Function build_table_cell_overflow

internal/cbm/sqlite_writer.c:848–868

Build a table leaf cell with overflow: stores only the first local_len bytes of payload inline, followed by a 4-byte overflow page number. total_payload_len is the FULL original payload length (written as the payload-size varint so SQLite knows the real record size).

// total_payload_len is the FULL original payload length (written as the payload-size
// varint so SQLite knows the real record size).
static uint8_t *build_table_cell_overflow(int64_t rowid, const uint8_t *payload,
                                          int total_payload_len, int local_len,
                                          uint32_t overflow_page, int *out_cell_len) {
    int rl = varint_len(total_payload_len);
    int kl = varint_len(rowid);
    // cell = varint(total_payload_len) + varint(rowid) + payload[0..local_len) + uint32(overflow)
    int total = rl + kl + local_len + BTREE_PTR_SIZE;
    uint8_t *cell = (uint8_t *)malloc(total);
    if (!cell) {
        return NULL;
    }
    int pos = 0;
    pos += put_varint(cell + pos, total_payload_len);
    pos += put_varint(cell + pos, rowid);
    memcpy(cell + pos, payload, local_len);
    pos += local_len;
    put_u32(cell + pos, overflow_page);
    pos += BTREE_PTR_SIZE;
    *out_cell_len = pos;
    return cell;
}

// --- Overflow page writer ---
// Writes overflow pages for payload bytes that exceed local storage.