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  1. /*
  2.  * Copyright (C) 2006 Ondrej Palkovsky
  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.  *
  9.  * - Redistributions of source code must retain the above copyright
  10.  *   notice, this list of conditions and the following disclaimer.
  11.  * - 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.  * - 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.  
  29. #include <types.h>
  30. #include <errno.h>
  31.  
  32. #include "ppm.h"
  33.  
  34. static void skip_whitespace(unsigned char **data)
  35. {
  36. retry:
  37.     while (**data == ' ' || **data == '\t' || **data == '\n' || **data == '\r')
  38.         (*data)++;
  39.     if (**data == '#') {
  40.         while (1) {
  41.             if (**data == '\n' || **data == '\r')
  42.                 break;
  43.             (*data)++;
  44.         }
  45.         goto retry;
  46.     }
  47. }
  48.  
  49. static void read_num(unsigned char **data, unsigned int *num)
  50. {
  51.     *num = 0;
  52.     while (**data >= '0' && **data <= '9') {
  53.         *num *= 10;
  54.         *num += **data - '0';
  55.         (*data)++;
  56.     }
  57. }
  58.  
  59. /** Draw PPM pixmap
  60.  *
  61.  * @param data Pointer to PPM data
  62.  * @param datasz Maximum data size
  63.  * @param x Coordinate of upper left corner
  64.  * @param y Coordinate of upper left corner
  65.  * @param maxwidth Maximum allowed width for picture
  66.  * @param maxheight Maximum allowed height for picture
  67.  * @param putpixel Putpixel function used to print bitmap
  68.  */
  69. int draw_ppm(unsigned char *data, size_t datasz, unsigned int sx,
  70.          unsigned int sy,
  71.          unsigned int maxwidth, unsigned int maxheight,
  72.          void (*putpixel)(int,unsigned int, unsigned int, int),int vp)
  73. {
  74.     unsigned int width, height;
  75.     unsigned int maxcolor;
  76.     int i;
  77.     void *maxdatap = data + datasz;
  78.     unsigned int color;
  79.     unsigned int coef;
  80.  
  81.     /* Read magic */
  82.     if (data[0] != 'P' || data[1] != '6')
  83.         return EINVAL;
  84.  
  85.     data+=2;
  86.     skip_whitespace(&data);
  87.     read_num(&data, &width);
  88.     skip_whitespace(&data);
  89.     read_num(&data,&height);
  90.     skip_whitespace(&data);
  91.     read_num(&data,&maxcolor);
  92.     data++;
  93.  
  94.     if (maxcolor == 0 || maxcolor > 255 || width*height > datasz) {
  95.         return EINVAL;
  96.     }
  97.     coef = 255/maxcolor;
  98.     if (coef*maxcolor > 255)
  99.         coef -= 1;
  100.    
  101.     for (i=0; i < width*height; i++) {
  102.         /* Crop picture if we don't fit into region */
  103.         if (i % width > maxwidth || i/width > maxheight) {
  104.             data += 3;
  105.             continue;
  106.         }
  107.         color = ((data[0]*coef) << 16) + ((data[1]*coef) << 8) + data[0]*coef;
  108.        
  109.         (*putpixel)(vp, sx+(i % width), sy+(i / width), color);
  110.         data += 3;
  111.     }
  112. }
  113.