From 895b942df3aaa574d34e23ea2cde6bfcaf9c31f4 Mon Sep 17 00:00:00 2001
From: Daniel Wolf <dwolf@dannad.de>
Date: Tue, 19 Apr 2016 22:04:43 +0200
Subject: [PATCH] Implemented AudioStreamSegment

---
 CMakeLists.txt                   |  1 +
 src/audio/AudioStreamSegment.cpp | 50 ++++++++++++++++++++++++++++++++
 src/audio/AudioStreamSegment.h   | 21 ++++++++++++++
 3 files changed, 72 insertions(+)
 create mode 100644 src/audio/AudioStreamSegment.cpp
 create mode 100644 src/audio/AudioStreamSegment.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4b69f82..3cfe336 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -103,6 +103,7 @@ set(SOURCE_FILES
 	src/platformTools.cpp src/platformTools.h
 	src/tools.cpp src/tools.h
 	src/audio/AudioStream.cpp src/audio/AudioStream.h
+	src/audio/AudioStreamSegment.cpp src/audio/AudioStreamSegment.h
 	src/audio/DCOffset.cpp src/audio/DCOffset.h
 	src/audio/SampleRateConverter.cpp src/audio/SampleRateConverter.h
 	src/audio/UnboundedStream.cpp src/audio/UnboundedStream.h
diff --git a/src/audio/AudioStreamSegment.cpp b/src/audio/AudioStreamSegment.cpp
new file mode 100644
index 0000000..e9dc91f
--- /dev/null
+++ b/src/audio/AudioStreamSegment.cpp
@@ -0,0 +1,50 @@
+#include "AudioStreamSegment.h"
+#include <stdexcept>
+
+AudioStreamSegment::AudioStreamSegment(std::unique_ptr<AudioStream> audioStream, const TimeRange& range) :
+	audioStream(std::move(audioStream))
+{
+	sampleOffset = range.getStart().count() * this->audioStream->getSampleRate() / 100;
+	sampleCount = range.getLength().count() * this->audioStream->getSampleRate() / 100;
+	seek(0);
+
+	if (sampleOffset < 0 || sampleOffset + sampleCount > this->audioStream->getSampleCount()) {
+		throw std::invalid_argument("Segment extends beyond input stream.");
+	}
+}
+
+AudioStreamSegment::AudioStreamSegment(const AudioStreamSegment& rhs, bool reset) :
+	audioStream(rhs.audioStream->clone(false)),
+	sampleOffset(rhs.sampleOffset),
+	sampleCount(rhs.sampleCount)
+{
+	if (reset) seek(0);
+}
+
+std::unique_ptr<AudioStream> AudioStreamSegment::clone(bool reset) const {
+	return std::make_unique<AudioStreamSegment>(*this, reset);
+}
+
+int AudioStreamSegment::getSampleRate() const {
+	return audioStream->getSampleRate();
+}
+
+int AudioStreamSegment::getSampleCount() const {
+	return sampleCount;
+}
+
+int AudioStreamSegment::getSampleIndex() const {
+	return audioStream->getSampleIndex() - sampleOffset;
+}
+
+void AudioStreamSegment::seek(int sampleIndex) {
+	audioStream->seek(sampleIndex + sampleOffset);
+}
+
+float AudioStreamSegment::readSample() {
+	return audioStream->readSample();
+}
+
+std::unique_ptr<AudioStream> createSegment(std::unique_ptr<AudioStream> audioStream, const TimeRange& range) {
+	return std::make_unique<AudioStreamSegment>(std::move(audioStream), range);
+}
diff --git a/src/audio/AudioStreamSegment.h b/src/audio/AudioStreamSegment.h
new file mode 100644
index 0000000..c2df40f
--- /dev/null
+++ b/src/audio/AudioStreamSegment.h
@@ -0,0 +1,21 @@
+#pragma once
+#include <audio/AudioStream.h>
+#include <TimeRange.h>
+
+class AudioStreamSegment : public AudioStream {
+public:
+	AudioStreamSegment(std::unique_ptr<AudioStream> audioStream, const TimeRange& range);
+	AudioStreamSegment(const AudioStreamSegment& rhs, bool reset);
+	std::unique_ptr<AudioStream> clone(bool reset) const override;
+	int getSampleRate() const override;
+	int getSampleCount() const override;
+	int getSampleIndex() const override;
+	void seek(int sampleIndex) override;
+	float readSample() override;
+
+private:
+	std::unique_ptr<AudioStream> audioStream;
+	int sampleOffset, sampleCount;
+};
+
+std::unique_ptr<AudioStream> createSegment(std::unique_ptr<AudioStream> audioStream, const TimeRange& range);