1 /*- 2 * Copyright (c) 1994 S�ren Schmidt 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer, 10 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software withough specific prior written permission 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $Id: decode.c,v 1.2 1995/01/28 22:18:02 sos Exp $ 29 */ 30 31 #include <stdio.h> 32 33 int decode(FILE *fd, char *buffer) 34 { 35 int n, pos = 0; 36 char *p; 37 char temp[128]; 38 39 #define DEC(c) (((c) - ' ') & 0x3f) 40 41 do { 42 if (!fgets(temp, sizeof(temp), fd)) 43 return(0); 44 } while (strncmp(temp, "begin ", 6)); 45 sscanf(temp, "begin %o %s", &n, temp); 46 for (;;) { 47 if (!fgets(p = temp, sizeof(temp), fd)) 48 return(0); 49 if ((n = DEC(*p)) <= 0) 50 break; 51 for (++p; n > 0; p += 4, n -= 3) 52 if (n >= 3) { 53 buffer[pos++] = DEC(p[0])<<2 | DEC(p[1])>>4; 54 buffer[pos++] = DEC(p[1])<<4 | DEC(p[2])>>2; 55 buffer[pos++] = DEC(p[2])<<6 | DEC(p[3]); 56 } 57 else { 58 if (n >= 1) { 59 buffer[pos++] = 60 DEC(p[0])<<2 | DEC(p[1])>>4; 61 } 62 if (n >= 2) { 63 buffer[pos++] = 64 DEC(p[1])<<4 | DEC(p[2])>>2; 65 } 66 if (n >= 3) { 67 buffer[pos++] = 68 DEC(p[2])<<6 | DEC(p[3]); 69 } 70 } 71 } 72 if (!fgets(temp, sizeof(temp), fd) || strcmp(temp, "end\n")) 73 return(0); 74 return(pos); 75 } 76