17363955dSSøren Schmidt /*-
2*1de7b4b8SPedro F. Giffuni * SPDX-License-Identifier: BSD-3-Clause
3*1de7b4b8SPedro F. Giffuni *
4f76b3199SUlrich Spörlein * Copyright (c) 1994 Søren Schmidt
57363955dSSøren Schmidt * All rights reserved.
67363955dSSøren Schmidt *
77363955dSSøren Schmidt * Redistribution and use in source and binary forms, with or without
87363955dSSøren Schmidt * modification, are permitted provided that the following conditions
97363955dSSøren Schmidt * are met:
107363955dSSøren Schmidt * 1. Redistributions of source code must retain the above copyright
11a926a37bSSøren Schmidt * notice, this list of conditions and the following disclaimer,
12a926a37bSSøren Schmidt * in this position and unchanged.
137363955dSSøren Schmidt * 2. Redistributions in binary form must reproduce the above copyright
147363955dSSøren Schmidt * notice, this list of conditions and the following disclaimer in the
157363955dSSøren Schmidt * documentation and/or other materials provided with the distribution.
167363955dSSøren Schmidt * 3. The name of the author may not be used to endorse or promote products
1721dc7d4fSJens Schweikhardt * derived from this software without specific prior written permission
187363955dSSøren Schmidt *
197363955dSSøren Schmidt * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
207363955dSSøren Schmidt * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
217363955dSSøren Schmidt * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
227363955dSSøren Schmidt * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
237363955dSSøren Schmidt * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
247363955dSSøren Schmidt * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
257363955dSSøren Schmidt * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
267363955dSSøren Schmidt * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
277363955dSSøren Schmidt * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
287363955dSSøren Schmidt * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
297363955dSSøren Schmidt */
307363955dSSøren Schmidt
317363955dSSøren Schmidt #include <stdio.h>
32bfc214e3SBrian Somers #include <string.h>
33bfc214e3SBrian Somers #include "decode.h"
347363955dSSøren Schmidt
decode(FILE * fd,char * buffer,int len)355e0db936SMaxim Sobolev int decode(FILE *fd, char *buffer, int len)
367363955dSSøren Schmidt {
375e0db936SMaxim Sobolev int n, pos = 0, tpos;
385e0db936SMaxim Sobolev char *bp, *p;
395e0db936SMaxim Sobolev char tbuffer[3];
407363955dSSøren Schmidt char temp[128];
417363955dSSøren Schmidt
427363955dSSøren Schmidt #define DEC(c) (((c) - ' ') & 0x3f)
437363955dSSøren Schmidt
447363955dSSøren Schmidt do {
457363955dSSøren Schmidt if (!fgets(temp, sizeof(temp), fd))
467363955dSSøren Schmidt return(0);
477363955dSSøren Schmidt } while (strncmp(temp, "begin ", 6));
489a03b27dSXin LI sscanf(temp, "begin %o %s", (unsigned *)&n, temp);
495e0db936SMaxim Sobolev bp = buffer;
507363955dSSøren Schmidt for (;;) {
517363955dSSøren Schmidt if (!fgets(p = temp, sizeof(temp), fd))
527363955dSSøren Schmidt return(0);
537363955dSSøren Schmidt if ((n = DEC(*p)) <= 0)
547363955dSSøren Schmidt break;
555e0db936SMaxim Sobolev for (++p; n > 0; p += 4, n -= 3) {
565e0db936SMaxim Sobolev tpos = 0;
577363955dSSøren Schmidt if (n >= 3) {
585e0db936SMaxim Sobolev tbuffer[tpos++] = DEC(p[0])<<2 | DEC(p[1])>>4;
595e0db936SMaxim Sobolev tbuffer[tpos++] = DEC(p[1])<<4 | DEC(p[2])>>2;
605e0db936SMaxim Sobolev tbuffer[tpos++] = DEC(p[2])<<6 | DEC(p[3]);
617363955dSSøren Schmidt }
627363955dSSøren Schmidt else {
637363955dSSøren Schmidt if (n >= 1) {
645e0db936SMaxim Sobolev tbuffer[tpos++] =
657363955dSSøren Schmidt DEC(p[0])<<2 | DEC(p[1])>>4;
667363955dSSøren Schmidt }
677363955dSSøren Schmidt if (n >= 2) {
685e0db936SMaxim Sobolev tbuffer[tpos++] =
697363955dSSøren Schmidt DEC(p[1])<<4 | DEC(p[2])>>2;
707363955dSSøren Schmidt }
717363955dSSøren Schmidt if (n >= 3) {
725e0db936SMaxim Sobolev tbuffer[tpos++] =
737363955dSSøren Schmidt DEC(p[2])<<6 | DEC(p[3]);
747363955dSSøren Schmidt }
757363955dSSøren Schmidt }
765e0db936SMaxim Sobolev if (tpos == 0)
775e0db936SMaxim Sobolev continue;
785e0db936SMaxim Sobolev if (tpos + pos > len) {
795e0db936SMaxim Sobolev tpos = len - pos;
805e0db936SMaxim Sobolev /*
815e0db936SMaxim Sobolev * Arrange return value > len to indicate
825e0db936SMaxim Sobolev * overflow.
835e0db936SMaxim Sobolev */
845e0db936SMaxim Sobolev pos++;
855e0db936SMaxim Sobolev }
865e0db936SMaxim Sobolev bcopy(tbuffer, bp, tpos);
875e0db936SMaxim Sobolev pos += tpos;
885e0db936SMaxim Sobolev bp += tpos;
895e0db936SMaxim Sobolev if (pos > len)
905e0db936SMaxim Sobolev return(pos);
915e0db936SMaxim Sobolev }
927363955dSSøren Schmidt }
937363955dSSøren Schmidt if (!fgets(temp, sizeof(temp), fd) || strcmp(temp, "end\n"))
947363955dSSøren Schmidt return(0);
957363955dSSøren Schmidt return(pos);
967363955dSSøren Schmidt }
97