/* ** This function is used to allocate and populate UnpackedRecord ** structures intended to be compared against sample index keys stored ** in the sqlite_stat4 table. ** ** A single call to this function attempts to populates field iVal (leftmost ** is 0 etc.) of the unpacked record with a value extracted from expression ** pExpr. Extraction of values is possible if: ** ** * (pExpr==0). In this case the value is assumed to be an SQL NULL, ** ** * The expression is a bound variable, and this is a reprepare, or ** ** * The sqlite3ValueFromExpr() function is able to extract a value ** from the expression (i.e. the expression is a literal value). ** ** If a value can be extracted, the affinity passed as the 5th argument ** is applied to it before it is copied into the UnpackedRecord. Output ** parameter *pbOk is set to true if a value is extracted, or false ** otherwise. ** ** When this function is called, *ppRec must either point to an object ** allocated by an earlier call to this function, or must be NULL. If it ** is NULL and a value can be successfully extracted, a new UnpackedRecord ** is allocated (and *ppRec set to point to it) before returning. ** ** Unless an error is encountered, SQLITE_OK is returned. It is not an ** error if a value cannot be extracted from pExpr. If an error does ** occur, an SQLite error code is returned. */ SQLITE_PRIVATE int sqlite3Stat4ProbeSetValue( Parse *pParse, /* Parse context */ Index *pIdx, /* Index being probed */ UnpackedRecord **ppRec, /* IN/OUT: Probe record */ Expr *pExpr, /* The expression to extract a value from */ u8 affinity, /* Affinity to use */ int iVal, /* Array element to populate */ int *pbOk /* OUT: True if value was extracted */ ){ int rc = SQLITE_OK; sqlite3_value *pVal = 0; sqlite3 *db = pParse->db; struct ValueNewStat4Ctx alloc; alloc.pParse = pParse; alloc.pIdx = pIdx; alloc.ppRec = ppRec; alloc.iVal = iVal; /* Skip over any TK_COLLATE nodes */ pExpr = sqlite3ExprSkipCollate(pExpr); if( !pExpr ){ pVal = valueNew(db, &alloc); if( pVal ){ sqlite3VdbeMemSetNull((Mem*)pVal); *pbOk = 1; } }else if( pExpr->op==TK_VARIABLE || (pExpr->op==TK_REGISTER && pExpr->op2==TK_VARIABLE) ){ Vdbe *v; int iBindVar = pExpr->iColumn; sqlite3VdbeSetVarmask(pParse->pVdbe, iBindVar); if( (v = pParse->pReprepare)!=0 ){ pVal = valueNew(db, &alloc); if( pVal ){ rc = sqlite3VdbeMemCopy((Mem*)pVal, &v->aVar[iBindVar-1]); if( rc==SQLITE_OK ){ sqlite3ValueApplyAffinity(pVal, affinity, ENC(db)); } pVal->db = pParse->db; *pbOk = 1; sqlite3VdbeMemStoreType((Mem*)pVal); } }else{ *pbOk = 0; } }else{ rc = valueFromExpr(db, pExpr, ENC(db), affinity, &pVal, &alloc); *pbOk = (pVal!=0); } assert( pVal==0 || pVal->db==db ); return rc; }
/* ** Check to see if the given expression is a LIKE or GLOB operator that ** can be optimized using inequality constraints. Return TRUE if it is ** so and false if not. ** ** In order for the operator to be optimizible, the RHS must be a string ** literal that does not begin with a wildcard. The LHS must be a column ** that may only be NULL, a string, or a BLOB, never a number. (This means ** that virtual tables cannot participate in the LIKE optimization.) The ** collating sequence for the column on the LHS must be appropriate for ** the operator. */ static int isLikeOrGlob( Parse *pParse, /* Parsing and code generating context */ Expr *pExpr, /* Test this expression */ Expr **ppPrefix, /* Pointer to TK_STRING expression with pattern prefix */ int *pisComplete, /* True if the only wildcard is % in the last character */ int *pnoCase /* True if uppercase is equivalent to lowercase */ ){ const char *z = 0; /* String on RHS of LIKE operator */ Expr *pRight, *pLeft; /* Right and left size of LIKE operator */ ExprList *pList; /* List of operands to the LIKE operator */ int c; /* One character in z[] */ int cnt; /* Number of non-wildcard prefix characters */ char wc[3]; /* Wildcard characters */ sqlite3 *db = pParse->db; /* Database connection */ sqlite3_value *pVal = 0; int op; /* Opcode of pRight */ if( !sqlite3IsLikeFunction(db, pExpr, pnoCase, wc) ){ return 0; } #ifdef SQLITE_EBCDIC if( *pnoCase ) return 0; #endif pList = pExpr->x.pList; pLeft = pList->a[1].pExpr; if( pLeft->op!=TK_COLUMN || sqlite3ExprAffinity(pLeft)!=SQLITE_AFF_TEXT || IsVirtual(pLeft->pTab) /* Value might be numeric */ ){ /* IMP: R-02065-49465 The left-hand side of the LIKE or GLOB operator must ** be the name of an indexed column with TEXT affinity. */ return 0; } assert( pLeft->iColumn!=(-1) ); /* Because IPK never has AFF_TEXT */ pRight = sqlite3ExprSkipCollate(pList->a[0].pExpr); op = pRight->op; if( op==TK_VARIABLE ){ Vdbe *pReprepare = pParse->pReprepare; int iCol = pRight->iColumn; pVal = sqlite3VdbeGetBoundValue(pReprepare, iCol, SQLITE_AFF_BLOB); if( pVal && sqlite3_value_type(pVal)==SQLITE_TEXT ){ z = (char *)sqlite3_value_text(pVal); } sqlite3VdbeSetVarmask(pParse->pVdbe, iCol); assert( pRight->op==TK_VARIABLE || pRight->op==TK_REGISTER ); }else if( op==TK_STRING ){ z = pRight->u.zToken; } if( z ){ cnt = 0; while( (c=z[cnt])!=0 && c!=wc[0] && c!=wc[1] && c!=wc[2] ){ cnt++; } if( cnt!=0 && 255!=(u8)z[cnt-1] ){ Expr *pPrefix; *pisComplete = c==wc[0] && z[cnt+1]==0; pPrefix = sqlite3Expr(db, TK_STRING, z); if( pPrefix ) pPrefix->u.zToken[cnt] = 0; *ppPrefix = pPrefix; if( op==TK_VARIABLE ){ Vdbe *v = pParse->pVdbe; sqlite3VdbeSetVarmask(v, pRight->iColumn); if( *pisComplete && pRight->u.zToken[1] ){ /* If the rhs of the LIKE expression is a variable, and the current ** value of the variable means there is no need to invoke the LIKE ** function, then no OP_Variable will be added to the program. ** This causes problems for the sqlite3_bind_parameter_name() ** API. To work around them, add a dummy OP_Variable here. */ int r1 = sqlite3GetTempReg(pParse); sqlite3ExprCodeTarget(pParse, pRight, r1); sqlite3VdbeChangeP3(v, sqlite3VdbeCurrentAddr(v)-1, 0); sqlite3ReleaseTempReg(pParse, r1); } } }else{ z = 0; } } sqlite3ValueFree(pVal); return (z!=0); }