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Separate the column NULL value constant into a separate routine for greater

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commonality with the sessions branch.

FossilOrigin-Name: 12cbebb997705e37769460e00a4aaa52c12f305e
This commit is contained in:
drh
2014-03-05 12:47:55 +00:00
parent ef4668bc05
commit b1a1c29a07
3 changed files with 33 additions and 30 deletions
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47
src/vdbeapi.c
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@@ -727,6 +727,30 @@ int sqlite3_data_count(sqlite3_stmt *pStmt){
return pVm->nResColumn;
}
/*
** Return a pointer to static memory containing an SQL NULL value.
*/
static const Mem *columnNullValue(void){
/* Even though the Mem structure contains an element
** of type i64, on certain architectures (x86) with certain compiler
** switches (-Os), gcc may align this Mem object on a 4-byte boundary
** instead of an 8-byte one. This all works fine, except that when
** running with SQLITE_DEBUG defined the SQLite code sometimes assert()s
** that a Mem structure is located on an 8-byte boundary. To prevent
** these assert()s from failing, when building with SQLITE_DEBUG defined
** using gcc, we force nullMem to be 8-byte aligned using the magical
** __attribute__((aligned(8))) macro. */
static const Mem nullMem
#if defined(SQLITE_DEBUG) && defined(__GNUC__)
__attribute__((aligned(8)))
#endif
= {0, "", (double)0, {0}, 0, MEM_Null, 0,
#ifdef SQLITE_DEBUG
0, 0, /* pScopyFrom, pFiller */
#endif
0, 0 };
return &nullMem;
}
/*
** Check to see if column iCol of the given statement is valid. If
@@ -743,32 +767,11 @@ static Mem *columnMem(sqlite3_stmt *pStmt, int i){
sqlite3_mutex_enter(pVm->db->mutex);
pOut = &pVm->pResultSet[i];
}else{
/* If the value passed as the second argument is out of range, return
** a pointer to the following static Mem object which contains the
** value SQL NULL. Even though the Mem structure contains an element
** of type i64, on certain architectures (x86) with certain compiler
** switches (-Os), gcc may align this Mem object on a 4-byte boundary
** instead of an 8-byte one. This all works fine, except that when
** running with SQLITE_DEBUG defined the SQLite code sometimes assert()s
** that a Mem structure is located on an 8-byte boundary. To prevent
** these assert()s from failing, when building with SQLITE_DEBUG defined
** using gcc, we force nullMem to be 8-byte aligned using the magical
** __attribute__((aligned(8))) macro. */
static const Mem nullMem
#if defined(SQLITE_DEBUG) && defined(__GNUC__)
__attribute__((aligned(8)))
#endif
= {0, "", (double)0, {0}, 0, MEM_Null, 0,
#ifdef SQLITE_DEBUG
0, 0, /* pScopyFrom, pFiller */
#endif
0, 0 };
if( pVm && ALWAYS(pVm->db) ){
sqlite3_mutex_enter(pVm->db->mutex);
sqlite3Error(pVm->db, SQLITE_RANGE, 0);
}
pOut = (Mem*)&nullMem;
pOut = (Mem*)columnNullValue();
}
return pOut;
}