--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.3/spandsp-0.0.3/src/spandsp/v42.h	Fri Jun 25 16:00:21 2010 +0200
@@ -0,0 +1,231 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * v42.h
+ *
+ * Written by Steve Underwood <steveu@coppice.org>
+ *
+ * Copyright (C) 2003 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: v42.h,v 1.17 2006/10/24 13:22:02 steveu Exp $
+ */
+
+/*! \page v42_page V.42 modem error correction
+\section v42_page_sec_1 What does it do?
+The V.42 specification defines an error correcting protocol for PSTN modems, based on
+HDLC and LAP. This makes it similar to an X.25 link. A special variant of LAP, known
+as LAP-M, is defined in the V.42 specification. A means for modems to determine if the
+far modem supports V.42 is also defined.
+
+\section v42_page_sec_2 How does it work?
+*/
+
+#if !defined(_V42_H_)
+#define _V42_H_
+
+enum
+{
+    LAPM_DETECT = 0,
+    LAPM_ESTABLISH = 1,
+    LAPM_DATA = 2,
+    LAPM_RELEASE = 3,
+    LAPM_SIGNAL = 4,
+    LAPM_SETPARM = 5,
+    LAPM_TEST = 6,
+    LAPM_UNSUPPORTED = 7
+};
+
+typedef void (*v42_status_func_t)(void *user_data, int status);
+typedef void (*v42_frame_handler_t)(void *user_data, const uint8_t *pkt, int len);
+
+typedef struct lapm_frame_queue_s
+{
+    struct lapm_frame_queue_s *next;
+    int len;
+    uint8_t frame[];
+} lapm_frame_queue_t;
+
+/*!
+    LAP-M descriptor. This defines the working state for a single instance of LAP-M.
+*/
+typedef struct
+{
+    int handle;
+    hdlc_rx_state_t hdlc_rx;
+    hdlc_tx_state_t hdlc_tx;
+    
+    v42_frame_handler_t iframe_receive;
+    void *iframe_receive_user_data;
+
+    v42_status_func_t status_callback;
+    void *status_callback_user_data;
+
+    int state;
+    int tx_waiting;
+    int debug;
+    /*! TRUE if originator. FALSE if answerer */
+    int we_are_originator;
+    /*! Remote network type (unknown, answerer. originator) */
+    int peer_is_originator;
+    /*! Next N(S) for transmission */
+    int next_tx_frame;
+    /*! The last of our frames which the peer acknowledged */
+    int last_frame_peer_acknowledged;
+    /*! Next N(R) for reception */
+    int next_expected_frame;
+    /*! The last of the peer's frames which we acknowledged */
+    int last_frame_we_acknowledged;
+    /*! TRUE if we sent an I or S frame with the F-bit set */
+    int solicit_f_bit;
+    /*! Retransmission count */
+    int retransmissions;
+    /*! TRUE if peer is busy */
+    int busy;
+
+    /*! Acknowledgement timer */
+    int t401_timer;
+    /*! Reply delay timer - optional */
+    int t402_timer;
+    /*! Inactivity timer - optional */
+    int t403_timer;
+    /*! Maximum number of octets in an information field */
+    int n401;
+    /*! Window size */
+    int window_size_k;
+	
+    lapm_frame_queue_t *txqueue;
+    lapm_frame_queue_t *tx_next;
+    lapm_frame_queue_t *tx_last;
+    queue_t tx_queue;
+    
+    span_sched_state_t sched;
+    /*! \brief Error and flow logging control */
+    logging_state_t logging;
+} lapm_state_t;
+
+/*!
+    V.42 descriptor. This defines the working state for a single instance of V.42.
+*/
+typedef struct
+{
+    /*! TRUE if we are the calling party, otherwise FALSE */
+    int caller;
+    /*! TRUE if we should detect whether the far end is V.42 capable. FALSE if we go
+        directly to protocol establishment */
+    int detect;
+
+    /*! Stage in negotiating V.42 support */
+    int rx_negotiation_step;
+    int rxbits;
+    int rxstream;
+    int rxoks;
+    int odp_seen;
+    int txbits;
+    int txstream;
+    int txadps;
+    /*! The LAP.M context */
+    lapm_state_t lapm;
+
+    /*! V.42 support detection timer */
+    int t400_timer;
+    /*! \brief Error and flow logging control */
+    logging_state_t logging;
+} v42_state_t;
+
+/*! Log the raw HDLC frames */
+#define LAPM_DEBUG_LAPM_RAW         (1 << 0)
+/*! Log the interpreted frames */
+#define LAPM_DEBUG_LAPM_DUMP        (1 << 1)
+/*! Log state machine changes */
+#define LAPM_DEBUG_LAPM_STATE 	    (1 << 2)
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+const char *lapm_status_to_str(int status);
+
+/*! Dump LAP.M frames in a raw and/or decoded forms
+    \param frame The frame itself
+    \param len The length of the frame, in octets
+    \param showraw TRUE if the raw octets should be dumped
+    \param txrx TRUE if tx, FALSE if rx. Used to highlight the packet's direction.
+*/
+void lapm_dump(lapm_state_t *s, const uint8_t *frame, int len, int showraw, int txrx);
+
+/*! Accept an HDLC packet
+*/
+void lapm_receive(void *user_data, int ok, const uint8_t *buf, int len);
+
+/*! Transmit a LAP.M frame
+*/
+int lapm_tx(lapm_state_t *s, const void *buf, int len);
+
+/*! Transmit a LAP.M information frame
+*/
+int lapm_tx_iframe(lapm_state_t *s, const void *buf, int len, int cr);
+
+/*! Send a break over a LAP.M connection
+*/
+int lapm_break(lapm_state_t *s, int enable);
+
+/*! Initiate an orderly release of a LAP.M connection
+*/
+int lapm_release(lapm_state_t *s);
+
+/*! Enable or disable loopback of a LAP.M connection
+*/
+int lapm_loopback(lapm_state_t *s, int enable);
+
+/*! Assign or remove a callback routine used to deal with V.42 status changes.
+*/
+void v42_set_status_callback(v42_state_t *s, v42_status_func_t callback, void *user_data);
+
+/*! Process a newly received bit for a V.42 context.
+*/
+void v42_rx_bit(void *user_data, int bit);
+
+/*! Get the next transmit bit for a V.42 context.
+*/
+int v42_tx_bit(void *user_data);
+
+/*! Initialise a V.42 context.
+    \param s The V.42 context.
+    \param caller TRUE if caller mode, else answerer mode.
+    \param frame_handler A callback function to handle received frames of data.
+    \param user_data An opaque pointer passed to the frame handler routine.
+    \return ???
+*/
+v42_state_t *v42_init(v42_state_t *s, int caller, int detect, v42_frame_handler_t frame_handler, void *user_data);
+
+/*! Restart a V.42 context.
+    \param s The V.42 context.
+*/
+void v42_restart(v42_state_t *s);
+
+/*! Release a V.42 context.
+    \param s The V.42 context.
+    \return 0 if OK */
+int v42_release(v42_state_t *s);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/*- End of file ------------------------------------------------------------*/