zerovec/ule/
tuple.rs

1// This file is part of ICU4X. For terms of use, please see the file
2// called LICENSE at the top level of the ICU4X source tree
3// (online at: https://github.com/unicode-org/icu4x/blob/main/LICENSE ).
4
5//! ULE impls for tuples.
6//!
7//! Rust does not guarantee the layout of tuples, so [`ZeroVec`](crate::ZeroVec) defines its own tuple ULE types.
8//!
9//! Impls are defined for tuples of up to 6 elements. For longer tuples, use a custom struct
10//! with [`#[make_ule]`](crate::make_ule).
11//!
12//! # Examples
13//!
14//! ```
15//! use zerovec::ZeroVec;
16//!
17//! // ZeroVec of tuples!
18//! let zerovec: ZeroVec<(u32, char)> = [(1, 'a'), (1234901, '啊'), (100, 'अ')]
19//!     .iter()
20//!     .copied()
21//!     .collect();
22//!
23//! assert_eq!(zerovec.get(1), Some((1234901, '啊')));
24//! ```
25
26use super::*;
27use core::fmt;
28
29macro_rules! tuple_ule {
30    ($name:ident, $len:literal, [ $($t:ident $i:tt),+ ]) => {
31        #[doc = concat!("ULE type for tuples with ", $len, " elements.")]
32        #[repr(C, packed)]
33        #[allow(clippy::exhaustive_structs)] // stable
34        pub struct $name<$($t),+>($(pub $t),+);
35
36        // Safety (based on the safety checklist on the ULE trait):
37        //  1. TupleULE does not include any uninitialized or padding bytes.
38        //     (achieved by `#[repr(C, packed)]` on a struct containing only ULE fields)
39        //  2. TupleULE is aligned to 1 byte.
40        //     (achieved by `#[repr(C, packed)]` on a struct containing only ULE fields)
41        //  3. The impl of validate_bytes() returns an error if any byte is not valid.
42        //  4. The impl of validate_bytes() returns an error if there are extra bytes.
43        //  5. The other ULE methods use the default impl.
44        //  6. TupleULE byte equality is semantic equality by relying on the ULE equality
45        //     invariant on the subfields
46        unsafe impl<$($t: ULE),+> ULE for $name<$($t),+> {
47            fn validate_bytes(bytes: &[u8]) -> Result<(), UleError> {
48                // expands to: 0size + size_of::<A>() + size_of::<B>();
49                let ule_bytes = 0usize $(+ size_of::<$t>())+;
50                if bytes.len() % ule_bytes != 0 {
51                    return Err(UleError::length::<Self>(bytes.len()));
52                }
53                for chunk in bytes.chunks(ule_bytes) {
54                    let mut i = 0;
55                    $(
56                        let j = i;
57                        i += size_of::<$t>();
58                        #[expect(clippy::indexing_slicing)] // length checked
59                        <$t>::validate_bytes(&chunk[j..i])?;
60                    )+
61                }
62                Ok(())
63            }
64        }
65
66        impl<$($t: AsULE),+> AsULE for ($($t),+) {
67            type ULE = $name<$(<$t>::ULE),+>;
68
69            #[inline]
70            fn to_unaligned(self) -> Self::ULE {
71                $name($(
72                    self.$i.to_unaligned()
73                ),+)
74            }
75
76            #[inline]
77            fn from_unaligned(unaligned: Self::ULE) -> Self {
78                ($(
79                    <$t>::from_unaligned(unaligned.$i)
80                ),+)
81            }
82        }
83
84        impl<$($t: fmt::Debug + ULE),+> fmt::Debug for $name<$($t),+> {
85            fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
86                ($(self.$i),+).fmt(f)
87            }
88        }
89
90        // We need manual impls since `#[derive()]` is disallowed on packed types
91        impl<$($t: PartialEq + ULE),+> PartialEq for $name<$($t),+> {
92            fn eq(&self, other: &Self) -> bool {
93                ($(self.$i),+).eq(&($(other.$i),+))
94            }
95        }
96
97        impl<$($t: Eq + ULE),+> Eq for $name<$($t),+> {}
98
99        impl<$($t: PartialOrd + ULE),+> PartialOrd for $name<$($t),+> {
100            fn partial_cmp(&self, other: &Self) -> Option<core::cmp::Ordering> {
101                ($(self.$i),+).partial_cmp(&($(other.$i),+))
102            }
103        }
104
105        impl<$($t: Ord + ULE),+> Ord for $name<$($t),+> {
106            fn cmp(&self, other: &Self) -> core::cmp::Ordering {
107                ($(self.$i),+).cmp(&($(other.$i),+))
108            }
109        }
110
111        impl<$($t: ULE),+> Clone for $name<$($t),+> {
112            fn clone(&self) -> Self {
113                *self
114            }
115        }
116
117        impl<$($t: ULE),+> Copy for $name<$($t),+> {}
118
119        #[cfg(feature = "alloc")]
120        impl<'a, $($t: Ord + AsULE + 'static),+> crate::map::ZeroMapKV<'a> for ($($t),+) {
121            type Container = crate::ZeroVec<'a, ($($t),+)>;
122            type Slice = crate::ZeroSlice<($($t),+)>;
123            type GetType = $name<$(<$t>::ULE),+>;
124            type OwnedType = ($($t),+);
125        }
126    };
127}
128
129tuple_ule!(Tuple2ULE, "2", [ A 0, B 1 ]);
130tuple_ule!(Tuple3ULE, "3", [ A 0, B 1, C 2 ]);
131tuple_ule!(Tuple4ULE, "4", [ A 0, B 1, C 2, D 3 ]);
132tuple_ule!(Tuple5ULE, "5", [ A 0, B 1, C 2, D 3, E 4 ]);
133tuple_ule!(Tuple6ULE, "6", [ A 0, B 1, C 2, D 3, E 4, F 5 ]);
134
135#[test]
136fn test_pairule_validate() {
137    use crate::ZeroVec;
138    let vec: Vec<(u32, char)> = vec![(1, 'a'), (1234901, '啊'), (100, 'अ')];
139    let zerovec: ZeroVec<(u32, char)> = vec.iter().copied().collect();
140    let bytes = zerovec.as_bytes();
141    let zerovec2 = ZeroVec::parse_bytes(bytes).unwrap();
142    assert_eq!(zerovec, zerovec2);
143
144    // Test failed validation with a correctly sized but differently constrained tuple
145    // Note: 1234901 is not a valid char
146    let zerovec3 = ZeroVec::<(char, u32)>::parse_bytes(bytes);
147    assert!(zerovec3.is_err());
148}
149
150#[test]
151fn test_tripleule_validate() {
152    use crate::ZeroVec;
153    let vec: Vec<(u32, char, i8)> = vec![(1, 'a', -5), (1234901, '啊', 3), (100, 'अ', -127)];
154    let zerovec: ZeroVec<(u32, char, i8)> = vec.iter().copied().collect();
155    let bytes = zerovec.as_bytes();
156    let zerovec2 = ZeroVec::parse_bytes(bytes).unwrap();
157    assert_eq!(zerovec, zerovec2);
158
159    // Test failed validation with a correctly sized but differently constrained tuple
160    // Note: 1234901 is not a valid char
161    let zerovec3 = ZeroVec::<(char, i8, u32)>::parse_bytes(bytes);
162    assert!(zerovec3.is_err());
163}
164
165#[test]
166fn test_quadule_validate() {
167    use crate::ZeroVec;
168    let vec: Vec<(u32, char, i8, u16)> =
169        vec![(1, 'a', -5, 3), (1234901, '啊', 3, 11), (100, 'अ', -127, 0)];
170    let zerovec: ZeroVec<(u32, char, i8, u16)> = vec.iter().copied().collect();
171    let bytes = zerovec.as_bytes();
172    let zerovec2 = ZeroVec::parse_bytes(bytes).unwrap();
173    assert_eq!(zerovec, zerovec2);
174
175    // Test failed validation with a correctly sized but differently constrained tuple
176    // Note: 1234901 is not a valid char
177    let zerovec3 = ZeroVec::<(char, i8, u16, u32)>::parse_bytes(bytes);
178    assert!(zerovec3.is_err());
179}
zerovec/ule/tuple.rs

zerovec/ule/
tuple.rs
