1 files changed, 115 insertions, 0 deletions
diff --git a/wx+/zlib_wrap.h b/wx+/zlib_wrap.h
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+++ b/wx+/zlib_wrap.h
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+// **************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under *
+// * GNU General Public License: http://www.gnu.org/licenses/gpl.html       *
+// * Copyright (C) ZenJu (zhnmju123 AT gmx DOT de) - All Rights Reserved    *
+// **************************************************************************
+
+#ifndef SIMPLE_H_INCLUDED_18134135134135345489
+#define SIMPLE_H_INCLUDED_18134135134135345489
+
+#include <wx+/serialize.h>
+
+namespace zen
+{
+class ZlibInternalError {};
+
+// compression level must be between 0 and 9:
+// 0: no compression
+// 9: best compression
+template <class BinContainer> //as specified in serialize.h
+BinContainer compress(const BinContainer& stream, int level); //throw ZlibInternalError
+//caveat: output stream is physically larger than input! => strip additional reserved space if needed: "BinContainer(output.begin(), output.end())"
+
+template <class BinContainer>
+BinContainer decompress(const BinContainer& stream);          //throw ZlibInternalError
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+//######################## implementation ##########################
+namespace impl
+{
+size_t zlib_compressBound(size_t len);
+size_t zlib_compress  (const void* src, size_t srcLen, void* trg, size_t trgLen, int level); //throw ZlibInternalError
+size_t zlib_decompress(const void* src, size_t srcLen, void* trg, size_t trgLen);            //throw ZlibInternalError
+}
+
+
+template <class BinContainer>
+BinContainer compress(const BinContainer& stream, int level) //throw ZlibInternalError
+{
+    BinContainer contOut;
+
+    //save uncompressed stream size for decompression
+    const std::uint64_t uncompressedSize = stream.size(); //use portable number type!
+    contOut.resize(sizeof(uncompressedSize));
+    std::copy(reinterpret_cast<const char*>(&uncompressedSize),
+              reinterpret_cast<const char*>(&uncompressedSize) + sizeof(uncompressedSize),
+              &*contOut.begin());
+
+    const size_t bufferEstimate = impl::zlib_compressBound(stream.size()); //upper limit for buffer size, larger than input size!!!
+
+    contOut.resize(contOut.size() + bufferEstimate);
+
+    const size_t bytesWritten = impl::zlib_compress(&*stream.begin(),
+                                                    stream.size(),
+                                                    &*contOut.begin() + contOut.size() - bufferEstimate,
+                                                    bufferEstimate,
+                                                    level); //throw ZlibInternalError
+    if (bytesWritten < bufferEstimate)
+        contOut.resize(contOut.size() - (bufferEstimate - bytesWritten)); //caveat: unsigned arithmetics
+    //caveat: physical memory consumption still *unchanged*!
+
+    return contOut;
+}
+
+
+template <class BinContainer>
+BinContainer decompress(const BinContainer& stream) //throw ZlibInternalError
+{
+    //retrieve size of uncompressed data
+    std::uint64_t uncompressedSize = 0; //use portable number type!
+    if (stream.size() < sizeof(uncompressedSize))
+        throw ZlibInternalError();
+    std::copy(&*stream.begin(),
+              &*stream.begin() + sizeof(uncompressedSize),
+              reinterpret_cast<char*>(&uncompressedSize));
+
+    BinContainer contOut;
+    try
+    {
+        contOut.resize(uncompressedSize); //throw std::bad_alloc
+    }
+    catch (std::bad_alloc&) //most likely due to data corruption!
+    {
+        throw ZlibInternalError();
+    }
+
+    const size_t bytesWritten = impl::zlib_decompress(&*stream.begin() + sizeof(uncompressedSize),
+                                                      stream.size() - sizeof(uncompressedSize),
+                                                      &*contOut.begin(),
+                                                      uncompressedSize); //throw ZlibInternalError
+    if (bytesWritten != uncompressedSize)
+        throw ZlibInternalError();
+
+    return contOut;
+}
+}
+
+#endif //SIMPLE_H_INCLUDED_18134135134135345489