t38_terminal.h

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00001 /*
00002  * SpanDSP - a series of DSP components for telephony
00003  *
00004  * t38_terminal.h - T.38 termination, less the packet exchange part
00005  *
00006  * Written by Steve Underwood <steveu@coppice.org>
00007  *
00008  * Copyright (C) 2005 Steve Underwood
00009  *
00010  * All rights reserved.
00011  *
00012  * This program is free software; you can redistribute it and/or modify
00013  * it under the terms of the GNU General Public License version 2, as
00014  * published by the Free Software Foundation.
00015  *
00016  * This program is distributed in the hope that it will be useful,
00017  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  * GNU General Public License for more details.
00020  *
00021  * You should have received a copy of the GNU General Public License
00022  * along with this program; if not, write to the Free Software
00023  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
00024  *
00025  * $Id: t38_terminal.h,v 1.24 2007/11/30 12:20:35 steveu Exp $
00026  */
00027 
00028 /*! \file */
00029 
00030 #if !defined(_SPANDSP_T38_TERMINAL_H_)
00031 #define _SPANDSP_T38_TERMINAL_H_
00032 
00033 /*! \page t38_terminal_page T.38 real time FAX over IP termination
00034 \section t38_terminal_page_sec_1 What does it do?
00035 
00036 \section t38_terminal_page_sec_2 How does it work?
00037 */
00038 
00039 /* Make sure the HDLC frame buffers are big enough for ECM frames. */
00040 #define T38_MAX_HDLC_LEN        260
00041 
00042 typedef struct
00043 {
00044     t38_core_state_t t38;
00045 
00046     /*! \brief Use (actually allow time for) talker echo protection when transmitting. */
00047     int use_tep;    
00048 
00049     /*! \brief HDLC transmit buffer */
00050     uint8_t tx_buf[T38_MAX_HDLC_LEN];
00051     int tx_len;
00052     int tx_ptr;
00053 
00054     /*! \brief HDLC receive buffer */
00055     uint8_t rx_buf[T38_MAX_HDLC_LEN];
00056     int rx_len;
00057 
00058     /*! \brief The current transmit step being timed */
00059     int timed_step;
00060 
00061     /*! \brief The next queued tramsit indicator */
00062     int next_tx_indicator;
00063     /*! \brief The current T.38 data type being transmitted */
00064     int current_tx_data_type;
00065 
00066     /*! \brief TRUE if a carrier is present. Otherwise FALSE. */
00067     int rx_signal_present;
00068 
00069     /*! \brief The T.30 back-end */
00070     t30_state_t t30_state;
00071 
00072     int current_rx_type;
00073     int current_tx_type;
00074     
00075     int trailer_bytes;
00076 
00077     /*! \brief TRUE is there has been some T.38 data missed (i.e. lost packets) */
00078     int missing_data;
00079 
00080     /*! \brief The number of octets to send in each image packet (non-ECM or ECM) at the current
00081                rate and the current specified packet interval. */
00082     int octets_per_data_packet;
00083     
00084     int ms_per_tx_chunk;
00085     int merge_tx_fields;
00086 
00087     /*! \brief The number of times an indicator packet will be sent. Numbers greater than one
00088                will increase reliability for UDP transmission. Zero is valid, to suppress all
00089                indicator packets for TCP transmission. */
00090     int indicator_tx_count;
00091 
00092     /*! \brief The number of times a data packet which ends transmission will be sent. Numbers
00093                greater than one will increase reliability for UDP transmission. Zero is not valid. */
00094     int data_end_tx_count;
00095 
00096     /*! \brief A "sample" count, used to time events */
00097     int32_t samples;
00098     int32_t next_tx_samples;
00099     int32_t timeout_rx_samples;
00100 
00101     logging_state_t logging;
00102 } t38_terminal_state_t;
00103 
00104 #if defined(__cplusplus)
00105 extern "C"
00106 {
00107 #endif
00108 
00109 int t38_terminal_send_timeout(t38_terminal_state_t *s, int samples);
00110 
00111 void t38_terminal_set_config(t38_terminal_state_t *s, int without_pacing);
00112 
00113 /*! Select whether the time for talker echo protection tone will be allowed for when sending.
00114     \brief Select whether TEP time will be allowed for.
00115     \param s The T.38 context.
00116     \param use_tep TRUE if TEP should be allowed for.
00117 */
00118 void t38_terminal_set_tep_mode(t38_terminal_state_t *s, int use_tep);
00119 
00120     /*! \brief Initialise a termination mode T.38 context.
00121     \param s The T.38 context.
00122     \param calling_party TRUE if the context is for a calling party. FALSE if the
00123            context is for an answering party.
00124     \param tx_packet_handler A callback routine to encapsulate and transmit T.38 packets.
00125     \param tx_packet_user_data An opaque pointer passed to the tx_packet_handler routine.
00126     \return A pointer to the termination mode T.38 context, or NULL if there was a problem. */
00127 t38_terminal_state_t *t38_terminal_init(t38_terminal_state_t *s,
00128                                         int calling_party,
00129                                         t38_tx_packet_handler_t *tx_packet_handler,
00130                                         void *tx_packet_user_data);
00131 
00132 /*! Release a termination mode T.38 context.
00133     \brief Release a T.38 context.
00134     \param s The T.38 context.
00135     \return 0 for OK, else -1. */
00136 int t38_terminal_release(t38_terminal_state_t *s);
00137 
00138 /*! Free a a termination mode T.38 context.
00139     \brief Free a T.38 context.
00140     \param s The T.38 context.
00141     \return 0 for OK, else -1. */
00142 int t38_terminal_free(t38_terminal_state_t *s);
00143 
00144 #if defined(__cplusplus)
00145 }
00146 #endif
00147 
00148 #endif
00149 /*- End of file ------------------------------------------------------------*/

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