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Overview
Comment:Performance optimization in the yy_find_shift_action() routine of the Lemon-generated parser.
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SHA1: ba6663beefcc8060e6f3be6ab37c13fdbb08b7de
User & Date: drh 2016-08-10 01:43:30.837
Context
2016-08-10
11:50
Fix pcache1TruncateUnsafe() run faster for the case where iLimit is very close to iMaxKey. (check-in: b07a26df06 user: drh tags: trunk)
01:43
Performance optimization in the yy_find_shift_action() routine of the Lemon-generated parser. (check-in: ba6663beef user: drh tags: trunk)
2016-08-09
21:01
Fix harmless compiler warning. (check-in: 9a5a4f6e3b user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to tool/lempar.c.
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  int i;
  int stateno = pParser->yytos->stateno;
 
  if( stateno>=YY_MIN_REDUCE ) return stateno;
  assert( stateno <= YY_SHIFT_COUNT );
  do{
    i = yy_shift_ofst[stateno];
    if( i==YY_SHIFT_USE_DFLT ) return yy_default[stateno];
    assert( iLookAhead!=YYNOCODE );
    i += iLookAhead;
    if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){
      if( iLookAhead>0 ){
#ifdef YYFALLBACK
        YYCODETYPE iFallback;            /* Fallback token */
        if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
               && (iFallback = yyFallback[iLookAhead])!=0 ){
#ifndef NDEBUG
          if( yyTraceFILE ){
            fprintf(yyTraceFILE, "%sFALLBACK %s => %s\n",
               yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[iFallback]);
          }
#endif
          assert( yyFallback[iFallback]==0 ); /* Fallback loop must terminate */
          iLookAhead = iFallback;
          continue;
        }
#endif
#ifdef YYWILDCARD
        {
          int j = i - iLookAhead + YYWILDCARD;
          if( 
#if YY_SHIFT_MIN+YYWILDCARD<0
            j>=0 &&
#endif
#if YY_SHIFT_MAX+YYWILDCARD>=YY_ACTTAB_COUNT
            j<YY_ACTTAB_COUNT &&
#endif
            yy_lookahead[j]==YYWILDCARD
          ){
#ifndef NDEBUG
            if( yyTraceFILE ){
              fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
                 yyTracePrompt, yyTokenName[iLookAhead],
                 yyTokenName[YYWILDCARD]);
            }
#endif /* NDEBUG */
            return yy_action[j];
          }
        }
#endif /* YYWILDCARD */
      }
      return yy_default[stateno];
    }else{
      return yy_action[i];
    }
  }while(1);
}









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  int i;
  int stateno = pParser->yytos->stateno;
 
  if( stateno>=YY_MIN_REDUCE ) return stateno;
  assert( stateno <= YY_SHIFT_COUNT );
  do{
    i = yy_shift_ofst[stateno];

    assert( iLookAhead!=YYNOCODE );
    i += iLookAhead;
    if( i<0 || i>=YY_ACTTAB_COUNT || yy_lookahead[i]!=iLookAhead ){

#ifdef YYFALLBACK
      YYCODETYPE iFallback;            /* Fallback token */
      if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
             && (iFallback = yyFallback[iLookAhead])!=0 ){
#ifndef NDEBUG
        if( yyTraceFILE ){
          fprintf(yyTraceFILE, "%sFALLBACK %s => %s\n",
             yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[iFallback]);
        }
#endif
        assert( yyFallback[iFallback]==0 ); /* Fallback loop must terminate */
        iLookAhead = iFallback;
        continue;
      }
#endif
#ifdef YYWILDCARD
      {
        int j = i - iLookAhead + YYWILDCARD;
        if( 
#if YY_SHIFT_MIN+YYWILDCARD<0
          j>=0 &&
#endif
#if YY_SHIFT_MAX+YYWILDCARD>=YY_ACTTAB_COUNT
          j<YY_ACTTAB_COUNT &&
#endif
          yy_lookahead[j]==YYWILDCARD && iLookAhead>0
        ){
#ifndef NDEBUG
          if( yyTraceFILE ){
            fprintf(yyTraceFILE, "%sWILDCARD %s => %s\n",
               yyTracePrompt, yyTokenName[iLookAhead],
               yyTokenName[YYWILDCARD]);
          }
#endif /* NDEBUG */
          return yy_action[j];
        }
      }
#endif /* YYWILDCARD */

      return yy_default[stateno];
    }else{
      return yy_action[i];
    }
  }while(1);
}
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