00001 /* 00002 * SpanDSP - a series of DSP components for telephony 00003 * 00004 * bitstream.h - Bitstream composition and decomposition routines. 00005 * 00006 * Written by Steve Underwood <steveu@coppice.org> 00007 * 00008 * Copyright (C) 2006 Steve Underwood 00009 * 00010 * All rights reserved. 00011 * 00012 * This program is free software; you can redistribute it and/or modify 00013 * it under the terms of the GNU General Public License version 2, as 00014 * published by the Free Software Foundation. 00015 * 00016 * This program is distributed in the hope that it will be useful, 00017 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00018 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 00019 * GNU General Public License for more details. 00020 * 00021 * You should have received a copy of the GNU General Public License 00022 * along with this program; if not, write to the Free Software 00023 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 00024 * 00025 * $Id: bitstream.h,v 1.7 2007/08/20 15:22:22 steveu Exp $ 00026 */ 00027 00028 /*! \file */ 00029 00030 #if !defined(_SPANDSP_BITSTREAM_H_) 00031 #define _SPANDSP_BITSTREAM_H_ 00032 00033 /*! \page bitstream_page Bitstream composition and decomposition 00034 \section bitstream_page_sec_1 What does it do? 00035 00036 \section bitstream_page_sec_2 How does it work? 00037 */ 00038 00039 typedef struct 00040 { 00041 unsigned int bitstream; 00042 unsigned int residue; 00043 } bitstream_state_t; 00044 00045 00046 #if defined(__cplusplus) 00047 extern "C" 00048 { 00049 #endif 00050 00051 /*! \brief Put a chunk of bits into the output buffer. 00052 \param s A pointer to the bitstream context. 00053 \param c A pointer to the bitstream output buffer. 00054 \param value The value to be pushed into the output buffer. 00055 \param bits The number of bits of value to be pushed. 1 to 25 bit is valid. */ 00056 void bitstream_put(bitstream_state_t *s, uint8_t **c, unsigned int value, int bits); 00057 00058 void bitstream_put2(bitstream_state_t *s, uint8_t **c, unsigned int value, int bits); 00059 00060 /*! \brief Get a chunk of bits from the input buffer. 00061 \param s A pointer to the bitstream context. 00062 \param c A pointer to the bitstream input buffer. 00063 \param bits The number of bits of value to be grabbed. 1 to 25 bit is valid. 00064 \return The value retrieved from the input buffer. */ 00065 unsigned int bitstream_get(bitstream_state_t *s, const uint8_t **c, int bits); 00066 00067 unsigned int bitstream_get2(bitstream_state_t *s, const uint8_t **c, int bits); 00068 00069 /*! \brief Flush any residual bit to the output buffer. 00070 \param s A pointer to the bitstream context. 00071 \param c A pointer to the bitstream output buffer. */ 00072 void bitstream_flush(bitstream_state_t *s, uint8_t **c); 00073 00074 void bitstream_flush2(bitstream_state_t *s, uint8_t **c); 00075 00076 /*! \brief Initialise a bitstream context. 00077 \param s A pointer to the bitstream context. 00078 \return A pointer to the bitstream context. */ 00079 bitstream_state_t *bitstream_init(bitstream_state_t *s); 00080 00081 #if defined(__cplusplus) 00082 } 00083 #endif 00084 00085 #endif 00086 /*- End of file ------------------------------------------------------------*/