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Use u64's for internal file offsets.

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These are better aligned with Rust's APIs, and lay the groundwork for more
convenient support of Zip64 files.
This commit is contained in:
Peter Williams 2017-08-12 13:38:07 -04:00
parent 5a123f2767
commit 89f33c9348
2 changed files with 21 additions and 18 deletions
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14
src/read.rs
View file

@ -54,7 +54,7 @@ pub struct ZipArchive<R: Read + io::Seek>
reader: R,
files: Vec<ZipFileData>,
names_map: HashMap<String, usize>,
offset: u32,
offset: u64,
}
enum ZipFileReader<'a> {
@ -85,11 +85,11 @@ impl<R: Read+io::Seek> ZipArchive<R>
// Some zip files have data prepended to them, resulting in the offsets all being too small. Get the amount of
// error by comparing the actual file position we found the CDE at with the offset recorded in the CDE.
let archive_offset = cde_start_pos.checked_sub(footer.central_directory_size)
.and_then(|x| x.checked_sub(footer.central_directory_offset))
let archive_offset = cde_start_pos.checked_sub(footer.central_directory_size as u64)
.and_then(|x| x.checked_sub(footer.central_directory_offset as u64))
.ok_or(ZipError::InvalidArchive("Invalid central directory size or offset"))?;
let directory_start = (footer.central_directory_offset + archive_offset) as u64;
let directory_start = footer.central_directory_offset as u64 + archive_offset;
let number_of_files = footer.number_of_files_on_this_disk as usize;
let mut files = Vec::with_capacity(number_of_files);
@ -132,7 +132,7 @@ impl<R: Read+io::Seek> ZipArchive<R>
///
/// Normally this value is zero, but if the zip has arbitrary data prepended to it, then this value will be the size
/// of that prepended data.
pub fn offset(&self) -> u32 {
pub fn offset(&self) -> u64 {
self.offset
}
@ -198,7 +198,7 @@ impl<R: Read+io::Seek> ZipArchive<R>
}
}
fn central_header_to_zip_file<R: Read+io::Seek>(reader: &mut R, archive_offset: u32) -> ZipResult<ZipFileData>
fn central_header_to_zip_file<R: Read+io::Seek>(reader: &mut R, archive_offset: u64) -> ZipResult<ZipFileData>
{
// Parse central header
let signature = try!(reader.read_u32::<LittleEndian>());
@ -230,7 +230,7 @@ fn central_header_to_zip_file<R: Read+io::Seek>(reader: &mut R, archive_offset:
let file_comment_raw = try!(ReadPodExt::read_exact(reader, file_comment_length));
// Account for shifted zip offsets.
offset += archive_offset as u64;
offset += archive_offset;
let file_name = match is_utf8
{

25
src/spec.rs
View file

@ -48,29 +48,32 @@ impl CentralDirectoryEnd
})
}
pub fn find_and_parse<T: Read+io::Seek>(reader: &mut T) -> ZipResult<(CentralDirectoryEnd, u32)>
pub fn find_and_parse<T: Read+io::Seek>(reader: &mut T) -> ZipResult<(CentralDirectoryEnd, u64)>
{
let header_size = 22;
let bytes_between_magic_and_comment_size = header_size - 6;
let file_length = try!(reader.seek(io::SeekFrom::End(0))) as i64;
const HEADER_SIZE: u64 = 22;
const BYTES_BETWEEN_MAGIC_AND_COMMENT_SIZE: u64 = HEADER_SIZE - 6;
let file_length = try!(reader.seek(io::SeekFrom::End(0)));
let search_upper_bound = ::std::cmp::max(0, file_length - header_size - ::std::u16::MAX as i64);
let search_upper_bound = file_length.checked_sub(HEADER_SIZE + ::std::u16::MAX as u64).unwrap_or(0);
let mut pos = file_length - header_size;
let mut pos = file_length - HEADER_SIZE;
while pos >= search_upper_bound
{
try!(reader.seek(io::SeekFrom::Start(pos as u64)));
if try!(reader.read_u32::<LittleEndian>()) == CENTRAL_DIRECTORY_END_SIGNATURE
{
try!(reader.seek(io::SeekFrom::Current(bytes_between_magic_and_comment_size)));
let comment_length = try!(reader.read_u16::<LittleEndian>()) as i64;
if file_length - pos - header_size == comment_length
try!(reader.seek(io::SeekFrom::Current(BYTES_BETWEEN_MAGIC_AND_COMMENT_SIZE as i64)));
let comment_length = try!(reader.read_u16::<LittleEndian>()) as u64;
if file_length - pos - HEADER_SIZE == comment_length
{
let cde_start_pos = try!(reader.seek(io::SeekFrom::Start(pos as u64))) as u32;
let cde_start_pos = try!(reader.seek(io::SeekFrom::Start(pos as u64)));
return CentralDirectoryEnd::parse(reader).map(|cde| (cde, cde_start_pos));
}
}
pos -= 1;
pos = match pos.checked_sub(1) {
Some(p) => p,
None => break,
};
}
Err(ZipError::InvalidArchive("Could not find central directory end"))
}