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/*
* Copyright (c) 2013 Remko Tronçon
* Licensed under the GNU General Public License v3.
* See Documentation/Licenses/GPLv3.txt for more information.
*/
#include <Swiften/StringCodecs/Base64.h>
#pragma clang diagnostic ignored "-Wconversion"
using namespace Swift;
namespace {
const char* encodeMap =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
const unsigned char decodeMap[255] = {
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 255, 255, 255, 255, 255,
255, 255, 255, 62, 255, 255, 255, 63,
52, 53, 54, 55, 56, 57, 58, 59,
60, 61, 255, 255, 255, 255, 255, 255,
255, 0, 1, 2, 3, 4, 5, 6,
7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22,
23, 24, 25, 255, 255, 255, 255, 255,
255, 26, 27, 28, 29, 30, 31, 32,
33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48,
49, 50, 51, 255, 255, 255, 255, 255
};
template<typename ResultType, typename InputType>
ResultType encodeDetail(const InputType& input) {
ResultType result;
size_t i = 0;
for (; i < (input.size()/3)*3; i += 3) {
unsigned int c = input[i+2] | (input[i+1]<<8) | (input[i]<<16);
result.push_back(encodeMap[(c&0xFC0000)>>18]);
result.push_back(encodeMap[(c&0x3F000)>>12]);
result.push_back(encodeMap[(c&0xFC0)>>6]);
result.push_back(encodeMap[c&0x3F]);
}
if (input.size() % 3 == 2) {
unsigned int c = (input[i+1]<<8) | (input[i]<<16);
result.push_back(encodeMap[(c&0xFC0000)>>18]);
result.push_back(encodeMap[(c&0x3F000)>>12]);
result.push_back(encodeMap[(c&0xFC0)>>6]);
result.push_back('=');
}
else if (input.size() % 3 == 1) {
unsigned int c = input[i]<<16;
result.push_back(encodeMap[(c&0xFC0000)>>18]);
result.push_back(encodeMap[(c&0x3F000)>>12]);
result.push_back('=');
result.push_back('=');
}
return result;
}
}
std::string Base64::encode(const ByteArray& s) {
return encodeDetail<std::string>(s);
}
SafeByteArray Base64::encode(const SafeByteArray& s) {
return encodeDetail<SafeByteArray>(s);
}
ByteArray Base64::decode(const std::string& input) {
ByteArray result;
if (input.size() % 4) {
return ByteArray();
}
for (size_t i = 0; i < input.size(); i += 4) {
unsigned char c1 = input[i+0];
unsigned char c2 = input[i+1];
unsigned char c3 = input[i+2];
unsigned char c4 = input[i+3];
if (c3 == '=') {
unsigned int c = (((decodeMap[c1]<<6)|decodeMap[c2])&0xFF0)>>4;
result.push_back(c);
}
else if (c4 == '=') {
unsigned int c = (((decodeMap[c1]<<12)|(decodeMap[c2]<<6)|decodeMap[c3])&0x3FFFC)>>2;
result.push_back((c&0xFF00) >> 8);
result.push_back(c&0xFF);
}
else {
unsigned int c = (decodeMap[c1]<<18) | (decodeMap[c2]<<12) | (decodeMap[c3]<<6) | decodeMap[c4];
result.push_back((c&0xFF0000) >> 16);
result.push_back((c&0xFF00) >> 8);
result.push_back(c&0xFF);
}
}
return result;
}
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