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/*
** Copyright 1998 - 1999 Double Precision, Inc. See COPYING for
** distribution information.
*/
#include "rfc2045.h"
#include <ctype.h>
#include <string.h>
extern void rfc2045_add_buf( char **, size_t *, size_t *,
const char *, size_t);
extern void rfc2045_add_workbuf(struct rfc2045 *, const char *, size_t);
extern void rfc2045_add_workbufch(struct rfc2045 *, int);
static int decode_raw(struct rfc2045 *p, const char *s, size_t l)
{
if (s && l) return ((*p->udecode_func)(s,l,p->misc_decode_ptr));
return (0);
}
static const char xdigit[]="0123456789ABCDEF";
static int tou(char c)
{
if (c >= 'a' && c <= 'f')
return c + ('A'-'a');
return c;
}
static int do_decode_qp(struct rfc2045 *p)
{
char *a, *b, *c, *end;
int d;
end=p->workbuf + p->workbuflen;
for (a=b=p->workbuf; a < end; )
{
if (*a != '=')
{
*b++ = *a++;
continue;
}
++a;
if (!*a || a >= end || isspace((int)(unsigned char)*a))
break;
if ((c=strchr(xdigit, tou(*a))) == 0) continue;
d= (c-xdigit)*16;
++a;
if (!*a || a >= end)
break;
if ((c=strchr(xdigit, tou(*a))) == 0) continue;
d += c-xdigit;
++a;
*b++=d;
}
p->workbuflen= b-p->workbuf;
d=(*p->udecode_func)(p->workbuf, p->workbuflen, p->misc_decode_ptr);
p->workbuflen=0;
return (d);
}
static const unsigned char decode64tab[256]={
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,62,100,100,100,63,
52,53,54,55,56,57,58,59,60,61,100,100,100,99,100,100,
100,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,
15,16,17,18,19,20,21,22,23,24,25,100,100,100,100,100,
100,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,
41,42,43,44,45,46,47,48,49,50,51,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,
100,100,100,100,100,100,100,100,100,100,100,100,100,100,100,100
};
/* When we have enough base64-encoded data in the buffer, decode it. */
static int do_decode_base64(struct rfc2045 *p)
{
size_t i, j;
char a,b,c;
size_t k;
int rc;
/* Remove everything except base64encoded data */
for (i=j=0; i<p->workbuflen; i++)
if (decode64tab[(int)(unsigned char)p->workbuf[i]] < 100)
p->workbuf[j++]=p->workbuf[i];
p->workbuflen=j;
/* Decode the data, in 4-byte pieces */
i=j / 4;
i=i*4;
k=0;
for (j=0; j<i; j += 4)
{
int w=decode64tab[(int)(unsigned char)p->workbuf[j]];
int x=decode64tab[(int)(unsigned char)p->workbuf[j+1]];
int y=decode64tab[(int)(unsigned char)p->workbuf[j+2]];
int z=decode64tab[(int)(unsigned char)p->workbuf[j+3]];
a= (w << 2) | (x >> 4);
b= (x << 4) | (y >> 2);
c= (y << 6) | z;
p->workbuf[k++]=a;
if ( p->workbuf[j+2] != '=')
p->workbuf[k++]=b;
if ( p->workbuf[j+3] != '=')
p->workbuf[k++]=c;
}
rc=(*p->udecode_func)(p->workbuf, k, p->misc_decode_ptr);
/* Anything left? Move it to the start of the buffer */
k=0;
while (j < p->workbuflen)
p->workbuf[k++]=p->workbuf[j++];
p->workbuflen=k;
return (rc);
}
static int decode_qp(struct rfc2045 *p, const char *s, size_t l)
{
size_t start,i;
int rc;
if (!s)
return (do_decode_qp(p));
for (start=0; start<l; )
{
for (i=start; i<l; i++)
{
if (s[i] != '\n') continue;
rfc2045_add_workbuf(p, s+start, i-start);
rfc2045_add_workbufch(p, '\n');
if ((rc=do_decode_qp(p)) != 0) return (rc);
start= ++i;
break;
}
rfc2045_add_workbuf(p, s+start, i-start);
if (p->workbuflen > 1024)
{
char buf[10];
int i;
for (i=p->workbuflen - 5; i<p->workbuflen; i++)
if (p->workbuf[i] == '=') break;
if (i < p->workbuflen)
{
int j=p->workbuflen-i;
memcpy(buf, p->workbuf+i, j);
buf[j]=0;
p->workbuflen=i;
}
else buf[0]=0;
if ((rc=do_decode_qp(p)) != 0) return (rc);
rfc2045_add_workbuf(p, buf, strlen(buf));
}
start=i;
}
return (0);
}
static int decode_base64(struct rfc2045 *p, const char *s, size_t l)
{
if (!s)
return (do_decode_base64(p));
rfc2045_add_workbuf(p, s, l);
if (p->workbuflen > 256)
return (do_decode_base64(p));
return (0);
}
void rfc2045_cdecode_start(struct rfc2045 *p,
int (*u)(const char *, size_t, void *), void *miscptr)
{
p->misc_decode_ptr=miscptr;
p->udecode_func=u;
p->decode_func= &decode_raw;
p->workbuflen=0;
if (p->content_transfer_encoding)
{
if (strcmp(p->content_transfer_encoding,
"quoted-printable") == 0)
p->decode_func= &decode_qp;
else if (strcmp(p->content_transfer_encoding, "base64") == 0)
p->decode_func= &decode_base64;
}
}
int rfc2045_cdecode_end(struct rfc2045 *p)
{
return ((*p->decode_func)(p, NULL, 0));
}
int rfc2045_cdecode(struct rfc2045 *p, const char *s, size_t l)
{
if (s && l) return ((*p->decode_func)(p, s, l));
return (0);
}
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