1 files changed, 101 insertions, 11 deletions

diff --git a/library/binary.cpp b/library/binary.cpp
index 409b024a..8b8fd2ec 100644
--- a/library/binary.cpp
+++ b/library/binary.cpp
@@ -5,32 +5,122 @@
 // **************************************************************************
 //
 #include "binary.h"
-#include <boost/scoped_array.hpp>
 #include "../shared/fileIO.h"
+#include <vector>
+#include <wx/stopwatch.h>
 
 
-bool FreeFileSync::filesHaveSameContent(const Zstring& filename1, const Zstring& filename2, CompareCallback& callback)
+inline
+void setMinSize(std::vector<char>& buffer, size_t minSize)
+{
+    if (buffer.size() < minSize) //this is similar to reserve(), but be need a "properly initialized" array here
+        buffer.resize(minSize);
+}
+
+
+namespace
 {
-    const size_t BUFFER_SIZE = 512 * 1024; //512 kb seems to be the perfect buffer size
-    static boost::scoped_array<unsigned char> memory1(new unsigned char[BUFFER_SIZE]);
-    static boost::scoped_array<unsigned char> memory2(new unsigned char[BUFFER_SIZE]);
+class BufferSize
+{
+public:
+    BufferSize() : bufSize(BUFFER_SIZE_START) {}
+
+    void inc()
+    {
+        if (bufSize < BUFFER_SIZE_MAX)
+            bufSize *= 2;
+    }
+
+    void dec()
+    {
+        if (bufSize > BUFFER_SIZE_MIN)
+            bufSize /= 2;
+    }
+
+    operator size_t() const
+    {
+        return bufSize;
+    }
+
+private:
+    static const size_t BUFFER_SIZE_MIN   =       128 * 1024;
+    static const size_t BUFFER_SIZE_START =       512 * 1024; //512 kb seems to be a reasonable initial buffer size
+    static const size_t BUFFER_SIZE_MAX   = 16 * 1024 * 1024;
+
+    /*Tests on Win7 x64 show that buffer size does NOT matter if files are located on different physical disks!
+    Impact of buffer size when files are on same disk:
+
+    buffer  MB/s
+    ------------
+    64      10
+    128     19
+    512     40
+    1024    48
+    2048    56
+    4096    56
+    8192    56
+    */
 
+    size_t bufSize;
+};
+}
+
+
+bool FreeFileSync::filesHaveSameContent(const Zstring& filename1, const Zstring& filename2, CompareCallback& callback)
+{
     FileInput file1(filename1); //throw FileError()
     FileInput file2(filename2); //throw FileError()
 
+    BufferSize bufferSize;
+
+    static std::vector<char> memory1;
+    static std::vector<char> memory2;
+
     wxLongLong bytesCompared;
+
+    wxLongLong lastDelayViolation = wxGetLocalTimeMillis();
+
     do
     {
-        const size_t length1 = file1.read(memory1.get(), BUFFER_SIZE); //returns actual number of bytes read; throw FileError()
-        const size_t length2 = file2.read(memory2.get(), BUFFER_SIZE); //
+        setMinSize(memory1, bufferSize);
+        setMinSize(memory2, bufferSize);
 
-        if (length1 != length2 || ::memcmp(memory1.get(), memory2.get(), length1) != 0)
+        const wxLongLong startTime = wxGetLocalTimeMillis();
+
+        const size_t length1 = file1.read(&memory1[0], bufferSize); //returns actual number of bytes read; throw FileError()
+        const size_t length2 = file2.read(&memory2[0], bufferSize); //
+
+        const wxLongLong stopTime = wxGetLocalTimeMillis();
+
+        //-------- dynamically set buffer size to keep callback interval between 200 - 500ms ---------------------
+        const wxLongLong loopTime = stopTime - startTime;
+        if (loopTime < 200 && stopTime - lastDelayViolation > 2000) //avoid "flipping back": e.g. DVD-Roms read 32MB at once, so first read may be > 300 ms, but second one will be 0ms!
+        {
+            lastDelayViolation = stopTime;
+            bufferSize.inc(); //practically no costs!
+        }
+        else if (loopTime > 500)
+        {
+            lastDelayViolation = stopTime;
+            bufferSize.dec(); //
+        }
+        //------------------------------------------------------------------------------------------------
+
+//#warning
+//        static wxLongLong blorg = wxGetLocalTimeMillis();
+//        if (wxGetLocalTimeMillis() - blorg > 5000)
+//        {
+//            blorg = wxGetLocalTimeMillis();
+//            wxMessageBox(numberToZstring<size_t>(bufferSize).c_str());
+//        }
+
+
+
+        if (length1 != length2 || ::memcmp(&memory1[0], &memory2[0], length1) != 0)
             return false;
 
         bytesCompared += length1 * 2;
-
-        //send progress updates
-        callback.updateCompareStatus(bytesCompared);
+        callback.updateCompareStatus(bytesCompared); //send progress updates
     }
     while (!file1.eof());