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/*
** Copyright 2002 Double Precision, Inc. See COPYING for
** distribution information.
*/
#include "rfc2045_config.h"
#include "base64.h"
#include <string.h>
#include <stdio.h>
void base64_decode_init(struct base64decode *b,
int (*f)(const char *, int, void *),
void *a)
{
b->workbuflen=0;
b->decode_func=f;
b->decode_func_arg=a;
}
static int doflush(struct base64decode *);
static const char base64tab[]=
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
int base64_decode(struct base64decode *b, const char *p, int l)
{
while (l)
{
char c;
if (b->workbuflen >= sizeof(b->workbuf))
{
int rc=doflush(b);
if (rc)
return (rc);
}
if (*p == '=')
{
c=100;
}
else
{
char *s=strchr(base64tab, *p);
if (s == NULL)
{
++p;
--l;
continue;
}
c= s-base64tab;
}
b->workbuf[b->workbuflen++]=c;
++p;
--l;
}
return (0);
}
int base64_decode_end(struct base64decode *b)
{
return (doflush(b));
}
static int doflush(struct base64decode *p)
{
int i=p->workbuflen / 4;
int j;
int k=0;
i= i * 4;
for (j=0; j<i; j += 4)
{
char a,b,c;
int w=p->workbuf[j];
int x=p->workbuf[j+1];
int y=p->workbuf[j+2];
int z=p->workbuf[j+3];
a= (w << 2) | (x >> 4);
b= (x << 4) | (y >> 2);
c= (y << 6) | z;
p->workbuf[k++]=a;
if ( y != 100)
p->workbuf[k++]=b;
if ( z != 100)
p->workbuf[k++]=c;
}
j= (*p->decode_func)(p->workbuf, k, p->decode_func_arg);
k=0;
while (i < p->workbuflen)
{
p->workbuf[k]=p->workbuf[i];
++k;
++i;
}
p->workbuflen=k;
return (j);
}
/* ---- */
static int save_str(const char *p, int l, void *vp)
{
memcpy(*(char **)vp, p, l);
*(char **)vp += l;
return (0);
}
char *base64_decode_str(const char *s)
{
struct base64decode b;
char *p=strdup(s);
char *pp;
if (!p)
return (NULL);
pp= p;
base64_decode_init(&b, save_str, &pp);
base64_decode(&b, s, strlen(s));
base64_decode_end(&b);
*pp=0;
return p;
}
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