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Update page offsets in drop_cell and update cell pointer array after dropping a cell.

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This commit is contained in:
krishvishal
2025-01-26 17:27:07 +05:30
parent 73dae3003d
commit 8263bd0482
1 changed files with 24 additions and 2 deletions
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26
core/storage/btree.rs
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@@ -947,14 +947,36 @@ impl BTreeCursor {
/// Drop a cell from a page.
/// This is done by freeing the range of bytes that the cell occupies.
fn drop_cell(&self, page: &mut PageContent, cell_idx: usize) {
let cell_count = page.cell_count();
let (cell_start, cell_len) = page.cell_get_raw_region(
cell_idx,
self.payload_overflow_threshold_max(page.page_type()),
self.payload_overflow_threshold_min(page.page_type()),
self.usable_space(),
);
self.free_cell_range(page, cell_start as u16, cell_len as u16);
page.write_u16(PAGE_HEADER_OFFSET_CELL_COUNT, page.cell_count() as u16 - 1);
self.free_cell_range(page, cell_start as u16, cell_len as u16)
.expect("Failed to free cell range");
let new_cell_count = cell_count - 1;
page.write_u16(PAGE_HEADER_OFFSET_CELL_COUNT, new_cell_count as u16);
if new_cell_count == 0 {
page.write_u16(PAGE_HEADER_OFFSET_FIRST_FREEBLOCK, 0);
page.write_u8(PAGE_HEADER_OFFSET_FRAGMENTED_BYTES_COUNT, 0);
page.write_u16(
PAGE_HEADER_OFFSET_CELL_CONTENT_AREA,
self.usable_space() as u16,
);
} else {
let (pointer_array_start, _) = page.cell_pointer_array_offset_and_size();
let buf = page.as_ptr();
buf.copy_within(
pointer_array_start + (2 * (cell_idx + 1)) // src
..pointer_array_start + (2 * cell_count),
pointer_array_start + (2 * cell_idx), // dst
);
}
}
/// Balance a leaf page.