dlls/wineps.drv/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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  */
  20 #include <ctype.h>
  21 #include <stdio.h>
  22 #include <string.h>
  23
  24 #include "psdrv.h"
  25
  26 DWORD RLE_encode(BYTE *in_buf, DWORD len, BYTE *out_buf)
  27 {
  28     BYTE *next_in = in_buf, *next_out = out_buf;
  29     DWORD rl;
  30
  31     while(next_in < in_buf + len) {
  32         if(next_in + 1 < in_buf + len) {
  33             if(*next_in == *(next_in + 1)) {
  34                 next_in += 2;
  35                 rl = 2;
  36                 while(next_in < in_buf + len && *next_in == *(next_in - 1) && rl < 128) {
  37                     next_in++;
  38                     rl++;
  39                 }
  40                 *next_out++ = 257 - rl;
  41                 *next_out++ = *(next_in - 1);
  42             } else {
  43                 rl = 0;
  44                 next_out++;
  45                 while(next_in < in_buf + len && rl < 128) {
  46                     if(next_in + 2 < in_buf + len && *next_in == *(next_in + 1)) {
  47                         if(rl == 127 || *next_in == *(next_in + 2))
  48                             break;
  49                     }
  50                     *next_out++ = *next_in++;
  51                     rl++;
  52                 }
  53                 *(next_out - rl - 1) = rl - 1;
  54             }
  55         } else { /* special case: begin of run on last byte */
  56             *next_out++ = 0;
  57             *next_out++ = *next_in;
  58             break;
  59         }
  60     }
  61     *next_out++ = 128;
  62     return next_out - out_buf;
  63 }
  64
  65 DWORD ASCII85_encode(BYTE *in_buf, DWORD len, BYTE *out_buf)
  66 {
  67     DWORD number;
  68     BYTE *next_in = in_buf, *next_out = out_buf;
  69     int i;
  70
  71     while(next_in + 3 < in_buf + len) {
  72         number = (next_in[0] << 24) |
  73                  (next_in[1] << 16) |
  74                  (next_in[2] <<  8) |
  75                  (next_in[3]      );
  76         next_in += 4;
  77         if(number == 0)
  78             *next_out++ = 'z';
  79         else {
  80             for(i = 4; i >= 0; i--) {
  81                 next_out[i] = number % 85 + '!';
  82                 number /= 85;
  83             }
  84             next_out += 5;
  85         }
  86     }
  87
  88     if(next_in != in_buf + len) {
  89         number = (*next_in++ << 24) & 0xff000000;
  90         if(next_in < in_buf + len)
  91             number |= ((*next_in++ << 16) & 0x00ff0000);
  92         if(next_in < in_buf + len)
  93             number |= ((*next_in++ <<  8) & 0x0000ff00);
  94
  95         for(i = len % 4 + 1; i < 5; i++)
  96             number /= 85;
  97
  98         for(i = len % 4; i >= 0; i--) {
  99             next_out[i] = number % 85 + '!';
 100             number /= 85;
 101         }
 102         next_out += len % 4 + 1;
 103     }
 104
 105     return next_out - out_buf;
 106 }