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use crate::read::{self, Error, ReadError as _};
use crate::{endian, CompressedFileRange, CompressionFormat, ReadRef, U32Bytes};
// Attempt to parse the the CompressedFileRange for a section using the GNU-style
// inline compression header format. This is used by the Go compiler in Mach-O files
// as well as by the GNU linker in some ELF files.
pub(super) fn compressed_file_range<'data, R: ReadRef<'data>>(
file_data: R,
section_offset: u64,
section_size: u64,
) -> read::Result<CompressedFileRange> {
let mut offset = section_offset;
// Assume ZLIB-style uncompressed data is no more than 4GB to avoid accidentally
// huge allocations. This also reduces the chance of accidentally matching on a
// .debug_str that happens to start with "ZLIB".
let header = file_data
.read_bytes(&mut offset, 8)
.read_error("GNU compressed section is too short")?;
if header != b"ZLIB\0\0\0\0" {
return Err(Error("Invalid GNU compressed section header"));
}
let uncompressed_size = file_data
.read::<U32Bytes<_>>(&mut offset)
.read_error("GNU compressed section is too short")?
.get(endian::BigEndian)
.into();
let compressed_size = section_size
.checked_sub(offset - section_offset)
.read_error("GNU compressed section is too short")?;
Ok(CompressedFileRange {
format: CompressionFormat::Zlib,
offset,
compressed_size,
uncompressed_size,
})
}