aljaz/turso
1
0
Fork 0
mirror of https://github.com/aljazceru/turso.git synced 2026-02-23 00:45:37 +01:00
Code Issues Packages Projects Releases Wiki Activity

use more descriptive names in BTreeCursor::insert_into_cell()

Browse Source
This commit is contained in:
jussisaurio
2024-12-24 10:28:53 +02:00
parent a94d4ca8bc
commit 91cca0d5b7
1 changed files with 17 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
core/storage/btree.rs
View File

@@ -742,7 +742,8 @@ impl BTreeCursor {
/// i.e. whether we need to balance the btree after the insert.
fn insert_into_cell(&self, page: &mut PageContent, payload: &[u8], cell_idx: usize) {
let free = self.compute_free_space(page, RefCell::borrow(&self.database_header));
let enough_space = payload.len() + 2 <= free as usize;
const CELL_POINTER_SIZE_BYTES: usize = 2;
let enough_space = payload.len() + CELL_POINTER_SIZE_BYTES <= free as usize;
if !enough_space {
// add to overflow cell
page.overflow_cells.push(OverflowCell {
@@ -753,27 +754,30 @@ impl BTreeCursor {
}
// TODO: insert into cell payload in internal page
let pc = self.allocate_cell_space(page, payload.len() as u16);
let new_cell_data_pointer = self.allocate_cell_space(page, payload.len() as u16);
let buf = page.as_ptr();
// copy data
buf[pc as usize..pc as usize + payload.len()].copy_from_slice(payload);
buf[new_cell_data_pointer as usize..new_cell_data_pointer as usize + payload.len()]
.copy_from_slice(payload);
// memmove(pIns+2, pIns, 2*(pPage->nCell - i));
let (pointer_area_pc_by_idx, _) = page.cell_get_raw_pointer_region();
let pointer_area_pc_by_idx = pointer_area_pc_by_idx + (2 * cell_idx);
let (cell_pointer_array_start, _) = page.cell_get_raw_pointer_region();
let cell_pointer_cur_idx = cell_pointer_array_start + (CELL_POINTER_SIZE_BYTES * cell_idx);
// move previous pointers forward and insert new pointer there
let n_cells_forward = 2 * (page.cell_count() - cell_idx);
if n_cells_forward > 0 {
// move existing pointers forward by CELL_POINTER_SIZE_BYTES...
let n_cells_forward = page.cell_count() - cell_idx;
let n_bytes_forward = CELL_POINTER_SIZE_BYTES * n_cells_forward;
if n_bytes_forward > 0 {
buf.copy_within(
pointer_area_pc_by_idx..pointer_area_pc_by_idx + n_cells_forward,
pointer_area_pc_by_idx + 2,
cell_pointer_cur_idx..cell_pointer_cur_idx + n_bytes_forward,
cell_pointer_cur_idx + CELL_POINTER_SIZE_BYTES,
);
}
page.write_u16(pointer_area_pc_by_idx - page.offset, pc);
// ...and insert new cell pointer at the current index
page.write_u16(cell_pointer_cur_idx - page.offset, new_cell_data_pointer);
// update first byte of content area
page.write_u16(PAGE_HEADER_OFFSET_CELL_CONTENT_AREA, pc);
// update first byte of content area (cell data always appended to the left, so cell content area pointer moves to point to the new cell data)
page.write_u16(PAGE_HEADER_OFFSET_CELL_CONTENT_AREA, new_cell_data_pointer);
// update cell count
let new_n_cells = (page.cell_count() + 1) as u16;