spandsp  0.0.6
private/v42bis.h
1 /*
2  * SpanDSP - a series of DSP components for telephony
3  *
4  * private/v42bis.h
5  *
6  * Written by Steve Underwood <steveu@coppice.org>
7  *
8  * Copyright (C) 2005 Steve Underwood
9  *
10  * All rights reserved.
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU Lesser General Public License version 2.1,
14  * as published by the Free Software Foundation.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19  * GNU Lesser General Public License for more details.
20  *
21  * You should have received a copy of the GNU Lesser General Public
22  * License along with this program; if not, write to the Free Software
23  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24  */
25 
26 #if !defined(_SPANDSP_PRIVATE_V42BIS_H_)
27 #define _SPANDSP_PRIVATE_V42BIS_H_
28 
29 /*!
30  V.42bis dictionary node.
31  Note that 0 is not a valid node to point to (0 is always a control code), so 0 is used
32  as a "no such value" marker in this structure.
33 */
34 typedef struct
35 {
36  /*! \brief The value of the octet represented by the current dictionary node */
37  uint8_t node_octet;
38  /*! \brief The parent of this node */
39  uint16_t parent;
40  /*! \brief The first child of this node */
41  uint16_t child;
42  /*! \brief The next node at the same depth */
43  uint16_t next;
45 
46 /*!
47  V.42bis compression or decompression. This defines the working state for a single instance
48  of V.42bis compression or decompression.
49 */
50 typedef struct
51 {
52  /*! \brief Compression enabled. */
54  /*! \brief Compression mode. */
56  /*! \brief Callback function to handle output data. */
58  /*! \brief An opaque pointer passed in calls to the data handler. */
59  void *user_data;
60  /*! \brief The maximum amount to be passed to the data handler. */
62 
63  /*! \brief TRUE if we are in transparent (i.e. uncompressable) mode */
65  /*! \brief Next empty dictionary entry */
66  uint16_t v42bis_parm_c1;
67  /*! \brief Current codeword size */
68  uint16_t v42bis_parm_c2;
69  /*! \brief Threshold for codeword size change */
70  uint16_t v42bis_parm_c3;
71  /*! \brief The current update point in the dictionary */
72  uint16_t update_at;
73  /*! \brief The last entry matched in the dictionary */
74  uint16_t last_matched;
75  /*! \brief The last entry added to the dictionary */
76  uint16_t last_added;
77  /*! \brief Total number of codewords in the dictionary */
79  /*! \brief Maximum permitted string length */
81  /*! \brief The dictionary */
82  v42bis_dict_node_t dict[V42BIS_MAX_CODEWORDS];
83 
84  /*! \brief The octet string in progress */
85  uint8_t string[V42BIS_MAX_STRING_SIZE];
86  /*! \brief The current length of the octet string in progress */
88  /*! \brief The amount of the octet string in progress which has already
89  been flushed out of the buffer */
91 
92  /*! \brief Compression performance metric */
94 
95  /*! \brief Outgoing bit buffer (compression), or incoming bit buffer (decompression) */
96  uint32_t bit_buffer;
97  /*! \brief Outgoing bit count (compression), or incoming bit count (decompression) */
98  int bit_count;
99 
100  /*! \brief The output composition buffer */
101  uint8_t output_buf[V42BIS_MAX_OUTPUT_LENGTH];
102  /*! \brief The length of the contents of the output composition buffer */
104 
105  /*! \brief The current value of the escape code */
106  uint8_t escape_code;
107  /*! \brief TRUE if we just hit an escape code, and are waiting for the following octet */
108  int escaped;
110 
111 /*!
112  V.42bis compression/decompression descriptor. This defines the working state for a
113  single instance of V.42bis compress/decompression.
114 */
116 {
117  /*! \brief Compression state. */
119  /*! \brief Decompression state. */
121 
122  /*! \brief Error and flow logging control */
124 };
125 
126 #endif
127 /*- End of file ------------------------------------------------------------*/
void(* put_msg_func_t)(void *user_data, const uint8_t *msg, int len)
Definition: async.h:93
put_msg_func_t handler
Callback function to handle output data.
Definition: private/v42bis.h:57
uint16_t compression_performance
Compression performance metric.
Definition: private/v42bis.h:93
int v42bis_parm_n2
Total number of codewords in the dictionary.
Definition: private/v42bis.h:78
int bit_count
Outgoing bit count (compression), or incoming bit count (decompression)
Definition: private/v42bis.h:98
v42bis_comp_state_t decompress
Decompression state.
Definition: private/v42bis.h:120
uint16_t v42bis_parm_c3
Threshold for codeword size change.
Definition: private/v42bis.h:70
int flushed_length
The amount of the octet string in progress which has already been flushed out of the buffer...
Definition: private/v42bis.h:90
Definition: private/v42bis.h:34
int max_output_len
The maximum amount to be passed to the data handler.
Definition: private/v42bis.h:61
uint16_t child
The first child of this node.
Definition: private/v42bis.h:41
logging_state_t logging
Error and flow logging control.
Definition: private/v42bis.h:123
int escaped
TRUE if we just hit an escape code, and are waiting for the following octet.
Definition: private/v42bis.h:108
int compression_mode
Compression mode.
Definition: private/v42bis.h:55
uint8_t node_octet
The value of the octet represented by the current dictionary node.
Definition: private/v42bis.h:37
uint16_t v42bis_parm_c2
Current codeword size.
Definition: private/v42bis.h:68
uint16_t last_added
The last entry added to the dictionary.
Definition: private/v42bis.h:76
int v42bis_parm_n7
Maximum permitted string length.
Definition: private/v42bis.h:80
int v42bis_parm_p0
Compression enabled.
Definition: private/v42bis.h:53
Definition: private/v42bis.h:50
Definition: private/logging.h:33
v42bis_comp_state_t compress
Compression state.
Definition: private/v42bis.h:118
Definition: private/v42bis.h:115
int transparent
TRUE if we are in transparent (i.e. uncompressable) mode.
Definition: private/v42bis.h:64
uint16_t parent
The parent of this node.
Definition: private/v42bis.h:39
uint32_t bit_buffer
Outgoing bit buffer (compression), or incoming bit buffer (decompression)
Definition: private/v42bis.h:96
int output_octet_count
The length of the contents of the output composition buffer.
Definition: private/v42bis.h:103
uint8_t escape_code
The current value of the escape code.
Definition: private/v42bis.h:106
void * user_data
An opaque pointer passed in calls to the data handler.
Definition: private/v42bis.h:59
uint16_t v42bis_parm_c1
Next empty dictionary entry.
Definition: private/v42bis.h:66
uint16_t last_matched
The last entry matched in the dictionary.
Definition: private/v42bis.h:74
uint16_t update_at
The current update point in the dictionary.
Definition: private/v42bis.h:72
uint16_t next
The next node at the same depth.
Definition: private/v42bis.h:43
int string_length
The current length of the octet string in progress.
Definition: private/v42bis.h:87