1 files changed, 246 insertions, 0 deletions
diff --git a/src/common/base58.cpp b/src/common/base58.cpp
new file mode 100644
index 000000000..30042eeba
--- /dev/null
+++ b/src/common/base58.cpp
@@ -0,0 +1,246 @@
+// 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;
+    }
+  }
+}