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/*
* Copyright (C) 2001-2019 Jacek Sieka, arnetheduck on gmail point com
*
* 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, see <https://www.gnu.org/licenses/>.
*/
#include "stdinc.h"
#include "Encoder.h"
#include "Exception.h"
#include <cstring>
#include "debug.h"
namespace dcpp {
const int8_t Encoder::base32Table[] = {
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,26,27,28,29,30,31,-1,-1,-1,-1,-1,-1,-1,-1,
-1, 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,-1,-1,-1,-1,-1,
-1, 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,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
};
const char Encoder::base32Alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
string& Encoder::toBase32(const uint8_t* src, size_t len, string& dst) {
// Code snagged from the bitzi bitcollider
size_t i, index;
uint8_t word;
dst.reserve(((len * 8) / 5) + 1);
for(i = 0, index = 0; i < len;) {
/* Is the current word going to span a byte boundary? */
if (index > 3) {
word = (uint8_t)(src[i] & (0xFF >> index));
index = (index + 5) % 8;
word <<= index;
if ((i + 1) < len)
word |= src[i + 1] >> (8 - index);
i++;
} else {
word = (uint8_t)(src[i] >> (8 - (index + 5))) & 0x1F;
index = (index + 5) % 8;
if (index == 0)
i++;
}
dcassert(word < 32);
dst += base32Alphabet[word];
}
return dst;
}
void Encoder::fromBase32(const char* src, uint8_t* dst, size_t len) {
size_t i, index, offset;
memset(dst, 0, len);
for(i = 0, index = 0, offset = 0; src[i]; i++) {
// Skip what we don't recognise
int8_t tmp = base32Table[(unsigned char)src[i]];
if(tmp == -1)
continue;
if (index <= 3) {
index = (index + 5) % 8;
if (index == 0) {
dst[offset] |= tmp;
offset++;
if(offset == len)
break;
} else {
dst[offset] |= tmp << (8 - index);
}
} else {
index = (index + 5) % 8;
dst[offset] |= (tmp >> index);
offset++;
if(offset == len)
break;
dst[offset] |= tmp << (8 - index);
}
}
}
bool Encoder::isBase32(const string& str) {
return str.find_first_not_of(base32Alphabet) == string::npos;
}
uint8_t decode16(char c) {
if (c >= '0' && c <= '9')
return c - '0';
if (c >= 'A' && c <= 'F')
return c - 'A';
if (c >= 'a' && c <= 'f')
return c - 'a';
throw Exception("can't decode");
}
void Encoder::fromBase16(const char* src, uint8_t* dst, size_t len) {
memset(dst, 0, len);
for(size_t i = 0; src[i] && src[i+1] && i < len * 2; i += 2) {
// Skip what we don't recognise
auto tmp = decode16(src[i]);
auto tmp2 = decode16(src[i+1]);
dst[i/2] = (tmp << 4) + tmp2;
}
}
} // namespace dcpp
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