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-rw-r--r--zen/zlib_wrap.h94
1 files changed, 8 insertions, 86 deletions
diff --git a/zen/zlib_wrap.h b/zen/zlib_wrap.h
index 41d7428a..d672707b 100644
--- a/zen/zlib_wrap.h
+++ b/zen/zlib_wrap.h
@@ -7,7 +7,7 @@
#ifndef ZLIB_WRAP_H_428597064566
#define ZLIB_WRAP_H_428597064566
-#include "serialize.h"
+#include <functional>
#include "sys_error.h"
@@ -16,21 +16,21 @@ namespace zen
// 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 SysError
+std::string compress(const std::string_view& stream, int level); //throw SysError
//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 SysError
+std::string decompress(const std::string_view& stream); //throw SysError
class InputStreamAsGzip //convert input stream into gzip on the fly
{
public:
- explicit InputStreamAsGzip( //throw SysError
- const std::function<size_t(void* buffer, size_t bytesToRead)>& readBlock /*throw X; returning 0 signals EOF: Posix read() semantics*/);
+ explicit InputStreamAsGzip(const std::function<size_t(void* buffer, size_t bytesToRead)>& tryReadBlock /*throw X; may return short, only 0 means EOF!*/,
+ size_t blockSize); //throw SysError
~InputStreamAsGzip();
+ size_t getBlockSize() const;
+
size_t read(void* buffer, size_t bytesToRead); //throw SysError, X; return "bytesToRead" bytes unless end of stream!
private:
@@ -38,85 +38,7 @@ private:
const std::unique_ptr<Impl> pimpl_;
};
-std::string compressAsGzip(const void* buffer, size_t bufSize); //throw SysError
-
-
-
-
-
-
-//######################## 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 SysError
-size_t zlib_decompress(const void* src, size_t srcLen, void* trg, size_t trgLen); //throw SysError
-}
-
-
-template <class BinContainer>
-BinContainer compress(const BinContainer& stream, int level) //throw SysError
-{
- BinContainer contOut;
- if (!stream.empty()) //don't dereference iterator into empty container!
- {
- //save uncompressed stream size for decompression
- const uint64_t uncompressedSize = stream.size(); //use portable number type!
- contOut.resize(sizeof(uncompressedSize));
- std::memcpy(&contOut[0], &uncompressedSize, sizeof(uncompressedSize));
-
- 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 SysError
- 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 SysError
-{
- BinContainer contOut;
- if (!stream.empty()) //don't dereference iterator into empty container!
- {
- //retrieve size of uncompressed data
- uint64_t uncompressedSize = 0; //use portable number type!
- if (stream.size() < sizeof(uncompressedSize))
- throw SysError(L"zlib error: stream size < 8");
-
- std::memcpy(&uncompressedSize, &*stream.begin(), sizeof(uncompressedSize));
-
- //attention: contOut MUST NOT be empty! Else it will pass a nullptr to zlib_decompress() => Z_STREAM_ERROR although "uncompressedSize == 0"!!!
- //secondary bug: don't dereference iterator into empty container!
- if (uncompressedSize == 0) //cannot be 0: compress() directly maps empty -> empty container skipping zlib!
- throw SysError(L"zlib error: uncompressed size == 0");
-
- try
- {
- contOut.resize(static_cast<size_t>(uncompressedSize)); //throw std::bad_alloc
- }
- //most likely this is due to data corruption:
- catch (const std::length_error& e) { throw SysError(L"zlib error: " + _("Out of memory.") + L' ' + utfTo<std::wstring>(e.what())); }
- catch (const std::bad_alloc& e) { throw SysError(L"zlib error: " + _("Out of memory.") + L' ' + utfTo<std::wstring>(e.what())); }
-
- const size_t bytesWritten = impl::zlib_decompress(&*stream.begin() + sizeof(uncompressedSize),
- stream.size() - sizeof(uncompressedSize),
- &*contOut.begin(),
- static_cast<size_t>(uncompressedSize)); //throw SysError
- if (bytesWritten != static_cast<size_t>(uncompressedSize))
- throw SysError(formatSystemError("zlib_decompress", L"", L"bytes written != uncompressed size."));
- }
- return contOut;
-}
+std::string compressAsGzip(const std::string_view& stream); //throw SysError
}
#endif //ZLIB_WRAP_H_428597064566
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