sprite_file.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
 * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "../stdafx.h"
#include "sprite_file_type.hpp"
 
extern const uint8_t _grf_cont_v2_sig[8] = {'G', 'R', 'F', 0x82, 0x0D, 0x0A, 0x1A, 0x0A};
 
static uint8_t GetGRFContainerVersion(SpriteFile &file)
{
  size_t pos = file.GetPos();
 
  if (file.ReadWord() == 0) {
    /* Check for GRF container version 2, which is identified by the bytes
     * '47 52 46 82 0D 0A 1A 0A' at the start of the file. */
    for (const auto &expected_sig_byte : _grf_cont_v2_sig) {
      if (file.ReadByte() != expected_sig_byte) return 0; // Invalid format
    }
 
    return 2;
  }
 
  /* Container version 1 has no header, rewind to start. */
  file.SeekTo(pos, SEEK_SET);
  return 1;
}
 
SpriteFile::SpriteFile(const std::string &filename, Subdirectory subdir, bool palette_remap)
  : RandomAccessFile(filename, subdir), palette_remap(palette_remap)
{
  this->container_version = GetGRFContainerVersion(*this);
  this->content_begin = this->GetPos();
}