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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /third_party/rust/arrayref/src | |
parent | Initial commit. (diff) | |
download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip |
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'third_party/rust/arrayref/src')
-rw-r--r-- | third_party/rust/arrayref/src/lib.rs | 476 |
1 files changed, 476 insertions, 0 deletions
diff --git a/third_party/rust/arrayref/src/lib.rs b/third_party/rust/arrayref/src/lib.rs new file mode 100644 index 0000000000..b59b2fcd9c --- /dev/null +++ b/third_party/rust/arrayref/src/lib.rs @@ -0,0 +1,476 @@ +//! This package contains just four macros, which enable the creation +//! of array references to portions of arrays or slices (or things +//! that can be sliced). +//! +//! # Examples +//! +//! Here is a simple example of slicing and dicing a slice into array +//! references with these macros. Here we implement a simple +//! little-endian conversion from bytes to `u16`, and demonstrate code +//! that uses `array_ref!` to extract an array reference from a larger +//! array. Note that the documentation for each macro also has an +//! example of its use. +//! +//! ``` +//! #[macro_use] +//! extern crate arrayref; +//! +//! fn read_u16(bytes: &[u8; 2]) -> u16 { +//! bytes[0] as u16 + ((bytes[1] as u16) << 8) +//! } +//! // ... +//! # fn main() { +//! let data = [0,1,2,3,4,0,6,7,8,9]; +//! assert_eq!(256, read_u16(array_ref![data,0,2])); +//! assert_eq!(4, read_u16(array_ref![data,4,2])); +//! # } +//! ``` +#![deny(warnings)] +#![no_std] + +#[cfg(test)] +#[macro_use] +extern crate std; + +/// You can use `array_ref` to generate an array reference to a subset +/// of a sliceable bit of data (which could be an array, or a slice, +/// or a Vec). +/// +/// **Panics** if the slice is out of bounds. +/// +/// ``` +/// #[macro_use] +/// extern crate arrayref; +/// +/// fn read_u16(bytes: &[u8; 2]) -> u16 { +/// bytes[0] as u16 + ((bytes[1] as u16) << 8) +/// } +/// // ... +/// # fn main() { +/// let data = [0,1,2,3,4,0,6,7,8,9]; +/// assert_eq!(256, read_u16(array_ref![data,0,2])); +/// assert_eq!(4, read_u16(array_ref![data,4,2])); +/// # } +/// ``` + +#[macro_export] +macro_rules! array_ref { + ($arr:expr, $offset:expr, $len:expr) => {{ + { + #[inline] + unsafe fn as_array<T>(slice: &[T]) -> &[T; $len] { + &*(slice.as_ptr() as *const [_; $len]) + } + let offset = $offset; + let slice = & $arr[offset..offset + $len]; + #[allow(unused_unsafe)] + unsafe { + as_array(slice) + } + } + }} +} + +/// You can use `array_refs` to generate a series of array references +/// to an input array reference. The idea is if you want to break an +/// array into a series of contiguous and non-overlapping arrays. +/// `array_refs` is a bit funny in that it insists on slicing up the +/// *entire* array. This is intentional, as I find it handy to make +/// me ensure that my sub-arrays add up to the entire array. This +/// macro will *never* panic, since the sizes are all checked at +/// compile time. +/// +/// Note that unlike `array_ref!`, `array_refs` *requires* that the +/// first argument be an array reference. The following arguments are +/// the lengths of each subarray you wish a reference to. The total +/// of these arguments *must* equal the size of the array itself. +/// +/// ``` +/// #[macro_use] +/// extern crate arrayref; +/// +/// fn read_u16(bytes: &[u8; 2]) -> u16 { +/// bytes[0] as u16 + ((bytes[1] as u16) << 8) +/// } +/// // ... +/// # fn main() { +/// let data = [0,1,2,3,4,0,6,7]; +/// let (a,b,c) = array_refs![&data,2,2,4]; +/// assert_eq!(read_u16(a), 256); +/// assert_eq!(read_u16(b), 3*256+2); +/// assert_eq!(*c, [4,0,6,7]); +/// # } +/// ``` +#[macro_export] +macro_rules! array_refs { + ( $arr:expr, $( $pre:expr ),* ; .. ; $( $post:expr ),* ) => {{ + { + use std::slice; + #[inline] + #[allow(unused_assignments)] + #[allow(eval_order_dependence)] + unsafe fn as_arrays<T>(a: &[T]) -> ( $( &[T; $pre], )* &[T], $( &[T; $post], )*) { + let min_len = $( $pre + )* $( $post + )* 0; + let var_len = a.len() - min_len; + assert!(a.len() >= min_len); + let mut p = a.as_ptr(); + ( $( { + let aref = & *(p as *const [T; $pre]); + p = p.offset($pre as isize); + aref + } ),* , { + let sl = slice::from_raw_parts(p as *const T, var_len); + p = p.offset(var_len as isize); + sl + }, $( { + let aref = & *(p as *const [T; $post]); + p = p.offset($post as isize); + aref + } ),*) + } + let input = $arr; + #[allow(unused_unsafe)] + unsafe { + as_arrays(input) + } + } + }}; + ( $arr:expr, $( $len:expr ),* ) => {{ + { + #[inline] + #[allow(unused_assignments)] + #[allow(eval_order_dependence)] + unsafe fn as_arrays<T>(a: &[T; $( $len + )* 0 ]) -> ( $( &[T; $len], )* ) { + let mut p = a.as_ptr(); + ( $( { + let aref = &*(p as *const [T; $len]); + p = p.offset($len as isize); + aref + } ),* ) + } + let input = $arr; + #[allow(unused_unsafe)] + unsafe { + as_arrays(input) + } + } + }} +} + + +/// You can use `mut_array_refs` to generate a series of mutable array +/// references to an input mutable array reference. The idea is if +/// you want to break an array into a series of contiguous and +/// non-overlapping mutable array references. Like `array_refs!`, +/// `mut_array_refs!` is a bit funny in that it insists on slicing up +/// the *entire* array. This is intentional, as I find it handy to +/// make me ensure that my sub-arrays add up to the entire array. +/// This macro will *never* panic, since the sizes are all checked at +/// compile time. +/// +/// Note that unlike `array_mut_ref!`, `mut_array_refs` *requires* +/// that the first argument be a mutable array reference. The +/// following arguments are the lengths of each subarray you wish a +/// reference to. The total of these arguments *must* equal the size +/// of the array itself. Also note that this macro allows you to take +/// out multiple mutable references to a single object, which is both +/// weird and powerful. +/// +/// ``` +/// #[macro_use] +/// extern crate arrayref; +/// +/// fn write_u16(bytes: &mut [u8; 2], num: u16) { +/// bytes[0] = num as u8; +/// bytes[1] = (num >> 8) as u8; +/// } +/// fn write_u32(bytes: &mut [u8; 4], num: u32) { +/// bytes[0] = num as u8; +/// bytes[1] = (num >> 8) as u8; // this is buggy to save space... +/// } +/// // ... +/// # fn main() { +/// let mut data = [0,1,2,3,4,0,6,7]; +/// let (a,b,c) = mut_array_refs![&mut data,2,2,4]; +/// // let's write out some nice prime numbers! +/// write_u16(a, 37); +/// write_u16(b, 73); +/// write_u32(c, 137); // approximate inverse of the fine structure constant! +/// # } +/// ``` +#[macro_export] +macro_rules! mut_array_refs { + ( $arr:expr, $( $pre:expr ),* ; .. ; $( $post:expr ),* ) => {{ + { + use std::slice; + #[inline] + #[allow(unused_assignments)] + #[allow(eval_order_dependence)] + unsafe fn as_arrays<T>(a: &mut [T]) -> ( $( &mut [T; $pre], )* &mut [T], $( &mut [T; $post], )*) { + let min_len = $( $pre + )* $( $post + )* 0; + let var_len = a.len() - min_len; + assert!(a.len() >= min_len); + let mut p = a.as_mut_ptr(); + ( $( { + let aref = &mut *(p as *mut [T; $pre]); + p = p.offset($pre as isize); + aref + } ),* , { + let sl = slice::from_raw_parts_mut(p as *mut T, var_len); + p = p.offset(var_len as isize); + sl + }, $( { + let aref = &mut *(p as *mut [T; $post]); + p = p.offset($post as isize); + aref + } ),*) + } + let input = $arr; + #[allow(unused_unsafe)] + unsafe { + as_arrays(input) + } + } + }}; + ( $arr:expr, $( $len:expr ),* ) => {{ + { + #[inline] + #[allow(unused_assignments)] + #[allow(eval_order_dependence)] + unsafe fn as_arrays<T>(a: &mut [T; $( $len + )* 0 ]) -> ( $( &mut [T; $len], )* ) { + let mut p = a.as_mut_ptr(); + ( $( { + let aref = &mut *(p as *mut [T; $len]); + p = p.offset($len as isize); + aref + } ),* ) + } + let input = $arr; + #[allow(unused_unsafe)] + unsafe { + as_arrays(input) + } + } + }}; +} + +/// You can use `array_mut_ref` to generate a mutable array reference +/// to a subset of a sliceable bit of data (which could be an array, +/// or a slice, or a Vec). +/// +/// **Panics** if the slice is out of bounds. +/// +/// ``` +/// #[macro_use] +/// extern crate arrayref; +/// +/// fn write_u16(bytes: &mut [u8; 2], num: u16) { +/// bytes[0] = num as u8; +/// bytes[1] = (num >> 8) as u8; +/// } +/// // ... +/// # fn main() { +/// let mut data = [0,1,2,3,4,0,6,7,8,9]; +/// write_u16(array_mut_ref![data,0,2], 1); +/// write_u16(array_mut_ref![data,2,2], 5); +/// assert_eq!(*array_ref![data,0,4], [1,0,5,0]); +/// *array_mut_ref![data,4,5] = [4,3,2,1,0]; +/// assert_eq!(data, [1,0,5,0,4,3,2,1,0,9]); +/// # } +/// ``` +#[macro_export] +macro_rules! array_mut_ref { + ($arr:expr, $offset:expr, $len:expr) => {{ + { + #[inline] + unsafe fn as_array<T>(slice: &mut [T]) -> &mut [T; $len] { + &mut *(slice.as_mut_ptr() as *mut [_; $len]) + } + let offset = $offset; + let slice = &mut $arr[offset..offset + $len]; + #[allow(unused_unsafe)] + unsafe { + as_array(slice) + } + } + }} +} + + +#[cfg(test)] +mod test { + +extern crate quickcheck; + +use std::vec::Vec; + +// use super::*; + +#[test] +#[should_panic] +fn checks_bounds() { + let foo: [u8; 11] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + let bar = array_ref!(foo, 1, 11); + println!("I am checking that I can dereference bar[0] = {}", bar[0]); +} + +#[test] +fn simple_case_works() { + fn check(expected: [u8; 3], actual: &[u8; 3]) { + for (e, a) in (&expected).iter().zip(actual.iter()) { + assert_eq!(e, a) + } + } + let mut foo: [u8; 11] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; + { + let bar = array_ref!(foo, 2, 3); + check([2, 3, 4], bar); + } + check([0, 1, 2], array_ref!(foo, 0, 3)); + fn zero2(x: &mut [u8; 2]) { + x[0] = 0; + x[1] = 0; + } + zero2(array_mut_ref!(foo, 8, 2)); + check([0, 0, 10], array_ref!(foo, 8, 3)); +} + + +#[test] +fn check_array_ref_5() { + fn f(data: Vec<u8>, offset: usize) -> quickcheck::TestResult { + if data.len() < offset + 5 { + return quickcheck::TestResult::discard(); + } + let out = array_ref!(data, offset, 5); + quickcheck::TestResult::from_bool(out.len() == 5) + } + quickcheck::quickcheck(f as fn(Vec<u8>, usize) -> quickcheck::TestResult); +} + +#[test] +fn check_array_ref_out_of_bounds_5() { + fn f(data: Vec<u8>, offset: usize) -> quickcheck::TestResult { + if data.len() >= offset + 5 { + return quickcheck::TestResult::discard(); + } + quickcheck::TestResult::must_fail(move || { + array_ref!(data, offset, 5); + }) + } + quickcheck::quickcheck(f as fn(Vec<u8>, usize) -> quickcheck::TestResult); +} + +#[test] +fn check_array_mut_ref_7() { + fn f(mut data: Vec<u8>, offset: usize) -> quickcheck::TestResult { + if data.len() < offset + 7 { + return quickcheck::TestResult::discard(); + } + let out = array_mut_ref!(data, offset, 7); + out[6] = 3; + quickcheck::TestResult::from_bool(out.len() == 7) + } + quickcheck::quickcheck(f as fn(Vec<u8>, usize) -> quickcheck::TestResult); +} + + +#[test] +fn check_array_mut_ref_out_of_bounds_32() { + fn f(mut data: Vec<u8>, offset: usize) -> quickcheck::TestResult { + if data.len() >= offset + 32 { + return quickcheck::TestResult::discard(); + } + quickcheck::TestResult::must_fail(move || { + array_mut_ref!(data, offset, 32); + }) + } + quickcheck::quickcheck(f as fn(Vec<u8>, usize) -> quickcheck::TestResult); +} + + +#[test] +fn test_5_array_refs() { + let mut data: [usize; 128] = [0; 128]; + for i in 0..128 { + data[i] = i; + } + let data = data; + let (a,b,c,d,e) = array_refs!(&data, 1, 14, 3, 100, 10); + assert_eq!(a.len(), 1 as usize); + assert_eq!(b.len(), 14 as usize); + assert_eq!(c.len(), 3 as usize); + assert_eq!(d.len(), 100 as usize); + assert_eq!(e.len(), 10 as usize); + assert_eq!(a, array_ref![data, 0, 1]); + assert_eq!(b, array_ref![data, 1, 14]); + assert_eq!(c, array_ref![data, 15, 3]); + assert_eq!(e, array_ref![data, 118, 10]); +} + +#[test] +fn test_5_array_refs_dotdot() { + let mut data: [usize; 128] = [0; 128]; + for i in 0..128 { + data[i] = i; + } + let data = data; + let (a,b,c,d,e) = array_refs!(&data, 1, 14, 3; ..; 10); + assert_eq!(a.len(), 1 as usize); + assert_eq!(b.len(), 14 as usize); + assert_eq!(c.len(), 3 as usize); + assert_eq!(d.len(), 100 as usize); + assert_eq!(e.len(), 10 as usize); + assert_eq!(a, array_ref![data, 0, 1]); + assert_eq!(b, array_ref![data, 1, 14]); + assert_eq!(c, array_ref![data, 15, 3]); + assert_eq!(e, array_ref![data, 118, 10]); +} + + +#[test] +fn test_5_mut_xarray_refs() { + let mut data: [usize; 128] = [0; 128]; + { + // temporarily borrow the data to modify it. + let (a,b,c,d,e) = mut_array_refs!(&mut data, 1, 14, 3, 100, 10); + assert_eq!(a.len(), 1 as usize); + assert_eq!(b.len(), 14 as usize); + assert_eq!(c.len(), 3 as usize); + assert_eq!(d.len(), 100 as usize); + assert_eq!(e.len(), 10 as usize); + *a = [1; 1]; + *b = [14; 14]; + *c = [3; 3]; + *d = [100; 100]; + *e = [10; 10]; + } + assert_eq!(&[1;1], array_ref![data, 0, 1]); + assert_eq!(&[14;14], array_ref![data, 1, 14]); + assert_eq!(&[3;3], array_ref![data, 15, 3]); + assert_eq!(&[10;10], array_ref![data, 118, 10]); +} + +#[test] +fn test_5_mut_xarray_refs_with_dotdot() { + let mut data: [usize; 128] = [0; 128]; + { + // temporarily borrow the data to modify it. + let (a,b,c,d,e) = mut_array_refs!(&mut data, 1, 14, 3; ..; 10); + assert_eq!(a.len(), 1 as usize); + assert_eq!(b.len(), 14 as usize); + assert_eq!(c.len(), 3 as usize); + assert_eq!(d.len(), 100 as usize); + assert_eq!(e.len(), 10 as usize); + *a = [1; 1]; + *b = [14; 14]; + *c = [3; 3]; + *e = [10; 10]; + } + assert_eq!(&[1;1], array_ref![data, 0, 1]); + assert_eq!(&[14;14], array_ref![data, 1, 14]); + assert_eq!(&[3;3], array_ref![data, 15, 3]); + assert_eq!(&[10;10], array_ref![data, 118, 10]); +} + +} // mod test |