use super::{
BinaryReader, BinaryReaderError, OperatorsReader, Range, Result, SectionIteratorLimited,
SectionReader, SectionWithLimitedItems, Type,
};
#[derive(Debug, Clone)]
pub struct FunctionBody<'a> {
offset: usize,
data: &'a [u8],
}
impl<'a> FunctionBody<'a> {
pub fn new(offset: usize, data: &'a [u8]) -> Self {
Self { offset, data }
}
pub fn get_binary_reader<'b>(&self) -> BinaryReader<'b>
where
'a: 'b,
{
BinaryReader::new_with_offset(self.data, self.offset)
}
fn skip_locals(reader: &mut BinaryReader) -> Result<()> {
let count = reader.read_var_u32()?;
for _ in 0..count {
reader.skip_var_32()?;
reader.skip_type()?;
}
Ok(())
}
pub fn get_locals_reader<'b>(&self) -> Result<LocalsReader<'b>>
where
'a: 'b,
{
let mut reader = BinaryReader::new_with_offset(self.data, self.offset);
let count = reader.read_var_u32()?;
Ok(LocalsReader { reader, count })
}
pub fn get_operators_reader<'b>(&self) -> Result<OperatorsReader<'b>>
where
'a: 'b,
{
let mut reader = BinaryReader::new_with_offset(self.data, self.offset);
Self::skip_locals(&mut reader)?;
let pos = reader.position;
Ok(OperatorsReader::new(&self.data[pos..], self.offset + pos))
}
pub fn range(&self) -> Range {
Range {
start: self.offset,
end: self.offset + self.data.len(),
}
}
}
pub struct LocalsReader<'a> {
reader: BinaryReader<'a>,
count: u32,
}
impl<'a> LocalsReader<'a> {
pub fn get_count(&self) -> u32 {
self.count
}
pub fn original_position(&self) -> usize {
self.reader.original_position()
}
pub fn read(&mut self) -> Result<(u32, Type)> {
let count = self.reader.read_var_u32()?;
let value_type = self.reader.read_type()?;
Ok((count, value_type))
}
}
pub struct CodeSectionReader<'a> {
reader: BinaryReader<'a>,
count: u32,
}
impl<'a> IntoIterator for LocalsReader<'a> {
type Item = Result<(u32, Type)>;
type IntoIter = LocalsIterator<'a>;
fn into_iter(self) -> Self::IntoIter {
let count = self.count;
LocalsIterator {
reader: self,
left: count,
err: false,
}
}
}
pub struct LocalsIterator<'a> {
reader: LocalsReader<'a>,
left: u32,
err: bool,
}
impl<'a> Iterator for LocalsIterator<'a> {
type Item = Result<(u32, Type)>;
fn next(&mut self) -> Option<Self::Item> {
if self.err || self.left == 0 {
return None;
}
let result = self.reader.read();
self.err = result.is_err();
self.left -= 1;
Some(result)
}
fn size_hint(&self) -> (usize, Option<usize>) {
let count = self.reader.get_count() as usize;
(count, Some(count))
}
}
impl<'a> CodeSectionReader<'a> {
pub fn new(data: &'a [u8], offset: usize) -> Result<CodeSectionReader<'a>> {
let mut reader = BinaryReader::new_with_offset(data, offset);
let count = reader.read_var_u32()?;
Ok(CodeSectionReader { reader, count })
}
pub fn original_position(&self) -> usize {
self.reader.original_position()
}
pub fn get_count(&self) -> u32 {
self.count
}
fn verify_body_end(&self, end: usize) -> Result<()> {
if self.reader.buffer.len() < end {
return Err(BinaryReaderError::new(
"Function body extends past end of the code section",
self.reader.original_offset + self.reader.buffer.len(),
));
}
Ok(())
}
pub fn read<'b>(&mut self) -> Result<FunctionBody<'b>>
where
'a: 'b,
{
let size = self.reader.read_var_u32()? as usize;
let body_start = self.reader.position;
let body_end = body_start + size;
self.verify_body_end(body_end)?;
self.reader.skip_to(body_end);
Ok(FunctionBody {
offset: self.reader.original_offset + body_start,
data: &self.reader.buffer[body_start..body_end],
})
}
}
impl<'a> SectionReader for CodeSectionReader<'a> {
type Item = FunctionBody<'a>;
fn read(&mut self) -> Result<Self::Item> {
CodeSectionReader::read(self)
}
fn eof(&self) -> bool {
self.reader.eof()
}
fn original_position(&self) -> usize {
CodeSectionReader::original_position(self)
}
fn range(&self) -> Range {
self.reader.range()
}
}
impl<'a> SectionWithLimitedItems for CodeSectionReader<'a> {
fn get_count(&self) -> u32 {
CodeSectionReader::get_count(self)
}
}
impl<'a> IntoIterator for CodeSectionReader<'a> {
type Item = Result<FunctionBody<'a>>;
type IntoIter = SectionIteratorLimited<CodeSectionReader<'a>>;
fn into_iter(self) -> Self::IntoIter {
SectionIteratorLimited::new(self)
}
}