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authorAntonio Juarez <antonio.maria.juarez@live.com>2014-03-03 22:07:58 +0000
committerAntonio Juarez <antonio.maria.juarez@live.com>2014-03-03 22:07:58 +0000
commit296ae46ed8f8f6e5f986f978febad302e3df231a (patch)
tree1629164454a239308f33c9e12afb22e7f3cd8eeb /src/common/base58.cpp
parentchanged name (diff)
downloadmonero-296ae46ed8f8f6e5f986f978febad302e3df231a.tar.xz
moved all stuff to github
Diffstat (limited to 'src/common/base58.cpp')
-rw-r--r--src/common/base58.cpp246
1 files changed, 246 insertions, 0 deletions
diff --git a/src/common/base58.cpp b/src/common/base58.cpp
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+++ b/src/common/base58.cpp
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+// Copyright (c) 2012-2013 The Cryptonote developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+
+#include "base58.h"
+
+#include <assert.h>
+#include <string>
+#include <vector>
+
+#include "crypto/hash.h"
+#include "int-util.h"
+#include "util.h"
+#include "varint.h"
+
+namespace tools
+{
+ namespace base58
+ {
+ namespace
+ {
+ const char alphabet[] = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
+ const size_t alphabet_size = sizeof(alphabet) - 1;
+ const size_t encoded_block_sizes[] = {0, 2, 3, 5, 6, 7, 9, 10, 11};
+ const size_t full_block_size = sizeof(encoded_block_sizes) / sizeof(encoded_block_sizes[0]) - 1;
+ const size_t full_encoded_block_size = encoded_block_sizes[full_block_size];
+ const size_t addr_checksum_size = 4;
+
+ struct reverse_alphabet
+ {
+ reverse_alphabet()
+ {
+ m_data.resize(alphabet[alphabet_size - 1] - alphabet[0] + 1, -1);
+
+ for (size_t i = 0; i < alphabet_size; ++i)
+ {
+ size_t idx = static_cast<size_t>(alphabet[i] - alphabet[0]);
+ m_data[idx] = static_cast<int8_t>(i);
+ }
+ }
+
+ int operator()(char letter) const
+ {
+ size_t idx = static_cast<size_t>(letter - alphabet[0]);
+ return idx < m_data.size() ? m_data[idx] : -1;
+ }
+
+ static reverse_alphabet instance;
+
+ private:
+ std::vector<int8_t> m_data;
+ };
+
+ reverse_alphabet reverse_alphabet::instance;
+
+ struct decoded_block_sizes
+ {
+ decoded_block_sizes()
+ {
+ m_data.resize(encoded_block_sizes[full_block_size] + 1, -1);
+ for (size_t i = 0; i <= full_block_size; ++i)
+ {
+ m_data[encoded_block_sizes[i]] = static_cast<int>(i);
+ }
+ }
+
+ int operator()(size_t encoded_block_size) const
+ {
+ assert(encoded_block_size <= full_encoded_block_size);
+ return m_data[encoded_block_size];
+ }
+
+ static decoded_block_sizes instance;
+
+ private:
+ std::vector<int> m_data;
+ };
+
+ decoded_block_sizes decoded_block_sizes::instance;
+
+ uint64_t uint_8be_to_64(const uint8_t* data, size_t size)
+ {
+ assert(1 <= size && size <= sizeof(uint64_t));
+
+ uint64_t res = 0;
+ switch (9 - size)
+ {
+ case 1: res |= *data++;
+ case 2: res <<= 8; res |= *data++;
+ case 3: res <<= 8; res |= *data++;
+ case 4: res <<= 8; res |= *data++;
+ case 5: res <<= 8; res |= *data++;
+ case 6: res <<= 8; res |= *data++;
+ case 7: res <<= 8; res |= *data++;
+ case 8: res <<= 8; res |= *data; break;
+ default: assert(false);
+ }
+
+ return res;
+ }
+
+ void uint_64_to_8be(uint64_t num, size_t size, uint8_t* data)
+ {
+ assert(1 <= size && size <= sizeof(uint64_t));
+
+ uint64_t num_be = SWAP64BE(num);
+ memcpy(data, reinterpret_cast<uint8_t*>(&num_be) + sizeof(uint64_t) - size, size);
+ }
+
+ void encode_block(const char* block, size_t size, char* res)
+ {
+ assert(1 <= size && size <= sizeof(full_block_size));
+
+ uint64_t num = uint_8be_to_64(reinterpret_cast<const uint8_t*>(block), size);
+ int i = static_cast<int>(encoded_block_sizes[size]) - 1;
+ while (0 < num)
+ {
+ uint64_t remainder = num % alphabet_size;
+ num /= alphabet_size;
+ res[i] = alphabet[remainder];
+ --i;
+ }
+ }
+
+ bool decode_block(const char* block, size_t size, char* res)
+ {
+ assert(1 <= size && size <= full_encoded_block_size);
+
+ int res_size = decoded_block_sizes::instance(size);
+ if (res_size <= 0)
+ return false; // Invalid block size
+
+ uint64_t res_num = 0;
+ uint64_t order = 1;
+ for (size_t i = size - 1; i < size; --i)
+ {
+ int digit = reverse_alphabet::instance(block[i]);
+ if (digit < 0)
+ return false; // Invalid symbol
+
+ uint64_t product_hi;
+ uint64_t tmp = res_num + mul128(order, digit, &product_hi);
+ if (tmp < res_num || 0 != product_hi)
+ return false; // Overflow
+
+ res_num = tmp;
+ order *= alphabet_size; // Never overflows, 58^10 < 2^64
+ }
+
+ if (static_cast<size_t>(res_size) < full_block_size && (UINT64_C(1) << (8 * res_size)) <= res_num)
+ return false; // Overflow
+
+ uint_64_to_8be(res_num, res_size, reinterpret_cast<uint8_t*>(res));
+
+ return true;
+ }
+ }
+
+ std::string encode(const std::string& data)
+ {
+ if (data.empty())
+ return std::string();
+
+ size_t full_block_count = data.size() / full_block_size;
+ size_t last_block_size = data.size() % full_block_size;
+ size_t res_size = full_block_count * full_encoded_block_size + encoded_block_sizes[last_block_size];
+
+ std::string res(res_size, alphabet[0]);
+ for (size_t i = 0; i < full_block_count; ++i)
+ {
+ encode_block(data.data() + i * full_block_size, full_block_size, &res[i * full_encoded_block_size]);
+ }
+
+ if (0 < last_block_size)
+ {
+ encode_block(data.data() + full_block_count * full_block_size, last_block_size, &res[full_block_count * full_encoded_block_size]);
+ }
+
+ return res;
+ }
+
+ bool decode(const std::string& enc, std::string& data)
+ {
+ if (enc.empty())
+ {
+ data.clear();
+ return true;
+ }
+
+ size_t full_block_count = enc.size() / full_encoded_block_size;
+ size_t last_block_size = enc.size() % full_encoded_block_size;
+ int last_block_decoded_size = decoded_block_sizes::instance(last_block_size);
+ if (last_block_decoded_size < 0)
+ return false; // Invalid enc length
+ size_t data_size = full_block_count * full_block_size + last_block_decoded_size;
+
+ data.resize(data_size, 0);
+ for (size_t i = 0; i < full_block_count; ++i)
+ {
+ if (!decode_block(enc.data() + i * full_encoded_block_size, full_encoded_block_size, &data[i * full_block_size]))
+ return false;
+ }
+
+ if (0 < last_block_size)
+ {
+ if (!decode_block(enc.data() + full_block_count * full_encoded_block_size, last_block_size,
+ &data[full_block_count * full_block_size]))
+ return false;
+ }
+
+ return true;
+ }
+
+ std::string encode_addr(uint64_t tag, const std::string& data)
+ {
+ std::string buf = get_varint_data(tag);
+ buf += data;
+ crypto::hash hash = crypto::cn_fast_hash(buf.data(), buf.size());
+ const char* hash_data = reinterpret_cast<const char*>(&hash);
+ buf.append(hash_data, addr_checksum_size);
+ return encode(buf);
+ }
+
+ bool decode_addr(std::string addr, uint64_t& tag, std::string& data)
+ {
+ std::string addr_data;
+ bool r = decode(addr, addr_data);
+ if (!r) return false;
+
+ std::string checksum(addr_checksum_size, '\0');
+ checksum = addr_data.substr(addr_data.size() - addr_checksum_size);
+
+ addr_data.resize(addr_data.size() - addr_checksum_size);
+ crypto::hash hash = crypto::cn_fast_hash(addr_data.data(), addr_data.size());
+ std::string expected_checksum(reinterpret_cast<const char*>(&hash), addr_checksum_size);
+ if (expected_checksum != checksum) return false;
+
+ int read = tools::read_varint(addr_data.begin(), addr_data.end(), tag);
+ if (read <= 0) return false;
+
+ data = addr_data.substr(read);
+ return true;
+ }
+ }
+}