1 /*- 2 * Copyright (c) 1994 Søren 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 without 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 * $FreeBSD: src/usr.sbin/vidcontrol/decode.c,v 1.8.2.1 2001/05/28 17:36:56 sobomax Exp $ 29 * $DragonFly: src/usr.sbin/vidcontrol/decode.c,v 1.3 2005/12/05 01:23:23 swildner Exp $ 30 */ 31 32 #include <stdio.h> 33 #include <string.h> 34 #include "decode.h" 35 36 int 37 decode(FILE *fd, char *buffer, int len) 38 { 39 int n, pos = 0, tpos; 40 char *bp, *p; 41 char tbuffer[3]; 42 char temp[128]; 43 44 #define DEC(c) (((c) - ' ') & 0x3f) 45 46 do { 47 if (!fgets(temp, sizeof(temp), fd)) 48 return(0); 49 } while (strncmp(temp, "begin ", 6)); 50 sscanf(temp, "begin %o %s", &n, temp); 51 bp = buffer; 52 for (;;) { 53 if (!fgets(p = temp, sizeof(temp), fd)) 54 return(0); 55 if ((n = DEC(*p)) <= 0) 56 break; 57 for (++p; n > 0; p += 4, n -= 3) { 58 tpos = 0; 59 if (n >= 3) { 60 tbuffer[tpos++] = DEC(p[0])<<2 | DEC(p[1])>>4; 61 tbuffer[tpos++] = DEC(p[1])<<4 | DEC(p[2])>>2; 62 tbuffer[tpos++] = DEC(p[2])<<6 | DEC(p[3]); 63 } 64 else { 65 if (n >= 1) { 66 tbuffer[tpos++] = 67 DEC(p[0])<<2 | DEC(p[1])>>4; 68 } 69 if (n >= 2) { 70 tbuffer[tpos++] = 71 DEC(p[1])<<4 | DEC(p[2])>>2; 72 } 73 if (n >= 3) { 74 tbuffer[tpos++] = 75 DEC(p[2])<<6 | DEC(p[3]); 76 } 77 } 78 if (tpos == 0) 79 continue; 80 if (tpos + pos > len) { 81 tpos = len - pos; 82 /* 83 * Arrange return value > len to indicate 84 * overflow. 85 */ 86 pos++; 87 } 88 bcopy(tbuffer, bp, tpos); 89 pos += tpos; 90 bp += tpos; 91 if (pos > len) 92 return(pos); 93 } 94 } 95 if (!fgets(temp, sizeof(temp), fd) || strcmp(temp, "end\n")) 96 return(0); 97 return(pos); 98 } 99