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 * $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 1.2 2003/06/17 04:30:03 dillon Exp $ 30 */ 31 32 #include <stdio.h> 33 #include <string.h> 34 #include "decode.h" 35 36 int decode(FILE *fd, char *buffer, int len) 37 { 38 int n, pos = 0, tpos; 39 char *bp, *p; 40 char tbuffer[3]; 41 char temp[128]; 42 43 #define DEC(c) (((c) - ' ') & 0x3f) 44 45 do { 46 if (!fgets(temp, sizeof(temp), fd)) 47 return(0); 48 } while (strncmp(temp, "begin ", 6)); 49 sscanf(temp, "begin %o %s", &n, temp); 50 bp = buffer; 51 for (;;) { 52 if (!fgets(p = temp, sizeof(temp), fd)) 53 return(0); 54 if ((n = DEC(*p)) <= 0) 55 break; 56 for (++p; n > 0; p += 4, n -= 3) { 57 tpos = 0; 58 if (n >= 3) { 59 tbuffer[tpos++] = DEC(p[0])<<2 | DEC(p[1])>>4; 60 tbuffer[tpos++] = DEC(p[1])<<4 | DEC(p[2])>>2; 61 tbuffer[tpos++] = DEC(p[2])<<6 | DEC(p[3]); 62 } 63 else { 64 if (n >= 1) { 65 tbuffer[tpos++] = 66 DEC(p[0])<<2 | DEC(p[1])>>4; 67 } 68 if (n >= 2) { 69 tbuffer[tpos++] = 70 DEC(p[1])<<4 | DEC(p[2])>>2; 71 } 72 if (n >= 3) { 73 tbuffer[tpos++] = 74 DEC(p[2])<<6 | DEC(p[3]); 75 } 76 } 77 if (tpos == 0) 78 continue; 79 if (tpos + pos > len) { 80 tpos = len - pos; 81 /* 82 * Arrange return value > len to indicate 83 * overflow. 84 */ 85 pos++; 86 } 87 bcopy(tbuffer, bp, tpos); 88 pos += tpos; 89 bp += tpos; 90 if (pos > len) 91 return(pos); 92 } 93 } 94 if (!fgets(temp, sizeof(temp), fd) || strcmp(temp, "end\n")) 95 return(0); 96 return(pos); 97 } 98