127 lines
4.3 KiB
C
127 lines
4.3 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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#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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Note that 0 is not a valid node to point to (0 is always a control code), so 0 is used
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as a "no such value" marker in this structure.
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*/
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typedef struct
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{
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/*! \brief The value of the octet represented by the current dictionary node */
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uint8_t node_octet;
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/*! \brief The parent of this node */
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uint16_t parent;
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/*! \brief The first child of this node */
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uint16_t child;
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/*! \brief The next node at the same depth */
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uint16_t next;
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} v42bis_dict_node_t;
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/*!
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V.42bis compression or decompression. This defines the working state for a single instance
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of V.42bis compression or decompression.
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*/
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typedef struct
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{
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/*! \brief Compression enabled. */
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int v42bis_parm_p0;
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/*! \brief Compression mode. */
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int compression_mode;
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/*! \brief Callback function to handle output data. */
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put_msg_func_t handler;
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/*! \brief An opaque pointer passed in calls to the data handler. */
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void *user_data;
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/*! \brief The maximum amount to be passed to the data handler. */
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int max_output_len;
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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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/*! \brief Next empty dictionary entry */
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uint16_t v42bis_parm_c1;
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/*! \brief Current codeword size */
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uint16_t v42bis_parm_c2;
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/*! \brief Threshold for codeword size change */
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uint16_t v42bis_parm_c3;
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/*! \brief The current update point in the dictionary */
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uint16_t update_at;
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/*! \brief The last entry matched in the dictionary */
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uint16_t last_matched;
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/*! \brief The last entry added to the dictionary */
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uint16_t last_added;
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/*! \brief Total number of codewords in the dictionary */
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int v42bis_parm_n2;
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/*! \brief Maximum permitted string length */
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int v42bis_parm_n7;
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/*! \brief The dictionary */
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v42bis_dict_node_t dict[V42BIS_MAX_CODEWORDS];
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/*! \brief The octet string in progress */
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uint8_t string[V42BIS_MAX_STRING_SIZE];
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/*! \brief The current length of the octet string in progress */
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int string_length;
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/*! \brief The amount of the octet string in progress which has already
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been flushed out of the buffer */
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int flushed_length;
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/*! \brief Compression performance metric */
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uint16_t compression_performance;
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/*! \brief Outgoing bit buffer (compression), or incoming bit buffer (decompression) */
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uint32_t bit_buffer;
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/*! \brief Outgoing bit count (compression), or incoming bit count (decompression) */
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int bit_count;
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/*! \brief The output composition buffer */
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uint8_t output_buf[V42BIS_MAX_OUTPUT_LENGTH];
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/*! \brief The length of the contents of the output composition buffer */
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int output_octet_count;
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/*! \brief The current value of the escape code */
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uint8_t escape_code;
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/*! \brief TRUE if we just hit an escape code, and are waiting for the following octet */
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int escaped;
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} v42bis_comp_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 Compression state. */
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v42bis_comp_state_t compress;
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/*! \brief Decompression state. */
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v42bis_comp_state_t decompress;
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/*! \brief Error and flow logging control */
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};
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#endif
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/*- End of file ------------------------------------------------------------*/
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