add a peak input measuring object

deadly simplistic peak difference measuring object, after begin() just
goes through samples and find the maximum and minimum signed values,
natural behavior of begin() is to reset the max and min, member uint16_t
Dpp() returns maximum difference seen and .stop() does what it says.

Audio.h

@@ -48,6 +48,7 @@
 #include "analyze_fft256.h"
 #include "analyze_print.h"
 #include "analyze_tonedetect.h"
+#include "analyze_peakdetect.h"
 #include "control_sgtl5000.h"
 #include "control_wm8731.h"
 #include "effect_chorus.h"

analyze_peakdetect.cpp

@@ -0,0 +1,72 @@
+/* Audio Library for Teensy 3.X
+ * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
+ *
+ * Development of this audio library was funded by PJRC.COM, LLC by sales of
+ * Teensy and Audio Adaptor boards.  Please support PJRC's efforts to develop
+ * open source software by purchasing Teensy or other PJRC products.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice, development funding notice, and this permission
+ * notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "analyze_peakdetect.h"
+
+// #define PEAKREPORTVERBS
+
+void AudioPeak::update(void)
+{
+	audio_block_t *block;
+	const int16_t *p, *end;
+	block = receiveReadOnly();
+	if (!block) {
+#ifdef PEAKREPORTVERBS
+		Serial.println("AudioPeak !block");
+#endif
+		return;
+	}
+	if (!m_enabled) {
+		release(block);
+		return;
+	}
+	p = block->data;
+	end = p + AUDIO_BLOCK_SAMPLES;
+	do {
+		int16_t d=*p++;
+		if(d<min) min=d;
+		if(d>max) max=d;
+	} while (p < end);
+#ifdef PEAKREPORTVERBS
+	Serial.println("AudioPeak ran");
+#endif
+	release(block);
+}
+
+void AudioPeak::begin(bool noReset)
+{
+	if(!noReset)
+	{
+		min=0;
+		max=0;
+	}
+	m_enabled=true;
+}
+uint16_t AudioPeak::Dpp(void)
+{
+	return max-min;
+}
+

analyze_peakdetect.h

@@ -0,0 +1,50 @@
+/* Audio Library for Teensy 3.X
+ * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
+ *
+ * Development of this audio library was funded by PJRC.COM, LLC by sales of
+ * Teensy and Audio Adaptor boards.  Please support PJRC's efforts to develop
+ * open source software by purchasing Teensy or other PJRC products.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice, development funding notice, and this permission
+ * notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef analyze_peakdetect_h_
+#define analyze_peakdetect_h_
+
+#include "AudioStream.h"
+
+class AudioPeak : public AudioStream
+{
+public:
+	AudioPeak(void) : AudioStream(1, inputQueueArray) { }
+
+	virtual void update(void);
+
+	void begin(bool noReset);
+	void begin(void) { begin(false); }
+	void stop(void) { m_enabled=false; }
+	uint16_t Dpp(void);
+private:
+	audio_block_t *inputQueueArray[1];
+	bool m_enabled;
+	int16_t max;
+	int16_t min;
+};
+
+#endif