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make window size assertions much less complex with Magic

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Danny McClanahan 2024-05-18 04:04:32 -04:00
parent 7eb5907622
commit 83cdbadae8
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GPG key ID: 6105C10F1A199CC7
1 changed files with 6 additions and 6 deletions
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12
src/spec.rs
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@ -278,6 +278,8 @@ impl Zip32CentralDirectoryEnd {
let search_upper_bound = 0; let search_upper_bound = 0;
const END_WINDOW_SIZE: usize = 512; const END_WINDOW_SIZE: usize = 512;
/* TODO: use static_assertions!() */
assert!(END_WINDOW_SIZE > mem::size_of::<Magic>());
let sig_bytes = CENTRAL_DIRECTORY_END_SIGNATURE.to_le_bytes(); let sig_bytes = CENTRAL_DIRECTORY_END_SIGNATURE.to_le_bytes();
let finder = FinderRev::new(&sig_bytes); let finder = FinderRev::new(&sig_bytes);
@ -314,13 +316,12 @@ impl Zip32CentralDirectoryEnd {
if window_start == search_upper_bound { if window_start == search_upper_bound {
break; break;
} }
debug_assert!(END_WINDOW_SIZE > mem::size_of_val(&CENTRAL_DIRECTORY_END_SIGNATURE));
/* Shift the window by END_WINDOW_SIZE bytes, but make sure to cover matches that /* Shift the window by END_WINDOW_SIZE bytes, but make sure to cover matches that
* overlap our nice neat window boundaries! */ * overlap our nice neat window boundaries! */
window_start = (window_start window_start = (window_start
/* NB: To catch matches across window boundaries, we need to make our blocks overlap /* NB: To catch matches across window boundaries, we need to make our blocks overlap
* by the width of the pattern to match. */ * by the width of the pattern to match. */
+ mem::size_of_val(&CENTRAL_DIRECTORY_END_SIGNATURE) as u64) + mem::size_of::<Magic>() as u64)
/* This should never happen, but make sure we don't go past the end of the file. */ /* This should never happen, but make sure we don't go past the end of the file. */
.min(file_length); .min(file_length);
window_start = window_start window_start = window_start
@ -549,6 +550,8 @@ impl Zip64CentralDirectoryEnd {
let mut results = Vec::new(); let mut results = Vec::new();
const END_WINDOW_SIZE: usize = 2048; const END_WINDOW_SIZE: usize = 2048;
/* TODO: use static_assertions!() */
assert!(END_WINDOW_SIZE > mem::size_of::<Magic>());
let sig_bytes = ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE.to_le_bytes(); let sig_bytes = ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE.to_le_bytes();
let finder = FinderRev::new(&sig_bytes); let finder = FinderRev::new(&sig_bytes);
@ -592,15 +595,12 @@ impl Zip64CentralDirectoryEnd {
if window_start == nominal_offset { if window_start == nominal_offset {
break; break;
} }
debug_assert!(
END_WINDOW_SIZE > mem::size_of_val(&ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE)
);
/* Shift the window by END_WINDOW_SIZE bytes, but make sure to cover matches that /* Shift the window by END_WINDOW_SIZE bytes, but make sure to cover matches that
* overlap our nice neat window boundaries! */ * overlap our nice neat window boundaries! */
window_start = (window_start window_start = (window_start
/* NB: To catch matches across window boundaries, we need to make our blocks overlap /* NB: To catch matches across window boundaries, we need to make our blocks overlap
* by the width of the pattern to match. */ * by the width of the pattern to match. */
+ mem::size_of_val(&ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE) as u64) + mem::size_of::<Magic>() as u64)
/* This may never happen, but make sure we don't go past the end of the specified /* This may never happen, but make sure we don't go past the end of the specified
* range. */ * range. */
.min(search_upper_bound); .min(search_upper_bound);