text: /****************************************************************************
   * apps/graphics/traveler/tools/libwld/wld_readgraphicfile.c
   *
   *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name NuttX nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /*************************************************************************
   * Included files
   *************************************************************************/
  
  #include <string.h>
  #include <ctype.h>
  
  #include "trv_types.h"
  #include "wld_mem.h"
  #include "wld_bitmaps.h"
  #include "wld_graphicfile.h"
  #include "wld_pcx.h"
  #include "wld_utils.h"
  
  graphic_file_t *wld_LoadPPM(FILE * fp, char *filename);
  graphic_file_t *wld_LoadGIF(FILE * fp, char *filename);
  
  /*************************************************************************
   * Private Data
   *************************************************************************/
  
  static const char g_pcx_extension[] = ".PCX";
  
  /*************************************************************************
   * Private Functions
   *************************************************************************/
  
  /*************************************************************************
   * Name: wld_check_format
   * Description:
   ************************************************************************/
  
  static graphic_file_format_t wld_check_format(FILE * fp, char *filename)
  {
    char magic[MAGIC_LENGTH];
  
    if (fread(magic, 1, MAGIC_LENGTH, fp) != MAGIC_LENGTH)
      {
        wld_fatal_error("ERROR: Reading texture %s.", filename);
      }
  
    if (strncmp(magic, PPM_MAGIC, sizeof(PPM_MAGIC) - 1) == 0)
      {
        return FORMAT_PPM;
      }
    else if (strncmp(magic, GIF_MAGIC, sizeof(GIF_MAGIC) - 1) == 0)
      {
        return FORMAT_GIT87;
      }
    else if (strncmp(magic, GIF89_MAGIC, sizeof(GIF89_MAGIC) - 1) == 0)
      {
        return FORMAT_GIT89;
      }
    else
      {
        char *ptr1;
        char *ptr2;
  
        /* MS-DOS PCX files will have no magic number, we'll have to make an
         * educated guess based on the file extension.
         */
  
        /* Search for the PCX extension */
  
        for (ptr1 = filename; ((*ptr1) && (*ptr1 != '.')); ptr1++);
  
        /* Check if the extension matches */
  
        for (ptr2 = (char *)g_pcx_extension; ((*ptr1) && (*ptr2)); ptr1++, ptr2++)
          {
            if (toupper((int)*ptr1) != *ptr2)
              {
                return FORMAT_UNKNOWN;
              }
          }
  
        /* If it is an exact match, both pointers should refer to the NULL
         * terminator.
         */
  
        if (!(*ptr1) && !(*ptr2))
          {
            return FORMAT_PCX;
          }
      }
  
    return FORMAT_UNKNOWN;
  }
  
  /*************************************************************************
   * Public Functions
   *************************************************************************/
  
  /*************************************************************************
   * Name: wld_readgraphic_file
   *
   * Description:
   *
   ************************************************************************/
  
  graphic_file_t *wld_readgraphic_file(char *filename)
  {
    FILE *fp;
    graphic_file_format_t format;
    graphic_file_t *gfile = NULL;
  
    if ((fp = fopen(filename, "rb")) == NULL)
      {
        wld_fatal_error("Could not open texture %s", filename);
      }
  
    format = wld_check_format(fp, filename);
    fseek(fp, 0, SEEK_SET);
  
    switch (format)
      {
      case FORMAT_GIT89:
      case FORMAT_GIT87:
        gfile = wld_LoadGIF(fp, filename);
        break;
  
      case FORMAT_PPM:
        gfile = wld_LoadPPM(fp, filename);
        break;
  
      case FORMAT_PCX:
        gfile = wld_loadpcx(fp, filename);
        break;
  
      case FORMAT_UNKNOWN:
        wld_fatal_error("Unknown graphic file format.\n");
        break;
  
      default:
        wld_fatal_error("The graphic file reading code is really broken.\n");
        break;
      }
  
    if (gfile == NULL)
      {
        wld_fatal_error("ERROR: Reading texture %s\n");
      }
  
    fclose(fp);
    return gfile;
  }
  