ishan/sqlite-reader
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Travel right pages and parse them as well

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This commit is contained in:
Ishan Jain 2022-07-30 21:46:45 +05:30
parent 03eba911ab
commit df44ded31a
1 changed files with 25 additions and 7 deletions
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30
src/main.rs
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@ -123,11 +123,10 @@ fn main() -> Result<()> {
fn parse_page<'a>(
database: &'a [u8],
db_header: &'a DBHeader,
column_map: &'a HashMap<&str, usize>,
page_size: usize,
page_num: usize,
table_page_offset: usize,
) -> Option<Box<dyn Iterator<Item = (usize, Vec<ColumnValue<'a>>)> + 'a>> {
let table_page_offset = page_size * (page_num - 1);
let (read, page_header) =
PageHeader::parse(&database[table_page_offset..table_page_offset + 12]).unwrap();
@ -148,13 +147,32 @@ fn parse_page<'a>(
let (_rowid, _offset) = parse_varint(&stream[4..]);
parse_page(database, column_map, page_size, left_child_id as usize)
parse_page(
database,
db_header,
column_map,
db_header.page_size as usize * (left_child_id as usize - 1),
)
})
.flatten()
.flatten();
if let Some(rp) = page_header.right_most_pointer {
Some(Box::new(
rows.chain(
parse_page(
database,
db_header,
column_map,
db_header.page_size as usize * (rp as usize - 1),
)
.unwrap(),
),
))
} else {
Some(Box::new(rows))
}
}
BTreePage::LeafIndex => todo!(),
BTreePage::LeafTable => {
let rows = cell_pointers.into_iter().map(move |cp| {
@ -190,9 +208,9 @@ fn read_columns(query: &str, db_header: DBHeader, database: &[u8]) -> Result<(),
let rows = parse_page(
database,
&db_header,
&column_map,
db_header.page_size as usize,
schema.root_page as usize,
db_header.page_size as usize * (schema.root_page as usize - 1),
);
for (rowid, row) in rows.unwrap() {