From 8d1441db4bede7cdfd342fc8c85c9d50718f28d0 Mon Sep 17 00:00:00 2001
From: Kevin Atkinson <k@kevina.org>
Date: Mon, 28 Aug 2017 17:38:04 -0400
Subject: [PATCH] Make base32 encodings case preserving.

---
 multibase.go      | 50 ++++++++++++++++++++++++++++++++++-------------
 multibase_test.go | 18 ++++++++++++-----
 2 files changed, 49 insertions(+), 19 deletions(-)

diff --git a/multibase.go b/multibase.go
index eced3d6..2b56b70 100644
--- a/multibase.go
+++ b/multibase.go
@@ -51,14 +51,22 @@ func Encode(base Encoding, data []byte) (string, error) {
 		return string(Identity) + string(data), nil
 	case Base16, Base16Upper:
 		return string(Base16) + hex.EncodeToString(data), nil
-	case Base32, Base32Upper:
-		return string(Base32) + b32.RawStdEncoding.EncodeToString(data), nil
-	case Base32hex, Base32hexUpper:
-		return string(Base32hex) + b32.RawHexEncoding.EncodeToString(data), nil
-	case Base32pad, Base32padUpper:
-		return string(Base32pad) + b32.StdEncoding.EncodeToString(data), nil
-	case Base32hexPad, Base32hexPadUpper:
-		return string(Base32hexPad) + b32.HexEncoding.EncodeToString(data), nil
+	case Base32:
+		return string(Base32) + base32StdLowerNoPad.EncodeToString(data), nil
+	case Base32Upper:
+		return string(Base32Upper) + base32StdUpperNoPad.EncodeToString(data), nil
+	case Base32hex:
+		return string(Base32hex) + base32HexLowerNoPad.EncodeToString(data), nil
+	case Base32hexUpper:
+		return string(Base32hexUpper) + base32HexUpperNoPad.EncodeToString(data), nil
+	case Base32pad:
+		return string(Base32pad) + base32StdLowerPad.EncodeToString(data), nil
+	case Base32padUpper:
+		return string(Base32padUpper) + base32StdUpperPad.EncodeToString(data), nil
+	case Base32hexPad:
+		return string(Base32hexPad) + base32HexLowerPad.EncodeToString(data), nil
+	case Base32hexPadUpper:
+		return string(Base32hexPadUpper) + base32HexUpperPad.EncodeToString(data), nil
 	case Base58BTC:
 		return string(Base58BTC) + b58.EncodeAlphabet(data, b58.BTCAlphabet), nil
 	case Base58Flickr:
@@ -83,24 +91,26 @@ func Decode(data string) (Encoding, []byte, error) {
 		return 0, nil, fmt.Errorf("cannot decode multibase for zero length string")
 	}
 
-	switch data[0] {
+	enc := Encoding(data[0])
+
+	switch enc {
 	case Identity:
 		return Identity, []byte(data[1:]), nil
 	case Base16, Base16Upper:
 		bytes, err := hex.DecodeString(data[1:])
-		return Base16, bytes, err
+		return enc, bytes, err
 	case Base32, Base32Upper:
 		bytes, err := b32.RawStdEncoding.DecodeString(data[1:])
-		return Base32, bytes, err
+		return enc, bytes, err
 	case Base32hex, Base32hexUpper:
 		bytes, err := b32.RawHexEncoding.DecodeString(data[1:])
-		return Base32hex, bytes, err
+		return enc, bytes, err
 	case Base32pad, Base32padUpper:
 		bytes, err := b32.StdEncoding.DecodeString(data[1:])
-		return Base32pad, bytes, err
+		return enc, bytes, err
 	case Base32hexPad, Base32hexPadUpper:
 		bytes, err := b32.HexEncoding.DecodeString(data[1:])
-		return Base32hexPad, bytes, err
+		return enc, bytes, err
 	case Base58BTC:
 		return Base58BTC, b58.DecodeAlphabet(data[1:], b58.BTCAlphabet), nil
 	case Base58Flickr:
@@ -121,3 +131,15 @@ func Decode(data string) (Encoding, []byte, error) {
 		return -1, nil, ErrUnsupportedEncoding
 	}
 }
+
+var base32StdLowerPad = b32.NewEncodingCI("abcdefghijklmnopqrstuvwxyz234567")
+var base32StdLowerNoPad = base32StdLowerPad.WithPadding(b32.NoPadding)
+
+var base32StdUpperPad = b32.NewEncodingCI("ABCDEFGHIJKLMNOPQRSTUVWXYZ234567")
+var base32StdUpperNoPad = base32StdUpperPad.WithPadding(b32.NoPadding)
+
+var base32HexLowerPad = b32.NewEncodingCI("0123456789abcdefghijklmnopqrstuv")
+var base32HexLowerNoPad = base32HexLowerPad.WithPadding(b32.NoPadding)
+
+var base32HexUpperPad = b32.NewEncodingCI("0123456789ABCDEFGHIJKLMNOPQRSTUV")
+var base32HexUpperNoPad = base32HexUpperPad.WithPadding(b32.NoPadding)
diff --git a/multibase_test.go b/multibase_test.go
index e71f77f..5c9ada7 100644
--- a/multibase_test.go
+++ b/multibase_test.go
@@ -8,11 +8,19 @@ import (
 
 var sampleBytes = []byte("Decentralize everything!!")
 var encodedSamples = map[Encoding]string{
-	Identity:     string(0x00) + "Decentralize everything!!",
-	Base16:       "f446563656e7472616c697a652065766572797468696e672121",
-	Base58BTC:    "zUXE7GvtEk8XTXs1GF8HSGbVA9FCX9SEBPe",
-	Base64pad:    "MRGVjZW50cmFsaXplIGV2ZXJ5dGhpbmchIQ==",
-	Base64urlPad: "URGVjZW50cmFsaXplIGV2ZXJ5dGhpbmchIQ==",
+	Identity:          string(0x00) + "Decentralize everything!!",
+	Base16:            "f446563656e7472616c697a652065766572797468696e672121",
+	Base32:            "birswgzloorzgc3djpjssazlwmvzhs5dinfxgoijb",
+	Base32Upper:       "BIRSWGZLOORZGC3DJPJSSAZLWMVZHS5DINFXGOIJB",
+	Base32pad:         "cirswgzloorzgc3djpjssazlwmvzhs5dinfxgoijb",
+	Base32padUpper:    "CIRSWGZLOORZGC3DJPJSSAZLWMVZHS5DINFXGOIJB",
+	Base32hex:         "v8him6pbeehp62r39f9ii0pbmclp7it38d5n6e891",
+	Base32hexUpper:    "V8HIM6PBEEHP62R39F9II0PBMCLP7IT38D5N6E891",
+	Base32hexPad:      "t8him6pbeehp62r39f9ii0pbmclp7it38d5n6e891",
+	Base32hexPadUpper: "T8HIM6PBEEHP62R39F9II0PBMCLP7IT38D5N6E891",
+	Base58BTC:         "zUXE7GvtEk8XTXs1GF8HSGbVA9FCX9SEBPe",
+	Base64pad:         "MRGVjZW50cmFsaXplIGV2ZXJ5dGhpbmchIQ==",
+	Base64urlPad:      "URGVjZW50cmFsaXplIGV2ZXJ5dGhpbmchIQ==",
 }
 
 func testEncode(t *testing.T, encoding Encoding, bytes []byte, expected string) {