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/* <!-- copyright */
/*
* aria2 - a simple utility for downloading files faster
*
* Copyright (C) 2006 Tatsuhiro Tsujikawa
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* copyright --> */
#include "Base64.h"
static char base64_table[64] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/',
};
void Base64::part_encode(const unsigned char* sub, int subLength,
unsigned char* buf)
{
int shift = 2;
unsigned char carry = 0;
int index;
for(index = 0; index < subLength; index++) {
unsigned char cur = sub[index] >> shift | carry;
carry = (sub[index] << (6-shift)) & 0x3f;
shift += 2;
buf[index] = base64_table[(unsigned int)cur];
}
if(subLength == 1) {
buf[index] = base64_table[(unsigned int)carry];
buf[index+1] = buf[index+2] = '=';
} else if(subLength == 2) {
buf[index] = base64_table[(unsigned int)carry];
buf[index+1] = '=';
} else {
unsigned char cur = sub[subLength-1] & 0x3f;
buf[index] = base64_table[(unsigned int)cur];
}
}
string Base64::encode(const string& plainSrc)
{
unsigned char* result = 0;
int resultLength = 0;
encode((const unsigned char*)plainSrc.c_str(), plainSrc.size(),
result, resultLength);
string encoded(&result[0], &result[resultLength]);
delete [] result;
return encoded;
}
void Base64::encode(const unsigned char* src, int srcLength,
unsigned char*& result, int& resultLength) {
resultLength = (srcLength+(srcLength%3 == 0 ? 0 : 3-srcLength%3))/3*4;
result = new unsigned char[resultLength];
unsigned char* tail = result;
for(int index = 0; srcLength > index; index += 3) {
unsigned char temp[4];
part_encode(&src[index],
srcLength >= index+3 ? 3 : srcLength-index,
temp);
memcpy(tail, temp, sizeof(temp));
tail += sizeof(temp);
}
}
char Base64::getValue(char ch)
{
char retch;
if(ch >= 'A' && ch <= 'Z') {
retch = ch-'A';
} else if(ch >= 'a' && ch <= 'z') {
retch = ch-'a'+26;
} else if(ch >= '0' && ch <= '9') {
retch = ch-'0'+52;
} else if(ch == '+') {
retch = 62;
} else if(ch == '/') {
retch = 63;
} else {
retch = 0;
}
return retch;
}
string Base64::part_decode(const string& subCrypted)
{
int shift = 2;
string plain;
for(unsigned int index = 0; index < subCrypted.size()-1; ++index) {
if(subCrypted.at(index) == '=') break;
char cur = getValue(subCrypted.at(index)) << shift;
char carry = getValue(subCrypted.at(index+1)) >> (6-shift);
shift += 2;
plain += cur | carry;
}
return plain;
}
string Base64::decode(const string& crypted)
{
string plain;
int sIndex = 0;
for(int index = 0; crypted.size() > (unsigned int)index; index +=4) {
string subCrypted = crypted.substr(sIndex, 4);
string subPlain = part_decode(subCrypted);
sIndex += 4;
plain += subPlain;
}
return plain;
}
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