v 14.6

FreeFileSync/Source/base/binary.cpp

@@ -0,0 +1,79 @@
+// *****************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under    *
+// * GNU General Public License: https://www.gnu.org/licenses/gpl-3.0          *
+// * Copyright (C) Zenju (zenju AT freefilesync DOT org) - All Rights Reserved *
+// *****************************************************************************
+
+#include "binary.h"
+
+using namespace zen;
+using namespace fff;
+using AFS = AbstractFileSystem;
+
+
+bool fff::filesHaveSameContent(const AbstractPath& filePath1, const AbstractPath& filePath2, const IoCallback& notifyUnbufferedIO /*throw X*/) //throw FileError, X
+{
+    int64_t totalBytesNotified = 0;
+    IoCallback /*[!] as expected by InputStream::tryRead()*/ notifyIoDiv = IOCallbackDivider(notifyUnbufferedIO, totalBytesNotified);
+
+    const std::unique_ptr<AFS::InputStream> stream1 = AFS::getInputStream(filePath1); //throw FileError
+    const std::unique_ptr<AFS::InputStream> stream2 = AFS::getInputStream(filePath2); //
+
+    const size_t blockSize1 = stream1->getBlockSize(); //throw FileError
+    const size_t blockSize2 = stream2->getBlockSize(); //
+
+    const size_t bufCapacity = blockSize2 - 1 + blockSize1 + blockSize2;
+
+    const std::unique_ptr<std::byte[]> buf(new std::byte[bufCapacity]);
+
+    std::byte* const buf1 = buf.get() + blockSize2; //capacity: blockSize2 - 1 + blockSize1
+    std::byte* const buf2 = buf.get();              //capacity: blockSize2
+
+    size_t buf1PosEnd = 0;
+    for (;;)
+    {
+        const size_t bytesRead1 = stream1->tryRead(buf1 + buf1PosEnd, blockSize1, notifyIoDiv); //throw FileError, X; may return short; only 0 means EOF
+
+        if (bytesRead1 == 0) //end of file
+        {
+            size_t buf1Pos = 0;
+            while (buf1Pos < buf1PosEnd)
+            {
+                const size_t bytesRead2 = stream2->tryRead(buf2, blockSize2, notifyIoDiv); //throw FileError, X; may return short; only 0 means EOF
+
+                if (bytesRead2 == 0 ||//end of file
+                    bytesRead2 > buf1PosEnd - buf1Pos)
+                    return false;
+
+                if (std::memcmp(buf1 + buf1Pos, buf2, bytesRead2) != 0)
+                    return false;
+
+                buf1Pos += bytesRead2;
+            }
+            return stream2->tryRead(buf2, blockSize2, notifyIoDiv) == 0; //throw FileError, X; expect EOF
+        }
+        else
+        {
+            buf1PosEnd += bytesRead1;
+
+            size_t buf1Pos = 0;
+            while (buf1PosEnd - buf1Pos >= blockSize2)
+            {
+                const size_t bytesRead2 = stream2->tryRead(buf2, blockSize2, notifyIoDiv); //throw FileError, X; may return short; only 0 means EOF
+
+                if (bytesRead2 == 0) //end of file
+                    return false;
+
+                if (std::memcmp(buf1 + buf1Pos, buf2, bytesRead2) != 0)
+                    return false;
+
+                buf1Pos += bytesRead2;
+            }
+            if (buf1Pos > 0)
+            {
+                buf1PosEnd -= buf1Pos;
+                std::memmove(buf1, buf1 + buf1Pos, buf1PosEnd);
+            }
+        }
+    }
+}