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Diffstat (limited to 'gme/Data_Reader.h')
-rw-r--r-- | gme/Data_Reader.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/gme/Data_Reader.h b/gme/Data_Reader.h new file mode 100644 index 00000000..00b53b9e --- /dev/null +++ b/gme/Data_Reader.h @@ -0,0 +1,151 @@ +// Data reader interface for uniform access + +// File_Extractor 0.4.0 +#ifndef DATA_READER_H +#define DATA_READER_H + +#include "blargg_common.h" + +// Supports reading and finding out how many bytes are remaining +class Data_Reader { +public: + virtual ~Data_Reader() { } + + static const char eof_error []; // returned by read() when request goes beyond end + + // Read at most count bytes and return number actually read, or <= 0 if error + virtual long read_avail( void*, long n ) = 0; + + // Read exactly count bytes and return error if they couldn't be read + virtual blargg_err_t read( void*, long count ); + + // Number of bytes remaining until end of file + virtual long remain() const = 0; + + // Read and discard count bytes + virtual blargg_err_t skip( long count ); + +public: + Data_Reader() { } + typedef blargg_err_t error_t; // deprecated +private: + // noncopyable + Data_Reader( const Data_Reader& ); + Data_Reader& operator = ( const Data_Reader& ); +}; + +// Supports seeking in addition to Data_Reader operations +class File_Reader : public Data_Reader { +public: + // Size of file + virtual long size() const = 0; + + // Current position in file + virtual long tell() const = 0; + + // Go to new position + virtual blargg_err_t seek( long ) = 0; + + long remain() const; + blargg_err_t skip( long n ); +}; + +// Disk file reader +class Std_File_Reader : public File_Reader { +public: + blargg_err_t open( const char* path ); + void close(); + +public: + Std_File_Reader(); + ~Std_File_Reader(); + long size() const; + blargg_err_t read( void*, long ); + long read_avail( void*, long ); + long tell() const; + blargg_err_t seek( long ); +private: + void* file_; +}; + +// Treats range of memory as a file +class Mem_File_Reader : public File_Reader { +public: + Mem_File_Reader( const void*, long size ); + +public: + long size() const; + long read_avail( void*, long ); + long tell() const; + blargg_err_t seek( long ); +private: + const char* const begin; + const long size_; + long pos; +}; + +// Makes it look like there are only count bytes remaining +class Subset_Reader : public Data_Reader { +public: + Subset_Reader( Data_Reader*, long count ); + +public: + long remain() const; + long read_avail( void*, long ); +private: + Data_Reader* in; + long remain_; +}; + +// Joins already-read header and remaining data into original file (to avoid seeking) +class Remaining_Reader : public Data_Reader { +public: + Remaining_Reader( void const* header, long size, Data_Reader* ); + +public: + long remain() const; + long read_avail( void*, long ); + blargg_err_t read( void*, long ); +private: + char const* header; + char const* header_end; + Data_Reader* in; + long read_first( void* out, long count ); +}; + +// Invokes callback function to read data. Size of data must be specified in advance. +class Callback_Reader : public Data_Reader { +public: + typedef const char* (*callback_t)( void* data, void* out, long count ); + Callback_Reader( callback_t, long size, void* data = 0 ); +public: + long read_avail( void*, long ); + blargg_err_t read( void*, long ); + long remain() const; +private: + callback_t const callback; + void* const data; + long remain_; +}; + +#ifdef HAVE_ZLIB_H +// Gzip compressed file reader +class Gzip_File_Reader : public File_Reader { +public: + blargg_err_t open( const char* path ); + void close(); + +public: + Gzip_File_Reader(); + ~Gzip_File_Reader(); + long size() const; + long read_avail( void*, long ); + long tell() const; + blargg_err_t seek( long ); +private: + void* file_; + long size_; +}; +#endif + +#endif |