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// FILE: BufFileInput.cpp
// AUTHOR: Alexey Demakov (AVD) demakov@kazbek.ispras.ru
// CREATION: 26-JAN-1998
// DESCRIPTION: File Input Stream with lookahead for Scanner.
// See file BufFileInput.h for details
// Change History:
//
// 22-Jun-1998 assert.h -> PCCTS_ASSERT_H
// string.h -> PCCTS_STRING_H
//
// 28-May-1998 Add virtual destructor to release buffer.
//
// Add dummy definition for ANTLRTokenType
// to allow compilation without knowing
// token type codes.
//
// Manfred Kogler (km@cast.uni-linz.ac.at)
// (1.33MR14)
//
// 20-Jul-1998 MR14a - Reorder initialization list for ctor.
//
enum ANTLRTokenType {TER_HATES_CPP=0, SO_DO_OTHERS=9999 };
#include "pcctscfg.h"
#include "pccts_assert.h"
#include "pccts_string.h"
PCCTS_NAMESPACE_STD
#include "BufFileInput.h"
BufFileInput::BufFileInput( FILE *f, int buf_size )
: input( f ),
buf( new int[buf_size] ),
size( buf_size ),
start( 0 ),
len( 0 )
{
}
BufFileInput::~BufFileInput()
{
delete [] buf;
}
int BufFileInput::nextChar( void )
{
if( len > 0 )
{
// get char from buffer
int c = buf[start];
if( c != EOF )
{
start++; start %= size;
len--;
}
return c;
} else {
// get char from file
int c = getc( input );
if( c == EOF )
{
// if EOF - put it in the buffer as indicator
buf[start] = EOF;
len++;
}
return c;
}
}
int BufFileInput::lookahead( char* s )
{
int l = strlen( s );
assert( 0 < l && l <= size );
while( len < l )
{
int c = getc( input );
buf[ (start+len) % size ] = c;
len++;
if( c == EOF ) return 0;
}
for( int i = 0; i < l; i++ )
{
if( s[i] != buf[ (start+i) % size ] ) return 0;
}
return 1;
}
// End of file BufFileInput.cpp
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