 'a' + 10)
+ }
+ return 0
+}
+
+func DecToHexChar(i uint16) byte {
+ switch {
+ case 0 <= i && i <= 9:
+ return byte(48 + i)
+ case 10 <= i && i <= 15:
+ return byte(97 + (i - 10))
+ }
+ return 0
+}
diff --git a/lib/xor.go b/lib/xor.go
new file mode 100644
index 0000000..270999c
--- /dev/null
+++ b/lib/xor.go
@@ -0,0 +1,22 @@
+// Copyright © 2020 rsiddharth <s@ricketyspace.net>
+// SPDX-License-Identifier: ISC
+
+package lib
+
+func FixedXOR(a, b string) string {
+ cs := ""
+ if len(a) != len(b) {
+ return cs
+ }
+
+ ab := []byte(a)
+ bb := []byte(b)
+ for i := 0; i < len(ab); i++ {
+ p := HexCharToDec(ab[i])
+ q := HexCharToDec(bb[i])
+ r := DecToHexChar(p ^ q)
+
+ cs += string(r)
+ }
+ return cs
+}