pdfparse.hxx

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#ifndef INCLUDED_SDEXT_SOURCE_PDFIMPORT_INC_PDFPARSE_HXX
#define INCLUDED_SDEXT_SOURCE_PDFIMPORT_INC_PDFPARSE_HXX
 
#include <sal/types.h>
#include <rtl/ustring.hxx>
#include <rtl/string.hxx>
 
#include <string_view>
#include <unordered_map>
#include <utility>
#include <vector>
#include <memory>
 
namespace pdfparse
{
 
struct EmitImplData;
struct PDFContainer;
class EmitContext
{
public:
    virtual bool write( const void* pBuf, unsigned int nLen ) = 0;
    virtual unsigned int getCurPos() = 0;
    virtual bool copyOrigBytes( unsigned int nOrigOffset, unsigned int nLen ) = 0;
    virtual unsigned int readOrigBytes( unsigned int nOrigOffset, unsigned int nLen, void* pBuf ) = 0;
 
    explicit EmitContext( const PDFContainer* pTop = nullptr );
    virtual ~EmitContext();
 
    // set this to deflate contained streams
    bool m_bDeflate;
    // set this to decrypt the PDF file
    bool m_bDecrypt;
 
private:
    friend struct PDFEntry;
    std::unique_ptr<EmitImplData> m_pImplData;
};
 
struct PDFEntry
{
    PDFEntry() {}
    virtual ~PDFEntry();
 
    virtual bool emit( EmitContext& rWriteContext ) const = 0;
    virtual PDFEntry* clone() const = 0;
 
protected:
    static EmitImplData* getEmitData( EmitContext const & rContext );
    static void setEmitData( EmitContext& rContext, EmitImplData* pNewEmitData );
};
 
struct PDFComment final : public PDFEntry
{
    OString  m_aComment;
 
    explicit PDFComment( OString aComment )
    : PDFEntry(), m_aComment(std::move( aComment )) {}
    virtual ~PDFComment() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
};
 
struct PDFValue : public PDFEntry
{
    // abstract base class for simple values
    PDFValue() : PDFEntry() {}
    virtual ~PDFValue() override;
};
 
struct PDFName final : public PDFValue
{
    OString  m_aName;
 
    explicit PDFName( OString aName )
    : PDFValue(), m_aName(std::move( aName )) {}
    virtual ~PDFName() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
 
    OUString getFilteredName() const;
};
 
struct PDFString final : public PDFValue
{
    OString  m_aString;
 
    explicit PDFString( OString aString )
    : PDFValue(), m_aString(std::move( aString )) {}
    virtual ~PDFString() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
 
    OString getFilteredString() const;
};
 
struct PDFNumber final : public PDFValue
{
    double m_fValue;
 
    explicit PDFNumber( double fVal )
    : PDFValue(), m_fValue( fVal ) {}
    virtual ~PDFNumber() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
};
 
struct PDFBool final : public PDFValue
{
    bool m_bValue;
 
    explicit PDFBool( bool bVal )
    : PDFValue(), m_bValue( bVal ) {}
    virtual ~PDFBool() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
};
 
struct PDFObjectRef final : public PDFValue
{
    unsigned int    m_nNumber;
    unsigned int    m_nGeneration;
 
    PDFObjectRef( unsigned int nNr, unsigned int nGen )
    : PDFValue(), m_nNumber( nNr ), m_nGeneration( nGen ) {}
    virtual ~PDFObjectRef() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
};
 
struct PDFNull final : public PDFValue
{
    PDFNull() {}
    virtual ~PDFNull() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
};
 
struct PDFObject;
struct PDFContainer : public PDFEntry
{
    sal_Int32              m_nOffset;
    std::vector<std::unique_ptr<PDFEntry>> m_aSubElements;
 
    // this is an abstract base class for identifying
    // entries that can contain sub elements besides comments
    PDFContainer() : PDFEntry(), m_nOffset( 0 ) {}
    virtual ~PDFContainer() override;
    bool emitSubElements( EmitContext& rWriteContext ) const;
    void cloneSubElements( std::vector<std::unique_ptr<PDFEntry>>& rNewSubElements ) const;
 
    PDFObject* findObject( unsigned int nNumber, unsigned int nGeneration ) const;
    PDFObject* findObject( PDFObjectRef const * pRef ) const
    { return findObject( pRef->m_nNumber, pRef->m_nGeneration ); }
};
 
struct PDFArray final : public PDFContainer
{
    PDFArray() {}
    virtual ~PDFArray() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
};
 
struct PDFDict final : public PDFContainer
{
    typedef std::unordered_map<OString,PDFEntry*> Map;
    Map m_aMap;
 
    PDFDict() {}
    virtual ~PDFDict() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
 
    // inserting a value of NULL will remove rName and the previous value
    // from the dictionary
    void insertValue( const OString& rName, std::unique_ptr<PDFEntry> pValue );
    // removes a name/value pair from the dict
    void eraseValue( std::string_view rName );
    // builds new map as of sub elements
    // returns NULL if successful, else the first offending element
    PDFEntry* buildMap();
};
 
struct PDFStream final : public PDFEntry
{
    unsigned int    m_nBeginOffset;
    unsigned int    m_nEndOffset; // offset of the byte after the stream
    PDFDict*        m_pDict;
 
    PDFStream( unsigned int nBegin, unsigned int nEnd, PDFDict* pStreamDict )
    : PDFEntry(), m_nBeginOffset( nBegin ), m_nEndOffset( nEnd ), m_pDict( pStreamDict ) {}
    virtual ~PDFStream() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
 
    unsigned int getDictLength( const PDFContainer* pObjectContainer ) const; // get contents of the "Length" entry of the dict
};
 
struct PDFTrailer final : public PDFContainer
{
    PDFDict*        m_pDict;
 
    PDFTrailer() : PDFContainer(), m_pDict( nullptr ) {}
    virtual ~PDFTrailer() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
};
 
struct PDFFileImplData;
struct PDFFile final : public PDFContainer
{
private:
    mutable std::unique_ptr<PDFFileImplData> m_pData;
    PDFFileImplData*            impl_getData() const;
public:
    unsigned int        m_nMajor;           // PDF major
    unsigned int        m_nMinor;           // PDF minor
 
    PDFFile();
    virtual ~PDFFile() override;
 
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
 
    bool isEncrypted() const;
 
    bool usesSupportedEncryptionFormat() const;
 
    // this method checks whether rPwd is compatible with
    // either user or owner password and sets up decrypt data in that case
    // returns true if decryption can be done
    bool setupDecryptionData( const OString& rPwd ) const;
 
    bool decrypt( const sal_uInt8* pInBuffer, sal_uInt32 nLen,
                  sal_uInt8* pOutBuffer,
                  unsigned int nObject, unsigned int nGeneration ) const;
};
 
struct PDFObject final : public PDFContainer
{
    PDFEntry*       m_pObject;
    PDFStream*      m_pStream;
    unsigned int    m_nNumber;
    unsigned int    m_nGeneration;
 
    PDFObject( unsigned int nNr, unsigned int nGen )
    : m_pObject( nullptr ), m_pStream( nullptr ), m_nNumber( nNr ), m_nGeneration( nGen ) {}
    virtual ~PDFObject() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
 
    // writes only the contained stream, deflated if necessary
    void writeStream( EmitContext& rContext, const PDFFile* pPDFFile ) const;
 
private:
    // returns true if stream is deflated
    // fills *ppStream and *pBytes with start of stream and count of bytes
    // memory returned in *ppStream must be freed with std::free afterwards
    // fills in NULL and 0 in case of error
    bool getDeflatedStream( std::unique_ptr<char[]>& rpStream, unsigned int* pBytes, const PDFContainer* pObjectContainer, EmitContext& rContext ) const;
};
 
struct PDFPart final : public PDFContainer
{
    PDFPart() : PDFContainer() {}
    virtual ~PDFPart() override;
    virtual bool emit( EmitContext& rWriteContext ) const override;
    virtual PDFEntry* clone() const override;
};
 
struct PDFReader
{
    PDFReader() = delete;
 
    static std::unique_ptr<PDFEntry> read( const char* pFileName );
#ifdef _WIN32
    static std::unique_ptr<PDFEntry> read( const char* pBuffer, unsigned int nLen );
#endif
};
 
} // namespace
 
#endif
 
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