qse/qse/lib/cmn/alg-base64.c

116 lines
2.8 KiB
C

/*
* $Id$
*
Copyright 2006-2012 Chung, Hyung-Hwan.
This file is part of QSE.
QSE is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 of
the License, or (at your option) any later version.
QSE 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with QSE. If not, see <http://www.gnu.org/licenses/>.
*/
#if defined(macintosh)
# include <:qse:cmn:alg.h>
#else
# include <qse/cmn/alg.h>
#endif
#define ENC(x) \
((x < 26)? (QSE_MT('A') + x): \
(x < 52)? (QSE_MT('a') + (x - 26)): \
(x < 62)? (QSE_MT('0') + (x - 52)): \
(x == 62)? QSE_MT('+'): QSE_MT('/'))
#define DEC(x) \
((x >= QSE_MT('A') && x <= QSE_MT('Z'))? (x - QSE_MT('A')): \
(x >= QSE_MT('a') && x <= QSE_MT('z'))? (x - QSE_MT('a') + 26): \
(x >= QSE_MT('0') && x <= QSE_MT('9'))? (x - QSE_MT('0') + 52): \
(x == QSE_MT('+'))? 62: 63)
qse_size_t qse_enbase64 (
const void* in, qse_size_t isz,
qse_mchar_t* out, qse_size_t osz, qse_size_t* xsz)
{
const qse_uint8_t* ib = (const qse_uint8_t*)in;
qse_size_t idx = 0, idx2 = 0, i;
/* 3 8-bit values to 4 6-bit values */
for (i = 0; i < isz; i += 3)
{
qse_uint8_t b1, b2, b3;
qse_uint8_t c1, c2, c3, c4;
b1 = ib[i];
b2 = (i + 1 < isz)? ib[i + 1]: 0;
b3 = (i + 2 < isz)? ib[i + 2]: 0;
c1 = b1 >> 2;
c2 = ((b1 & 0x03) << 4) | (b2 >> 4);
c3 = ((b2 & 0x0F) << 2) | (b3 >> 6);
c4 = b3 & 0x3F;
if (idx + 3 < osz)
{
out[idx++] = ENC(c1);
out[idx++] = ENC(c2);
out[idx++] = (i + 1 < isz)? ENC(c3): QSE_MT('=');
out[idx++] = (i + 2 < isz)? ENC(c4): QSE_MT('=');
}
idx2 += 4;
}
if (xsz) *xsz = idx2;
return idx;
}
qse_size_t qse_debase64 (
const qse_mchar_t* in, qse_size_t isz,
void* out, qse_size_t osz, qse_size_t* xsz)
{
qse_uint8_t* ob = (qse_uint8_t*)out;
qse_size_t idx = 0, idx2 = 0, i;
for (i = 0; i < isz; i += 4)
{
qse_uint8_t c1, c2, c3, c4;
qse_uint8_t b1, b2, b3, b4;
c1 = in[i];
c2 = (i + 1 < isz)? in[i + 1]: QSE_MT('A');
c3 = (i + 2 < isz)? in[i + 2]: QSE_MT('A');
c4 = (i + 3 < isz)? in[i + 3]: QSE_MT('A');
b1 = DEC(c1);
b2 = DEC(c2);
b3 = DEC(c3);
b4 = DEC(c4);
idx2++;
if (idx < osz) ob[idx++] = (b1 << 2) | (b2 >> 4);
if (c3 != QSE_MT('='))
{
idx2++;
if (idx < osz) ob[idx++] = ((b2 & 0x0F) << 4) | (b3 >> 2);
}
if (c4 != QSE_MT('='))
{
idx2++;
if (idx < osz) ob[idx++] = ((b3 & 0x03) << 6) | b4;
}
}
if (xsz) *xsz = idx2;
return idx;
}