--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/spandsp/t38_gateway.h	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,215 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * t38_gateway.h - A T.38, less the packet exchange part
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2005, 2006, 2007 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.
+ *
+ * $Id: t38_gateway.h,v 1.63 2009/04/12 09:12:10 steveu Exp $
+ */
+
+/*! \file */
+
+#if !defined(_SPANDSP_T38_GATEWAY_H_)
+#define _SPANDSP_T38_GATEWAY_H_
+
+/*! \page t38_gateway_page T.38 real time FAX over IP PSTN gateway
+\section t38_gateway_page_sec_1 What does it do?
+
+The T.38 gateway facility provides a robust interface between T.38 IP packet streams and
+and 8k samples/second audio streams. It provides the buffering and flow control features needed
+to maximum the tolerance of jitter and packet loss on the IP network.
+
+\section t38_gateway_page_sec_2 How does it work?
+*/
+
+/*! The receive buffer length */
+#define T38_RX_BUF_LEN          2048
+/*! The number of HDLC transmit buffers */
+#define T38_TX_HDLC_BUFS        256
+/*! The maximum length of an HDLC frame buffer. This must be big enough for ECM frames. */
+#define T38_MAX_HDLC_LEN        260
+
+typedef struct t38_gateway_state_s t38_gateway_state_t;
+
+/*!
+    T.30 real time frame handler.
+    \brief T.30 real time frame handler.
+    \param s The T.30 context.
+    \param user_data An opaque pointer.
+    \param direction TRUE for incoming, FALSE for outgoing.
+    \param msg The HDLC message.
+    \param len The length of the message.
+*/
+typedef void (t38_gateway_real_time_frame_handler_t)(t38_gateway_state_t *s,
+                                                     void *user_data,
+                                                     int direction,
+                                                     const uint8_t *msg,
+                                                     int len);
+
+/*!
+    T.38 gateway results.
+ */
+typedef struct
+{
+    /*! \brief The current bit rate for image transfer. */
+    int bit_rate;
+    /*! \brief TRUE if error correcting mode is used. */
+    int error_correcting_mode;
+    /*! \brief The number of pages transferred so far. */
+    int pages_transferred;
+} t38_stats_t;
+
+#if defined(__cplusplus)
+extern "C"
+{
+#endif
+
+/*! \brief Initialise a gateway mode T.38 context.
+    \param s The T.38 context.
+    \param tx_packet_handler A callback routine to encapsulate and transmit T.38 packets.
+    \param tx_packet_user_data An opaque pointer passed to the tx_packet_handler routine.
+    \return A pointer to the termination mode T.38 context, or NULL if there was a problem. */
+SPAN_DECLARE(t38_gateway_state_t *) t38_gateway_init(t38_gateway_state_t *s,
+                                                     t38_tx_packet_handler_t *tx_packet_handler,
+                                                     void *tx_packet_user_data);
+
+/*! Release a gateway mode T.38 context.
+    \brief Release a T.38 context.
+    \param s The T.38 context.
+    \return 0 for OK, else -1. */
+SPAN_DECLARE(int) t38_gateway_release(t38_gateway_state_t *s);
+
+/*! Free a gateway mode T.38 context.
+    \brief Free a T.38 context.
+    \param s The T.38 context.
+    \return 0 for OK, else -1. */
+SPAN_DECLARE(int) t38_gateway_free(t38_gateway_state_t *s);
+
+/*! Process a block of received FAX audio samples.
+    \brief Process a block of received FAX audio samples.
+    \param s The T.38 context.
+    \param amp The audio sample buffer.
+    \param len The number of samples in the buffer.
+    \return The number of samples unprocessed. */
+SPAN_DECLARE(int) t38_gateway_rx(t38_gateway_state_t *s, int16_t amp[], int len);
+
+/*! Generate a block of FAX audio samples.
+    \brief Generate a block of FAX audio samples.
+    \param s The T.38 context.
+    \param amp The audio sample buffer.
+    \param max_len The number of samples to be generated.
+    \return The number of samples actually generated.
+*/
+SPAN_DECLARE(int) t38_gateway_tx(t38_gateway_state_t *s, int16_t amp[], int max_len);
+
+/*! Control whether error correcting mode (ECM) is allowed.
+    \brief Control whether error correcting mode (ECM) is allowed.
+    \param s The T.38 context.
+    \param ecm_allowed TRUE is ECM is to be allowed.
+*/
+SPAN_DECLARE(void) t38_gateway_set_ecm_capability(t38_gateway_state_t *s, int ecm_allowed);
+
+/*! Select whether silent audio will be sent when transmit is idle.
+    \brief Select whether silent audio will be sent when transmit is idle.
+    \param s The T.38 context.
+    \param transmit_on_idle TRUE if silent audio should be output when the FAX transmitter is
+           idle. FALSE to transmit zero length audio when the FAX transmitter is idle. The default
+           behaviour is FALSE.
+*/
+SPAN_DECLARE(void) t38_gateway_set_transmit_on_idle(t38_gateway_state_t *s, int transmit_on_idle);
+
+/*! Specify which modem types are supported by a T.30 context.
+    \brief Specify supported modems.
+    \param s The T.38 context.
+    \param supported_modems Bit field list of the supported modems.
+*/
+SPAN_DECLARE(void) t38_gateway_set_supported_modems(t38_gateway_state_t *s, int supported_modems);
+
+/*! Select whether NSC, NSF, and NSS should be suppressed. It selected, the contents of
+    these messages are forced to zero for all octets beyond the message type. This makes
+    them look like manufacturer specific messages, from a manufacturer which does not exist.
+    \brief Select whether NSC, NSF, and NSS should be suppressed.
+    \param s The T.38 context.
+    \param from_t38 A string of bytes to overwrite the header of any NSC, NSF, and NSS
+           frames passing through the gateway from T.38 the the modem.
+    \param from_t38_len The length of the overwrite string.
+    \param from_modem A string of bytes to overwrite the header of any NSC, NSF, and NSS
+           frames passing through the gateway from the modem to T.38.
+    \param from_modem_len The length of the overwrite string.
+*/
+SPAN_DECLARE(void) t38_gateway_set_nsx_suppression(t38_gateway_state_t *s,
+                                                   const uint8_t *from_t38,
+                                                   int from_t38_len,
+                                                   const uint8_t *from_modem,
+                                                   int from_modem_len);
+
+/*! Select whether talker echo protection tone will be sent for the image modems.
+    \brief Select whether TEP will be sent for the image modems.
+    \param s The T.38 context.
+    \param use_tep TRUE if TEP should be sent.
+*/
+SPAN_DECLARE(void) t38_gateway_set_tep_mode(t38_gateway_state_t *s, int use_tep);
+
+/*! Select whether non-ECM fill bits are to be removed during transmission.
+    \brief Select whether non-ECM fill bits are to be removed during transmission.
+    \param s The T.38 context.
+    \param remove TRUE if fill bits are to be removed.
+*/
+SPAN_DECLARE(void) t38_gateway_set_fill_bit_removal(t38_gateway_state_t *s, int remove);
+
+/*! Get the current transfer statistics for the current T.38 session.
+    \brief Get the current transfer statistics.
+    \param s The T.38 context.
+    \param t A pointer to a buffer for the statistics. */
+SPAN_DECLARE(void) t38_gateway_get_transfer_statistics(t38_gateway_state_t *s, t38_stats_t *t);
+
+/*! Get a pointer to the T.38 core IFP packet engine associated with a
+    gateway mode T.38 context.
+    \brief Get a pointer to the T.38 core IFP packet engine associated
+           with a T.38 context.
+    \param s The T.38 context.
+    \return A pointer to the T.38 core context, or NULL.
+*/
+SPAN_DECLARE(t38_core_state_t *) t38_gateway_get_t38_core_state(t38_gateway_state_t *s);
+
+/*! Get a pointer to the logging context associated with a T.38 context.
+    \brief Get a pointer to the logging context associated with a T.38 context.
+    \param s The T.38 context.
+    \return A pointer to the logging context, or NULL.
+*/
+SPAN_DECLARE(logging_state_t *) t38_gateway_get_logging_state(t38_gateway_state_t *s);
+
+/*! Set a callback function for T.30 frame exchange monitoring. This is called from the heart
+    of the signal processing, so don't take too long in the handler routine.
+    \brief Set a callback function for T.30 frame exchange monitoring.
+    \param s The T.30 context.
+    \param handler The callback function.
+    \param user_data An opaque pointer passed to the callback function. */
+SPAN_DECLARE(void) t38_gateway_set_real_time_frame_handler(t38_gateway_state_t *s,
+                                                           t38_gateway_real_time_frame_handler_t *handler,
+                                                           void *user_data);
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/