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use core::slice;
use crate::endian::{LittleEndian as LE, U16};
use crate::pe;
use crate::read::{Bytes, Error, ReadError, Result};
/// An iterator over the relocation blocks in the `.reloc` section of a PE file.
///
/// Returned by [`DataDirectories::relocation_blocks`](super::DataDirectories::relocation_blocks).
#[derive(Debug, Default, Clone, Copy)]
pub struct RelocationBlockIterator<'data> {
data: Bytes<'data>,
}
impl<'data> RelocationBlockIterator<'data> {
/// Construct a new iterator from the data of the `.reloc` section.
pub fn new(data: &'data [u8]) -> Self {
RelocationBlockIterator { data: Bytes(data) }
}
/// Read the next relocation page.
pub fn next(&mut self) -> Result<Option<RelocationIterator<'data>>> {
if self.data.is_empty() {
return Ok(None);
}
let result = self.parse().map(Some);
if result.is_err() {
self.data = Bytes(&[]);
}
result
}
fn parse(&mut self) -> Result<RelocationIterator<'data>> {
let header = self
.data
.read::<pe::ImageBaseRelocation>()
.read_error("Invalid PE reloc section size")?;
let virtual_address = header.virtual_address.get(LE);
let size = header.size_of_block.get(LE);
if size <= 8 || size & 3 != 0 {
return Err(Error("Invalid PE reloc block size"));
}
let count = (size - 8) / 2;
let relocs = self
.data
.read_slice::<U16<LE>>(count as usize)
.read_error("Invalid PE reloc block size")?
.iter();
Ok(RelocationIterator {
virtual_address,
size,
relocs,
})
}
}
impl<'data> Iterator for RelocationBlockIterator<'data> {
type Item = Result<RelocationIterator<'data>>;
fn next(&mut self) -> Option<Self::Item> {
self.next().transpose()
}
}
/// An iterator of the relocations in a block in the `.reloc` section of a PE file.
#[derive(Debug, Clone)]
pub struct RelocationIterator<'data> {
virtual_address: u32,
size: u32,
relocs: slice::Iter<'data, U16<LE>>,
}
impl<'data> RelocationIterator<'data> {
/// Return the virtual address of the page that this block of relocations applies to.
pub fn virtual_address(&self) -> u32 {
self.virtual_address
}
/// Return the size in bytes of this block of relocations.
pub fn size(&self) -> u32 {
self.size
}
}
impl<'data> Iterator for RelocationIterator<'data> {
type Item = Relocation;
fn next(&mut self) -> Option<Relocation> {
loop {
let reloc = self.relocs.next()?.get(LE);
if reloc != 0 {
return Some(Relocation {
virtual_address: self.virtual_address.wrapping_add((reloc & 0xfff) as u32),
typ: reloc >> 12,
});
}
}
}
}
/// A relocation in the `.reloc` section of a PE file.
#[derive(Debug, Default, Clone, Copy)]
pub struct Relocation {
/// The virtual address of the relocation.
pub virtual_address: u32,
/// One of the `pe::IMAGE_REL_BASED_*` constants.
pub typ: u16,
}