--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/src/spandsp/fax.h	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,197 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * fax.h - definitions for analogue line ITU T.30 fax processing
+ *
+ * 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 General Public License version 2, 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * $Id: fax.h,v 1.20 2006/10/24 13:45:28 steveu Exp $
+ */
+
+/*! \file */
+
+#if !defined(_FAX_H_)
+#define _FAX_H_
+
+/*! \page fax_page FAX over analogue modem handling
+
+\section fax_page_sec_1 What does it do?
+
+\section fax_page_sec_2 How does it work?
+*/
+
+typedef struct fax_state_s fax_state_t;
+
+typedef void (fax_flush_handler_t)(fax_state_t *s, void *user_data, int which);
+
+/*!
+    Analogue line T.30 FAX channel descriptor. This defines the state of a single working
+    instance of an analogue line soft-FAX machine.
+*/
+struct fax_state_s
+{
+    /* This must be kept the first thing in the structure, so it can be pointed
+       to reliably as the structures change over time. */
+    t30_state_t t30_state;
+
+    /*! TRUE is talker echo protection should be sent for the image modems */
+    int use_tep;
+
+    fax_flush_handler_t *flush_handler;
+    void *flush_user_data;
+
+    /*! The current receive signal handler */
+    span_rx_handler_t *rx_handler;
+    void *rx_user_data;
+
+    /*! The current transmit signal handler */
+    span_tx_handler_t *tx_handler;
+    void *tx_user_data;
+    int tx_hdlc_preamble_len;
+    /*! The transmit signal handler to be used when the current one has finished sending. */
+    span_tx_handler_t *next_tx_handler;
+    void *next_tx_user_data;
+    
+    /*! If TRUE, transmission is in progress */
+    int transmit;
+
+    /*! If TRUE, transmit silence when there is nothing else to transmit. If FALSE return only
+        the actual generated audio. Note that this only affects untimed silences. Timed silences
+        (e.g. the 75ms silence between V.21 and a high speed modem) will alway be transmitted as
+        silent audio. */
+    int transmit_on_idle;
+
+    /*! \brief A tone generator context used to generate supervisory tones during
+               FAX handling. */
+    tone_gen_state_t tone_gen;
+    /*! \brief An HDLC context used when receiving HDLC over V.21 messages. */
+    hdlc_rx_state_t hdlcrx;
+    /*! \brief An HDLC context used when transmitting HDLC over V.21 messages. */
+    hdlc_tx_state_t hdlctx;
+    /*! \brief A V.21 FSK modem context used when transmitting HDLC over V.21
+               messages. */
+    fsk_tx_state_t v21tx;
+    /*! \brief A V.21 FSK modem context used when receiving HDLC over V.21
+               messages. */
+    fsk_rx_state_t v21rx;
+#if defined(ENABLE_V17)
+    /*! \brief A V.17 modem context used when sending FAXes at 7200bps, 9600bps
+               12000bps or 14400bps*/
+    v17_tx_state_t v17tx;
+    /*! \brief A V.29 modem context used when receiving FAXes at 7200bps, 9600bps
+               12000bps or 14400bps*/
+    v17_rx_state_t v17rx;
+#endif
+    /*! \brief A V.27ter modem context used when sending FAXes at 2400bps or
+               4800bps */
+    v27ter_tx_state_t v27ter_tx;
+    /*! \brief A V.27ter modem context used when receiving FAXes at 2400bps or
+               4800bps */
+    v27ter_rx_state_t v27ter_rx;
+    /*! \brief A V.29 modem context used when sending FAXes at 7200bps or
+               9600bps */
+    v29_tx_state_t v29tx;
+    /*! \brief A V.29 modem context used when receiving FAXes at 7200bps or
+               9600bps */
+    v29_rx_state_t v29rx;
+    /*! \brief Used to insert timed silences. */
+    silence_gen_state_t silence_gen;
+    /*! \brief */
+    dc_restore_state_t dc_restore;
+
+    /*! \brief TRUE is the short training sequence should be used. */
+    int short_train;
+
+    /*! The currently select receiver type */
+    int current_rx_type;
+    /*! The currently select transmitter type */
+    int current_tx_type;
+
+    int first_tx_hdlc_frame;
+
+    /*! Audio logging file handles */
+    int fax_audio_rx_log;
+    int fax_audio_tx_log;
+    /*! \brief Error and flow logging control */
+    logging_state_t logging;
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*! Apply T.30 receive processing to a block of audio samples.
+    \brief Apply T.30 receive processing to a block of audio samples.
+    \param s The FAX context.
+    \param amp The audio sample buffer.
+    \param len The number of samples in the buffer.
+    \return The number of samples unprocessed. This should only be non-zero if
+            the software has reached the end of the FAX call.
+*/
+int fax_rx(fax_state_t *s, int16_t *amp, int len);
+
+/*! Apply T.30 transmit processing to generate a block of audio samples.
+    \brief Apply T.30 transmit processing to generate a block of audio samples.
+    \param s The FAX context.
+    \param amp The audio sample buffer.
+    \param max_len The number of samples to be generated.
+    \return The number of samples actually generated. This will be zero when
+            there is nothing to send.
+*/
+int fax_tx(fax_state_t *s, int16_t *amp, int max_len);
+
+void fax_set_flush_handler(fax_state_t *s, fax_flush_handler_t *handler, void *user_data);
+
+/*! Select whether silent audio will be sent when FAX transmit is idle.
+    \brief Select whether silent audio will be sent when FAX transmit is idle.
+    \param s The FAX 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.
+*/
+void fax_set_transmit_on_idle(fax_state_t *s, int transmit_on_idle);
+
+/*! 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 FAX context.
+    \param use_tep TRUE if TEP should be sent.
+*/
+void fax_set_tep_mode(fax_state_t *s, int use_tep);
+
+/*! Initialise a FAX context.
+    \brief Initialise a FAX context.
+    \param s The FAX context.
+    \param calling_party TRUE if the context is for a calling party. FALSE if the
+           context is for an answering party.
+    \return 0 for OK, else -1.
+*/
+int fax_init(fax_state_t *s, int calling_party);
+
+/*! Release a FAX context.
+    \brief Release a FAX context.
+    \param s The FAX context. */
+int fax_release(fax_state_t *s);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/