freeswitch/libs/spandsp/src/fax.c

//#define LOG_FAX_AUDIO
/*
 * SpanDSP - a series of DSP components for telephony
 *
 * fax.c - Analogue line ITU T.30 FAX transfer processing
 *
 * Written by Steve Underwood <steveu@coppice.org>
 *
 * Copyright (C) 2003, 2005, 2006 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: fax.c,v 1.84 2009/01/28 03:41:26 steveu Exp $
 */

/*! \file */

#if defined(HAVE_CONFIG_H)
#include "config.h"
#endif

#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#if defined(HAVE_TGMATH_H)
#include <tgmath.h>
#endif
#if defined(HAVE_MATH_H)
#include <math.h>
#endif
#include "floating_fudge.h"
#include <assert.h>
#include <fcntl.h>
#include <time.h>
#if defined(LOG_FAX_AUDIO)
#include <unistd.h>
#endif
#include <tiffio.h>

#include "spandsp/telephony.h"
#include "spandsp/logging.h"
#include "spandsp/queue.h"
#include "spandsp/dc_restore.h"
#include "spandsp/power_meter.h"
#include "spandsp/complex.h"
#include "spandsp/tone_detect.h"
#include "spandsp/tone_generate.h"
#include "spandsp/async.h"
#include "spandsp/hdlc.h"
#include "spandsp/silence_gen.h"
#include "spandsp/fsk.h"
#include "spandsp/v29tx.h"
#include "spandsp/v29rx.h"
#include "spandsp/v27ter_tx.h"
#include "spandsp/v27ter_rx.h"
#include "spandsp/v17tx.h"
#include "spandsp/v17rx.h"
#include "spandsp/super_tone_rx.h"
#include "spandsp/modem_connect_tones.h"
#include "spandsp/t4.h"

#include "spandsp/t30_fcf.h"
#include "spandsp/t35.h"
#include "spandsp/t30.h"
#include "spandsp/t30_api.h"
#include "spandsp/t30_logging.h"

#include "spandsp/fax_modems.h"
#include "spandsp/fax.h"

#include "spandsp/private/logging.h"
#include "spandsp/private/fsk.h"
#include "spandsp/private/v17tx.h"
#include "spandsp/private/v17rx.h"
#include "spandsp/private/v27ter_tx.h"
#include "spandsp/private/v27ter_rx.h"
#include "spandsp/private/v29tx.h"
#include "spandsp/private/v29rx.h"
#include "spandsp/private/modem_connect_tones.h"
#include "spandsp/private/hdlc.h"
#include "spandsp/private/fax_modems.h"
#include "spandsp/private/t4.h"
#include "spandsp/private/t30.h"
#include "spandsp/private/fax.h"

#define HDLC_FRAMING_OK_THRESHOLD       5

static void fax_send_hdlc(void *user_data, const uint8_t *msg, int len)
{
    fax_state_t *s;

    s = (fax_state_t *) user_data;
    
    hdlc_tx_frame(&s->modems.hdlc_tx, msg, len);
}
/*- End of function --------------------------------------------------------*/

static void tone_detected(void *user_data, int on, int level, int delay)
{
    t30_state_t *s;

    s = (t30_state_t *) user_data;
    span_log(&s->logging, SPAN_LOG_FLOW, "FAX tone declared %s (%ddBm0)\n", (on)  ?  "on"  :  "off", level);
}
/*- End of function --------------------------------------------------------*/

static void hdlc_underflow_handler(void *user_data)
{
    t30_state_t *s;

    s = (t30_state_t *) user_data;
    t30_front_end_status(s, T30_FRONT_END_SEND_STEP_COMPLETE);
}
/*- End of function --------------------------------------------------------*/

static int v17_v21_rx(void *user_data, const int16_t amp[], int len)
{
    fax_state_t *t;
    fax_modems_state_t *s;

    t = (fax_state_t *) user_data;
    s = &t->modems;
    v17_rx(&s->v17_rx, amp, len);
    if (t->t30.rx_trained)
    {
        /* The fast modem has trained, so we no longer need to run the slow
           one in parallel. */
        span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.17 (%.2fdBm0)\n", v17_rx_signal_power(&s->v17_rx));
        s->rx_handler = (span_rx_handler_t *) &v17_rx;
        s->rx_user_data = &s->v17_rx;
    }
    else
    {
        fsk_rx(&s->v21_rx, amp, len);
        if (t->t30.rx_frame_received)
        {
            /* We have received something, and the fast modem has not trained. We must
               be receiving valid V.21 */
            span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.17 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
            s->rx_handler = (span_rx_handler_t *) &fsk_rx;
            s->rx_user_data = &s->v21_rx;
        }
    }
    return 0;
}
/*- End of function --------------------------------------------------------*/

static int v27ter_v21_rx(void *user_data, const int16_t amp[], int len)
{
    fax_state_t *t;
    fax_modems_state_t *s;

    t = (fax_state_t *) user_data;
    s = &t->modems;
    v27ter_rx(&s->v27ter_rx, amp, len);
    if (t->t30.rx_trained)
    {
        /* The fast modem has trained, so we no longer need to run the slow
           one in parallel. */
        span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.27ter (%.2fdBm0)\n", v27ter_rx_signal_power(&s->v27ter_rx));
        s->rx_handler = (span_rx_handler_t *) &v27ter_rx;
        s->rx_user_data = &s->v27ter_rx;
    }
    else
    {
        fsk_rx(&s->v21_rx, amp, len);
        if (t->t30.rx_frame_received)
        {
            /* We have received something, and the fast modem has not trained. We must
               be receiving valid V.21 */
            span_log(&s->logging, SPAN_LOG_FLOW, "Switching from V.27ter + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
            s->rx_handler = (span_rx_handler_t *) &fsk_rx;
            s->rx_user_data = &s->v21_rx;
        }
    }
    return 0;
}
/*- End of function --------------------------------------------------------*/

static int v29_v21_rx(void *user_data, const int16_t amp[], int len)
{
    fax_state_t *t;
    fax_modems_state_t *s;

    t = (fax_state_t *) user_data;
    s = &t->modems;
    v29_rx(&s->v29_rx, amp, len);
    if (t->t30.rx_trained)
    {
        /* The fast modem has trained, so we no longer need to run the slow
           one in parallel. */
        span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.29 (%.2fdBm0)\n", v29_rx_signal_power(&s->v29_rx));
        s->rx_handler = (span_rx_handler_t *) &v29_rx;
        s->rx_user_data = &s->v29_rx;
    }
    else
    {
        fsk_rx(&s->v21_rx, amp, len);
        if (t->t30.rx_frame_received)
        {
            /* We have received something, and the fast modem has not trained. We must
               be receiving valid V.21 */
            span_log(&t->logging, SPAN_LOG_FLOW, "Switching from V.29 + V.21 to V.21 (%.2fdBm0)\n", fsk_rx_signal_power(&s->v21_rx));
            s->rx_handler = (span_rx_handler_t *) &fsk_rx;
            s->rx_user_data = &s->v21_rx;
        }
    }
    return 0;
}
/*- End of function --------------------------------------------------------*/

static void fax_fax_modems_init(fax_modems_state_t *s, int use_tep, void *user_data)
{
    s->use_tep = use_tep;

    hdlc_rx_init(&s->hdlc_rx, FALSE, FALSE, HDLC_FRAMING_OK_THRESHOLD, t30_hdlc_accept, user_data);
    hdlc_tx_init(&s->hdlc_tx, FALSE, 2, FALSE, hdlc_underflow_handler, user_data);
    fsk_rx_init(&s->v21_rx, &preset_fsk_specs[FSK_V21CH2], TRUE, (put_bit_func_t) hdlc_rx_put_bit, &s->hdlc_rx);
    fsk_rx_signal_cutoff(&s->v21_rx, -45.5);
    fsk_tx_init(&s->v21_tx, &preset_fsk_specs[FSK_V21CH2], (get_bit_func_t) hdlc_tx_get_bit, &s->hdlc_tx);
    v17_rx_init(&s->v17_rx, 14400, t30_non_ecm_put_bit, user_data);
    v17_tx_init(&s->v17_tx, 14400, s->use_tep, t30_non_ecm_get_bit, user_data);
    v29_rx_init(&s->v29_rx, 9600, t30_non_ecm_put_bit, user_data);
    v29_rx_signal_cutoff(&s->v29_rx, -45.5);
    v29_tx_init(&s->v29_tx, 9600, s->use_tep, t30_non_ecm_get_bit, user_data);
    v27ter_rx_init(&s->v27ter_rx, 4800, t30_non_ecm_put_bit, user_data);
    v27ter_tx_init(&s->v27ter_tx, 4800, s->use_tep, t30_non_ecm_get_bit, user_data);
    silence_gen_init(&s->silence_gen, 0);
    modem_connect_tones_tx_init(&s->connect_tx, MODEM_CONNECT_TONES_FAX_CNG);
    modem_connect_tones_rx_init(&s->connect_rx,
                                MODEM_CONNECT_TONES_FAX_CNG,
                                tone_detected,
                                user_data);
    dc_restore_init(&s->dc_restore);

    s->rx_signal_present = FALSE;
    s->rx_handler = (span_rx_handler_t *) &span_dummy_rx;
    s->rx_user_data = NULL;
    s->tx_handler = (span_tx_handler_t *) &silence_gen;
    s->tx_user_data = &s->silence_gen;
}
/*- End of function --------------------------------------------------------*/

int fax_rx(fax_state_t *s, int16_t *amp, int len)
{
    int i;

#if defined(LOG_FAX_AUDIO)
    if (s->modems.audio_rx_log >= 0)
        write(s->modems.audio_rx_log, amp, len*sizeof(int16_t));
#endif
    for (i = 0;  i < len;  i++)
        amp[i] = dc_restore(&s->modems.dc_restore, amp[i]);
    s->modems.rx_handler(s->modems.rx_user_data, amp, len);
    t30_timer_update(&s->t30, len);
    return 0;
}
/*- End of function --------------------------------------------------------*/

static int set_next_tx_type(fax_state_t *s)
{
    fax_modems_state_t *t;

    t = &s->modems;
    if (t->next_tx_handler)
    {
        t->tx_handler = t->next_tx_handler;
        t->tx_user_data = t->next_tx_user_data;
        t->next_tx_handler = NULL;
        return 0;
    }
    /* If there is nothing else to change to, so use zero length silence */
    silence_gen_alter(&t->silence_gen, 0);
    t->tx_handler = (span_tx_handler_t *) &silence_gen;
    t->tx_user_data = &t->silence_gen;
    t->next_tx_handler = NULL;
    t->transmit = FALSE;
    return -1;
}
/*- End of function --------------------------------------------------------*/

int fax_tx(fax_state_t *s, int16_t *amp, int max_len)
{
    int len;
#if defined(LOG_FAX_AUDIO)
    int required_len;
    
    required_len = max_len;
#endif
    len = 0;
    if (s->modems.transmit)
    {
        while ((len += s->modems.tx_handler(s->modems.tx_user_data, amp + len, max_len - len)) < max_len)
        {
            /* Allow for a change of tx handler within a block */
            if (set_next_tx_type(s)  &&  s->modems.current_tx_type != T30_MODEM_NONE  &&  s->modems.current_tx_type != T30_MODEM_DONE)
                t30_front_end_status(&s->t30, T30_FRONT_END_SEND_STEP_COMPLETE);
            if (!s->modems.transmit)
            {
                if (s->modems.transmit_on_idle)
                {
                    /* Pad to the requested length with silence */
                    memset(amp + len, 0, (max_len - len)*sizeof(int16_t));
                    len = max_len;        
                }
                break;
            }
        }
    }
    else
    {
        if (s->modems.transmit_on_idle)
        {
            /* Pad to the requested length with silence */
            memset(amp, 0, max_len*sizeof(int16_t));
            len = max_len;        
        }
    }
#if defined(LOG_FAX_AUDIO)
    if (s->modems.audio_tx_log >= 0)
    {
        if (len < required_len)
            memset(amp + len, 0, (required_len - len)*sizeof(int16_t));
        write(s->modems.audio_tx_log, amp, required_len*sizeof(int16_t));
    }
#endif
    return len;
}
/*- End of function --------------------------------------------------------*/

static void fax_set_rx_type(void *user_data, int type, int bit_rate, int short_train, int use_hdlc)
{
    fax_state_t *s;
    put_bit_func_t put_bit_func;
    void *put_bit_user_data;
    fax_modems_state_t *t;

    s = (fax_state_t *) user_data;
    t = &s->modems;
    span_log(&s->logging, SPAN_LOG_FLOW, "Set rx type %d\n", type);
    if (t->current_rx_type == type)
        return;
    t->current_rx_type = type;
    t->rx_bit_rate = bit_rate;
    if (use_hdlc)
    {
        put_bit_func = (put_bit_func_t) hdlc_rx_put_bit;
        put_bit_user_data = (void *) &t->hdlc_rx;
        hdlc_rx_init(&t->hdlc_rx, FALSE, FALSE, HDLC_FRAMING_OK_THRESHOLD, t30_hdlc_accept, &s->t30);
    }
    else
    {
        put_bit_func = t30_non_ecm_put_bit;
        put_bit_user_data = (void *) &s->t30;
    }
    switch (type)
    {
    case T30_MODEM_V21:
        fsk_rx_init(&t->v21_rx, &preset_fsk_specs[FSK_V21CH2], TRUE, (put_bit_func_t) hdlc_rx_put_bit, put_bit_user_data);
        fsk_rx_signal_cutoff(&t->v21_rx, -45.5);
        t->rx_handler = (span_rx_handler_t *) &fsk_rx;
        t->rx_user_data = &t->v21_rx;
        break;
    case T30_MODEM_V27TER:
        v27ter_rx_restart(&t->v27ter_rx, bit_rate, FALSE);
        v27ter_rx_set_put_bit(&t->v27ter_rx, put_bit_func, put_bit_user_data);
        t->rx_handler = (span_rx_handler_t *) &v27ter_v21_rx;
        t->rx_user_data = s;
        break;
    case T30_MODEM_V29:
        v29_rx_restart(&t->v29_rx, bit_rate, FALSE);
        v29_rx_set_put_bit(&t->v29_rx, put_bit_func, put_bit_user_data);
        t->rx_handler = (span_rx_handler_t *) &v29_v21_rx;
        t->rx_user_data = s;
        break;
    case T30_MODEM_V17:
        v17_rx_restart(&t->v17_rx, bit_rate, short_train);
        v17_rx_set_put_bit(&t->v17_rx, put_bit_func, put_bit_user_data);
        t->rx_handler = (span_rx_handler_t *) &v17_v21_rx;
        t->rx_user_data = s;
        break;
    case T30_MODEM_DONE:
        span_log(&s->logging, SPAN_LOG_FLOW, "FAX exchange complete\n");
    default:
        t->rx_handler = (span_rx_handler_t *) &span_dummy_rx;
        t->rx_user_data = s;
        break;
    }
}
/*- End of function --------------------------------------------------------*/

static void fax_set_tx_type(void *user_data, int type, int bit_rate, int short_train, int use_hdlc)
{
    fax_state_t *s;
    get_bit_func_t get_bit_func;
    void *get_bit_user_data;
    fax_modems_state_t *t;
    int tone;

    s = (fax_state_t *) user_data;
    t = &s->modems;
    span_log(&s->logging, SPAN_LOG_FLOW, "Set tx type %d\n", type);
    if (t->current_tx_type == type)
        return;
    if (use_hdlc)
    {
        get_bit_func = (get_bit_func_t) hdlc_tx_get_bit;
        get_bit_user_data = (void *) &t->hdlc_tx;
    }
    else
    {
        get_bit_func = t30_non_ecm_get_bit;
        get_bit_user_data = (void *) &s->t30;
    }
    switch (type)
    {
    case T30_MODEM_PAUSE:
        silence_gen_alter(&t->silence_gen, ms_to_samples(short_train));
        t->tx_handler = (span_tx_handler_t *) &silence_gen;
        t->tx_user_data = &t->silence_gen;
        t->next_tx_handler = NULL;
        t->transmit = TRUE;
        break;
    case T30_MODEM_CED:
    case T30_MODEM_CNG:
        if (type == T30_MODEM_CED)
            tone = MODEM_CONNECT_TONES_FAX_CED;
        else
            tone = MODEM_CONNECT_TONES_FAX_CNG;
        modem_connect_tones_tx_init(&t->connect_tx, tone);
        t->tx_handler = (span_tx_handler_t *) &modem_connect_tones_tx;
        t->tx_user_data = &t->connect_tx;
        t->next_tx_handler = NULL;
        t->transmit = TRUE;
        break;
    case T30_MODEM_V21:
        fsk_tx_init(&t->v21_tx, &preset_fsk_specs[FSK_V21CH2], get_bit_func, get_bit_user_data);
        /* The spec says 1s +-15% of preamble. So, the minimum is 32 octets. */
        hdlc_tx_flags(&t->hdlc_tx, 32);
        /* Pause before switching from phase C, as per T.30 5.3.2.2. If we omit this, the receiver
           might not see the carrier fall between the high speed and low speed sections. In practice,
           a 75ms gap before any V.21 transmission is harmless, adds little to the overall length of
           a call, and ensures the receiving end is ready. */
        silence_gen_alter(&t->silence_gen, ms_to_samples(75));
        t->tx_handler = (span_tx_handler_t *) &silence_gen;
        t->tx_user_data = &t->silence_gen;
        t->next_tx_handler = (span_tx_handler_t *) &fsk_tx;
        t->next_tx_user_data = &t->v21_tx;
        t->transmit = TRUE;
        break;
    case T30_MODEM_V27TER:
        silence_gen_alter(&t->silence_gen, ms_to_samples(75));
        /* For any fast modem, set 200ms of preamble flags */
        hdlc_tx_flags(&t->hdlc_tx, bit_rate/(8*5));
        v27ter_tx_restart(&t->v27ter_tx, bit_rate, t->use_tep);
        v27ter_tx_set_get_bit(&t->v27ter_tx, get_bit_func, get_bit_user_data);
        t->tx_handler = (span_tx_handler_t *) &silence_gen;
        t->tx_user_data = &t->silence_gen;
        t->next_tx_handler = (span_tx_handler_t *) &v27ter_tx;
        t->next_tx_user_data = &t->v27ter_tx;
        t->transmit = TRUE;
        break;
    case T30_MODEM_V29:
        silence_gen_alter(&t->silence_gen, ms_to_samples(75));
        /* For any fast modem, set 200ms of preamble flags */
        hdlc_tx_flags(&t->hdlc_tx, bit_rate/(8*5));
        v29_tx_restart(&t->v29_tx, bit_rate, t->use_tep);
        v29_tx_set_get_bit(&t->v29_tx, get_bit_func, get_bit_user_data);
        t->tx_handler = (span_tx_handler_t *) &silence_gen;
        t->tx_user_data = &t->silence_gen;
        t->next_tx_handler = (span_tx_handler_t *) &v29_tx;
        t->next_tx_user_data = &t->v29_tx;
        t->transmit = TRUE;
        break;
    case T30_MODEM_V17:
        silence_gen_alter(&t->silence_gen, ms_to_samples(75));
        /* For any fast modem, set 200ms of preamble flags */
        hdlc_tx_flags(&t->hdlc_tx, bit_rate/(8*5));
        v17_tx_restart(&t->v17_tx, bit_rate, t->use_tep, short_train);
        v17_tx_set_get_bit(&t->v17_tx, get_bit_func, get_bit_user_data);
        t->tx_handler = (span_tx_handler_t *) &silence_gen;
        t->tx_user_data = &t->silence_gen;
        t->next_tx_handler = (span_tx_handler_t *) &v17_tx;
        t->next_tx_user_data = &t->v17_tx;
        t->transmit = TRUE;
        break;
    case T30_MODEM_DONE:
        span_log(&s->logging, SPAN_LOG_FLOW, "FAX exchange complete\n");
        /* Fall through */
    default:
        silence_gen_alter(&t->silence_gen, 0);
        t->tx_handler = (span_tx_handler_t *) &silence_gen;
        t->tx_user_data = &t->silence_gen;
        t->next_tx_handler = NULL;
        t->transmit = FALSE;
        break;
    }
    t->tx_bit_rate = bit_rate;
    t->current_tx_type = type;
}
/*- End of function --------------------------------------------------------*/

void fax_set_transmit_on_idle(fax_state_t *s, int transmit_on_idle)
{
    s->modems.transmit_on_idle = transmit_on_idle;
}
/*- End of function --------------------------------------------------------*/

void fax_set_tep_mode(fax_state_t *s, int use_tep)
{
    s->modems.use_tep = use_tep;
}
/*- End of function --------------------------------------------------------*/

t30_state_t *fax_get_t30_state(fax_state_t *s)
{
    return &s->t30;
}
/*- End of function --------------------------------------------------------*/

logging_state_t *fax_get_logging_state(fax_state_t *s)
{
    return &s->logging;
}
/*- End of function --------------------------------------------------------*/

fax_state_t *fax_init(fax_state_t *s, int calling_party)
{
    if (s == NULL)
    {
        if ((s = (fax_state_t *) malloc(sizeof(*s))) == NULL)
            return NULL;
    }

    memset(s, 0, sizeof(*s));
    span_log_init(&s->logging, SPAN_LOG_NONE, NULL);
    span_log_set_protocol(&s->logging, "FAX");
    fax_fax_modems_init(&s->modems, FALSE, &s->t30);
    t30_init(&s->t30,
             calling_party,
             fax_set_rx_type,
             (void *) s,
             fax_set_tx_type,
             (void *) s,
             fax_send_hdlc,
             (void *) s);
    t30_set_supported_modems(&s->t30, T30_SUPPORT_V27TER | T30_SUPPORT_V29);
    t30_restart(&s->t30);
#if defined(LOG_FAX_AUDIO)
    {
        char buf[100 + 1];
        struct tm *tm;
        time_t now;

        time(&now);
        tm = localtime(&now);
        sprintf(buf,
                "/tmp/fax-rx-audio-%p-%02d%02d%02d%02d%02d%02d",
                s,
                tm->tm_year%100,
                tm->tm_mon + 1,
                tm->tm_mday,
                tm->tm_hour,
                tm->tm_min,
                tm->tm_sec);
        s->modems.audio_rx_log = open(buf, O_CREAT | O_TRUNC | O_WRONLY, 0666);
        sprintf(buf,
                "/tmp/fax-tx-audio-%p-%02d%02d%02d%02d%02d%02d",
                s,
                tm->tm_year%100,
                tm->tm_mon + 1,
                tm->tm_mday,
                tm->tm_hour,
                tm->tm_min,
                tm->tm_sec);
        s->modems.audio_tx_log = open(buf, O_CREAT | O_TRUNC | O_WRONLY, 0666);
    }
#endif
    return s;
}
/*- End of function --------------------------------------------------------*/

int fax_release(fax_state_t *s)
{
    t30_release(&s->t30);
    return 0;
}
/*- End of function --------------------------------------------------------*/

int fax_free(fax_state_t *s)
{
    t30_release(&s->t30);
    free(s);
    return 0;
}
/*- End of function --------------------------------------------------------*/
/*- End of file ------------------------------------------------------------*/