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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 <sys/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' ||
  38.         **data == '\r')
  39.         (*data)++;
  40.     if (**data == '#') {
  41.         while (1) {
  42.             if (**data == '\n' || **data == '\r')
  43.                 break;
  44.             (*data)++;
  45.         }
  46.         goto retry;
  47.     }
  48. }
  49.  
  50. static void read_num(unsigned char **data, unsigned int *num)
  51. {
  52.     *num = 0;
  53.     while (**data >= '0' && **data <= '9') {
  54.         *num *= 10;
  55.         *num += **data - '0';
  56.         (*data)++;
  57.     }
  58. }
  59.  
  60. int ppm_get_data(unsigned char *data, size_t dtsz, unsigned int *width,
  61.     unsigned int *height)
  62. {
  63.     /* Read magic */
  64.     if (data[0] != 'P' || data[1] != '6')
  65.         return EINVAL;
  66.  
  67.     data+=2;
  68.     skip_whitespace(&data);
  69.     read_num(&data, width);
  70.     skip_whitespace(&data);
  71.     read_num(&data,height);
  72.  
  73.     return 0;
  74. }
  75.  
  76. /** Draw PPM pixmap
  77.  *
  78.  * @param data Pointer to PPM data
  79.  * @param datasz Maximum data size
  80.  * @param sx Coordinate of upper left corner
  81.  * @param sy Coordinate of upper left corner
  82.  * @param maxwidth Maximum allowed width for picture
  83.  * @param maxheight Maximum allowed height for picture
  84.  * @param putpixel Putpixel function used to print bitmap
  85.  */
  86. int ppm_draw(unsigned char *data, size_t datasz, unsigned int sx,
  87.     unsigned int sy, unsigned int maxwidth, unsigned int maxheight,
  88.     putpixel_cb_t putpixel, void *vport)
  89. {
  90.     unsigned int width, height;
  91.     unsigned int maxcolor;
  92.     unsigned int i;
  93.     unsigned int color;
  94.     unsigned int coef;
  95.    
  96.     /* Read magic */
  97.     if ((data[0] != 'P') || (data[1] != '6'))
  98.         return EINVAL;
  99.    
  100.     data += 2;
  101.     skip_whitespace(&data);
  102.     read_num(&data, &width);
  103.     skip_whitespace(&data);
  104.     read_num(&data, &height);
  105.     skip_whitespace(&data);
  106.     read_num(&data, &maxcolor);
  107.     data++;
  108.    
  109.     if ((maxcolor == 0) || (maxcolor > 255) || (width * height > datasz))
  110.         return EINVAL;
  111.    
  112.     coef = 255 / maxcolor;
  113.     if (coef * maxcolor > 255)
  114.         coef -= 1;
  115.    
  116.     for (i = 0; i < width * height; i++) {
  117.         /* Crop picture if we don't fit into region */
  118.         if (i % width > maxwidth || i / width > maxheight) {
  119.             data += 3;
  120.             continue;
  121.         }
  122.         color = ((data[0] * coef) << 16) + ((data[1] * coef) << 8) +
  123.             data[2] * coef;
  124.        
  125.         (*putpixel)(vport, sx + (i % width), sy + (i / width), color);
  126.         data += 3;
  127.     }
  128.    
  129.     return 0;
  130. }
  131.