Struct iced_x86::Encoder

pub struct Encoder { /* fields omitted */ }

Encodes instructions decoded by the decoder or instructions created by other code. See also BlockEncoder which can encode any number of instructions.

use iced_x86::*;

// xchg ah,[rdx+rsi+16h]
let bytes = b"\x86\x64\x32\x16";
let mut decoder = Decoder::new(64, bytes, DecoderOptions::NONE);
decoder.set_ip(0x1234_5678);
let instr = decoder.decode();

let mut encoder = Encoder::new(64);
match encoder.encode(&instr, 0x5555_5555) {
    Ok(len) => assert_eq!(4, len),
    Err(err) => panic!("{}", err),
}
// We're done, take ownership of the buffer
let buffer = encoder.take_buffer();
assert_eq!(vec![0x86, 0x64, 0x32, 0x16], buffer);

Implementations

impl Encoder

#[must_use]pub fn new(bitness: u32) -> Self

Creates an encoder

Panics

Panics if bitness is not one of 16, 32, 64.

Arguments

• bitness: 16, 32 or 64

#[must_use]pub fn with_capacity(bitness: u32, capacity: usize) -> Self

Creates an encoder with an initial buffer capacity

Panics

Panics if bitness is not one of 16, 32, 64.

Arguments

• bitness: 16, 32 or 64
• capacity: Initial capacity of the u8 buffer

pub fn encode(
    &mut self,
    instruction: &Instruction,
    rip: u64
) -> Result<usize, String>

Encodes an instruction and returns the size of the encoded instruction

Errors

Returns an error message on failure.

Arguments

• instruction: Instruction to encode
• rip: RIP of the encoded instruction

Examples

use iced_x86::*;

// je short $+4
let bytes = b"\x75\x02";
let mut decoder = Decoder::new(64, bytes, DecoderOptions::NONE);
decoder.set_ip(0x1234_5678);
let instr = decoder.decode();

let mut encoder = Encoder::new(64);
// Use a different IP (orig rip + 0x10)
match encoder.encode(&instr, 0x1234_5688) {
    Ok(len) => assert_eq!(2, len),
    Err(err) => panic!("{}", err),
}
// We're done, take ownership of the buffer
let buffer = encoder.take_buffer();
assert_eq!(vec![0x75, 0xF2], buffer);

pub fn write_u8(&mut self, value: u8)

Writes a byte to the output buffer

Arguments

value: Value to write

Examples

use iced_x86::*;

let mut encoder = Encoder::new(64);
let instr = Instruction::with_reg_reg(Code::Add_r64_rm64, Register::R8, Register::RBP);
encoder.write_u8(0x90);
match encoder.encode(&instr, 0x5555_5555) {
    Ok(len) => assert_eq!(3, len),
    Err(err) => panic!("{}", err),
}
encoder.write_u8(0xCC);
// We're done, take ownership of the buffer
let buffer = encoder.take_buffer();
assert_eq!(vec![0x90, 0x4C, 0x03, 0xC5, 0xCC], buffer);

#[must_use]pub fn take_buffer(&mut self) -> Vec<u8>

Returns the buffer and initializes the internal buffer to an empty vector. Should be called when you've encoded all instructions and need the raw instruction bytes. See also set_buffer().

pub fn set_buffer(&mut self, buffer: Vec<u8>)

Overwrites the buffer with a new vector. The old buffer is dropped. See also take_buffer().

#[must_use]pub fn get_constant_offsets(&self) -> ConstantOffsets

Gets the offsets of the constants (memory displacement and immediate) in the encoded instruction. The caller can use this information to add relocations if needed.

#[must_use]pub fn prevent_vex2(&self) -> bool

Disables 2-byte VEX encoding and encodes all VEX instructions with the 3-byte VEX encoding

pub fn set_prevent_vex2(&mut self, new_value: bool)

Disables 2-byte VEX encoding and encodes all VEX instructions with the 3-byte VEX encoding

Arguments

• new_value: new value

#[must_use]pub fn vex_wig(&self) -> u32

Value of the VEX.W bit to use if it's an instruction that ignores the bit. Default is 0.

pub fn set_vex_wig(&mut self, new_value: u32)

Value of the VEX.W bit to use if it's an instruction that ignores the bit. Default is 0.

Arguments

• new_value: new value (0 or 1)

#[must_use]pub fn vex_lig(&self) -> u32

Value of the VEX.L bit to use if it's an instruction that ignores the bit. Default is 0.

pub fn set_vex_lig(&mut self, new_value: u32)

Value of the VEX.L bit to use if it's an instruction that ignores the bit. Default is 0.

Arguments

• new_value: new value (0 or 1)

#[must_use]pub fn evex_wig(&self) -> u32

Value of the EVEX.W bit to use if it's an instruction that ignores the bit. Default is 0.

pub fn set_evex_wig(&mut self, new_value: u32)

Value of the EVEX.W bit to use if it's an instruction that ignores the bit. Default is 0.

Arguments

• new_value: new value (0 or 1)

#[must_use]pub fn evex_lig(&self) -> u32

Value of the EVEX.L'L bits to use if it's an instruction that ignores the bits. Default is 0.

pub fn set_evex_lig(&mut self, new_value: u32)

Value of the EVEX.L'L bits to use if it's an instruction that ignores the bits. Default is 0.

Arguments

• new_value: new value (0 or 3)

#[must_use]pub fn bitness(&self) -> u32

Gets the bitness (16, 32 or 64)