Struct BufferReader 

pub struct BufferReader<'a> { /* private fields */ }

Decodes values from the WeaveFFI buffer format.

Every read_* method returns BufferDecodeError when the buffer is exhausted or holds invalid data, so a malformed buffer can never cause an out-of-bounds read.

Implementations

impl<'a> BufferReader<'a>

pub fn new(data: &'a [u8]) -> Self

Wrap an encoded buffer for reading. Object tokens in it are adopted by BufferValue::read_value, whose contract covers them.

pub fn token_free(data: &'a [u8]) -> Self

Wrap an encoded buffer whose object tokens must not be adopted: reading an interface value fails instead. Decoding through such a reader is sound for any input, which is how the runtime reads a callback’s error payload (see ForeignError::domain).

pub fn adopts_tokens(&self) -> bool

Whether this reader may adopt object tokens (it wasn’t built with token_free).

pub fn remaining(&self) -> usize

The number of bytes not yet consumed.

pub fn read_bool(&mut self) -> Result<bool, BufferDecodeError>

Read a bool.

Errors

Returns an error when the buffer is exhausted or the byte is not 0 or 1.

pub fn read_i8(&mut self) -> Result<i8, BufferDecodeError>

Read an i8.

Errors

Returns an error when the buffer is exhausted.

pub fn read_u8(&mut self) -> Result<u8, BufferDecodeError>

Read a u8.

Errors

Returns an error when the buffer is exhausted.

pub fn read_i16(&mut self) -> Result<i16, BufferDecodeError>

Read an i16 little-endian.

Errors

Returns an error when the buffer is exhausted.

pub fn read_u16(&mut self) -> Result<u16, BufferDecodeError>

Read a u16 little-endian.

Errors

Returns an error when the buffer is exhausted.

pub fn read_i32(&mut self) -> Result<i32, BufferDecodeError>

Read an i32 little-endian. Also decodes C-style enum values and rich-enum tags.

Errors

Returns an error when the buffer is exhausted.

pub fn read_u32(&mut self) -> Result<u32, BufferDecodeError>

Read a u32 little-endian.

Errors

Returns an error when the buffer is exhausted.

pub fn read_i64(&mut self) -> Result<i64, BufferDecodeError>

Read an i64 little-endian.

Errors

Returns an error when the buffer is exhausted.

pub fn read_u64(&mut self) -> Result<u64, BufferDecodeError>

Read a u64 little-endian. Also decodes object tokens.

Errors

Returns an error when the buffer is exhausted.

pub fn read_f32(&mut self) -> Result<f32, BufferDecodeError>

Read an f32 from its IEEE 754 bits, little-endian.

Errors

Returns an error when the buffer is exhausted.

pub fn read_f64(&mut self) -> Result<f64, BufferDecodeError>

Read an f64 from its IEEE 754 bits, little-endian.

Errors

Returns an error when the buffer is exhausted.

pub fn read_len(&mut self) -> Result<usize, BufferDecodeError>

Read the byte length of a string or byte buffer (a u32).

Errors

Returns an error when the buffer is exhausted or the decoded length exceeds the bytes remaining, which would make the follow-up read fail anyway; rejecting here gives a clearer error.

pub fn read_count(&mut self) -> Result<usize, BufferDecodeError>

Read a collection’s element count (a u32).

Unlike read_len this doesn’t bound the count by the bytes remaining: an element’s encoding can be empty (a record with no fields), so a large count is legitimate. Decoders bound their preallocation by remaining instead, and a hostile count fails as soon as the elements run out.

Errors

Returns an error when the buffer is exhausted.

pub fn read_raw(&mut self, n: usize) -> Result<&'a [u8], BufferDecodeError>

Read n raw bytes.

Errors

Returns an error when fewer than n bytes remain.

pub fn read_string(&mut self) -> Result<String, BufferDecodeError>

Read a string: u32 byte length + UTF-8 bytes.

Errors

Returns an error when the buffer is exhausted or the bytes are not valid UTF-8.

pub fn read_bytes(&mut self) -> Result<Vec<u8>, BufferDecodeError>

Read a byte buffer: u32 length + raw bytes.

Errors

Returns an error when the buffer is exhausted.

pub fn read_option_flag(&mut self) -> Result<bool, BufferDecodeError>

Read an optional’s presence flag.

Errors

Returns an error when the buffer is exhausted or the flag byte is not 0 or 1.

pub fn expect_end(&self) -> Result<(), BufferDecodeError>

Assert the whole buffer was consumed. Called after decoding a complete value to catch trailing garbage.

Errors

Returns an error when unconsumed bytes remain.

Trait Implementations

impl<'a> Debug for BufferReader<'a>

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

Formats the value using the given formatter.