deps/libchdr/include/libchdr/bitstream.h

   1 /* license:BSD-3-Clause
   2  * copyright-holders:Aaron Giles
   3 ***************************************************************************
   4
   5     bitstream.h
   6
   7     Helper classes for reading/writing at the bit level.
   8
   9 ***************************************************************************/
  10
  11 #pragma once
  12
  13 #ifndef __BITSTREAM_H__
  14 #define __BITSTREAM_H__
  15
  16 #include <stdint.h>
  17
  18 /***************************************************************************
  19  *  TYPE DEFINITIONS
  20  ***************************************************************************
  21  */
  22
  23 /* helper class for reading from a bit buffer */
  24 struct bitstream
  25 {
  26         uint32_t          buffer;       /* current bit accumulator */
  27         int               bits;         /* number of bits in the accumulator */
  28         const uint8_t *   read;         /* read pointer */
  29         uint32_t          doffset;      /* byte offset within the data */
  30         uint32_t          dlength;      /* length of the data */
  31 };
  32
  33 struct bitstream*       create_bitstream(const void *src, uint32_t srclength);
  34 int                             bitstream_overflow(struct bitstream* bitstream);
  35 uint32_t                        bitstream_read_offset(struct bitstream* bitstream);
  36
  37 uint32_t                        bitstream_read(struct bitstream* bitstream, int numbits);
  38 uint32_t                        bitstream_peek(struct bitstream* bitstream, int numbits);
  39 void                            bitstream_remove(struct bitstream* bitstream, int numbits);
  40 uint32_t                        bitstream_flush(struct bitstream* bitstream);
  41
  42
  43 #endif