utility::string_t uri::decode(const utility::string_t &encoded)
{
std::string utf8raw;
for(auto iter = encoded.begin(); iter != encoded.end(); ++iter)
{
if(*iter == _XPLATSTR('%'))
{
if(++iter == encoded.end())
{
throw uri_exception("Invalid URI string, two hexadecimal digits must follow '%'");
}
int decimal_value = hex_char_digit_to_decimal_char(static_cast<int>(*iter)) << 4;
if(++iter == encoded.end())
{
throw uri_exception("Invalid URI string, two hexadecimal digits must follow '%'");
}
decimal_value += hex_char_digit_to_decimal_char(static_cast<int>(*iter));
utf8raw.push_back(static_cast<char>(decimal_value));
}
else
{
// encoded string has to be ASCII.
utf8raw.push_back(reinterpret_cast<const char &>(*iter));
}
}
return to_string_t(utf8raw);
}
std::vector<unsigned char> _from_base64(const utility::string_t& input)
{
std::vector<unsigned char> result;
if ( input.empty() )
return result;
size_t padding = 0;
// Validation
{
auto size = input.size();
if ( (size % 4) != 0 )
{
throw std::runtime_error("length of base64 string is not an even multiple of 4");
}
for (auto iter = input.begin(); iter != input.end(); ++iter,--size)
{
auto ch = *iter;
if ( ch < 0 || _base64_dectbl[ch] == 255 )
{
throw std::runtime_error("invalid character found in base64 string");
}
if ( _base64_dectbl[ch] == 254 )
{
padding++;
// padding only at the end
if ( size > 2 || (size == 2 && _base64_dectbl[*(iter+1)] != 254) )
{
throw std::runtime_error("invalid padding character found in base64 string");
}
}
}
}
auto size = input.size();
const char_t* ptr = &input[0];
auto outsz = (size / 4)*3;
outsz -= padding;
result.resize(outsz);
size_t idx = 0;
for (; size > 4; ++idx )
{
unsigned char target[3];
memset(target, 0, sizeof(target));
_triple_byte* record = reinterpret_cast<_triple_byte*>(target);
unsigned char val0 = _base64_dectbl[ptr[0]];
unsigned char val1 = _base64_dectbl[ptr[1]];
unsigned char val2 = _base64_dectbl[ptr[2]];
unsigned char val3 = _base64_dectbl[ptr[3]];
record->_0 = val0;
record->_1_1 = val1 >> 4;
result[idx] = target[0];
record->_1_2 = val1 & 0xF;
record->_2_1 = val2 >> 2;
result[++idx] = target[1];
record->_2_2 = val2 & 0x3;
record->_3 = val3 & 0x3F;
result[++idx] = target[2];
ptr += 4;
size -= 4;
}
// Handle the last four bytes separately, to avoid having the conditional statements
// in all the iterations (a performance issue).
{
unsigned char target[3];
memset(target, 0, sizeof(target));
_triple_byte* record = reinterpret_cast<_triple_byte*>(target);
unsigned char val0 = _base64_dectbl[ptr[0]];
unsigned char val1 = _base64_dectbl[ptr[1]];
unsigned char val2 = _base64_dectbl[ptr[2]];
unsigned char val3 = _base64_dectbl[ptr[3]];
record->_0 = val0;
record->_1_1 = val1 >> 4;
result[idx] = target[0];
record->_1_2 = val1 & 0xF;
if ( val2 != 254 )
{
record->_2_1 = val2 >> 2;
result[++idx] = target[1];
}
else
{
// There shouldn't be any information (ones) in the unused bits,
if ( record->_1_2 != 0 )