database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-12 13:01:09 +03:00
Code Activity

Alternative implementation of exprCompareVariable(). Need to run tests on

Browse Source 
both this branch and the original to see which one to go with.

FossilOrigin-Name: b959c6297c151150ea2dca24aa1f68f3bd76dd6620eb6c03f8dfa59fdd5c13b2
This commit is contained in:
drh
2017-06-28 21:47:16 +00:00
parent 3e380a4485
commit c080422642
3 changed files with 30 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

44
src/expr.c
View File

@@ -4675,29 +4675,19 @@ void sqlite3ExprIfFalseDup(Parse *pParse, Expr *pExpr, int dest,int jumpIfNull){
*/
static int exprCompareVariable(Parse *pParse, Expr *pVar, Expr *pExpr){
int res = 0;
int iVar = pVar->iColumn;
Expr *p = pExpr;
while( p->op==TK_UMINUS ) p = p->pLeft;
if( p->op==TK_NULL || p->op==TK_INTEGER
|| p->op==TK_FLOAT || p->op==TK_STRING
|| p->op==TK_BLOB
){
int iVar;
sqlite3_value *pL, *pR = 0;
sqlite3ValueFromExpr(pParse->db, pExpr, SQLITE_UTF8, SQLITE_AFF_BLOB, &pR);
if( pR ){
iVar = pVar->iColumn;
sqlite3VdbeSetVarmask(pParse->pVdbe, iVar);
sqlite3_value *pL;
pL = sqlite3VdbeGetBoundValue(pParse->pReprepare, iVar, SQLITE_AFF_BLOB);
if( pL ){
sqlite3_value *pR = 0;
sqlite3ValueFromExpr(pParse->db, pExpr, SQLITE_UTF8, SQLITE_AFF_BLOB,&pR);
assert( pR || pParse->db->mallocFailed );
if( pR && 0==sqlite3MemCompare(pL, pR, 0) ){
res = 1;
}
sqlite3ValueFree(pR);
sqlite3ValueFree(pL);
}else if( p->op==TK_NULL ){
if( pL && 0==sqlite3MemCompare(pL, pR, 0) ){
res = 1;
}
sqlite3ValueFree(pR);
sqlite3ValueFree(pL);
}
return res;
@@ -4725,11 +4715,12 @@ static int exprCompareVariable(Parse *pParse, Expr *pVar, Expr *pExpr){
** just might result in some slightly slower code. But returning
** an incorrect 0 or 1 could lead to a malfunction.
**
** Argument pParse should normally be NULL. If it is not NULL and
** expression pA contains SQL variable references, then the values
** currently bound to those variable references may be compared to
** simple SQL values in pB. See comments above function exprCompareVariable()
** for details.
** If pParse is not NULL then TK_VARIABLE terms in pA with bindings in
** pParse->pReprepare can be matched against literals in pB. The
** pParse->pVdbe->expmask bitmask is updated for each variable referenced.
** If pParse is NULL (the normal case) then any TK_VARIABLE term in
** Argument pParse should normally be NULL. If it is not NULL and pA or
** pB causes a return value of 2.
*/
int sqlite3ExprCompare(Parse *pParse, Expr *pA, Expr *pB, int iTab){
u32 combinedFlags;
@@ -4833,6 +4824,11 @@ int sqlite3ExprCompareSkip(Expr *pA, Expr *pB, int iTab){
** When comparing TK_COLUMN nodes between pE1 and pE2, if pE2 has
** Expr.iTable<0 then assume a table number given by iTab.
**
** If pParse is not NULL, then the values of bound variables in pE1 are
** compared against literal values in pE2 and pParse->pVdbe->expmask is
** modified to record which bound variables are referenced. If pParse
** is NULL, then false will be returned if pE1 contains any bound variables.
**
** When in doubt, return false. Returning true might give a performance
** improvement. Returning false might cause a performance reduction, but
** it will always give the correct answer and is hence always safe.