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/***********************************************************************
* *
* This software is part of the ast package *
* Copyright (c) 1985-2009 AT&T Intellectual Property *
* and is licensed under the *
* Common Public License, Version 1.0 *
* by AT&T Intellectual Property *
* *
* A copy of the License is available at *
* http://www.opensource.org/licenses/cpl1.0.txt *
* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
* *
* Information and Software Systems Research *
* AT&T Research *
* Florham Park NJ *
* *
* Glenn Fowler <gsf@research.att.com> *
* David Korn <dgk@research.att.com> *
* Phong Vo <kpv@research.att.com> *
* *
***********************************************************************/
#pragma prototyped
/*
* mime base64 encode/decode
*
* Glenn Fowler
* David Korn
* AT&T Research
*/
#include <ast.h>
#define PAD '='
#define B64_UC 3
#define B64_EC 4
#define B64_CHUNK 15
#define B64_PAD 64
#define B64_SPC 65
#define B64_IGN 66
static unsigned char map[UCHAR_MAX+1];
static const char alp[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
/*
* mime base64 encode
*/
ssize_t
base64encode(const void* fb, size_t fz, void** fn, void* tb, size_t tz, void** tn)
{
register unsigned char* fp;
register unsigned char* tp;
register unsigned char* fe;
register unsigned char* te;
register unsigned char* tc;
register unsigned char* m;
register unsigned long b;
size_t n;
unsigned char tmp[B64_EC * B64_CHUNK];
m = (unsigned char*)alp;
fp = fe = (unsigned char*)fb;
if (fz >= 3)
{
n = fz % 3;
fe += fz - n;
fz = n;
}
if (tp = (unsigned char*)tb)
{
te = tp + tz - B64_EC + 1;
n = 0;
}
else
{
if (fn)
*fn = fp;
if (tn)
*tn = 0;
tp = tmp;
te = tp + sizeof(tmp) - B64_EC + 1;
n = 1;
}
for (;;)
{
tc = tp + B64_EC * B64_CHUNK;
do
{
if (fp >= fe)
goto done;
if (tp >= te)
{
if (fn)
*fn = fp;
if (tn)
*tn = tp;
n = tp - (unsigned char*)tb + 1;
tp = tmp;
te = tp + sizeof(tmp) - B64_EC + 1;
}
b = *fp++ << 16;
b |= *fp++ << 8;
b |= *fp++;
*tp++ = m[b >> 18];
*tp++ = m[(b >> 12) & 077];
*tp++ = m[(b >> 6) & 077];
*tp++ = m[b & 077];
} while (tp < tc);
if (n)
{
n += tp - tmp + (fp < fe);
tp = tmp;
}
else
*tp++ = '\n';
}
done:
if (fz)
{
b = *fp++ << 16;
if (fz == 2)
b |= *fp++ << 8;
*tp++ = m[b >> 18];
*tp++ = m[(b >> 12) & 077];
*tp++ = (fz == 2) ? m[(b >> 6) & 077] : PAD;
*tp++ = PAD;
}
if (n)
n += (tp - tmp) - 1;
else
{
if (tp > (unsigned char*)tb && *(tp - 1) == '\n')
tp--;
if (tp < te)
*tp = 0;
n = tp - (unsigned char*)tb;
if (tn)
*tn = tp;
if (fn)
*fn = fp;
}
return n;
}
/*
* mime base64 decode
*/
ssize_t
base64decode(const void* fb, size_t fz, void** fn, void* tb, size_t tz, void** tn)
{
register unsigned char* fp;
register unsigned char* tp;
register unsigned char* fe;
register unsigned char* te;
register unsigned char* tx;
register unsigned char* m;
register int c;
register int state;
register unsigned long v;
unsigned char* fc;
ssize_t n;
if (!(m = map)[0])
{
memset(m, B64_IGN, sizeof(map));
for (tp = (unsigned char*)alp; c = *tp; tp++)
m[c] = tp - (unsigned char*)alp;
m[PAD] = B64_PAD;
m[' '] = m['\t'] = m['\n'] = B64_SPC;
}
fp = (unsigned char*)fb;
fe = fp + fz;
if (tp = (unsigned char*)tb)
{
te = tp + tz;
if (tz > 2)
tz = 2;
tx = te - tz;
n = 0;
}
else
{
te = tx = tp;
n = 1;
}
for (;;)
{
fc = fp;
state = 0;
v = 0;
while (fp < fe)
{
if ((c = m[*fp++]) < 64)
{
v = (v << 6) | c;
if (++state == 4)
{
if (tp >= tx)
{
if (n)
n += 3;
else
{
n = tp - (unsigned char*)tb + 4;
if (tp < te)
{
*tp++ = (v >> 16);
if (tp < te)
{
*tp++ = (v >> 8);
if (tp < te)
*tp++ = (v);
}
}
if (tn)
*tn = tp;
if (fn)
*fn = fc;
}
}
else
{
*tp++ = (v >> 16);
*tp++ = (v >> 8);
*tp++ = (v);
}
fc = fp;
state = 0;
v = 0;
}
}
else if (c == B64_PAD)
break;
}
switch (state)
{
case 0:
goto done;
case 2:
if (tp < te)
*tp++ = v >> 4;
else if (n)
n++;
else
{
n = tp - (unsigned char*)tb + 2;
if (tn)
*tn = tp;
if (fn)
*fn = fc;
}
break;
case 3:
if (tp < te)
{
*tp++ = v >> 10;
if (tp < te)
*tp++ = v >> 2;
else
{
n = tp - (unsigned char*)tb + 2;
if (tn)
*tn = tp;
if (fn)
*fn = fc;
}
}
else if (n)
n += 2;
else
{
n = tp - (unsigned char*)tb + 3;
if (tn)
*tn = tp;
if (fn)
*fn = fc;
}
break;
}
while (fp < fe && ((c = m[*fp++]) == B64_PAD || c == B64_SPC));
if (fp >= fe || c >= 64)
break;
fp--;
}
done:
if (n)
n--;
else
{
if (tp < te)
*tp = 0;
n = tp - (unsigned char*)tb;
if (fn)
*fn = fp;
if (tn)
*tn = tp;
}
return n;
}
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