150 lines
3.4 KiB
C++
150 lines
3.4 KiB
C++
// Data reader interface for uniform access
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// File_Extractor 0.4.0
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#ifndef DATA_READER_H
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#define DATA_READER_H
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#include "blargg_common.h"
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#ifdef HAVE_ZLIB_H
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#include <zlib.h>
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#endif
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// Supports reading and finding out how many bytes are remaining
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class Data_Reader {
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public:
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virtual ~Data_Reader() { }
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static const char eof_error []; // returned by read() when request goes beyond end
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// Read at most count bytes and return number actually read, or <= 0 if error
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virtual long read_avail( void*, long n ) = 0;
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// Read exactly count bytes and return error if they couldn't be read
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virtual blargg_err_t read( void*, long count );
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// Number of bytes remaining until end of file
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virtual long remain() const = 0;
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// Read and discard count bytes
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virtual blargg_err_t skip( long count );
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public:
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Data_Reader() { }
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typedef blargg_err_t error_t; // deprecated
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private:
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// noncopyable
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Data_Reader( const Data_Reader& );
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Data_Reader& operator = ( const Data_Reader& );
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};
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// Supports seeking in addition to Data_Reader operations
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class File_Reader : public Data_Reader {
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public:
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// Size of file
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virtual long size() const = 0;
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// Current position in file
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virtual long tell() const = 0;
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// Go to new position
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virtual blargg_err_t seek( long ) = 0;
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long remain() const;
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blargg_err_t skip( long n );
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};
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// Disk file reader
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class Std_File_Reader : public File_Reader {
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public:
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blargg_err_t open( const char* path );
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void close();
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public:
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Std_File_Reader();
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~Std_File_Reader();
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long size() const;
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blargg_err_t read( void*, long );
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long read_avail( void*, long );
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long tell() const;
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blargg_err_t seek( long );
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private:
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void* file_; // Either FILE* or zlib's gzFile
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#ifdef HAVE_ZLIB_H
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long size_; // TODO: Fix ABI compat
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#endif /* HAVE_ZLIB_H */
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};
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// Treats range of memory as a file
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class Mem_File_Reader : public File_Reader {
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public:
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Mem_File_Reader( const void*, long size );
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#ifdef HAVE_ZLIB_H
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~Mem_File_Reader( );
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#endif /* HAVE_ZLIB_H */
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public:
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long size() const;
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long read_avail( void*, long );
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long tell() const;
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blargg_err_t seek( long );
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private:
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#ifdef HAVE_ZLIB_H
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bool gz_decompress();
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#endif /* HAVE_ZLIB_H */
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const char* m_begin;
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long m_size;
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long m_pos;
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#ifdef HAVE_ZLIB_H
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bool m_ownedPtr = false; // set if we must free m_begin
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#endif /* HAVE_ZLIB_H */
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};
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// Makes it look like there are only count bytes remaining
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class Subset_Reader : public Data_Reader {
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public:
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Subset_Reader( Data_Reader*, long count );
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public:
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long remain() const;
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long read_avail( void*, long );
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private:
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Data_Reader* in;
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long remain_;
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};
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// Joins already-read header and remaining data into original file (to avoid seeking)
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class Remaining_Reader : public Data_Reader {
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public:
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Remaining_Reader( void const* header, long size, Data_Reader* );
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public:
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long remain() const;
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long read_avail( void*, long );
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blargg_err_t read( void*, long );
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private:
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char const* header;
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char const* header_end;
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Data_Reader* in;
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long read_first( void* out, long count );
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};
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// Invokes callback function to read data. Size of data must be specified in advance.
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class Callback_Reader : public Data_Reader {
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public:
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typedef const char* (*callback_t)( void* data, void* out, int count );
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Callback_Reader( callback_t, long size, void* data = 0 );
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public:
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long read_avail( void*, long );
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blargg_err_t read( void*, long );
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long remain() const;
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private:
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callback_t const callback;
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void* const data;
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long remain_;
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};
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#endif
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