Replace DecodeBase58/EncodeBase58 with direct implementation.

This removes the bignum/OpenSSL dependency.

The base58 transformation code is also moved to a separate .cpp file.
This commit is contained in:
Pieter Wuille 2014-04-12 23:34:00 +02:00
parent 4a102fa9d9
commit b58be132c9
3 changed files with 101 additions and 93 deletions

View file

@ -121,6 +121,7 @@ libbitcoin_wallet_a_SOURCES = \
$(BITCOIN_CORE_H) $(BITCOIN_CORE_H)
libbitcoin_common_a_SOURCES = \ libbitcoin_common_a_SOURCES = \
base58.cpp \
allocators.cpp \ allocators.cpp \
chainparams.cpp \ chainparams.cpp \
core.cpp \ core.cpp \

91
src/base58.cpp Normal file
View file

@ -0,0 +1,91 @@
// 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;
}

View file

@ -14,7 +14,6 @@
#ifndef BITCOIN_BASE58_H #ifndef BITCOIN_BASE58_H
#define BITCOIN_BASE58_H #define BITCOIN_BASE58_H
#include "bignum.h"
#include "chainparams.h" #include "chainparams.h"
#include "hash.h" #include "hash.h"
#include "key.h" #include "key.h"
@ -27,51 +26,11 @@
#include <boost/variant/apply_visitor.hpp> #include <boost/variant/apply_visitor.hpp>
#include <boost/variant/static_visitor.hpp> #include <boost/variant/static_visitor.hpp>
/* All alphanumeric characters except for "0", "I", "O", and "l" */
static const char* pszBase58 = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
/** /**
* Encode a byte sequence as a base58-encoded string * Encode a byte sequence as a base58-encoded string.
* pbegin and pend cannot be NULL, unless both are.
*/ */
inline std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend) std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend);
{
CAutoBN_CTX pctx;
CBigNum bn58 = 58;
CBigNum bn0 = 0;
// Convert big endian data to little endian - the extra zero at the end will
// ensure bignum interprets it as a positive number */
std::vector<unsigned char> vchTmp(pend-pbegin+1, 0);
reverse_copy(pbegin, pend, vchTmp.begin());
// Convert little endian data to bignum
CBigNum bn;
bn.setvch(vchTmp);
// Convert bignum to std::string
std::string str;
// The expected size increase from base58 conversion is approximately 137%,
// but use 138% to be safe
str.reserve((pend - pbegin) * 138 / 100 + 1);
CBigNum dv;
CBigNum rem;
while (bn > bn0)
{
if (!BN_div(&dv, &rem, &bn, &bn58, pctx))
throw bignum_error("EncodeBase58 : BN_div failed");
bn = dv;
unsigned int c = rem.getulong();
str += pszBase58[c];
}
// Leading zeroes encoded as base58 zeros
for (const unsigned char* p = pbegin; p < pend && *p == 0; p++)
str += pszBase58[0];
// Convert little endian std::string to big endian
reverse(str.begin(), str.end());
return str;
}
/** /**
* Encode a byte vector as a base58-encoded string * Encode a byte vector as a base58-encoded string
@ -82,58 +41,15 @@ inline std::string EncodeBase58(const std::vector<unsigned char>& vch)
} }
/** /**
* Decode a base58-encoded string (psz) into a byte vector (vchRet) * Decode a base58-encoded string (psz) into a byte vector (vchRet).
* return true if decoding is successful * return true if decoding is successful.
* psz cannot be NULL.
*/ */
inline bool DecodeBase58(const char* psz, std::vector<unsigned char>& vchRet) bool DecodeBase58(const char* psz, std::vector<unsigned char>& vchRet);
{
CAutoBN_CTX pctx;
vchRet.clear();
CBigNum bn58 = 58;
CBigNum bn = 0;
CBigNum bnChar;
while (isspace(*psz))
psz++;
// Convert big endian string to bignum
for (const char* p = psz; *p; p++)
{
const char* p1 = strchr(pszBase58, *p);
if (p1 == NULL)
{
while (isspace(*p))
p++;
if (*p != '\0')
return false;
break;
}
bnChar.setulong(p1 - pszBase58);
if (!BN_mul(&bn, &bn, &bn58, pctx))
throw bignum_error("DecodeBase58 : BN_mul failed");
bn += bnChar;
}
// Get bignum as little endian data
std::vector<unsigned char> vchTmp = bn.getvch();
// Trim off the sign byte if present
if (vchTmp.size() >= 2 && vchTmp.end()[-1] == 0 && vchTmp.end()[-2] >= 0x80)
vchTmp.erase(vchTmp.end()-1);
// Restore leading zeros
int nLeadingZeros = 0;
for (const char* p = psz; *p == pszBase58[0]; p++)
nLeadingZeros++;
vchRet.assign(nLeadingZeros + vchTmp.size(), 0);
// Convert little endian data to big endian
reverse_copy(vchTmp.begin(), vchTmp.end(), vchRet.end() - vchTmp.size());
return true;
}
/** /**
* Decode a base58-encoded string (str) into a byte vector (vchRet) * Decode a base58-encoded string (str) into a byte vector (vchRet).
* return true if decoding is successful * return true if decoding is successful.
*/ */
inline bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet) inline bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet)
{ {