Struct FixedBytes 

pub struct FixedBytes<const N: usize> { /* private fields */ }

A helper to read at most a fixed number of N bytes from a column. This allocates the storage for the bytes read on the stack.

Implementations

impl<const N: usize> FixedBytes<N>

pub fn into_bytes(self) -> Option<[u8; N]>

Coerce into the underlying bytes if all of them have been initialized.

Examples

use sqlite_ll::{Connection, State, FixedBytes};

let c = Connection::open_memory()?;
c.execute(r##"
CREATE TABLE users (id BLOB);
INSERT INTO users (id) VALUES (X'01020304'), (X'05060708');
"##)?;

let mut stmt = c.prepare("SELECT id FROM users")?;

while let State::Row = stmt.step()? {
    let bytes = stmt.read::<FixedBytes<4>>(0)?;
    assert!(matches!(bytes.into_bytes(), Some([1, 2, 3, 4] | [5, 6, 7, 8])));
}

pub fn as_bytes(&self) -> &[u8]

Coerce into the slice of initialized memory which is present.

Examples

use sqlite_ll::{Connection, State, FixedBytes};

let c = Connection::open_memory()?;
c.execute(r##"
CREATE TABLE users (id BLOB);
INSERT INTO users (id) VALUES (X'01020304'), (X'0506070809');
"##)?;

let mut stmt = c.prepare("SELECT id FROM users")?;

while let State::Row = stmt.step()? {
    let bytes = stmt.read::<FixedBytes<10>>(0)?;
    assert!(matches!(bytes.as_bytes(), &[1, 2, 3, 4] | &[5, 6, 7, 8, 9]));
}

Trait Implementations

impl<const N: usize> Debug for FixedBytes<N>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<const N: usize> Readable for FixedBytes<N>

Readable implementation for FixedBytes which reads at most N bytes.

If the column contains more than N bytes, a [Code::MISMATCH] error is returned.

Examples

use sqlite_ll::{Connection, State, FixedBytes, Code};

let c = Connection::open_memory()?;
c.execute(r##"
CREATE TABLE users (id BLOB);
INSERT INTO users (id) VALUES (X'01020304'), (X'0506070809');
"##)?;

let mut stmt = c.prepare("SELECT id FROM users")?;

assert_eq!(stmt.step()?, State::Row);
let bytes = stmt.read::<FixedBytes<4>>(0)?;
assert_eq!(bytes.as_bytes(), &[1, 2, 3, 4]);

assert_eq!(stmt.step()?, State::Row);
let e = stmt.read::<FixedBytes<4>>(0).unwrap_err();
assert_eq!(e.code(), Code::MISMATCH);

let bytes = stmt.read::<FixedBytes<5>>(0)?;
assert_eq!(bytes.as_bytes(), &[5, 6, 7, 8, 9]);