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Overview
Comment:Size and performance optimizations on the sqlite3ExprAssignVarNumber() routine.
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SHA1: 109852e51e2cc2674940ba3e5097a92e66f88bb8
User & Date: drh 2016-10-03 16:33:14.952
Context
2016-10-03
18:13
Allow deterministic functions in the WHERE clause of a partial index. (check-in: c6e9b94218 user: drh tags: trunk)
16:33
Size and performance optimizations on the sqlite3ExprAssignVarNumber() routine. (check-in: 109852e51e user: drh tags: trunk)
15:28
Avoid unnecessary strlen() calls in sqlite3ExprAssignVarNumber() by passing in the token length from the parser. (check-in: d15ae2e530 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/expr.c.
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  assert( z[0]!=0 );
  assert( n==sqlite3Strlen30(z) );
  if( z[1]==0 ){
    /* Wildcard of the form "?".  Assign the next variable number */
    assert( z[0]=='?' );
    pExpr->iColumn = (ynVar)(++pParse->nVar);
  }else{
    ynVar x = 0;
    if( z[0]=='?' ){
      /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
      ** use it as the variable number */
      i64 i;
      int bOk = 0==sqlite3Atoi64(&z[1], &i, n-1, SQLITE_UTF8);
      pExpr->iColumn = x = (ynVar)i;
      testcase( i==0 );
      testcase( i==1 );
      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
      if( bOk==0 || i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
        sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
            db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);
        x = 0;

      }
      if( i>pParse->nVar ){
        pParse->nVar = (int)i;
      }
    }else{
      /* Wildcards like ":aaa", "$aaa" or "@aaa".  Reuse the same variable
      ** number as the prior appearance of the same name, or if the name
      ** has never appeared before, reuse the same variable number
      */
      ynVar i;
      for(i=0; i<pParse->nzVar; i++){
        if( pParse->azVar[i] && strcmp(pParse->azVar[i],z)==0 ){
          pExpr->iColumn = x = (ynVar)i+1;
          break;
        }
      }
      if( x==0 ) x = pExpr->iColumn = (ynVar)(++pParse->nVar);
    }
    if( x>0 ){
      if( x>pParse->nzVar ){
        char **a;
        a = sqlite3DbRealloc(db, pParse->azVar, x*sizeof(a[0]));
        if( a==0 ){
          assert( db->mallocFailed ); /* Error reported through mallocFailed */
          return;
        }
        pParse->azVar = a;
        memset(&a[pParse->nzVar], 0, (x-pParse->nzVar)*sizeof(a[0]));
        pParse->nzVar = x;
      }
      if( z[0]!='?' || pParse->azVar[x-1]==0 ){
        sqlite3DbFree(db, pParse->azVar[x-1]);
        pParse->azVar[x-1] = sqlite3DbStrNDup(db, z, n);
      }
    }
  } 
  if( !pParse->nErr && pParse->nVar>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
    sqlite3ErrorMsg(pParse, "too many SQL variables");
  }
}

/*
** Recursively delete an expression tree.
*/








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949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969

970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
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996
997
998
999
1000
1001

1002
1003
1004

1005
1006
1007
1008
1009
1010
1011
1012

  assert( z[0]!=0 );
  assert( n==sqlite3Strlen30(z) );
  if( z[1]==0 ){
    /* Wildcard of the form "?".  Assign the next variable number */
    assert( z[0]=='?' );
    pExpr->iColumn = (ynVar)(++pParse->nVar);
  }else{
    ynVar x;
    if( z[0]=='?' ){
      /* Wildcard of the form "?nnn".  Convert "nnn" to an integer and
      ** use it as the variable number */
      i64 i;
      int bOk = 0==sqlite3Atoi64(&z[1], &i, n-1, SQLITE_UTF8);
      x = (ynVar)i;
      testcase( i==0 );
      testcase( i==1 );
      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]-1 );
      testcase( i==db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] );
      if( bOk==0 || i<1 || i>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
        sqlite3ErrorMsg(pParse, "variable number must be between ?1 and ?%d",
            db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER]);

        return;
      }
      if( i>pParse->nVar ){
        pParse->nVar = (int)i;
      }
    }else{
      /* Wildcards like ":aaa", "$aaa" or "@aaa".  Reuse the same variable
      ** number as the prior appearance of the same name, or if the name
      ** has never appeared before, reuse the same variable number
      */
      ynVar i;
      for(i=x=0; i<pParse->nzVar; i++){
        if( pParse->azVar[i] && strcmp(pParse->azVar[i],z)==0 ){
          x = (ynVar)i+1;
          break;
        }
      }
      if( x==0 ) x = (ynVar)(++pParse->nVar);
    }
    pExpr->iColumn = x;
    if( x>pParse->nzVar ){
      char **a;
      a = sqlite3DbRealloc(db, pParse->azVar, x*sizeof(a[0]));
      if( a==0 ){
        assert( db->mallocFailed ); /* Error reported through mallocFailed */
        return;
      }
      pParse->azVar = a;
      memset(&a[pParse->nzVar], 0, (x-pParse->nzVar)*sizeof(a[0]));
      pParse->nzVar = x;
    }
    if( pParse->azVar[x-1]==0 ){

      pParse->azVar[x-1] = sqlite3DbStrNDup(db, z, n);
    }
  } 

  if( pParse->nVar>db->aLimit[SQLITE_LIMIT_VARIABLE_NUMBER] ){
    sqlite3ErrorMsg(pParse, "too many SQL variables");
  }
}

/*
** Recursively delete an expression tree.
*/
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