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Overview
| Comment: | Use memmove() rather than a home-made copy loop in dropCell() of btree.c, for a size reduction and performance improvement. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: | 78e1706804e88a0dd5dc40bee838a3a5 |
| User & Date: | drh 2013-12-09 01:58:11 |
Context
|
2013-12-09
| ||
| 02:32 | Use memmove() rather than a home-made copy loop in insertCell() too. check-in: a3d796b1 user: drh tags: trunk | |
| 01:58 | Use memmove() rather than a home-made copy loop in dropCell() of btree.c, for a size reduction and performance improvement. check-in: 78e17068 user: drh tags: trunk | |
| 01:04 | Avoid unnecessary no-op calls from getAndInitPage() to btreeInitPage() in the btree.c logic. check-in: 81f5ae13 user: drh tags: trunk | |
Changes
Changes to src/btree.c.
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**
** "sz" must be the number of bytes in the cell.
*/
static void dropCell(MemPage *pPage, int idx, int sz, int *pRC){
u32 pc; /* Offset to cell content of cell being deleted */
u8 *data; /* pPage->aData */
u8 *ptr; /* Used to move bytes around within data[] */
u8 *endPtr; /* End of loop */
int rc; /* The return code */
int hdr; /* Beginning of the header. 0 most pages. 100 page 1 */
if( *pRC ) return;
assert( idx>=0 && idx<pPage->nCell );
assert( sz==cellSize(pPage, idx) );
................................................................................
return;
}
rc = freeSpace(pPage, pc, sz);
if( rc ){
*pRC = rc;
return;
}
endPtr = &pPage->aCellIdx[2*pPage->nCell - 2];
assert( (SQLITE_PTR_TO_INT(ptr)&1)==0 ); /* ptr is always 2-byte aligned */
while( ptr<endPtr ){
*(u16*)ptr = *(u16*)&ptr[2];
ptr += 2;
}
pPage->nCell--;
put2byte(&data[hdr+3], pPage->nCell);
pPage->nFree += 2;
}
/*
** Insert a new cell on pPage at cell index "i". pCell points to the
** content of the cell.
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**
** "sz" must be the number of bytes in the cell.
*/
static void dropCell(MemPage *pPage, int idx, int sz, int *pRC){
u32 pc; /* Offset to cell content of cell being deleted */
u8 *data; /* pPage->aData */
u8 *ptr; /* Used to move bytes around within data[] */
int rc; /* The return code */
int hdr; /* Beginning of the header. 0 most pages. 100 page 1 */
if( *pRC ) return;
assert( idx>=0 && idx<pPage->nCell );
assert( sz==cellSize(pPage, idx) );
................................................................................
return;
}
rc = freeSpace(pPage, pc, sz);
if( rc ){
*pRC = rc;
return;
}
pPage->nCell--;
memmove(ptr, ptr+2, 2*(pPage->nCell - idx));
put2byte(&data[hdr+3], pPage->nCell);
pPage->nFree += 2;
}
/*
** Insert a new cell on pPage at cell index "i". pCell points to the
** content of the cell.
|