/usr/include/spandsp/v42bis.h is in libspandsp-dev 0.0.6~pre20-3.1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 | /*
* SpanDSP - a series of DSP components for telephony
*
* v42bis.h
*
* Written by Steve Underwood <steveu@coppice.org>
*
* Copyright (C) 2005 Steve Underwood
*
* All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 2.1,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*! \page v42bis_page V.42bis modem data compression
\section v42bis_page_sec_1 What does it do?
The v.42bis specification defines a data compression scheme, to work in
conjunction with the error correction scheme defined in V.42.
\section v42bis_page_sec_2 How does it work?
*/
#if !defined(_SPANDSP_V42BIS_H_)
#define _SPANDSP_V42BIS_H_
#define V42BIS_MIN_STRING_SIZE 6
#define V42BIS_MAX_STRING_SIZE 250
#define V42BIS_MIN_DICTIONARY_SIZE 512
#define V42BIS_MAX_BITS 12
#define V42BIS_MAX_CODEWORDS 4096 /* 2^V42BIS_MAX_BITS */
#define V42BIS_TABLE_SIZE 5021 /* This should be a prime >(2^V42BIS_MAX_BITS) */
enum
{
V42BIS_P0_NEITHER_DIRECTION = 0,
V42BIS_P0_INITIATOR_RESPONDER,
V42BIS_P0_RESPONDER_INITIATOR,
V42BIS_P0_BOTH_DIRECTIONS
};
enum
{
V42BIS_COMPRESSION_MODE_DYNAMIC = 0,
V42BIS_COMPRESSION_MODE_ALWAYS,
V42BIS_COMPRESSION_MODE_NEVER
};
typedef void (*v42bis_frame_handler_t)(void *user_data, const uint8_t *pkt, int len);
typedef void (*v42bis_data_handler_t)(void *user_data, const uint8_t *buf, int len);
/*!
V.42bis compression/decompression descriptor. This defines the working state for a
single instance of V.42bis compress/decompression.
*/
typedef struct v42bis_state_s v42bis_state_t;
#if defined(__cplusplus)
extern "C"
{
#endif
/*! Compress a block of octets.
\param s The V.42bis context.
\param buf The data to be compressed.
\param len The length of the data buffer.
\return 0 */
SPAN_DECLARE(int) v42bis_compress(v42bis_state_t *s, const uint8_t *buf, int len);
/*! Flush out any data remaining in a compression buffer.
\param s The V.42bis context.
\return 0 */
SPAN_DECLARE(int) v42bis_compress_flush(v42bis_state_t *s);
/*! Decompress a block of octets.
\param s The V.42bis context.
\param buf The data to be decompressed.
\param len The length of the data buffer.
\return 0 */
SPAN_DECLARE(int) v42bis_decompress(v42bis_state_t *s, const uint8_t *buf, int len);
/*! Flush out any data remaining in the decompression buffer.
\param s The V.42bis context.
\return 0 */
SPAN_DECLARE(int) v42bis_decompress_flush(v42bis_state_t *s);
/*! Set the compression mode.
\param s The V.42bis context.
\param mode One of the V.42bis compression modes -
V42BIS_COMPRESSION_MODE_DYNAMIC,
V42BIS_COMPRESSION_MODE_ALWAYS,
V42BIS_COMPRESSION_MODE_NEVER */
SPAN_DECLARE(void) v42bis_compression_control(v42bis_state_t *s, int mode);
/*! Initialise a V.42bis context.
\param s The V.42bis context.
\param negotiated_p0 The negotiated P0 parameter, from the V.42bis spec.
\param negotiated_p1 The negotiated P1 parameter, from the V.42bis spec.
\param negotiated_p2 The negotiated P2 parameter, from the V.42bis spec.
\param frame_handler Frame callback handler.
\param frame_user_data An opaque pointer passed to the frame callback handler.
\param max_frame_len The maximum length that should be passed to the frame handler.
\param data_handler data callback handler.
\param data_user_data An opaque pointer passed to the data callback handler.
\param max_data_len The maximum length that should be passed to the data handler.
\return The V.42bis context. */
SPAN_DECLARE(v42bis_state_t *) v42bis_init(v42bis_state_t *s,
int negotiated_p0,
int negotiated_p1,
int negotiated_p2,
v42bis_frame_handler_t frame_handler,
void *frame_user_data,
int max_frame_len,
v42bis_data_handler_t data_handler,
void *data_user_data,
int max_data_len);
/*! Release a V.42bis context.
\param s The V.42bis context.
\return 0 if OK */
SPAN_DECLARE(int) v42bis_release(v42bis_state_t *s);
/*! Free a V.42bis context.
\param s The V.42bis context.
\return 0 if OK */
SPAN_DECLARE(int) v42bis_free(v42bis_state_t *s);
#if defined(__cplusplus)
}
#endif
#endif
/*- End of file ------------------------------------------------------------*/
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