Struct Cursor 

pub struct Cursor { /* private fields */ }

A raw-pointer scan cursor over a NUL-terminated source buffer.

Implementations

impl Cursor

pub fn new(buffer: Rc<SourceBuffer>) -> Cursor

Create a cursor positioned at the start of buffer.

pub fn offset(&self) -> u32

The current byte offset from the start of the buffer.

pub fn at_end(&self) -> bool

True once the cursor has reached the terminating NUL.

pub fn peek(&self) -> u8

Byte at the cursor (or the NUL terminator at end).

pub fn peek_at(&self, n: usize) -> u8

Byte n ahead of the cursor. Only valid while the bytes in between were non-NUL (the C++ lookahead invariant); reading the terminating NUL is always in-bounds.

pub fn advance(&mut self, n: usize)

Advance the cursor by n bytes.

pub fn seek(&mut self, offset: u32)

Seek to an absolute byte offset.

pub fn seek_end(&mut self)

Move the cursor to EOF (the terminating NUL). Port of forceEOF.

pub fn slice_from(&self, from_offset: u32) -> &[u8]

Bytes in [from_offset, current offset).

pub fn slice(&self, from_offset: u32, to_offset: u32) -> &[u8]

Bytes in [from_offset, to_offset).

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

The NUL-terminated raw bytes of the underlying buffer.

pub fn peek_utf8(&self) -> (u32, u32)

Decode the (non-ASCII) UTF-8 char at the cursor WITHOUT advancing. Port of JSLexer::_peekUTF8 (JSLexer.h:1159-1167): it decodes with surrogates disallowed and swallows any errors. Returns (code_point, offset_after), where offset_after is the byte offset of the next character.

This stays in cursor.rs to keep the raw-pointer parity confined here, but it actually drives the safe utf8::decode_utf8 over raw() at a copied byte offset (no new unsafe).

pub fn buffer(&self) -> &Rc<SourceBuffer>

The underlying buffer (cloning the Rc is cheap).