Module table_page 

Table-leaf page layout: a slot directory + cell content.

A TablePage operates on the payload portion of a page (the 4089 bytes that follow the 7-byte per-page header). The 7-byte header itself (page type, next-page, legacy payload-length) is written by the caller when the page is flushed to disk — this module doesn’t touch it.

Layout inside the payload area (PAYLOAD_PER_PAGE = 4089 bytes):

  offset 0..2    slot_count                 u16 LE
  offset 2..4    cells_top                  u16 LE  (offset where cell
                                                     content begins)
  offset 4..     slot[0]..slot[n-1]         each u16 LE
                                            points at the start of a
                                            cell, ordered by rowid
  [free space]
  offset cells_top..PAYLOAD_PER_PAGE         cell content (unordered
                                            in physical position,
                                            ordered by slot)

cells_top = PAYLOAD_PER_PAGE on an empty page. Every insert shifts it down (toward the slot directory) by the new cell’s byte size; every insert also expands the slot directory up (away from the header) by 2 bytes.

Deletion leaves holes. Removing a cell only strips its slot; the cell bytes stay in place. This keeps deletion O(n) in slots-to-shift, not O(page_size) in bytes-to-compact. The hole is reclaimed by a future vacuum pass (not yet implemented). free_space therefore underreports available space in fragmented pages — caller should treat its answer as “contiguous free bytes”, which is what a cell write actually needs.

Structs

TablePage

A table-leaf page. Owns a heap-allocated 4089-byte payload buffer.

TablePageIter

Enums

Find

Result of searching for a rowid in the slot directory.