Merges Buffer refactorings from base58-native by Stephen Pair
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1 changed files with 38 additions and 51 deletions
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@ -2,78 +2,65 @@
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// Originally written by Mike Hearn for BitcoinJ
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// Originally written by Mike Hearn for BitcoinJ
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// Copyright (c) 2011 Google Inc
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// Copyright (c) 2011 Google Inc
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// Ported to JavaScript by Stefan Thomas
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// Ported to JavaScript by Stefan Thomas
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// Merged Buffer refactorings from base58-native by Stephen Pair
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// Copyright (c) 2013 BitPay Inc
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var BigInteger = require('./jsbn/jsbn')
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var BigInteger = require('./jsbn/jsbn')
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// FIXME: ? This is a Base58Check alphabet
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var ALPHABET = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz'
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var alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
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var ALPHABET_BUF = new Buffer(ALPHABET, 'ascii')
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var base = BigInteger.valueOf(58)
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var ALPHABET_MAP = {}
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for(var i = 0; i < ALPHABET.length; i++) {
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var alphabetMap = {}
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ALPHABET_MAP[ALPHABET[i]] = BigInteger.valueOf(i)
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for (var i=0; i<alphabet.length; ++i) {
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var chr = alphabet[i]
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alphabetMap[chr] = BigInteger.valueOf(i)
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}
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}
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var BASE = BigInteger.valueOf(58)
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// encode a byte array into a base58 encoded String
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// @return String
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function encode(buffer) {
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function encode(buffer) {
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var bi = BigInteger.fromByteArrayUnsigned(buffer)
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var bi = BigInteger.fromByteArrayUnsigned(buffer)
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var chars = []
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var result = new Buffer(buffer.length << 1)
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while (bi.compareTo(base) >= 0) {
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var i = result.length - 1
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var mod = bi.mod(base)
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while (bi.compareTo(BigInteger.ZERO) > 0) {
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bi = bi.subtract(mod).divide(base)
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var remainder = bi.mod(BASE)
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bi = bi.divide(BASE)
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chars.push(alphabet[mod.intValue()])
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result[i] = ALPHABET_BUF[remainder.intValue()]
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i--
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}
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}
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chars.push(alphabet[bi.intValue()])
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// deal with leading zeros
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var j = 0
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// Convert leading zeros too.
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while (buffer[j] === 0) {
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for (var i=0; i<buffer.length; i++) {
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result[i] = ALPHABET_BUF[0]
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if (buffer[i] !== 0x00) break
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j++
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i--
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chars.push(alphabet[0])
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}
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}
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return chars.reverse().join('')
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return result.slice(i + 1, result.length).toString('ascii')
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}
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}
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// decode a base58 encoded String into a byte array
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function decode(string) {
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// @return Array
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if (string.length === 0) return new Buffer(0)
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function decode(str) {
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var num = BigInteger.valueOf(0)
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var leading_zero = 0
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var num = BigInteger.ZERO.clone()
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var seen_other = false
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for (var i=0; i<str.length; ++i) {
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for (var i = 0; i < string.length; i++) {
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var chr = str[i]
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num = num.multiply(BASE)
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var bi = alphabetMap[chr]
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num = num.add(ALPHABET_MAP[string.charAt(i)])
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// if we encounter an invalid character, decoding fails
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if (bi === undefined) {
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throw new Error('invalid base58 string: ' + str)
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}
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num = num.multiply(base).add(bi)
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if (chr === '1' && !seen_other) {
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++leading_zero
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} else {
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seen_other = true
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}
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}
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}
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var bytes = num.toByteArrayUnsigned()
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// deal with leading zeros
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var i = 0
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// remove leading zeros
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while ((i < string.length) && (string[i] === ALPHABET[0])) {
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while (leading_zero-- > 0) {
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i++
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bytes.unshift(0)
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}
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}
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return new Buffer(bytes)
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// FIXME: If BigInteger supported buffers, this could be a copy
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var buffer = new Buffer(num.toByteArrayUnsigned())
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var padding = new Buffer(i)
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padding.fill(0)
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return Buffer.concat([padding, buffer])
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}
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}
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module.exports = {
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module.exports = {
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