Use stable_vector for AudioProviderRam's cache

stable_vector allocates its elements non-contiguously (as is required
for stability), while still giving O(1) indexing.

aegisub/libaegisub/lagi_pre.h

@@ -28,6 +28,11 @@
 #endif
 
 // Common C++
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable:4996)
+#endif
+
 #include <algorithm>
 #include <deque>
 #include <fstream>
@@ -47,6 +52,9 @@
 #include <tuple>
 #include <vector>
 
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
 
 // Boost
 #include <boost/container/list.hpp>

aegisub/src/audio_provider_ram.cpp

@@ -44,33 +44,22 @@
 #include <libaegisub/background_runner.h>
 #include <libaegisub/scoped_ptr.h>
 
-#define CacheBits ((22))
+#define CacheBits 22
+#define CacheBlockSize (1 << CacheBits)
 
-#define CacheBlockSize ((1 << CacheBits))
-
-RAMAudioProvider::RAMAudioProvider(AudioProvider *src, agi::BackgroundRunner *br) {
+RAMAudioProvider::RAMAudioProvider(AudioProvider *src, agi::BackgroundRunner *br)
+{
 	agi::scoped_ptr<AudioProvider> source(src);
 
-	samples_native_endian = source->AreSamplesNativeEndian();
-
-	// Allocate cache
-	int64_t ssize = source->GetNumSamples() * source->GetBytesPerSample();
-	blockcount = (ssize + CacheBlockSize - 1) >> CacheBits;
-	blockcache = new char*[blockcount];
-	memset(blockcache, 0, blockcount * sizeof(char*));
-
-	// Allocate cache blocks
 	try {
-		for (int i = 0; i < blockcount; i++) {
-			blockcache[i] = new char[std::min<size_t>(CacheBlockSize, ssize - i * CacheBlockSize)];
-		}
+		blockcache.resize((src->GetNumSamples() * src->GetBytesPerSample() + CacheBlockSize - 1) >> CacheBits);
 	}
 	catch (std::bad_alloc const&) {
-		Clear();
 		throw agi::AudioCacheOpenError("Couldn't open audio, not enough ram available.", 0);
 	}
 
 	// Copy parameters
+	samples_native_endian = source->AreSamplesNativeEndian();
 	bytes_per_sample = source->GetBytesPerSample();
 	num_samples = source->GetNumSamples();
 	channels = source->GetChannels();
@@ -81,47 +70,30 @@ RAMAudioProvider::RAMAudioProvider(AudioProvider *src, agi::BackgroundRunner *br
 	br->Run(std::bind(&RAMAudioProvider::FillCache, this, src, std::placeholders::_1));
 }
 
-RAMAudioProvider::~RAMAudioProvider() {
-	Clear();
-}
-
 void RAMAudioProvider::FillCache(AudioProvider *source, agi::ProgressSink *ps) {
 	ps->SetMessage(STD_STR(_("Reading into RAM")));
 
 	int64_t readsize = CacheBlockSize / source->GetBytesPerSample();
-	for (int i = 0; i < blockcount; i++) {
-		source->GetAudio((char*)blockcache[i], i * readsize, std::min(readsize, num_samples - i * readsize));
+	for (size_t i = 0; i < blockcache.size(); i++) {
+		source->GetAudio(&blockcache[i][0], i * readsize, std::min(readsize, num_samples - i * readsize));
 
-		ps->SetProgress(i, (blockcount - 1));
+		ps->SetProgress(i, blockcache.size() - 1);
 		if (ps->IsCancelled()) {
-			Clear();
 			return;
 		}
 	}
 }
 
-void RAMAudioProvider::Clear() {
-	// Free ram cache
-	if (blockcache) {
-		for (int i = 0; i < blockcount; i++) {
-			delete [] blockcache[i];
-		}
-		delete [] blockcache;
-	}
-}
-
 void RAMAudioProvider::FillBuffer(void *buf, int64_t start, int64_t count) const {
-	// Prepare copy
-	char *charbuf = (char *)buf;
+	char *charbuf = static_cast<char *>(buf);
 	int i = (start * bytes_per_sample) >> CacheBits;
 	int start_offset = (start * bytes_per_sample) & (CacheBlockSize-1);
 	int64_t bytesremaining = count * bytes_per_sample;
 
-	// Copy
 	while (bytesremaining) {
 		int readsize = std::min<int>(bytesremaining, CacheBlockSize - start_offset);
 
-		memcpy(charbuf,(char *)(blockcache[i++]+start_offset),readsize);
+		memcpy(charbuf, &blockcache[i++][start_offset], readsize);
 
 		charbuf += readsize;
 

aegisub/src/audio_provider_ram.h

@@ -34,23 +34,22 @@
 
 #include "include/aegisub/audio_provider.h"
 
+#include <boost/container/stable_vector.hpp>
+
 namespace agi {
 	class BackgroundRunner;
 	class ProgressSink;
 }
 
 class RAMAudioProvider : public AudioProvider {
-	char** blockcache;
-	int blockcount;
+	boost::container::stable_vector<char[1 << 22]> blockcache;
 	bool samples_native_endian;
 
-	void Clear();
 	void FillCache(AudioProvider *source, agi::ProgressSink *ps);
 	void FillBuffer(void *buf, int64_t start, int64_t count) const;
 
 public:
 	RAMAudioProvider(AudioProvider *source, agi::BackgroundRunner *br);
-	~RAMAudioProvider();
 
 	bool AreSamplesNativeEndian() const { return samples_native_endian; }
 };

aegisub/src/include/aegisub/audio_provider.h

@@ -68,6 +68,8 @@ public:
 	bool AreSamplesFloat() const  { return float_samples; }
 	virtual bool AreSamplesNativeEndian() const = 0;
 
+	virtual int64_t GetSamplesLoaded() const { return num_samples; }
+
 	/// @brief Does this provider benefit from external caching?
 	virtual bool NeedsCache() const { return false; }
 };