Struct Buffer 

pub struct Buffer<'buf, R: Read> {
    pub buf: &'buf mut [u8],
    pub n_bytes: usize,
    pub n_shifted_out: usize,
    pub pos_shifted: LinePosition,
    /* private fields */
}

A buffer for reading JSON data. Is a private struct, the “pub” is only for testing.

Fields

buf: &'buf mut [u8]

The working buffer for reading JSON data.

n_bytes: usize

Number of valid bytes in the buffer. Contract: n_bytes <= buf.len()

n_shifted_out: usize

Number of bytes that have been shifted out of the buffer.

pos_shifted: LinePosition

Line position correction due to shifting operations.

Implementations

impl<'buf, R: Read> Buffer<'buf, R>

pub fn new(reader: &'buf mut R, buf: &'buf mut [u8]) -> Self

Creates a new buffer with the given reader and buffer.

pub fn read_more(&mut self) -> RJiterResult<usize>

Read from the underlying reader into the buffer.

Returns the number of bytes read.

Errors

From the underlying reader.

pub fn shift_buffer(&mut self, to_pos: usize, from_pos: usize)

Shift the buffer to the left, and update the index and line-column position.

Arguments

• to_pos: The position to shift to. Usually is 0 or is 1 for strings.
• from_pos: The position to shift from. The case of outside the buffer is handled.

pub fn skip_spaces(&mut self, pos: usize) -> RJiterResult<()>

Skip over any ASCII whitespace characters starting at the given position. Read-shift-read-shift-read-shift… until non-whitespace is found or EOF is reached.

Arguments

• pos - The position in the buffer to start skipping from

Errors

From the underlying reader.

pub fn collect_while<F>( &mut self, predicate: F, start_pos: usize, allow_shift: bool, ) -> RJiterResult<(usize, usize)>

where F: Fn(u8) -> bool,

Collect bytes while a predicate is true, starting at the given position. Returns a tuple of (start_position, end_position) where end_position is the offset of the first rejected byte, or EOF. If buffer is full with all accepted bytes, it’s an error. The function can optionally shift the buffer once to discard bytes before start_pos.

Arguments

• predicate - A function that returns true if the byte should be accepted
• start_pos - The position in the buffer to start collecting from
• allow_shift - If true, allows shifting the buffer once when it fills up (discards bytes before start_pos)

Errors

Returns ErrorType::BufferFull if the buffer fills up with all accepted bytes. Also returns errors from the underlying reader.

pub fn collect_count( &mut self, count: usize, start_pos: usize, allow_shift: bool, ) -> RJiterResult<(usize, usize)>

Collect exactly count bytes starting at the given position, or until EOF. Returns a tuple of (start_position, end_position) where end_position is the offset after the collected bytes (start_pos + actual_collected). If buffer is too small to hold the requested bytes, it’s an error. The function can optionally shift the buffer once to discard bytes before start_pos.

Arguments

• count - The number of bytes to collect
• start_pos - The position in the buffer to start collecting from
• allow_shift - If true, allows shifting the buffer once when it fills up (discards bytes before start_pos)

Errors

Returns ErrorType::BufferFull if the buffer is too small to hold the requested bytes. Also returns errors from the underlying reader.

pub fn skip_n( &mut self, count: usize, start_pos: usize, ) -> RJiterResult<(usize, usize)>

Skip exactly count bytes starting at the given position, or until EOF. Returns the new position in the buffer after skipping.

This function works incrementally and can skip any number of bytes regardless of buffer size. It repeatedly shifts and reads as needed when the buffer is too small. When bytes fit in the buffer, it just returns the new position without shifting.

Arguments

• count - The number of bytes to skip
• start_pos - The position in the buffer to start skipping from

Errors

Returns errors from the underlying reader.

Trait Implementations

impl<R: Read> Debug for Buffer<'_, R>

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

Formats the value using the given formatter.