--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/src/spandsp/t31.h	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,242 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * t31.h - A T.31 compatible class 1 FAX modem interface.
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2004 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: t31.h,v 1.37 2006/10/24 13:45:28 steveu Exp $
+ */
+
+/*! \file */
+
+#if !defined(_T31_H_)
+#define _T31_H_
+
+/*! \page t31_page T.31 Class 1 FAX modem protocol handling
+\section t31_page_sec_1 What does it do?
+The T.31 class 1 FAX modem modules implements a class 1 interface to the FAX
+modems in spandsp.
+
+\section t31_page_sec_2 How does it work?
+*/
+
+typedef struct t31_state_s t31_state_t;
+
+typedef int (t31_modem_control_handler_t)(t31_state_t *s, void *user_data, int op, const char *num);
+
+#define T31_TX_BUF_LEN          (4096*32)
+#define T31_TX_BUF_HIGH_TIDE    (4096*32 - 1024)
+#define T31_TX_BUF_LOW_TIDE     (1024)
+
+/*!
+    T.31 descriptor. This defines the working state for a single instance of
+    a T.31 FAX modem.
+*/
+struct t31_state_s
+{
+    at_state_t at_state;
+    t31_modem_control_handler_t *modem_control_handler;
+    void *modem_control_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;
+    /*! 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, 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;
+
+    uint8_t hdlc_tx_buf[256];
+    int hdlc_tx_len;
+    int hdlc_tx_ptr;
+    /*! TRUE if DLE prefix just used */
+    int dled;
+    uint8_t tx_data[T31_TX_BUF_LEN];
+    /*! \brief The number of bytes stored in transmit buffer. */
+    int tx_in_bytes;
+    /*! \brief The number of bytes sent from the transmit buffer. */
+    int tx_out_bytes;
+    int tx_holding;
+    int tx_data_started;
+    int bit_no;
+    int current_byte;
+
+    /*! \brief The current bit rate for the FAX fast message transfer modem. */
+    int bit_rate;
+    int rx_message_received;
+
+    /*! \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.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 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 Used to insert timed silences. */
+    silence_gen_state_t silence_gen;
+
+    /*! \brief Rx power meter, use to detect silence */
+    power_meter_t rx_power;
+    int16_t last_sample;
+    int32_t silence_threshold_power;
+    
+    t38_core_state_t t38;
+
+	/*! \brief Samples of silence heard */
+    int silence_heard;
+	/*! \brief Samples of silence awaited */
+    int silence_awaited;
+    /*! \brief Samples elapsed in the current call */
+    int64_t call_samples;
+    int64_t dte_data_timeout;
+    int modem;
+    int short_train;
+    int hdlc_final;
+    int data_final;
+    queue_t rx_queue;
+
+    uint8_t hdlc_rx_buf[256];
+    int hdlc_rx_len;
+    
+    int t38_mode;
+    int timed_step;
+    int current_tx_data;
+    int64_t next_send_samples;
+    int next_tx_indicator;
+
+    int current_rx_type;
+    int current_tx_type;
+
+    /*! \brief TRUE is there has been some T.38 data missed */
+    int missing_data;
+
+    int octets_per_non_ecm_packet;
+
+    /*! \brief Error and flow logging control */
+    logging_state_t logging;
+};
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void t31_call_event(t31_state_t *s, int event);
+
+int t31_at_rx(t31_state_t *s, const char *t, int len);
+
+/*! Process a block of received T.31 modem audio samples.
+    \brief Process a block of received T.31 modem audio samples.
+    \param s The T.31 modem context.
+    \param amp The audio sample buffer.
+    \param len The number of samples in the buffer.
+    \return The number of samples unprocessed. */
+int t31_rx(t31_state_t *s, int16_t amp[], int len);
+
+/*! Generate a block of T.31 modem audio samples.
+    \brief Generate a block of T.31 modem audio samples.
+    \param s The T.31 modem context.
+    \param amp The audio sample buffer.
+    \param max_len The number of samples to be generated.
+    \return The number of samples actually generated.
+*/
+int t31_tx(t31_state_t *s, int16_t amp[], int max_len);
+
+int t31_t38_send_timeout(t31_state_t *s, int samples);
+
+/*! 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.31 modem context.
+    \param transmit_on_idle TRUE if silent audio should be output when the transmitter is
+           idle. FALSE to transmit zero length audio when the transmitter is idle. The default
+           behaviour is FALSE.
+*/
+void t31_set_transmit_on_idle(t31_state_t *s, int transmit_on_idle);
+
+/*! Initialise a T.31 context. This must be called before the first
+    use of the context, to initialise its contents.
+    \brief Initialise a T.31 context.
+    \param s The T.31 context.
+    \param at_tx_handler A callback routine to handle AT interpreter channel output.
+    \param at_tx_user_data An opaque pointer passed in called to at_tx_handler.
+    \param modem_control_handler A callback routine to handle control of the modem (off-hook, etc).
+    \param modem_control_user_data An opaque pointer passed in called to modem_control_handler.
+    \param tx_t38_packet_handler ???
+    \param tx_t38_packet_user_data ???
+    \return A pointer to the T.31 context. */
+t31_state_t *t31_init(t31_state_t *s,
+                      at_tx_handler_t *at_tx_handler,
+                      void *at_tx_user_data,
+                      t31_modem_control_handler_t *modem_control_handler,
+                      void *modem_control_user_data,
+                      t38_tx_packet_handler_t *tx_t38_packet_handler,
+                      void *tx_t38_packet_user_data);
+
+/*! Release a T.31 context.
+    \brief Release a T.31 context.
+    \param s The T.31 context.
+    \return 0 for OK */
+int t31_release(t31_state_t *s);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/