Add disabled code to use a cache for cso reading.

It doesn't seem like the cache is worth it, unfortunately.

pcsx2/CDVD/CsoFileReader.cpp

@@ -154,6 +154,9 @@ bool CsoFileReader::InitializeBuffers() {
 
 void CsoFileReader::Close() {
 	m_filename.Empty();
+#if CSO_USE_CHUNKSCACHE
+	m_cache.Clear();
+#endif
 
 	if (m_src) {
 		fclose(m_src);
@@ -193,18 +196,37 @@ int CsoFileReader::ReadSync(void* pBuffer, uint sector, uint count) {
 	int bytes = 0;
 
 	while (remaining > 0) {
-		int readBytes = ReadFromFrame(dest + bytes, pos + bytes, remaining);
-		if (readBytes == 0) {
-			// We hit EOF.
-			break;
+		int readBytes;
+
+#if CSO_USE_CHUNKSCACHE
+		// Try first to read from the cache.
+		readBytes = m_cache.Read(dest + bytes, pos + bytes, remaining);
+#else
+		readBytes = -1;
+#endif
+		if (readBytes < 0) {
+			readBytes = ReadFromFrame(dest + bytes, pos + bytes, remaining);
+			if (readBytes == 0) {
+				// We hit EOF.
+				break;
+			}
+
+#if CSO_USE_CHUNKSCACHE
+			// Add the bytes into the cache.  We need to allocate a buffer for it.
+			void *cached = malloc(readBytes);
+			memcpy(cached, dest + bytes, readBytes);
+			m_cache.Take(cached, pos + bytes, readBytes, readBytes);
+#endif
 		}
+
 		bytes += readBytes;
 		remaining -= readBytes;
 	}
+
 	return bytes;
 }
 
-int CsoFileReader::ReadFromFrame(u8 *dest, u64 pos, u64 maxBytes) {
+int CsoFileReader::ReadFromFrame(u8 *dest, u64 pos, int maxBytes) {
 	if (pos >= m_totalSize) {
 		// Can't read anything passed the end.
 		return 0;

pcsx2/CDVD/CsoFileReader.h

@@ -15,11 +15,23 @@
 
 #pragma once
 
+// Based on testing, the overhead of using this cache is high.
+//
+// The test was done with CSO files using a block size of 16KB.
+// Cache hit rates were observed in the range of 25%.
+// Cache overhead added 35% to the overall read time.
+//
+// For this reason, it's currently disabled.
+#define CSO_USE_CHUNKSCACHE 0
+
 #include "AsyncFileReader.h"
+#include "ChunksCache.h"
 
 struct CsoHeader;
 typedef struct z_stream_s z_stream;
 
+static const uint CSO_CHUNKCACHE_SIZE_MB = 200;
+
 class CsoFileReader : public AsyncFileReader
 {
 	DeclareNoncopyableObject(CsoFileReader);
@@ -31,6 +43,9 @@ public:
 		m_totalSize(0),
 		m_src(0),
 		m_z_stream(0),
+#if CSO_USE_CHUNKSCACHE
+		m_cache(CSO_CHUNKCACHE_SIZE_MB),
+#endif
 		m_bytesRead(0) {
 		m_blocksize = 2048;
 	};
@@ -59,7 +74,7 @@ private:
 	static bool ValidateHeader(const CsoHeader& hdr);
 	bool ReadFileHeader();
 	bool InitializeBuffers();
-	int ReadFromFrame(u8 *dest, u64 pos, u64 maxBytes);
+	int ReadFromFrame(u8 *dest, u64 pos, int maxBytes);
 	bool DecompressFrame(u32 frame, u32 readBufferSize);
 
 	u32 m_frameSize;
@@ -73,6 +88,11 @@ private:
 	// The actual source cso file handle.
 	FILE* m_src;
 	z_stream* m_z_stream;
+
+#if CSO_USE_CHUNKSCACHE
+	ChunksCache m_cache;
+#endif
+
 	// The result of a read is stored here between BeginRead() and FinishRead().
 	int m_bytesRead;
 };