Tools/CodeTools/Source/Pccts/h/BufFileInput.cpp

   1 // FILE:        BufFileInput.cpp
   2 // AUTHOR:      Alexey Demakov (AVD) demakov@kazbek.ispras.ru
   3 // CREATION:    26-JAN-1998
   4 // DESCRIPTION: File Input Stream with lookahead for Scanner.
   5 //   See file BufFileInput.h for details
   6
   7 // Change History:
   8 //
   9 //   22-Jun-1998    assert.h -> PCCTS_ASSERT_H
  10 //                  string.h -> PCCTS_STRING_H
  11 //
  12 //   28-May-1998    Add virtual destructor to release buffer.
  13 //
  14 //                  Add dummy definition for ANTLRTokenType
  15 //                  to allow compilation without knowing
  16 //                  token type codes.
  17 //
  18 //                  Manfred Kogler (km@cast.uni-linz.ac.at)
  19 //                  (1.33MR14)
  20 //
  21 //   20-Jul-1998    MR14a - Reorder initialization list for ctor.
  22 //
  23
  24 enum ANTLRTokenType {TER_HATES_CPP=0, SO_DO_OTHERS=9999 };
  25
  26 #include "pcctscfg.h"
  27 #include "pccts_assert.h"
  28 #include "pccts_string.h"
  29
  30 PCCTS_NAMESPACE_STD
  31
  32 #include "BufFileInput.h"
  33
  34 BufFileInput::BufFileInput( FILE *f, int buf_size )
  35 : input( f ),
  36   buf( new int[buf_size] ),
  37   size( buf_size ),
  38   start( 0 ),
  39   len( 0 )
  40 {
  41 }
  42
  43 BufFileInput::~BufFileInput()
  44 {
  45   delete [] buf;
  46 }
  47
  48 int BufFileInput::nextChar( void )
  49 {
  50     if( len > 0 )
  51     {
  52         // get char from buffer
  53         int c = buf[start];
  54
  55         if( c != EOF )
  56         {
  57             start++; start %= size;
  58             len--;
  59         }
  60         return c;
  61     } else {
  62         // get char from file
  63         int c = getc( input );
  64
  65         if( c == EOF )
  66         {
  67             // if EOF - put it in the buffer as indicator
  68             buf[start] = EOF;
  69             len++;
  70         }
  71         return c;
  72     }
  73 }
  74
  75 int BufFileInput::lookahead( char* s )
  76 {
  77     int l = strlen( s );
  78
  79     assert( 0 < l && l <= size );
  80
  81     while( len < l )
  82     {
  83         int c = getc( input );
  84
  85         buf[ (start+len) % size ] = c;
  86
  87         len++;
  88
  89         if( c == EOF ) return 0;
  90     }
  91
  92     for( int i = 0; i < l; i++ )
  93     {
  94         if( s[i] != buf[ (start+i) % size ] ) return 0;
  95     }
  96     return 1;
  97 }
  98
  99 // End of file BufFileInput.cpp
 100