newgrf_bytereader.h

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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/>.
 */
 
#ifndef NEWGRF_BYTEREADER_H
#define NEWGRF_BYTEREADER_H
 
class OTTDByteReaderSignal { };
 
class ByteReader {
public:
  ByteReader(const uint8_t *data, const uint8_t *end) : data(data), end(end) { }
 
  const uint8_t *ReadBytes(size_t size)
  {
    if (this->data + size >= this->end) {
      /* Put data at the end, as would happen if every byte had been individually read. */
      this->data = this->end;
      throw OTTDByteReaderSignal();
    }
 
    const uint8_t *ret = this->data;
    this->data += size;
    return ret;
  }
 
  uint8_t ReadByte()
  {
    if (this->data < this->end) return *this->data++;
    throw OTTDByteReaderSignal();
  }
  uint8_t ReadByte() {…}
 
  uint16_t ReadWord()
  {
    uint16_t val = this->ReadByte();
    return val | (this->ReadByte() << 8);
  }
  uint16_t ReadWord() {…}
 
  uint16_t ReadExtendedByte()
  {
    uint16_t val = this->ReadByte();
    return val == 0xFF ? this->ReadWord() : val;
  }
  uint16_t ReadExtendedByte() {…}
 
  uint32_t ReadDWord()
  {
    uint32_t val = this->ReadWord();
    return val | (this->ReadWord() << 16);
  }
  uint32_t ReadDWord() {…}
 
  uint32_t PeekDWord();
  uint32_t ReadVarSize(uint8_t size);
  std::string_view ReadString();
 
  size_t Remaining() const
  {
    return this->end - this->data;
  }
 
  bool HasData(size_t count = 1) const
  {
    return this->data + count <= this->end;
  }
 
  void Skip(size_t len)
  {
    this->data += len;
    /* It is valid to move the buffer to exactly the end of the data,
     * as there may not be any more data read. */
    if (this->data > this->end) throw OTTDByteReaderSignal();
  }
 
private:
  const uint8_t *data; 
  const uint8_t *end; 
};
class ByteReader {…};
 
#endif /* NEWGRF_BYTEREADER_H */