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Data_Reader.cpp
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Data_Reader.cpp
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// File_Extractor 0.4.0. http://www.slack.net/~ant/
#include "Data_Reader.h"
#include "blargg_endian.h"
#include <assert.h>
#include <string.h>
#include <stdio.h>
/* Copyright (C) 2005-2006 Shay Green. This module is free software; you
can redistribute it and/or modify it under the terms of the GNU Lesser
General Public License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version. This
module is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
details. You should have received a copy of the GNU Lesser General Public
License along with this module; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */
#include "blargg_source.h"
const char Data_Reader::eof_error [] = "Unexpected end of file";
blargg_err_t Data_Reader::read( void* p, long s )
{
long result = read_avail( p, s );
if ( result != s )
{
if ( result >= 0 && result < s )
return eof_error;
return "Read error";
}
return 0;
}
blargg_err_t Data_Reader::skip( long count )
{
char buf [512];
while ( count )
{
long n = sizeof buf;
if ( n > count )
n = count;
count -= n;
RETURN_ERR( read( buf, n ) );
}
return 0;
}
long File_Reader::remain() const { return size() - tell(); }
blargg_err_t File_Reader::skip( long n )
{
assert( n >= 0 );
if ( !n )
return 0;
return seek( tell() + n );
}
// Subset_Reader
Subset_Reader::Subset_Reader( Data_Reader* dr, long size )
{
in = dr;
remain_ = dr->remain();
if ( remain_ > size )
remain_ = size;
}
long Subset_Reader::remain() const { return remain_; }
long Subset_Reader::read_avail( void* p, long s )
{
if ( s > remain_ )
s = remain_;
remain_ -= s;
return in->read_avail( p, s );
}
// Remaining_Reader
Remaining_Reader::Remaining_Reader( void const* h, long size, Data_Reader* r )
{
header = (char const*) h;
header_end = header + size;
in = r;
}
long Remaining_Reader::remain() const { return header_end - header + in->remain(); }
long Remaining_Reader::read_first( void* out, long count )
{
long first = header_end - header;
if ( first )
{
if ( first > count )
first = count;
void const* old = header;
header += first;
memcpy( out, old, first );
}
return first;
}
long Remaining_Reader::read_avail( void* out, long count )
{
long first = read_first( out, count );
long second = count - first;
if ( second )
{
second = in->read_avail( (char*) out + first, second );
if ( second <= 0 )
return second;
}
return first + second;
}
blargg_err_t Remaining_Reader::read( void* out, long count )
{
long first = read_first( out, count );
long second = count - first;
if ( !second )
return 0;
return in->read( (char*) out + first, second );
}
// Mem_File_Reader
Mem_File_Reader::Mem_File_Reader( const void* p, long s ) :
begin( (const char*) p ),
size_( s )
{
pos = 0;
}
long Mem_File_Reader::size() const { return size_; }
long Mem_File_Reader::read_avail( void* p, long s )
{
long r = remain();
if ( s > r )
s = r;
memcpy( p, begin + pos, s );
pos += s;
return s;
}
long Mem_File_Reader::tell() const { return pos; }
blargg_err_t Mem_File_Reader::seek( long n )
{
if ( n > size_ )
return eof_error;
pos = n;
return 0;
}
// Callback_Reader
Callback_Reader::Callback_Reader( callback_t c, long size, void* d ) :
callback( c ),
data( d )
{
remain_ = size;
}
long Callback_Reader::remain() const { return remain_; }
long Callback_Reader::read_avail( void* out, long count )
{
if ( count > remain_ )
count = remain_;
if ( Callback_Reader::read( out, count ) )
count = -1;
return count;
}
blargg_err_t Callback_Reader::read( void* out, long count )
{
if ( count > remain_ )
return eof_error;
return callback( data, out, count );
}
// Std_File_Reader
Std_File_Reader::Std_File_Reader() : file_( 0 ) { }
Std_File_Reader::~Std_File_Reader() { close(); }
blargg_err_t Std_File_Reader::open( const char* path )
{
file_ = fopen( path, "rb" );
if ( !file_ )
return "Couldn't open file";
return 0;
}
long Std_File_Reader::size() const
{
long pos = tell();
fseek( (FILE*) file_, 0, SEEK_END );
long result = tell();
fseek( (FILE*) file_, pos, SEEK_SET );
return result;
}
long Std_File_Reader::read_avail( void* p, long s )
{
return fread( p, 1, s, (FILE*) file_ );
}
blargg_err_t Std_File_Reader::read( void* p, long s )
{
if ( s == (long) fread( p, 1, s, (FILE*) file_ ) )
return 0;
if ( feof( (FILE*) file_ ) )
return eof_error;
return "Couldn't read from file";
}
long Std_File_Reader::tell() const { return ftell( (FILE*) file_ ); }
blargg_err_t Std_File_Reader::seek( long n )
{
if ( !fseek( (FILE*) file_, n, SEEK_SET ) )
return 0;
if ( n > size() )
return eof_error;
return "Error seeking in file";
}
void Std_File_Reader::close()
{
if ( file_ )
{
fclose( (FILE*) file_ );
file_ = 0;
}
}
// Gzip_File_Reader
#ifdef HAVE_ZLIB_H
#include "zlib.h"
static const char* get_gzip_eof( const char* path, long* eof )
{
FILE* file = fopen( path, "rb" );
if ( !file )
return "Couldn't open file";
unsigned char buf [4];
if ( fread( buf, 2, 1, file ) > 0 && buf [0] == 0x1F && buf [1] == 0x8B )
{
fseek( file, -4, SEEK_END );
fread( buf, 4, 1, file );
*eof = get_le32( buf );
}
else
{
fseek( file, 0, SEEK_END );
*eof = ftell( file );
}
const char* err = (ferror( file ) || feof( file )) ? "Couldn't get file size" : 0;
fclose( file );
return err;
}
Gzip_File_Reader::Gzip_File_Reader() : file_( 0 ) { }
Gzip_File_Reader::~Gzip_File_Reader() { close(); }
blargg_err_t Gzip_File_Reader::open( const char* path )
{
close();
RETURN_ERR( get_gzip_eof( path, &size_ ) );
file_ = gzopen( path, "rb" );
if ( !file_ )
return "Couldn't open file";
return 0;
}
long Gzip_File_Reader::size() const { return size_; }
long Gzip_File_Reader::read_avail( void* p, long s ) { return gzread( file_, p, s ); }
long Gzip_File_Reader::tell() const { return gztell( file_ ); }
blargg_err_t Gzip_File_Reader::seek( long n )
{
if ( gzseek( file_, n, SEEK_SET ) >= 0 )
return 0;
if ( n > size_ )
return eof_error;
return "Error seeking in file";
}
void Gzip_File_Reader::close()
{
if ( file_ )
{
gzclose( file_ );
file_ = 0;
}
}
#endif

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Data_Reader.cpp (6 KB)

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