152 lines
4.5 KiB
C
152 lines
4.5 KiB
C
/*
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* SpanDSP - a series of DSP components for telephony
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*
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* private/v42bis.h
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*
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* Written by Steve Underwood <steveu@coppice.org>
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*
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* Copyright (C) 2005 Steve Underwood
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License version 2.1,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id: v42bis.h,v 1.1 2008/11/15 14:43:08 steveu Exp $
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*/
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#if !defined(_SPANDSP_PRIVATE_V42BIS_H_)
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#define _SPANDSP_PRIVATE_V42BIS_H_
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/*!
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V.42bis dictionary node.
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*/
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typedef struct
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{
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/*! \brief The prior code for each defined code. */
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uint16_t parent_code;
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/*! \brief The number of leaf nodes this node has */
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int16_t leaves;
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/*! \brief This leaf octet for each defined code. */
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uint8_t node_octet;
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/*! \brief Bit map of the children which exist */
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uint32_t children[8];
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} v42bis_dict_node_t;
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/*!
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V.42bis compression. This defines the working state for a single instance
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of V.42bis compression.
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*/
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typedef struct
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{
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/*! \brief Compression mode. */
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int compression_mode;
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/*! \brief Callback function to handle received frames. */
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v42bis_frame_handler_t handler;
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/*! \brief An opaque pointer passed in calls to frame_handler. */
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void *user_data;
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/*! \brief The maximum frame length allowed */
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int max_len;
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uint32_t string_code;
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uint32_t latest_code;
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int string_length;
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uint32_t output_bit_buffer;
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int output_bit_count;
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int output_octet_count;
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uint8_t output_buf[1024];
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v42bis_dict_node_t dict[V42BIS_MAX_CODEWORDS];
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/*! \brief TRUE if we are in transparent (i.e. uncompressable) mode */
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int transparent;
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int change_transparency;
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/*! \brief IIR filter state, used in assessing compressibility. */
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int compressibility_filter;
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int compressibility_persistence;
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/*! \brief Next empty dictionary entry */
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uint32_t v42bis_parm_c1;
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/*! \brief Current codeword size */
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int v42bis_parm_c2;
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/*! \brief Threshold for codeword size change */
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uint32_t v42bis_parm_c3;
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/*! \brief Mark that this is the first octet/code to be processed */
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int first;
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uint8_t escape_code;
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} v42bis_compress_state_t;
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/*!
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V.42bis decompression. This defines the working state for a single instance
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of V.42bis decompression.
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*/
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typedef struct
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{
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/*! \brief Callback function to handle decompressed data. */
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v42bis_data_handler_t handler;
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/*! \brief An opaque pointer passed in calls to data_handler. */
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void *user_data;
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/*! \brief The maximum decompressed data block length allowed */
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int max_len;
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uint32_t old_code;
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uint32_t last_old_code;
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uint32_t input_bit_buffer;
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int input_bit_count;
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int octet;
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int last_length;
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int output_octet_count;
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uint8_t output_buf[1024];
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v42bis_dict_node_t dict[V42BIS_MAX_CODEWORDS];
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/*! \brief TRUE if we are in transparent (i.e. uncompressable) mode */
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int transparent;
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int last_extra_octet;
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/*! \brief Next empty dictionary entry */
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uint32_t v42bis_parm_c1;
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/*! \brief Current codeword size */
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int v42bis_parm_c2;
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/*! \brief Threshold for codeword size change */
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uint32_t v42bis_parm_c3;
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/*! \brief Mark that this is the first octet/code to be processed */
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int first;
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uint8_t escape_code;
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int escaped;
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} v42bis_decompress_state_t;
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/*!
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V.42bis compression/decompression descriptor. This defines the working state for a
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single instance of V.42bis compress/decompression.
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*/
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struct v42bis_state_s
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{
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/*! \brief V.42bis data compression directions. */
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int v42bis_parm_p0;
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/*! \brief Compression state. */
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v42bis_compress_state_t compress;
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/*! \brief Decompression state. */
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v42bis_decompress_state_t decompress;
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/*! \brief Maximum codeword size (bits) */
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int v42bis_parm_n1;
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/*! \brief Total number of codewords */
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uint32_t v42bis_parm_n2;
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/*! \brief Maximum string length */
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int v42bis_parm_n7;
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};
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#endif
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/*- End of file ------------------------------------------------------------*/
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