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// Copyright (c) 2014 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include <assert.h>
#include <stdint.h>
#include <string.h>
#include <vector>
#include <string>
/* All alphanumeric characters except for "0", "I", "O", and "l" */
static const char* pszBase58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
bool DecodeBase58(const char *psz, std::vector<unsigned char>& vch) {
// Skip leading spaces.
while (*psz && isspace(*psz))
psz++;
// Skip and count leading '1's.
int zeroes = 0;
while (*psz == '1') {
zeroes++;
psz++;
}
// Allocate enough space in big-endian base256 representation.
std::vector<unsigned char> b256(strlen(psz) * 733 / 1000 + 1); // log(58) / log(256), rounded up.
// Process the characters.
while (*psz && !isspace(*psz)) {
// Decode base58 character
const char *ch = strchr(pszBase58, *psz);
if (ch == NULL)
return false;
// Apply "b256 = b256 * 58 + ch".
int carry = ch - pszBase58;
for (std::vector<unsigned char>::reverse_iterator it = b256.rbegin(); it != b256.rend(); it++) {
carry += 58 * (*it);
*it = carry % 256;
carry /= 256;
}
assert(carry == 0);
psz++;
}
// Skip trailing spaces.
while (isspace(*psz))
psz++;
if (*psz != 0)
return false;
// Skip leading zeroes in b256.
std::vector<unsigned char>::iterator it = b256.begin();
while (it != b256.end() && *it == 0)
it++;
// Copy result into output vector.
vch.reserve(zeroes + (b256.end() - it));
vch.assign(zeroes, 0x00);
while (it != b256.end())
vch.push_back(*(it++));
return true;
}
std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend) {
// Skip & count leading zeroes.
int zeroes = 0;
while (pbegin != pend && *pbegin == 0) {
pbegin++;
zeroes++;
}
// Allocate enough space in big-endian base58 representation.
std::vector<unsigned char> b58((pend - pbegin) * 138 / 100 + 1); // log(256) / log(58), rounded up.
// Process the bytes.
while (pbegin != pend) {
int carry = *pbegin;
// Apply "b58 = b58 * 256 + ch".
for (std::vector<unsigned char>::reverse_iterator it = b58.rbegin(); it != b58.rend(); it++) {
carry += 256 * (*it);
*it = carry % 58;
carry /= 58;
}
assert(carry == 0);
pbegin++;
}
// Skip leading zeroes in base58 result.
std::vector<unsigned char>::iterator it = b58.begin();
while (it != b58.end() && *it == 0)
it++;
// Translate the result into a string.
std::string str;
str.reserve(zeroes + (b58.end() - it));
str.assign(zeroes, '1');
while (it != b58.end())
str += pszBase58[*(it++)];
return str;
}
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