dlls/wineps/encode.c

   1 /*
   2  *      PostScript filter functions
   3  *
   4  *      Copyright 2003  Huw D M Davies
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20 #include <ctype.h>
  21 #include <stdio.h>
  22 #include <string.h>
  23
  24 #include "psdrv.h"
  25 #include "wine/debug.h"
  26
  27 WINE_DEFAULT_DEBUG_CHANNEL(psdrv);
  28
  29 DWORD RLE_encode(BYTE *in_buf, DWORD len, BYTE *out_buf)
  30 {
  31     BYTE *next_in = in_buf, *next_out = out_buf;
  32     DWORD rl;
  33
  34     while(next_in < in_buf + len) {
  35         if(next_in + 1 < in_buf + len) {
  36             if(*next_in == *(next_in + 1)) {
  37                 next_in += 2;
  38                 rl = 2;
  39                 while(next_in < in_buf + len && *next_in == *(next_in - 1) && rl < 128) {
  40                     next_in++;
  41                     rl++;
  42                 }
  43                 *next_out++ = 257 - rl;
  44                 *next_out++ = *(next_in - 1);
  45             } else {
  46                 rl = 0;
  47                 next_out++;
  48                 while(next_in < in_buf + len && rl < 128) {
  49                     if(next_in + 2 < in_buf + len && *next_in == *(next_in + 1)) {
  50                         if(rl == 127 || *next_in == *(next_in + 2))
  51                             break;
  52                     }
  53                     *next_out++ = *next_in++;
  54                     rl++;
  55                 }
  56                 *(next_out - rl - 1) = rl - 1;
  57             }
  58         } else { /* special case: begin of run on last byte */
  59             *next_out++ = 0;
  60             *next_out++ = *next_in;
  61             break;
  62         }
  63     }
  64     *next_out++ = 128;
  65     return next_out - out_buf;
  66 }
  67
  68 DWORD ASCII85_encode(BYTE *in_buf, DWORD len, BYTE *out_buf)
  69 {
  70     DWORD number;
  71     BYTE *next_in = in_buf, *next_out = out_buf;
  72     int i;
  73
  74     while(next_in + 3 < in_buf + len) {
  75         number = (next_in[0] << 24) |
  76                  (next_in[1] << 16) |
  77                  (next_in[2] <<  8) |
  78                  (next_in[3]      );
  79         next_in += 4;
  80         if(number == 0)
  81             *next_out++ = 'z';
  82         else {
  83             for(i = 4; i >= 0; i--) {
  84                 next_out[i] = number % 85 + '!';
  85                 number /= 85;
  86             }
  87             next_out += 5;
  88         }
  89     }
  90
  91     if(next_in != in_buf + len) {
  92         number = (*next_in++ << 24) & 0xff000000;
  93         if(next_in < in_buf + len)
  94             number |= ((*next_in++ << 16) & 0x00ff0000);
  95         if(next_in < in_buf + len)
  96             number |= ((*next_in++ <<  8) & 0x0000ff00);
  97
  98         for(i = len % 4 + 1; i < 5; i++)
  99             number /= 85;
 100
 101         for(i = len % 4; i >= 0; i--) {
 102             next_out[i] = number % 85 + '!';
 103             number /= 85;
 104         }
 105         next_out += len % 4 + 1;
 106     }
 107
 108     return next_out - out_buf;
 109 }