bitstream.h

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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 Lesser General Public License version 2.1,
00014  * as 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 Lesser General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU Lesser General Public
00022  * License 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 1.14 2009/02/10 13:06:47 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 /*! Bitstream handler state */
00040 typedef struct bitstream_state_s bitstream_state_t;
00041 
00042 
00043 #if defined(__cplusplus)
00044 extern "C"
00045 {
00046 #endif
00047 
00048 /*! \brief Put a chunk of bits into the output buffer.
00049     \param s A pointer to the bitstream context.
00050     \param c A pointer to the bitstream output buffer.
00051     \param value The value to be pushed into the output buffer.
00052     \param bits The number of bits of value to be pushed. 1 to 25 bits is valid. */
00053 SPAN_DECLARE(void) bitstream_put(bitstream_state_t *s, uint8_t **c, uint32_t value, int bits);
00054 
00055 SPAN_DECLARE(void) bitstream_put2(bitstream_state_t *s, uint8_t **c, uint32_t value, int bits);
00056 
00057 /*! \brief Get a chunk of bits from the input buffer.
00058     \param s A pointer to the bitstream context.
00059     \param c A pointer to the bitstream input buffer.
00060     \param bits The number of bits of value to be grabbed. 1 to 25 bits is valid.
00061     \return The value retrieved from the input buffer. */
00062 SPAN_DECLARE(uint32_t) bitstream_get(bitstream_state_t *s, const uint8_t **c, int bits);
00063 
00064 SPAN_DECLARE(uint32_t) bitstream_get2(bitstream_state_t *s, const uint8_t **c, int bits);
00065 
00066 /*! \brief Flush any residual bit to the output buffer.
00067     \param s A pointer to the bitstream context.
00068     \param c A pointer to the bitstream output buffer. */
00069 SPAN_DECLARE(void) bitstream_flush(bitstream_state_t *s, uint8_t **c);
00070 
00071 SPAN_DECLARE(void) bitstream_flush2(bitstream_state_t *s, uint8_t **c);
00072 
00073 /*! \brief Initialise a bitstream context.
00074     \param s A pointer to the bitstream context.
00075     \return A pointer to the bitstream context. */
00076 SPAN_DECLARE(bitstream_state_t *) bitstream_init(bitstream_state_t *s);
00077 
00078 SPAN_DECLARE(int) bitstream_release(bitstream_state_t *s);
00079 
00080 SPAN_DECLARE(int) bitstream_free(bitstream_state_t *s);
00081 
00082 #if defined(__cplusplus)
00083 }
00084 #endif
00085 
00086 #endif
00087 /*- End of file ------------------------------------------------------------*/

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