Struct flatbuffers::Builder

pub struct Builder {
    // some fields omitted
}

Builder provides functions to build Flatbuffer data.

A Builder constructs byte buffers in a last-first manner for simplicity and performance.

Methods

impl Builder

fn with_capacity(size: usize) -> Self

Start a new FlatBuffer Builder backed by a buffer with an initial capacity of size.

fn start_object(&mut self, num_fields: usize)

Start encoding a new object in the buffer.

fn end_object(&mut self) -> UOffsetT

finish off writing the object that is under construction.

Returns the offset of the object in the inside the buffer.

fn read_object(&self, offset: UOffsetT) -> Table

Read a completed object at offset.

The offset is the UOffsetT returned by end_object.

fn read_table(&self, offset: UOffsetT) -> Table

Read a completed object at offset.

The offset is the UOffsetT returned by end_table.

fn start_vector(&mut self, elem_size: usize, num_elems: usize, alignment: usize)

Initializes bookkeeping for writing a new vector.

fn end_vector(&mut self) -> UOffsetT

finish off writing the current vector.

fn end_vector_with(&mut self, len: u32) -> UOffsetT

Finish off writing the current vector of length len.

Useful if you dont know the exact size of the vector when you start it.

fn create_string(&mut self, value: &str) -> UOffsetT

Create a string in the buffer from an already encoded UTF-8 String.

fn create_vector(&mut self, value: &[u8]) -> UOffsetT

Create a vector in the buffer from an already encoded byte vector.

fn create_uoffset_vector(&mut self, value: &[UOffsetT]) -> UOffsetT

Create a vector of UOffsetT in the buffer. This function will encode the values to LittleEndian.

fn finish_table(&mut self, root_table: UOffsetT) -> UOffsetT

Finalize a table, pointing to the given root_table.

fn get_bytes(&self) -> &[u8]

Get a reference to the underlying buffer. Buffer starts from the first byte of useful data i.e. &[pos..].

fn swap_out(&mut self, new_buffer: Vec<u8>) -> Vec<u8>

Returns the current buffer and replaces it with a new_buffer.

Thie function facilitates some reuse of the Builder object. Use into() if the Builder is no longer required.

fn reset(&mut self)

Resets the builder.

Clears the buffer without resizing. This allows for reuse without allocating new memeory.

fn len(&self) -> usize

Returns the length of the buffer.

fn offset(&self) -> UOffsetT

Offset relative to the end of the buffer.

fn pos(&self) -> usize

Returns the offset relative to the beggining of the buffer.

fn prep(&mut self, size: usize, additional_bytes: usize)

prepare to write an element of size after additional_bytes have been written.

fn pad(&mut self, n: usize)

pad places zeros at the current offset.

impl Builder

fn put_bool(&mut self, boolean: bool)

Add a bool to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_u8(&mut self, byte: u8)

Add a byte to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_i8(&mut self, value: i8)

Add a value of type i8 to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_u16(&mut self, value: u16)

Add a value of type u16 to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_i16(&mut self, value: i16)

Add a value of type i16 to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_u32(&mut self, value: u32)

Add a value of type u32 to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_i32(&mut self, value: i32)

Add a value of type i32 to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_u64(&mut self, value: u64)

Add a value of type u64 to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_i64(&mut self, value: i64)

Add a value of type i64 to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_f32(&mut self, value: f32)

Add a value of type f32 to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_f64(&mut self, value: f64)

Add a value of type f64 to the buffer, backwards from the current location. Doesn't align nor check for space.

fn put_uoffset(&mut self, value: UOffsetT)

Add a value of type UOffsetT to the buffer, backwards from the current location. Doesn't align nor check for space.

fn add_bool(&mut self, value: bool)

Add a bool to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_u8(&mut self, value: u8)

Add a value of type u8 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_i8(&mut self, value: i8)

Add a value of type i8 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_u16(&mut self, value: u16)

Add a value of type u16 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_i16(&mut self, value: i16)

Add a value of type i16 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_u32(&mut self, value: u32)

Add a value of type u32 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_i32(&mut self, value: i32)

Add a value of type i32 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_u64(&mut self, value: u64)

Add a value of type u64 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_i64(&mut self, value: i64)

Add a value of type i64 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_f32(&mut self, value: f32)

Add a value of type f32 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_f64(&mut self, value: f64)

Add a value of type f64 to the buffer, properly aligned, and grows the buffer (if necessary).

fn add_uoffset(&mut self, value: UOffsetT)

Add a value of type f64 to the buffer, properly aligned, and grows the buffer (if necessary). prepends an UOffsetT, relative to where it will be written.

fn slot(&mut self, slot: usize)

Slot sets the vtable key voffset to the current location in the buffer.

fn add_slot_bool(&mut self, o: usize, value: bool, d: bool)

Add a bool onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_u8(&mut self, o: usize, value: u8, d: u8)

Add a value of type u8 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_i8(&mut self, o: usize, value: i8, d: i8)

Add a value of type i8 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_u16(&mut self, o: usize, value: u16, d: u16)

Add a value of type u16 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_i16(&mut self, o: usize, value: i16, d: i16)

Add a value of type i16 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_u32(&mut self, o: usize, value: u32, d: u32)

Add a value of type u32 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_i32(&mut self, o: usize, value: i32, d: i32)

Add a value of type i32 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_u64(&mut self, o: usize, value: u64, d: u64)

Add a value of type u64 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_i64(&mut self, o: usize, value: i64, d: i64)

Add a value of type i64 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_f32(&mut self, o: usize, value: f32, d: f32)

Add a value of type f32 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_f64(&mut self, o: usize, value: f64, d: f64)

Add a value of type f64 onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

fn add_slot_uoffset(&mut self, o: usize, value: UOffsetT, d: UOffsetT)

Add a value of type UOffsetT onto the object at vtable slot o. If value x equals default d, then the slot will be set to zero and no other data will be written.

prepends an UOffsetT, relative to where it will be written.

fn add_slot_struct(&mut self, o: usize, value: UOffsetT, d: UOffsetT)

PrependStructSlot prepends a struct onto the object at vtable slot o. Structs are stored inline, so nothing additional is being added. In generated code, d is always 0.

fn place_u8(&mut self, pos: usize, value: u8)

Place a u8 at pos relative to the beginning of the underlaying buffer.

fn place_u32(&mut self, pos: usize, value: u32)

Place a u32 with LittleEndian encoding at pos relative to the beginning of the underlaying buffer.

fn place_i32(&mut self, pos: usize, value: i32)

Place a i32 with LittleEndian encoding at pos relative to the beginning of the underlaying buffer.

fn place_u64(&mut self, pos: usize, value: u64)

Place a u64 with LittleEndian encoding at pos relative to the beginning of the underlaying buffer.

fn assert_not_finished(&self)

Check to assert finish has not been called.

fn assert_not_nested(&self)

Check to assert start_object has not been called.

fn assert_nested(&self)

Check to assert start_object has been called.

fn get_u16(&self, pos: usize) -> VOffsetT

Helper method to read a VOffsetT at pos relative to the beginning of the underlying buffer - this may not be the start of any useful data. Use with offset() to get the UOffsetT of useful data.

fn get_32(&self, pos: usize) -> UOffsetT

Helper method to read a UOffsetT at pos relative to the beginning of the underlying buffer - this may not be the start of any useful data. Use with offset() to get the UOffsetT of useful data.

fn grow(&mut self)

Doubles the size of the buffer.

Copies the old data towards the end of the new buffer (since we build the buffer backwards). Max buffer size is 2 Gigabytes - otherwise u16 index values might be invalid.

Trait Implementations

impl Clone for Builder

fn clone(&self) -> Builder

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Builder

fn fmt(&self, __arg_0: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Default for Builder

fn default() -> Builder

Returns the "default value" for a type.

impl Into<Vec<u8>> for Builder

fn into(self) -> Vec<u8>

Performs the conversion.