use super::{
BinaryReader, BinaryReaderError, InitExpr, Range, Result, SectionIteratorLimited,
SectionReader, SectionWithLimitedItems,
};
#[derive(Debug, Copy, Clone)]
pub struct Data<'a> {
pub kind: DataKind<'a>,
pub data: &'a [u8],
}
#[derive(Debug, Copy, Clone)]
pub enum DataKind<'a> {
Passive,
Active {
memory_index: u32,
init_expr: InitExpr<'a>,
},
}
#[derive(Clone)]
pub struct DataSectionReader<'a> {
reader: BinaryReader<'a>,
count: u32,
forbid_bulk_memory: bool,
}
impl<'a> DataSectionReader<'a> {
pub fn new(data: &'a [u8], offset: usize) -> Result<DataSectionReader<'a>> {
let mut reader = BinaryReader::new_with_offset(data, offset);
let count = reader.read_var_u32()?;
Ok(DataSectionReader {
reader,
count,
forbid_bulk_memory: false,
})
}
pub fn original_position(&self) -> usize {
self.reader.original_position()
}
pub fn get_count(&self) -> u32 {
self.count
}
pub fn forbid_bulk_memory(&mut self, forbid: bool) {
self.forbid_bulk_memory = forbid;
}
fn verify_data_end(&self, end: usize) -> Result<()> {
if self.reader.buffer.len() < end {
return Err(BinaryReaderError::new(
"Data segment extends past end of the data section",
self.reader.original_offset + self.reader.buffer.len(),
));
}
Ok(())
}
pub fn read<'b>(&mut self) -> Result<Data<'b>>
where
'a: 'b,
{
let flags = self.reader.read_var_u32()?;
let kind = if !self.forbid_bulk_memory && flags == 1 {
DataKind::Passive
} else {
let memory_index = match flags {
0 => 0,
_ if self.forbid_bulk_memory => flags,
2 => self.reader.read_var_u32()?,
_ => {
return Err(BinaryReaderError::new(
"invalid flags byte in data segment",
self.reader.original_position() - 1,
));
}
};
let init_expr = {
let expr_offset = self.reader.position;
self.reader.skip_init_expr()?;
let data = &self.reader.buffer[expr_offset..self.reader.position];
InitExpr::new(data, self.reader.original_offset + expr_offset)
};
DataKind::Active {
memory_index,
init_expr,
}
};
let data_len = self.reader.read_var_u32()? as usize;
let data_end = self.reader.position + data_len;
self.verify_data_end(data_end)?;
let data = &self.reader.buffer[self.reader.position..data_end];
self.reader.skip_to(data_end);
Ok(Data { kind, data })
}
}
impl<'a> SectionReader for DataSectionReader<'a> {
type Item = Data<'a>;
fn read(&mut self) -> Result<Self::Item> {
DataSectionReader::read(self)
}
fn eof(&self) -> bool {
self.reader.eof()
}
fn original_position(&self) -> usize {
DataSectionReader::original_position(self)
}
fn range(&self) -> Range {
self.reader.range()
}
}
impl<'a> SectionWithLimitedItems for DataSectionReader<'a> {
fn get_count(&self) -> u32 {
DataSectionReader::get_count(self)
}
}
impl<'a> IntoIterator for DataSectionReader<'a> {
type Item = Result<Data<'a>>;
type IntoIter = SectionIteratorLimited<DataSectionReader<'a>>;
fn into_iter(self) -> Self::IntoIter {
SectionIteratorLimited::new(self)
}
}