--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/spandsp-0.0.6pre17/src/power_meter.c	Fri Jun 25 15:50:58 2010 +0200
@@ -0,0 +1,214 @@
+/*
+ * SpanDSP - a series of DSP components for telephony
+ *
+ * power_meter.c
+ *
+ * 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 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: power_meter.c,v 1.31 2009/05/30 17:29:23 steveu Exp $
+ */
+
+/*! \file */
+
+#if defined(HAVE_CONFIG_H)
+#include "config.h"
+#endif
+
+#include <inttypes.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <float.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 "spandsp/telephony.h"
+#include "spandsp/power_meter.h"
+
+SPAN_DECLARE(power_meter_t *) power_meter_init(power_meter_t *s, int shift)
+{
+    if (s == NULL)
+    {
+        if ((s = (power_meter_t *) malloc(sizeof(*s))) == NULL)
+            return NULL;
+    }
+    s->shift = shift;
+    s->reading = 0;
+    return s;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) power_meter_release(power_meter_t *s)
+{
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) power_meter_free(power_meter_t *s)
+{
+    if (s)
+        free(s);
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(power_meter_t *) power_meter_damping(power_meter_t *s, int shift)
+{
+    s->shift = shift;
+    return s;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int32_t) power_meter_update(power_meter_t *s, int16_t amp)
+{
+    s->reading += ((amp*amp - s->reading) >> s->shift);
+    return s->reading;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int32_t) power_meter_level_dbm0(float level)
+{
+    float l;
+
+    level -= DBM0_MAX_POWER;
+    if (level > 0.0)
+        level = 0.0;
+    l = powf(10.0f, level/10.0f)*(32767.0f*32767.0f);
+    return (int32_t) l;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int32_t) power_meter_level_dbov(float level)
+{
+    float l;
+
+    if (level > 0.0)
+        level = 0.0;
+    l = powf(10.0f, level/10.0f)*(32767.0f*32767.0f);
+    return (int32_t) l;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int32_t) power_meter_current(power_meter_t *s)
+{
+    return s->reading;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(float) power_meter_current_dbm0(power_meter_t *s)
+{
+    if (s->reading <= 0)
+        return -96.329f + DBM0_MAX_POWER;
+    /* This is based on A-law, but u-law is only 0.03dB different, so don't worry. */
+    return log10f((float) s->reading/(32767.0f*32767.0f))*10.0f + DBM0_MAX_POWER;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(float) power_meter_current_dbov(power_meter_t *s)
+{
+    if (s->reading <= 0)
+        return -96.329f;
+    return log10f((float) s->reading/(32767.0f*32767.0f))*10.0f;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int32_t) power_surge_detector(power_surge_detector_state_t *s, int16_t amp)
+{
+    int32_t pow_short;
+    int32_t pow_medium;
+
+    pow_short = power_meter_update(&s->short_term, amp);
+    pow_medium = power_meter_update(&s->medium_term, amp);
+    if (pow_medium < s->min)
+        return 0;
+    if (!s->signal_present)
+    {
+        if (pow_short <= s->surge*(pow_medium >> 10))
+            return 0;
+        s->signal_present = TRUE;
+        s->medium_term.reading = s->short_term.reading;
+    }
+    else
+    {
+        if (pow_short < s->sag*(pow_medium >> 10))
+        {
+            s->signal_present = FALSE;
+            s->medium_term.reading = s->short_term.reading;
+            return 0;
+        }
+    }
+    return pow_short;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(float) power_surge_detector_current_dbm0(power_surge_detector_state_t *s)
+{
+    return power_meter_current_dbm0(&s->short_term);
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(float) power_surge_detector_current_dbov(power_surge_detector_state_t *s)
+{
+    return power_meter_current_dbov(&s->short_term);
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(power_surge_detector_state_t *) power_surge_detector_init(power_surge_detector_state_t *s, float min, float surge)
+{
+    float ratio;
+
+    if (s == NULL)
+    {
+        if ((s = (power_surge_detector_state_t *) malloc(sizeof(*s))) == NULL)
+            return NULL;
+    }
+    memset(s, 0, sizeof(*s));
+    power_meter_init(&s->short_term, 4);
+    power_meter_init(&s->medium_term, 7);
+    ratio = powf(10.0f, surge/10.0f);
+    s->surge = 1024.0f*ratio;
+    s->sag = 1024.0f/ratio;
+    s->min = power_meter_level_dbm0(min);
+    s->medium_term.reading = s->min + 1;
+    return s;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) power_surge_detector_release(power_surge_detector_state_t *s)
+{
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+
+SPAN_DECLARE(int) power_surge_detector_free(power_surge_detector_state_t *s)
+{
+    if (s)
+        free(s);
+    return 0;
+}
+/*- End of function --------------------------------------------------------*/
+/*- End of file ------------------------------------------------------------*/