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use std::{
alloc::{self, Layout},
fmt::Display,
ptr::NonNull,
};
use super::{
errors::InstructionsError, instruction::Instruction, opcode::OpCode,
};
#[derive(Debug, Clone, PartialEq)]
pub struct Instructions {
/// actual bytes are stored in here
byte: NonNull<u8>,
/// position of next instruction will be written
cursor: *mut u8,
/// capacity of [`Self::byte`] ( bytes )
cap: usize,
/// actual length of whole instructions ( bytes )
len: usize,
}
/// default size of instructions, 2048 (0x800) bytes
const SIZE: usize = 1 << 11;
const SUCCESS: Result<(), InstructionsError> = Ok(());
impl Instructions {
/// create [`Instructions`]
///
/// # Panics
///
/// Panics if OOM (out of memory) and panic_flag is set to true
///
/// # Errors [`InstructionsError::AllocationFailed`]
///
/// This function will return an error if panic_flag is set to false
/// and OOM occured
pub fn create() -> Result<Self, InstructionsError> {
let layout = Layout::array::<u8>(SIZE).unwrap();
let new_ptr = unsafe { alloc::alloc(layout) };
let ptr = match NonNull::new(new_ptr) {
Some(p) => p,
None => {
// HACK: change this to configuration
let panic_flag = false;
if panic_flag {
// May panic here if OOM (Out of memory)
// depending on env_config and if panic_flag is true,
// global configuration, it may either panic (resulting in unwinding or aborting as per
// configuration for all panics), or abort the process (with no unwinding).
alloc::handle_alloc_error(layout);
}
return Err(InstructionsError::AllocationFailed(layout));
}
};
Ok(Self {
byte: ptr,
cursor: ptr.as_ptr(),
cap: SIZE,
len: 0,
})
}
/// Stringify this [`Instructions`]
///
/// * hidx - index of highlight target
pub fn to_string_with_highlight(&self, hidx: usize) -> String {
let mut buf = String::new();
let mut idx = 0;
while idx < self.len {
let res = self.read_instruction(idx);
if res.is_err() {
return format!(
"Error have occured on reading instruction. Error: {:?}",
res.unwrap_err()
);
}
let ins = res.unwrap();
if idx == hidx {
buf += &format!(">>{:0>5}\t\t", idx);
} else {
buf += &format!("{:0>5}\t\t", idx);
}
buf += &ins.to_string();
buf += "\n";
idx += ins.opcode().length();
}
buf
}
/// Add new instruction at the end.
/// return new Instruction's offset
///
/// # Errors [`InstructionsError`]
///
/// This function will return an error if this [`Instructions::grow()`] have failed.
pub fn add_instruction(
&mut self,
ins: Instruction,
) -> Result<usize, InstructionsError> {
if self.len + ins.opcode().length() > self.cap {
self.grow()?;
}
unsafe {
std::ptr::copy(
ins.as_byte().as_ptr(),
self.cursor,
ins.opcode().length(),
);
self.cursor = self.cursor.add(ins.opcode().length());
}
let offset = self.len;
self.len += ins.opcode().length();
Ok(offset)
}
/// Update instruction at `offset` with given `ins`
///
/// # Safety
/// if lengths are different between `ins` and instruction at `offset`,
/// There will be Corruption of this [`Instructions`]
pub unsafe fn update_instruction(
&mut self,
ins: Instruction,
offset: usize,
) {
unsafe {
std::ptr::copy(
ins.as_byte().as_ptr(),
self.byte.as_ptr().add(offset),
ins.opcode().length(),
);
}
}
/// Remove instructions by set [`Self::len`] with `new_len`
///
/// This will move [`Self::cursor`] with new position of next instruction's one
pub fn remove_instruction(&mut self, new_len: usize) {
unsafe {
self.cursor = self.byte.as_ptr().add(new_len);
}
self.len = new_len;
}
/// Read Instruction at given `offset`
///
/// # Errors [`InstructionsError::CannotRead`]
///
/// This function will return an error if failed to read opcode
/// from [`Self::byte`] at `offset` to convert it as [`Instruction`]
pub fn read_instruction(
&self,
offset: usize,
) -> Result<Instruction, InstructionsError> {
unsafe {
let opcode =
std::ptr::read(self.byte.as_ptr().add(offset) as *const OpCode);
let instruction = match opcode {
OpCode::PUSH => Instruction::PUSH,
OpCode::POP => Instruction::POP,
OpCode::ADD => Instruction::ADD,
OpCode::SUB => Instruction::SUB,
OpCode::PRODUCT => Instruction::PRODUCT,
OpCode::DIVIDE => Instruction::DIVIDE,
OpCode::MOD => Instruction::MOD,
OpCode::BANG => Instruction::BANG,
OpCode::NEG => Instruction::NEG,
OpCode::CGT => Instruction::CGT,
OpCode::CGTE => Instruction::CGTE,
OpCode::CLT => Instruction::CLT,
OpCode::CLTE => Instruction::CLTE,
OpCode::CEQ => Instruction::CEQ,
OpCode::CNEQ => Instruction::CNEQ,
OpCode::AND => Instruction::AND,
OpCode::OR => Instruction::OR,
OpCode::BAND => Instruction::BAND,
OpCode::BOR => Instruction::BOR,
OpCode::INDEX => Instruction::INDEX,
OpCode::RETN => Instruction::RETN,
OpCode::RETV => Instruction::RETV,
OpCode::GETCUR => Instruction::GETCUR,
has_argument => {
let arg_1 = std::ptr::read(
self.byte.as_ptr().add(offset + 1) as *const usize,
);
match has_argument {
OpCode::CONST => Instruction::CONST { idx: arg_1 },
OpCode::DEFGLB => Instruction::DEFGLB { idx: arg_1 },
OpCode::GETGLB => Instruction::GETGLB { idx: arg_1 },
OpCode::DEFLCL => Instruction::DEFLCL { idx: arg_1 },
OpCode::GETLCL => Instruction::GETLCL { idx: arg_1 },
OpCode::GETFREE => Instruction::GETFREE { idx: arg_1 },
OpCode::JMP => Instruction::JMP { idx: arg_1 },
OpCode::JIS => Instruction::JIS { idx: arg_1 },
OpCode::JNS => Instruction::JNS { idx: arg_1 },
OpCode::JEQ => Instruction::JEQ { idx: arg_1 },
OpCode::JNEQ => Instruction::JNEQ { idx: arg_1 },
OpCode::ARRAY => Instruction::ARRAY { count: arg_1 },
OpCode::CALL => Instruction::CALL { arg_len: arg_1 },
OpCode::CLOSURE => {
let arg_2 = std::ptr::read(
self.byte.as_ptr().add(offset + 1 + 8)
as *const usize,
);
Instruction::CLOSURE {
idx: arg_1,
free: arg_2,
}
}
_not_matched => {
return Err(InstructionsError::CannotRead {
offset,
});
}
}
}
};
Ok(instruction)
}
}
/// Returns the length of this [`Instructions`].
pub fn length(&self) -> usize {
self.len
}
/// grow size of [`Self::byte`] by twice
///
/// # Panics
///
/// Panics if OOM (out of memory) and panic_flag is set to true
///
/// # Errors [`InstructionsError::AllocationFailed`]
///
/// This function will return an error if panic_flag is set to false
/// and OOM occured
fn grow(&mut self) -> Result<(), InstructionsError> {
let new_cap = 2 * self.cap;
let new_layout = Layout::array::<u8>(new_cap).unwrap();
if new_layout.size() <= isize::MAX as usize {
return Err(InstructionsError::TooLargeToAllocate);
}
let old_layout = Layout::array::<u8>(self.cap).unwrap();
let old_ptr = self.byte.as_ptr();
let new_ptr =
unsafe { alloc::realloc(old_ptr, old_layout, new_layout.size()) };
self.byte = match NonNull::new(new_ptr) {
Some(p) => p,
None => {
// HACK: change this to configuration
let panic_flag = false;
if panic_flag {
// May panic here if OOM (Out of memory)
// depending on env_config and if panic_flag is true,
// global configuration, it may either panic (resulting in unwinding or aborting as per
// configuration for all panics), or abort the process (with no unwinding).
alloc::handle_alloc_error(new_layout);
}
return Err(InstructionsError::AllocationFailed(new_layout));
}
};
self.cap = new_cap;
SUCCESS
}
/// Returns the manual drop of this [`Instructions`].
///
/// # Safety
/// this is unsafe because of possibility of multiple owner of this
#[allow(dead_code)]
unsafe fn manual_drop(&mut self) {
dbg!("drop...", &self);
unsafe {
alloc::dealloc(
self.byte.as_ptr(),
Layout::array::<u8>(self.cap).unwrap(),
);
}
}
}
impl Display for Instructions {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
let mut buf = String::new();
let mut idx = 0;
while idx < self.len {
let res = self.read_instruction(idx);
if res.is_err() {
f.write_fmt(format_args!(
"Error have occured on reading instruction. Error: {:?}",
res.unwrap_err()
))?;
return Ok(());
}
let ins = res.unwrap();
buf += &format!("{:0>5}\t\t", idx);
buf += &ins.to_string();
buf += "\n";
idx += ins.opcode().length();
}
f.write_str(buf.as_str())
}
}