encoding.base58: remove one unnecessary map access per the most common BTC usages; implement encode_bytes, decode_bytes, encode_walpha_bytes, decode_walpha_bytes functions

vlib/encoding/base58/alphabet.v

@@ -1,23 +1,24 @@
 module base58
 
-// alphabets is a map of common base58 alphabets
-pub const alphabets = init_alphabets()
+const impossible = 'this should never happen'
 
-// init_alphabet instantiates the preconfigured `Alphabet`s and returns them as `map[string]Alphabet`.
-// This is a temporary function. Setting const alphabets to the value returned in this function
-// causes a C error right now.
-fn init_alphabets() map[string]Alphabet {
-	return {
-		'btc':    new_alphabet('123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz') or {
-			panic(@MOD + '.' + @FN + ': this should never happen')
-		}
-		'flickr': new_alphabet('123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ') or {
-			panic(@MOD + '.' + @FN + ': this should never happen')
-		}
-		'ripple': new_alphabet('rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz') or {
-			panic(@MOD + '.' + @FN + ': this should never happen')
-		}
-	}
+pub const btc_alphabet = new_alphabet('123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz') or {
+	panic(impossible)
+}
+
+pub const flickr_alphabet = new_alphabet('123456789abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ') or {
+	panic(impossible)
+}
+
+pub const ripple_alphabet = new_alphabet('rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz') or {
+	panic(impossible)
+}
+
+// alphabets is a map of common base58 alphabets:
+pub const alphabets = {
+	'btc':    btc_alphabet
+	'flickr': flickr_alphabet
+	'ripple': ripple_alphabet
 }
 
 // Alphabet is the series of characters that an input

vlib/encoding/base58/base58.v

@@ -6,7 +6,7 @@ import math
 
 // encode_int encodes any integer type to base58 string with Bitcoin alphabet
 pub fn encode_int(input int) ?string {
-	return encode_int_walpha(input, alphabets['btc'])
+	return encode_int_walpha(input, btc_alphabet)
 }
 
 // encode_int_walpha any integer type to base58 string with custom alphabet
@@ -30,22 +30,34 @@ pub fn encode_int_walpha(input int, alphabet Alphabet) ?string {
 	return buffer.reverse().bytestr()
 }
 
-// encode encodes byte array to base58 with Bitcoin alphabet
+// encode encodes the input string to base58 with the Bitcoin alphabet
 pub fn encode(input string) string {
-	return encode_walpha(input, alphabets['btc'])
+	return encode_walpha(input, btc_alphabet)
 }
 
-// encode_walpha encodes byte array to base58 with custom aplhabet
+// encode_bytes encodes the input array to base58, with the Bitcoin alphabet
+pub fn encode_bytes(input []u8) []u8 {
+	return encode_walpha_bytes(input, btc_alphabet)
+}
+
+// encode_walpha encodes the input string to base58 with a custom aplhabet
 pub fn encode_walpha(input string, alphabet Alphabet) string {
 	if input.len == 0 {
 		return ''
 	}
-
 	bin := input.bytes()
-	mut sz := bin.len
+	return encode_walpha_bytes(bin, alphabet).bytestr()
+}
+
+// encode_walpha encodes the input array to base58 with a custom aplhabet
+pub fn encode_walpha_bytes(input []u8, alphabet Alphabet) []u8 {
+	if input.len == 0 {
+		return []
+	}
+	mut sz := input.len
 
 	mut zcount := 0
-	for zcount < sz && bin[zcount] == 0 {
+	for zcount < sz && input[zcount] == 0 {
 		zcount++
 	}
 
@@ -61,7 +73,7 @@ pub fn encode_walpha(input string, alphabet Alphabet) string {
 	mut carry := u32(0)
 
 	high = sz - 1
-	for b in bin {
+	for b in input {
 		i = sz - 1
 		for carry = u32(b); i > high || carry != 0; i-- {
 			carry = carry + 256 * u32(out[i])
@@ -81,12 +93,12 @@ pub fn encode_walpha(input string, alphabet Alphabet) string {
 		out[i] = alphabet.encode[val[i]]
 	}
 
-	return out[..sz].bytestr()
+	return out[..sz]
 }
 
 // decode_int decodes base58 string to an integer with Bitcoin alphabet
 pub fn decode_int(input string) ?int {
-	return decode_int_walpha(input, alphabets['btc'])
+	return decode_int_walpha(input, btc_alphabet)
 }
 
 // decode_int_walpha decodes base58 string to an integer with custom alphabet
@@ -108,22 +120,37 @@ pub fn decode_int_walpha(input string, alphabet Alphabet) ?int {
 	return total
 }
 
-// decode decodes base58 string using the Bitcoin alphabet
+// decode decodes the base58 input string, using the Bitcoin alphabet
 pub fn decode(str string) ?string {
-	return decode_walpha(str, alphabets['btc'])
+	return decode_walpha(str, btc_alphabet)
 }
 
-// decode_walpha decodes base58 string using custom alphabet
-pub fn decode_walpha(str string, alphabet Alphabet) ?string {
-	if str.len == 0 {
+// decode_bytes decodes the base58 encoded input array, using the Bitcoin alphabet
+pub fn decode_bytes(input []u8) ?[]u8 {
+	return decode_walpha_bytes(input, btc_alphabet)
+}
+
+// decode_walpha decodes the base58 encoded input string, using custom alphabet
+pub fn decode_walpha(input string, alphabet Alphabet) ?string {
+	if input.len == 0 {
 		return ''
 	}
+	bin := input.bytes()
+	res := decode_walpha_bytes(bin, alphabet)?
+	return res.bytestr()
+}
+
+// decode_walpha_bytes decodes the base58 encoded input array using a custom alphabet
+pub fn decode_walpha_bytes(input []u8, alphabet Alphabet) ?[]u8 {
+	if input.len == 0 {
+		return []
+	}
 
 	zero := alphabet.encode[0]
-	b58sz := str.len
+	b58sz := input.len
 
 	mut zcount := 0
-	for i := 0; i < b58sz && str[i] == zero; i++ {
+	for i := 0; i < b58sz && input[i] == zero; i++ {
 		zcount++
 	}
 
@@ -134,7 +161,7 @@ pub fn decode_walpha(str string, alphabet Alphabet) ?string {
 	mut binu := []u8{len: 2 * ((b58sz * 406 / 555) + 1)}
 	mut outi := []u32{len: (b58sz + 3) / 4}
 
-	for _, r in str {
+	for _, r in input {
 		if r > 127 {
 			panic(@MOD + '.' + @FN +
 				': high-bit set on invalid digit; outside of ascii range ($r). This should never happen.')
@@ -172,10 +199,10 @@ pub fn decode_walpha(str string, alphabet Alphabet) ?string {
 	// find the most significant byte post-decode, if any
 	for msb := zcount; msb < binu.len; msb++ { // loop relies on u32 overflow
 		if binu[msb] > 0 {
-			return binu[msb - zcount..out_len].bytestr()
+			return binu[msb - zcount..out_len]
 		}
 	}
 
 	// it's all zeroes
-	return binu[..out_len].bytestr()
+	return binu[..out_len]
 }

vlib/encoding/base58/base58_usage_test.v

@@ -0,0 +1,42 @@
+import encoding.base58
+import encoding.hex
+
+fn test_encode() ? {
+	for input, expected in {
+		'':                    ''
+		'6263':                '2PMCRQ'
+		'hello world':         'StV1DL6CwTryKyV'
+		'\x00\x00hello world': '11StV1DL6CwTryKyV'
+	} {
+		output := base58.encode(input)
+		println('> input: `$input` | $input.bytes().hex() | => output: `$output`')
+		assert output == expected
+	}
+}
+
+fn test_encode_int() ? {
+	for input, expected in {
+		0x6263:   '8VG'
+		0x61:     '2g'
+		0x626262: 'a3gV'
+		0x636363: 'aPEr'
+	} {
+		output := base58.encode_int(input)?
+		println('> input: 0x${input:x} | => output: `$output`')
+		assert output == expected
+	}
+}
+
+fn test_decode() ? {
+	for output, expected in {
+		'USm3fpXnKG5EUBx2ndxBDMPVciP5hGey2Jh4NDv6gmeo1LkMeiKrLJUUBk6Z': 'The quick brown fox jumps over the lazy dog.'
+		'11StV1DL6CwTryKyV':                                            '\x00\x00hello world'
+		'2NEpo7TZRRrLZSi2U':                                            'Hello World!'
+		'14cxpo3MBCYYWCgF74SWTdcmxipnGUsPw3':                           hex.decode('0027b5891b01da2db74cde1689a97a2acbe23d5fb1c0205bf6')?.bytestr()
+		'3vQB7B6MrGQZaxCuFg4oh':                                        hex.decode('68656c6c6f20776f726c64bc62d4b8')?.bytestr()
+	} {
+		input := base58.decode(output)?
+		println('> output: `$output` | decoded input: `$input` | bytes: $input.bytes().hex()')
+		assert input.bytes().hex() == expected.bytes().hex()
+	}
+}