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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. int ppm_get_data(unsigned char *data, size_t dtsz, int *width, int *height)
  60. {
  61.     /* Read magic */
  62.     if (data[0] != 'P' || data[1] != '6')
  63.         return EINVAL;
  64.  
  65.     data+=2;
  66.     skip_whitespace(&data);
  67.     read_num(&data, width);
  68.     skip_whitespace(&data);
  69.     read_num(&data,height);
  70.  
  71.     return 0;
  72. }
  73.  
  74. /** Draw PPM pixmap
  75.  *
  76.  * @param data Pointer to PPM data
  77.  * @param datasz Maximum data size
  78.  * @param x Coordinate of upper left corner
  79.  * @param y Coordinate of upper left corner
  80.  * @param maxwidth Maximum allowed width for picture
  81.  * @param maxheight Maximum allowed height for picture
  82.  * @param putpixel Putpixel function used to print bitmap
  83.  */
  84. int ppm_draw(unsigned char *data, size_t datasz, unsigned int sx,
  85.          unsigned int sy,
  86.          unsigned int maxwidth, unsigned int maxheight,
  87.          putpixel_cb_t putpixel,void *vport)
  88. {
  89.     unsigned int width, height;
  90.     unsigned int maxcolor;
  91.     int i;
  92.     void *maxdatap = data + datasz;
  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) + data[2]*coef;
  123.        
  124.         (*putpixel)(vport, sx+(i % width), sy+(i / width), color);
  125.         data += 3;
  126.     }
  127. }
  128.