gen/libsaio/unpackbits.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1988, 1989, 1990, 1991 Sam Leffler
  27  * Copyright (c) 1991 Silicon Graphics, Inc.
  28  *
  29  * Permission to use, copy, modify, distribute, and sell this software and
  30  * its documentation for any purpose is hereby granted without fee, provided
  31  * that (i) the above copyright notices and this permission notice appear in
  32  * all copies of the software and related documentation, and (ii) the names of
  33  * Sam Leffler and Silicon Graphics may not be used in any advertising or
  34  * publicity relating to the software without the specific, prior written
  35  * permission of Sam Leffler and Silicon Graphics.
  36  *
  37  * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
  38  * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
  39  * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
  40  *
  41  * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
  42  * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
  43  * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  44  * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
  45  * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  46  * OF THIS SOFTWARE.
  47  */
  48
  49 /*
  50  * TIFF Library.
  51  *
  52  * PackBits Compression Algorithm Support
  53  */
  54 #import "bitmap.h"
  55 #import "libsa.h"
  56
  57 typedef unsigned int u_int;
  58 typedef unsigned char u_char;
  59
  60 int
  61 PackBitsDecode(tif, op, occ, s)
  62         TIFF *tif;
  63         register u_char *op;
  64         register int occ;
  65         u_int s;
  66 {
  67         register char *bp;
  68         register int n, b;
  69         register int cc;
  70
  71         bp = tif->tif_rawcp; cc = tif->tif_rawcc;
  72         while (cc > 0 && occ > 0) {
  73                 n = (int) *bp++; cc--;
  74                 /*
  75                  * Watch out for compilers that
  76                  * don't sign extend chars...
  77                  */
  78                 if (n >= 128)
  79                         n -= 256;
  80                 if (n < 0) {            /* replicate next byte -n+1 times */
  81                         cc--;
  82                         if (n == -128)  /* nop */
  83                                 continue;
  84                         n = -n + 1;
  85                         occ -= n;
  86                         for (b = *bp++; n-- > 0;)
  87                                 *op++ = b;
  88                 } else {                /* copy next n+1 bytes literally */
  89                         bcopy(bp, op, ++n);
  90                         op += n; occ -= n;
  91                         bp += n; cc -= n;
  92                 }
  93         }
  94         tif->tif_rawcp = bp;
  95         tif->tif_rawcc = cc;
  96         if (occ > 0) {
  97 //              TIFFError(tif->tif_name,
  98 //                  "PackBitsDecode: Not enough data for scanline %d",
  99 //                  tif->tif_row);
 100 //              reallyPrint("Not enough data\n");
 101                 return (0);
 102         }
 103         /* check for buffer overruns? */
 104         return (1);
 105 }