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qpdf/include/qpdf/ClosedFileInputSource.hh

78 lines
2.6 KiB
C++

// Copyright (c) 2005-2023 Jay Berkenbilt
//
// This file is part of qpdf.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
// in compliance with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
// or implied. See the License for the specific language governing permissions and limitations under
// the License.
//
// Versions of qpdf prior to version 7 were released under the terms of version 2.0 of the Artistic
// License. At your option, you may continue to consider qpdf to be licensed under those terms.
// Please see the manual for additional information.
#ifndef QPDF_CLOSEDFILEINPUTSOURCE_HH
#define QPDF_CLOSEDFILEINPUTSOURCE_HH
// This is an input source that reads from files, like FileInputSource, except that it opens and
// closes the file surrounding every operation. This decreases efficiency, but it allows many more
// of these to exist at once than the maximum number of open file descriptors. This is used for
// merging large numbers of files.
#include <qpdf/InputSource.hh>
#include <qpdf/PointerHolder.hh> // unused -- remove in qpdf 12 (see #785)
#include <memory>
class FileInputSource;
class QPDF_DLL_CLASS ClosedFileInputSource: public InputSource
{
public:
QPDF_DLL
ClosedFileInputSource(char const* filename);
QPDF_DLL
~ClosedFileInputSource() override;
QPDF_DLL
qpdf_offset_t findAndSkipNextEOL() override;
QPDF_DLL
std::string const& getName() const override;
QPDF_DLL
qpdf_offset_t tell() override;
QPDF_DLL
void seek(qpdf_offset_t offset, int whence) override;
QPDF_DLL
void rewind() override;
QPDF_DLL
size_t read(char* buffer, size_t length) override;
QPDF_DLL
void unreadCh(char ch) override;
// The file stays open between calls to stayOpen(true) and stayOpen(false). You can use this to
// surround multiple operations on a single ClosedFileInputSource to reduce the overhead of a
// separate open/close on each call.
QPDF_DLL
void stayOpen(bool);
private:
ClosedFileInputSource(ClosedFileInputSource const&) = delete;
ClosedFileInputSource& operator=(ClosedFileInputSource const&) = delete;
QPDF_DLL_PRIVATE
void before();
QPDF_DLL_PRIVATE
void after();
std::string filename;
qpdf_offset_t offset;
std::shared_ptr<FileInputSource> fis;
bool stay_open;
};
#endif // QPDF_CLOSEDFILEINPUTSOURCE_HH