core/MsBinaryFile/XlsFile/Format/Binary/CFStreamCacheReader.h

/*
 * (c) Copyright Ascensio System SIA 2010-2023
 *
 * This program is a free software product. You can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License (AGPL)
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 * that Ascensio System SIA expressly excludes the warranty of non-infringement
 * of any third-party rights.
 *
 * This program is distributed WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR  PURPOSE. For
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 */
#pragma once

#include "CFRecordType.h"
#include "BinSmartPointers.h"
#include "../Logic/GlobalWorkbookInfo.h"
#include "../Logic/Biff_structures/ODRAW/OfficeArtRecordHeader.h"
#include "../../../../OOXML/Binary/Presentation/BinaryFileReaderWriter.h"

namespace XLS
{

// The only purpose of the reader is to avoid seeking back through IStream when, for example, 
// we have read a record from a binary stream to the CFRecord, but the record of this type is
// not waitable right at the moment and shall be read a little bit later.
// Example of a construction: 
// PIVOTTH = SXTH *ContinueFrt
// ContinueFrt may appear in the stream and may not. So, this class will increase performance much


class StreamCacheReader
{
public:
	StreamCacheReader(const GlobalWorkbookInfoPtr global_info);
	virtual ~StreamCacheReader();

	// Reads the next CFRecord from the CFStream and if it's type is not the desired one, caches it for the next call
	virtual CFRecordPtr getNextRecord(const CFRecordType::TypeId desirable_type, const bool gen_except = false) = 0;
	// Check if the next read record would be of desired type
	const bool checkNextRecord(const CFRecordType::TypeId desirable_type, const size_t num_records_to_check = 1);
	// Checks whether the next record is Continue and append its data to the real record if so
	virtual void checkAndAppendContinueData() = 0;

	virtual bool isEOF() = 0;
	// Skip the specified number of unsigned chars without processing
	virtual void skipNunBytes(const size_t n) = 0;

	virtual const int GetRecordPosition() { return 0; }
    virtual void SetRecordPosition(const int) {}

	void SkipRecord(bool log_debug = true);
	// Seek to the next substream (Read all records till EOF then skip EOF)
	// Doesn't generate EndOfStreamReached if the stream is the last one
	const bool SeekToEOF(); 
	// Extract the next record from the stream leaving it in the cache for future read.
	// Always call resetPointerToBegin for the extracted CFRecord after using it
	CFRecordPtr touchTheNextRecord();
	// Check the next record type
	const CFRecordType::TypeId getNextRecordType();

	GlobalWorkbookInfoPtr getGlobalWorkbookInfo() { return global_info_; }

	// Make sure the internal buffer has concrete number of records. Returns number of records read
	virtual const size_t readFromStream(const size_t num_of_records_min_necessary) = 0;

	CFRecordPtrList records_cache;
	GlobalWorkbookInfoPtr global_info_;
	std::vector<std::string> skippable_records_names;	
};

class CFStreamCacheReader : public StreamCacheReader
{
public:
	CFStreamCacheReader(CFStreamPtr stream, const GlobalWorkbookInfoPtr global_info);
	virtual ~CFStreamCacheReader();

	virtual CFRecordPtr getNextRecord(const CFRecordType::TypeId desirable_type, const bool gen_except = false);
	virtual void skipNunBytes(const size_t n);
	virtual void checkAndAppendContinueData();
	virtual bool isEOF();
private:
	virtual const size_t readFromStream(const size_t num_of_records_min_necessary);
	CFStreamPtr stream_;
};

class FileStreamCacheReader : public StreamCacheReader
{
public:
	FileStreamCacheReader(const std::wstring &file_name, const GlobalWorkbookInfoPtr global_info);
	virtual ~FileStreamCacheReader();

	virtual CFRecordPtr getNextRecord(const CFRecordType::TypeId desirable_type, const bool gen_except = false);
	virtual void skipNunBytes(const size_t n);
	virtual void checkAndAppendContinueData();
	virtual bool isEOF();
private:
	virtual const size_t readFromStream(const size_t num_of_records_min_necessary);
	NSFile::CFileBinary file_;
};

class BinaryStreamCacheReader : public StreamCacheReader
{
public:
    BinaryStreamCacheReader(boost::shared_ptr<NSBinPptxRW::CBinaryFileReader> binaryStream, const GlobalWorkbookInfoPtr global_info);
    virtual ~BinaryStreamCacheReader();

    CFRecordPtr getNextRecord(const CFRecordType::TypeId desirable_type, const bool gen_except = false) override;
    void skipNunBytes(const size_t n) override;
    void checkAndAppendContinueData() override;
    bool isEOF() override;
private:
    const size_t readFromStream(const size_t num_of_records_min_necessary) override;
    const int GetRecordPosition() override;
    void SetRecordPosition(const int) override;

    boost::shared_ptr<NSBinPptxRW::CBinaryFileReader> binaryStream_;
};
} // namespace XLS