spandsp  0.0.6
private/hdlc.h
1 /*
2  * SpanDSP - a series of DSP components for telephony
3  *
4  * private/hdlc.h
5  *
6  * Written by Steve Underwood <steveu@coppice.org>
7  *
8  * Copyright (C) 2003 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_HDLC_H_)
27 #define _SPANDSP_PRIVATE_HDLC_H_
28 
29 /*!
30  HDLC receive descriptor. This contains all the state information for an HDLC receiver.
31  */
33 {
34  /*! 2 for CRC-16, 4 for CRC-32 */
35  int crc_bytes;
36  /*! \brief Maximum permitted frame length. */
37  size_t max_frame_len;
38  /*! \brief The callback routine called to process each good received frame. */
39  hdlc_frame_handler_t frame_handler;
40  /*! \brief An opaque parameter passed to the frame callback routine. */
42  /*! \brief The callback routine called to report status changes. */
44  /*! \brief An opaque parameter passed to the status callback routine. */
46  /*! \brief TRUE if bad frames are to be reported. */
48  /*! \brief The number of consecutive flags which must be seen before framing is
49  declared OK. */
51  /*! \brief TRUE if framing OK has been announced. */
53  /*! \brief Number of consecutive flags seen so far. */
55 
56  /*! \brief The raw (stuffed) bit stream buffer. */
57  unsigned int raw_bit_stream;
58  /*! \brief The destuffed bit stream buffer. */
59  unsigned int byte_in_progress;
60  /*! \brief The current number of bits in byte_in_progress. */
61  int num_bits;
62  /*! \brief TRUE if in octet counting mode (e.g. for MTP). */
64  /*! \brief Octet count, to achieve the functionality needed for things
65  like MTP. */
67  /*! \brief The number of octets to be allowed between octet count reports. */
69 
70  /*! \brief Buffer for a frame in progress. */
71  uint8_t buffer[HDLC_MAXFRAME_LEN + 4];
72  /*! \brief Length of a frame in progress. */
73  size_t len;
74 
75  /*! \brief The number of bytes of good frames received (CRC not included). */
76  unsigned long int rx_bytes;
77  /*! \brief The number of good frames received. */
78  unsigned long int rx_frames;
79  /*! \brief The number of frames with CRC errors received. */
80  unsigned long int rx_crc_errors;
81  /*! \brief The number of too short and too long frames received. */
82  unsigned long int rx_length_errors;
83  /*! \brief The number of HDLC aborts received. */
84  unsigned long int rx_aborts;
85 };
86 
87 /*!
88  HDLC transmit descriptor. This contains all the state information for an
89  HDLC transmitter.
90  */
92 {
93  /*! 2 for CRC-16, 4 for CRC-32 */
94  int crc_bytes;
95  /*! \brief The callback routine called to indicate transmit underflow. */
96  hdlc_underflow_handler_t underflow_handler;
97  /*! \brief An opaque parameter passed to the callback routine. */
98  void *user_data;
99  /*! \brief The minimum flag octets to insert between frames. */
101  /*! \brief TRUE if frame creation works in progressive mode. */
103  /*! \brief Maximum permitted frame length. */
105 
106  /*! \brief The stuffed bit stream being created. */
108  /*! \brief The number of bits currently in octets_in_progress. */
109  int num_bits;
110  /*! \brief The currently rotated state of the flag octet. */
112  /*! \brief The number of flag octets to send for a timed burst of flags. */
114  /*! \brief The number of abort octets to send for a timed burst of aborts. */
116  /*! \brief TRUE if the next underflow of timed flag octets should be reported */
118 
119  /*! \brief The current message being transmitted, with its CRC attached. */
120  uint8_t buffer[HDLC_MAXFRAME_LEN + 4];
121  /*! \brief The length of the message in the buffer. */
122  size_t len;
123  /*! \brief The current send position within the buffer. */
124  size_t pos;
125  /*! \brief The running CRC, as data fills the frame buffer. */
126  uint32_t crc;
127 
128  /*! \brief The current byte being broken into bits for transmission. */
129  int byte;
130  /*! \brief The number of bits remaining in byte. */
131  int bits;
132 
133  /*! \brief TRUE if transmission should end on buffer underflow .*/
134  int tx_end;
135 };
136 
137 #endif
138 /*- End of file ------------------------------------------------------------*/