decode.c revision 8857
12089Ssos/*- 22089Ssos * Copyright (c) 1994 S�ren Schmidt 32089Ssos * All rights reserved. 42089Ssos * 52089Ssos * Redistribution and use in source and binary forms, with or without 62089Ssos * modification, are permitted provided that the following conditions 72089Ssos * are met: 82089Ssos * 1. Redistributions of source code must retain the above copyright 95994Ssos * notice, this list of conditions and the following disclaimer, 105994Ssos * in this position and unchanged. 112089Ssos * 2. Redistributions in binary form must reproduce the above copyright 122089Ssos * notice, this list of conditions and the following disclaimer in the 132089Ssos * documentation and/or other materials provided with the distribution. 142089Ssos * 3. The name of the author may not be used to endorse or promote products 152089Ssos * derived from this software withough specific prior written permission 162089Ssos * 172089Ssos * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 182089Ssos * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 192089Ssos * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 202089Ssos * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 212089Ssos * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 222089Ssos * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 232089Ssos * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 242089Ssos * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 252089Ssos * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 262089Ssos * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 272089Ssos * 288857Srgrimes * $Id: decode.c,v 1.2 1995/01/28 22:18:02 sos Exp $ 292089Ssos */ 302089Ssos 312089Ssos#include <stdio.h> 322089Ssos 332089Ssosint decode(FILE *fd, char *buffer) 342089Ssos{ 352089Ssos int n, pos = 0; 362089Ssos char *p; 372089Ssos char temp[128]; 382089Ssos 392089Ssos#define DEC(c) (((c) - ' ') & 0x3f) 402089Ssos 412089Ssos do { 428857Srgrimes if (!fgets(temp, sizeof(temp), fd)) 432089Ssos return(0); 442089Ssos } while (strncmp(temp, "begin ", 6)); 452089Ssos sscanf(temp, "begin %o %s", &n, temp); 462089Ssos for (;;) { 472089Ssos if (!fgets(p = temp, sizeof(temp), fd)) 482089Ssos return(0); 492089Ssos if ((n = DEC(*p)) <= 0) 502089Ssos break; 512089Ssos for (++p; n > 0; p += 4, n -= 3) 522089Ssos if (n >= 3) { 532089Ssos buffer[pos++] = DEC(p[0])<<2 | DEC(p[1])>>4; 542089Ssos buffer[pos++] = DEC(p[1])<<4 | DEC(p[2])>>2; 552089Ssos buffer[pos++] = DEC(p[2])<<6 | DEC(p[3]); 562089Ssos } 572089Ssos else { 582089Ssos if (n >= 1) { 592089Ssos buffer[pos++] = 602089Ssos DEC(p[0])<<2 | DEC(p[1])>>4; 612089Ssos } 622089Ssos if (n >= 2) { 638857Srgrimes buffer[pos++] = 642089Ssos DEC(p[1])<<4 | DEC(p[2])>>2; 652089Ssos } 662089Ssos if (n >= 3) { 672089Ssos buffer[pos++] = 682089Ssos DEC(p[2])<<6 | DEC(p[3]); 692089Ssos } 702089Ssos } 712089Ssos } 722089Ssos if (!fgets(temp, sizeof(temp), fd) || strcmp(temp, "end\n")) 732089Ssos return(0); 742089Ssos return(pos); 752089Ssos} 76