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/*-
* Copyright (c) 1994 Søren Schmidt
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer,
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software withough specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef lint
static const char rcsid[] =
"$FreeBSD$";
#endif /* not lint */
#include <stdio.h>
#include <string.h>
#include "decode.h"
int decode(FILE *fd, char *buffer, int len)
{
int n, pos = 0, tpos;
char *bp, *p;
char tbuffer[3];
char temp[128];
#define DEC(c) (((c) - ' ') & 0x3f)
do {
if (!fgets(temp, sizeof(temp), fd))
return(0);
} while (strncmp(temp, "begin ", 6));
sscanf(temp, "begin %o %s", &n, temp);
bp = buffer;
for (;;) {
if (!fgets(p = temp, sizeof(temp), fd))
return(0);
if ((n = DEC(*p)) <= 0)
break;
for (++p; n > 0; p += 4, n -= 3) {
tpos = 0;
if (n >= 3) {
tbuffer[tpos++] = DEC(p[0])<<2 | DEC(p[1])>>4;
tbuffer[tpos++] = DEC(p[1])<<4 | DEC(p[2])>>2;
tbuffer[tpos++] = DEC(p[2])<<6 | DEC(p[3]);
}
else {
if (n >= 1) {
tbuffer[tpos++] =
DEC(p[0])<<2 | DEC(p[1])>>4;
}
if (n >= 2) {
tbuffer[tpos++] =
DEC(p[1])<<4 | DEC(p[2])>>2;
}
if (n >= 3) {
tbuffer[tpos++] =
DEC(p[2])<<6 | DEC(p[3]);
}
}
if (tpos == 0)
continue;
if (tpos + pos > len) {
tpos = len - pos;
/*
* Arrange return value > len to indicate
* overflow.
*/
pos++;
}
bcopy(tbuffer, bp, tpos);
pos += tpos;
bp += tpos;
if (pos > len)
return(pos);
}
}
if (!fgets(temp, sizeof(temp), fd) || strcmp(temp, "end\n"))
return(0);
return(pos);
}
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