83 lines
1.6 KiB
C
83 lines
1.6 KiB
C
// Copyright (c) 1993-1999 Microsoft Corporation
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#include "y1.h"
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/*
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* ycpfir.1c
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*
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* Modified to make debug code conditionally compile.
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* 28-Aug-81
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* Bob Denny
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*/
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void
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cpfir( void )
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{
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/* compute an array with the first of nonterminals */
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SSIZE_T *p, **s, i, **t, ch, changes;
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zzcwp = &wsets[nnonter];
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NTLOOP(i)
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{
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aryfil( wsets[i].ws.lset, tbitset, 0 );
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t = pres[i+1];
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for( s=pres[i]; s<t; ++s )
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{
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/* initially fill the sets */
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for( p = *s; (ch = *p) > 0 ; ++p )
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{
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if( ch < NTBASE )
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{
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SETBIT( wsets[i].ws.lset, ch );
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break;
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}
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else if( !pempty[ch-NTBASE] ) break;
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}
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}
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}
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/* now, reflect transitivity */
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changes = 1;
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while( changes )
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{
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changes = 0;
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NTLOOP(i)
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{
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t = pres[i+1];
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for( s=pres[i]; s<t; ++s )
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{
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for( p = *s; ( ch = (*p-NTBASE) ) >= 0; ++p )
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{
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changes |= setunion( wsets[i].ws.lset, wsets[ch].ws.lset );
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if( !pempty[ch] ) break;
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}
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}
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}
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}
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NTLOOP(i) pfirst[i] = flset( &wsets[i].ws );
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#ifdef debug
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if( (foutput!=NULL) )
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{
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NTLOOP(i)
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{
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fprintf( foutput, "\n%s: ", nontrst[i].name );
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prlook( pfirst[i] );
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fprintf( foutput, " %d\n", pempty[i] );
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}
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}
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#endif
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}
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