src/random_access_file_type.h

   1 /*
   2  * This file is part of OpenTTD.
   3  * 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.
   4  * 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.
   5  * 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/>.
   6  */
   7
   8  /** @file random_access_file_type.h Class related to random access to files. */
   9
  10 #ifndef RANDOM_ACCESS_FILE_TYPE_H
  11 #define RANDOM_ACCESS_FILE_TYPE_H
  12
  13 #include "fileio_type.h"
  14 #include <string>
  15
  16 /**
  17  * A file from which bytes, words and double words are read in (potentially) a random order.
  18  *
  19  * This is mostly intended to be used for things that can be read from GRFs when needed, so
  20  * the graphics but also the sounds. This also ties into the spritecache as it uses these
  21  * files to load the sprites from when needed.
  22  */
  23 class RandomAccessFile {
  24         /** The number of bytes to allocate for the buffer. */
  25         static constexpr int BUFFER_SIZE = 512;
  26
  27         std::string filename;            ///< Full name of the file; relative path to subdir plus the extension of the file.
  28         std::string simplified_filename; ///< Simplified lowecase name of the file; only the name, no path or extension.
  29
  30         FILE *file_handle;               ///< File handle of the open file.
  31         size_t pos;                      ///< Position in the file of the end of the read buffer.
  32
  33         byte *buffer;                    ///< Current position within the local buffer.
  34         byte *buffer_end;                ///< Last valid byte of buffer.
  35         byte buffer_start[BUFFER_SIZE];  ///< Local buffer when read from file.
  36
  37 public:
  38         RandomAccessFile(const std::string &filename, Subdirectory subdir);
  39         RandomAccessFile(const RandomAccessFile&) = delete;
  40         void operator=(const RandomAccessFile&) = delete;
  41
  42         virtual ~RandomAccessFile();
  43
  44         const std::string &GetFilename() const;
  45         const std::string &GetSimplifiedFilename() const;
  46
  47         size_t GetPos() const;
  48         void SeekTo(size_t pos, int mode);
  49
  50         byte ReadByte();
  51         uint16 ReadWord();
  52         uint32 ReadDword();
  53
  54         void ReadBlock(void *ptr, size_t size);
  55         void SkipBytes(int n);
  56 };
  57
  58 #endif /* RANDOM_ACCESS_FILE_TYPE_H */