furnace/src/baseutils.cpp
2024-01-16 21:26:57 -05:00

89 lines
2.5 KiB
C++

/**
* Furnace Tracker - multi-system chiptune tracker
* Copyright (C) 2021-2024 tildearrow and contributors
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "baseutils.h"
#include <string.h>
const char* base64Table="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
std::string taEncodeBase64(const std::string& data) {
std::string ret;
ret.reserve((2+data.size()*4)/3);
unsigned int groupOfThree=0;
unsigned char pos=0;
for (const char& i: data) {
groupOfThree|=((unsigned char)i)<<((2-pos)<<3);
if (++pos>=3) {
pos=0;
ret+=base64Table[(groupOfThree>>18)&63];
ret+=base64Table[(groupOfThree>>12)&63];
ret+=base64Table[(groupOfThree>>6)&63];
ret+=base64Table[groupOfThree&63];
groupOfThree=0;
}
}
if (pos==2) {
ret+=base64Table[(groupOfThree>>18)&63];
ret+=base64Table[(groupOfThree>>12)&63];
ret+=base64Table[(groupOfThree>>6)&63];
ret+='=';
} else if (pos==1) {
ret+=base64Table[(groupOfThree>>18)&63];
ret+=base64Table[(groupOfThree>>12)&63];
ret+="==";
}
return ret;
}
std::string taDecodeBase64(const char* buf) {
std::string data;
unsigned int groupOfThree=0;
signed char pos=18;
for (const char* i=buf; *i; i++) {
unsigned char nextVal=0;
if ((*i)=='/') {
nextVal=63;
} else if ((*i)=='+') {
nextVal=62;
} else if ((*i)>='0' && (*i)<='9') {
nextVal=52+((*i)-'0');
} else if ((*i)>='a' && (*i)<='z') {
nextVal=26+((*i)-'a');
} else if ((*i)>='A' && (*i)<='Z') {
nextVal=((*i)-'A');
} else {
nextVal=0;
}
groupOfThree|=nextVal<<pos;
pos-=6;
if (pos<0) {
pos=18;
if ((groupOfThree>>16)&0xff) data+=(groupOfThree>>16)&0xff;
if ((groupOfThree>>8)&0xff) data+=(groupOfThree>>8)&0xff;
if (groupOfThree&0xff) data+=groupOfThree&0xff;
groupOfThree=0;
}
}
return data;
}