Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 239 insertions, 0 deletions

diff --git a/third_party/rust/object/src/pod.rs b/third_party/rust/object/src/pod.rs
new file mode 100644
index 0000000000..8ee78164f5
--- /dev/null
+++ b/third_party/rust/object/src/pod.rs
@@ -0,0 +1,239 @@
+//! Tools for converting file format structures to and from bytes.
+//!
+//! This module should be replaced once rust provides safe transmutes.
+
+// This module provides functions for both read and write features.
+#![cfg_attr(
+    not(all(feature = "read_core", feature = "write_core")),
+    allow(dead_code)
+)]
+
+use core::{mem, result, slice};
+
+type Result<T> = result::Result<T, ()>;
+
+/// A trait for types that can safely be converted from and to byte slices.
+///
+/// # Safety
+/// A type that is `Pod` must:
+/// - be `#[repr(C)]` or `#[repr(transparent)]`
+/// - have no invalid byte values
+/// - have no padding
+pub unsafe trait Pod: Copy + 'static {}
+
+/// Cast a byte slice to a `Pod` type.
+///
+/// Returns the type and the tail of the slice.
+#[inline]
+pub fn from_bytes<T: Pod>(data: &[u8]) -> Result<(&T, &[u8])> {
+    let size = mem::size_of::<T>();
+    let tail = data.get(size..).ok_or(())?;
+    let ptr = data.as_ptr();
+    if (ptr as usize) % mem::align_of::<T>() != 0 {
+        return Err(());
+    }
+    // Safety:
+    // The alignment and size are checked by this function.
+    // The Pod trait ensures the type is valid to cast from bytes.
+    let val = unsafe { &*ptr.cast() };
+    Ok((val, tail))
+}
+
+/// Cast a mutable byte slice to a `Pod` type.
+///
+/// Returns the type and the tail of the slice.
+#[inline]
+pub fn from_bytes_mut<T: Pod>(data: &mut [u8]) -> Result<(&mut T, &mut [u8])> {
+    let size = mem::size_of::<T>();
+    if size > data.len() {
+        return Err(());
+    }
+    let (data, tail) = data.split_at_mut(size);
+    let ptr = data.as_mut_ptr();
+    if (ptr as usize) % mem::align_of::<T>() != 0 {
+        return Err(());
+    }
+    // Safety:
+    // The alignment and size are checked by this function.
+    // The Pod trait ensures the type is valid to cast from bytes.
+    let val = unsafe { &mut *ptr.cast() };
+    Ok((val, tail))
+}
+
+/// Cast a byte slice to a slice of a `Pod` type.
+///
+/// Returns the type slice and the tail of the byte slice.
+#[inline]
+pub fn slice_from_bytes<T: Pod>(data: &[u8], count: usize) -> Result<(&[T], &[u8])> {
+    let size = count.checked_mul(mem::size_of::<T>()).ok_or(())?;
+    let tail = data.get(size..).ok_or(())?;
+    let ptr = data.as_ptr();
+    if (ptr as usize) % mem::align_of::<T>() != 0 {
+        return Err(());
+    }
+    // Safety:
+    // The alignment and size are checked by this function.
+    // The Pod trait ensures the type is valid to cast from bytes.
+    let slice = unsafe { slice::from_raw_parts(ptr.cast(), count) };
+    Ok((slice, tail))
+}
+
+/// Cast a mutable byte slice to a slice of a `Pod` type.
+///
+/// Returns the type slice and the tail of the byte slice.
+#[inline]
+pub fn slice_from_bytes_mut<T: Pod>(
+    data: &mut [u8],
+    count: usize,
+) -> Result<(&mut [T], &mut [u8])> {
+    let size = count.checked_mul(mem::size_of::<T>()).ok_or(())?;
+    if size > data.len() {
+        return Err(());
+    }
+    let (data, tail) = data.split_at_mut(size);
+    let ptr = data.as_mut_ptr();
+    if (ptr as usize) % mem::align_of::<T>() != 0 {
+        return Err(());
+    }
+    // Safety:
+    // The alignment and size are checked by this function.
+    // The Pod trait ensures the type is valid to cast from bytes.
+    let slice = unsafe { slice::from_raw_parts_mut(ptr.cast(), count) };
+    Ok((slice, tail))
+}
+
+/// Cast a `Pod` type to a byte slice.
+#[inline]
+pub fn bytes_of<T: Pod>(val: &T) -> &[u8] {
+    let size = mem::size_of::<T>();
+    // Safety:
+    // Any alignment is allowed.
+    // The size is determined in this function.
+    // The Pod trait ensures the type is valid to cast to bytes.
+    unsafe { slice::from_raw_parts(slice::from_ref(val).as_ptr().cast(), size) }
+}
+
+/// Cast a `Pod` type to a mutable byte slice.
+#[inline]
+pub fn bytes_of_mut<T: Pod>(val: &mut T) -> &mut [u8] {
+    let size = mem::size_of::<T>();
+    // Safety:
+    // Any alignment is allowed.
+    // The size is determined in this function.
+    // The Pod trait ensures the type is valid to cast to bytes.
+    unsafe { slice::from_raw_parts_mut(slice::from_mut(val).as_mut_ptr().cast(), size) }
+}
+
+/// Cast a slice of a `Pod` type to a byte slice.
+#[inline]
+pub fn bytes_of_slice<T: Pod>(val: &[T]) -> &[u8] {
+    let size = val.len().wrapping_mul(mem::size_of::<T>());
+    // Safety:
+    // Any alignment is allowed.
+    // The size is determined in this function.
+    // The Pod trait ensures the type is valid to cast to bytes.
+    unsafe { slice::from_raw_parts(val.as_ptr().cast(), size) }
+}
+
+/// Cast a slice of a `Pod` type to a mutable byte slice.
+#[inline]
+pub fn bytes_of_slice_mut<T: Pod>(val: &mut [T]) -> &mut [u8] {
+    let size = val.len().wrapping_mul(mem::size_of::<T>());
+    // Safety:
+    // Any alignment is allowed.
+    // The size is determined in this function.
+    // The Pod trait ensures the type is valid to cast to bytes.
+    unsafe { slice::from_raw_parts_mut(val.as_mut_ptr().cast(), size) }
+}
+
+macro_rules! unsafe_impl_pod {
+    ($($struct_name:ident),+ $(,)?) => {
+        $(
+            unsafe impl Pod for $struct_name { }
+        )+
+    }
+}
+
+unsafe_impl_pod!(u8, u16, u32, u64);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn single() {
+        let x = u32::to_be(0x0123_4567);
+        let mut x_mut = x;
+        let bytes = bytes_of(&x);
+        let bytes_mut = bytes_of_mut(&mut x_mut);
+        assert_eq!(bytes, [0x01, 0x23, 0x45, 0x67]);
+        assert_eq!(bytes, bytes_mut);
+
+        let x16 = [u16::to_be(0x0123), u16::to_be(0x4567)];
+
+        let (y, tail) = from_bytes::<u32>(bytes).unwrap();
+        let (y_mut, tail_mut) = from_bytes_mut::<u32>(bytes_mut).unwrap();
+        assert_eq!(*y, x);
+        assert_eq!(y, y_mut);
+        assert_eq!(tail, &[]);
+        assert_eq!(tail, tail_mut);
+
+        let (y, tail) = from_bytes::<u16>(bytes).unwrap();
+        let (y_mut, tail_mut) = from_bytes_mut::<u16>(bytes_mut).unwrap();
+        assert_eq!(*y, x16[0]);
+        assert_eq!(y, y_mut);
+        assert_eq!(tail, &bytes[2..]);
+        assert_eq!(tail, tail_mut);
+
+        let (y, tail) = from_bytes::<u16>(&bytes[2..]).unwrap();
+        let (y_mut, tail_mut) = from_bytes_mut::<u16>(&mut bytes_mut[2..]).unwrap();
+        assert_eq!(*y, x16[1]);
+        assert_eq!(y, y_mut);
+        assert_eq!(tail, &[]);
+        assert_eq!(tail, tail_mut);
+
+        assert_eq!(from_bytes::<u16>(&bytes[1..]), Err(()));
+        assert_eq!(from_bytes::<u16>(&bytes[3..]), Err(()));
+        assert_eq!(from_bytes::<u16>(&bytes[4..]), Err(()));
+        assert_eq!(from_bytes_mut::<u16>(&mut bytes_mut[1..]), Err(()));
+        assert_eq!(from_bytes_mut::<u16>(&mut bytes_mut[3..]), Err(()));
+        assert_eq!(from_bytes_mut::<u16>(&mut bytes_mut[4..]), Err(()));
+    }
+
+    #[test]
+    fn slice() {
+        let x = [
+            u16::to_be(0x0123),
+            u16::to_be(0x4567),
+            u16::to_be(0x89ab),
+            u16::to_be(0xcdef),
+        ];
+        let mut x_mut = x;
+
+        let bytes = bytes_of_slice(&x);
+        let bytes_mut = bytes_of_slice_mut(&mut x_mut);
+        assert_eq!(bytes, [0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef]);
+        assert_eq!(bytes, bytes_mut);
+
+        let (y, tail) = slice_from_bytes::<u16>(bytes, 4).unwrap();
+        let (y_mut, tail_mut) = slice_from_bytes_mut::<u16>(bytes_mut, 4).unwrap();
+        assert_eq!(y, x);
+        assert_eq!(y, y_mut);
+        assert_eq!(tail, &[]);
+        assert_eq!(tail, tail_mut);
+
+        let (y, tail) = slice_from_bytes::<u16>(&bytes[2..], 2).unwrap();
+        let (y_mut, tail_mut) = slice_from_bytes::<u16>(&mut bytes_mut[2..], 2).unwrap();
+        assert_eq!(y, &x[1..3]);
+        assert_eq!(y, y_mut);
+        assert_eq!(tail, &bytes[6..]);
+        assert_eq!(tail, tail_mut);
+
+        assert_eq!(slice_from_bytes::<u16>(bytes, 5), Err(()));
+        assert_eq!(slice_from_bytes::<u16>(&bytes[2..], 4), Err(()));
+        assert_eq!(slice_from_bytes::<u16>(&bytes[1..], 2), Err(()));
+        assert_eq!(slice_from_bytes_mut::<u16>(bytes_mut, 5), Err(()));
+        assert_eq!(slice_from_bytes_mut::<u16>(&mut bytes_mut[2..], 4), Err(()));
+        assert_eq!(slice_from_bytes_mut::<u16>(&mut bytes_mut[1..], 2), Err(()));
+    }
+}