82 lines
2.4 KiB
C++
82 lines
2.4 KiB
C++
#include <memory>
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#include <fc/crypto/bigint.hpp>
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#include <fc/io/sstream.hpp>
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#include <fc/log/logger.hpp>
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namespace fc
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{
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fc::string to_base36( const char* data, size_t len )
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{
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if( len == 0 ) return fc::string();
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const char* src = data;
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int src_len = len;
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std::unique_ptr<char[]> buffer(new char[len+1]);
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if (*data & 0x80) {
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buffer[0] = 0;
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memcpy( buffer.get() + 1, data, len );
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src = buffer.get();
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src_len++;
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}
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fc::bigint value( src, src_len );
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auto base36 = "0123456789abcdefghijklmnopqrstuvwxyz";
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std::vector<char> out( static_cast<size_t>(len * 1.6) + 2 );
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int pos = out.size() - 1;
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out[pos] = '\0';
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fc::bigint _36(36);
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do {
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if( value ) {
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--pos;
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out[pos] = base36[(value % _36).to_int64()];
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}
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} while (value /= _36);
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while (len-- > 0 && *data++ == 0) {
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out[--pos] = '0';
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}
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return &out[pos]; //fc::string( &out[pos], out.size() - pos);
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}
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fc::string to_base36( const std::vector<char>& vec )
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{
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return to_base36( (const char*)vec.data(), vec.size() );
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}
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std::vector<char> from_base36( const fc::string& b36 )
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{
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if ( b36.empty() ) {
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std::vector<char> empty;
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return empty;
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}
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fc::bigint value;
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fc::bigint pos = 0;
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fc::bigint _36(36);
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for( auto itr = b36.rbegin(); itr != b36.rend(); ++itr )
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{
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if( *itr >= '0' && *itr <= '9' )
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value = value + _36.exp(pos) * fc::bigint(*itr - '0');
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else if( *itr >= 'a' && *itr <= 'z' )
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value = value + (_36.exp(pos) * fc::bigint(10+*itr - 'a'));
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else if( *itr >= 'A' && *itr <= 'Z' )
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value = value + (_36.exp(pos) * fc::bigint(10+*itr - 'A'));
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else
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{
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wlog("unknown '${char}'", ("char",fc::string(&*itr,1)) );
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}
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++pos;
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}
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std::vector<char> bytes = value;
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int leading_zeros = 0, len = bytes.size();
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const char *in = b36.c_str();
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while (*in++ == '0') { leading_zeros++; }
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char* first = bytes.data();
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while (len > 0 && *first == 0) { first++; len--; }
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std::vector<char> result;
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result.resize(leading_zeros + len, 0);
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memcpy( result.data() + leading_zeros, first, len );
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return result;
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}
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}
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