24195165729

Committed 09 Apr 2026 02:17PM UTC coverage: 70.88% (-0.1%) from 71.015%

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Removed slow tests from testing

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/src/array/partial_array.rs

/*
 * SPDX-FileCopyrightText: 2025 Sebastiano Vigna
 *
 * SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
 */

//! Immutable [partial array](PartialArray) implementations.

use std::marker::PhantomData;

use mem_dbg::*;
use value_traits::slices::SliceByValue;

use crate::bits::{BitFieldVec, BitVec};
use crate::dict::EliasFanoBuilder;
use crate::dict::elias_fano::EliasFano;
use crate::panic_if_out_of_bounds;
use crate::rank_sel::{Rank9, SelectZeroAdaptConst};
use crate::traits::Backend;
use crate::traits::TryIntoUnaligned;
use crate::traits::Unaligned;
use crate::traits::{BitVecOps, BitVecOpsMut};
use crate::traits::{RankUnchecked, SuccUnchecked};

// Rank9 is inherently u64-based, so the dense index must use u64 backing
// regardless of usize.
type DenseIndex = Rank9<BitVec<Box<[u64]>>>;

/// An internal index for sparse partial arrays.
///
/// We cannot use directly an [Elias–Fano](crate::dict::EliasFano) structure
/// because we need to keep track of the first invalid position; and we need to
/// keep track of the first invalid position because we want to implement just
/// [`SuccUnchecked`](crate::traits::SuccUnchecked) on the Elias–Fano structure,
/// because it requires just
/// [`SelectZeroUnchecked`](crate::traits::SelectZeroUnchecked), whereas
/// [`Succ`](crate::traits::Succ) would require
/// [`SelectUnchecked`](crate::traits::SelectUnchecked) as well.
#[doc(hidden)]
#[derive(Debug, Clone, MemDbg, MemSize)]
#[cfg_attr(feature = "epserde", derive(epserde::Epserde))]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct SparseIndex<D, L = BitFieldVec<Box<[u64]>>> {
    ef: EliasFano<u64, SelectZeroAdaptConst<BitVec<D>, Box<[usize]>, 12, 3>, L>,
    /// self.ef should not be queried for values >= self.first_invalid_position
    first_invalid_pos: usize,
}

/// Builder for creating an immutable partial array.
///
/// The builder allows you to specify the array length and then add
/// (position, value) pairs. Positions must be added in strictly
/// increasing order.
///
/// To get a builder you can use either [new_dense] or [new_sparse].
#[derive(Debug, Clone, MemDbg, MemSize)]
pub struct PartialArrayBuilder<T, B> {
    builder: B,
    values: Vec<T>,
    len: usize,
    min_next_pos: usize,
}

/// Creates a new builder for a dense partial array of the given length.
///
/// A dense partial array stores a bit vector of the given length to mark
/// which positions contain values, and uses ranking on this bit vector to
/// map positions to indices in a contiguous value array.
///
/// If your set of values is really sparse, consider using a
/// [sparse partial array](new_sparse).
///
/// # Examples
///
/// ```rust
/// # use sux::array::partial_array;
/// let mut builder = partial_array::new_dense(10);
/// builder.set(1, "foo");
/// builder.set(2, "hello");
/// builder.set(7, "world");
///
/// let array = builder.build();
/// assert_eq!(array.get(1), Some(&"foo"));
/// assert_eq!(array.get(2), Some(&"hello"));
/// assert_eq!(array.get(3), None);
/// assert_eq!(array.get(7), Some(&"world"));
/// ```
pub fn new_dense<T>(len: usize) -> PartialArrayBuilder<T, BitVec<Box<[u64]>>> {
    let n_of_words = len.div_ceil(64);
    // SAFETY: the backing has exactly enough words for len bits
    let bit_vec = unsafe { BitVec::from_raw_parts(vec![0u64; n_of_words].into_boxed_slice(), len) };
    PartialArrayBuilder {
        builder: bit_vec,
        values: vec![],
        len,
        min_next_pos: 0,
    }
}

impl<T> PartialArrayBuilder<T, BitVec<Box<[u64]>>> {
    /// Sets a value at the given position.
    ///
    /// The provided position must be greater than the last position set.
    pub fn set(&mut self, position: usize, value: T) {
        if position < self.min_next_pos {
            panic!(
                "Positions must be set in increasing order: got {} after {}",
                position,
                self.min_next_pos - 1
            );
        }
        panic_if_out_of_bounds!(position, self.len);

        // SAFETY: position < len
        unsafe {
            self.builder.set_unchecked(position, true);
        }
        self.values.push(value);
        self.min_next_pos = position + 1;
    }

    /// Builds the immutable dense partial array.
    pub fn build(self) -> PartialArray<T, Rank9<BitVec<Box<[u64]>>>> {
        let (bit_vec, values) = (self.builder, self.values);
        let rank9 = Rank9::new(bit_vec);
        let values = values.into_boxed_slice();

        PartialArray {
            index: rank9,
            values,
            _marker: PhantomData,
        }
    }
}

/// Creates a new builder for a sparse partial array of the given length.
///
/// A sparse partial array stores the non-empty positions of the array in an
/// [Elias-Fano](crate::dict::EliasFano) structure.
///
/// If your set of values is really dense, consider using a [dense partial
/// array](new_dense).
///
/// # Examples
///
/// ```rust
/// # use sux::array::partial_array;
/// let mut builder = partial_array::new_sparse(10, 3);
/// builder.set(1, "foo");
/// builder.set(2, "hello");
/// builder.set(7, "world");
///
/// let array = builder.build();
/// assert_eq!(array.get(1), Some(&"foo"));
/// assert_eq!(array.get(2), Some(&"hello"));
/// assert_eq!(array.get(3), None);
/// assert_eq!(array.get(7), Some(&"world"));
/// ```
///
/// Note that you must specify the number of values in advance.
pub fn new_sparse<T>(
    len: usize,
    num_values: usize,
) -> PartialArrayBuilder<T, EliasFanoBuilder<u64>> {
    PartialArrayBuilder {
        builder: EliasFanoBuilder::<u64>::new(num_values, len as u64),
        values: vec![],
        len,
        min_next_pos: 0,
    }
}

impl<T> PartialArrayBuilder<T, EliasFanoBuilder<u64>> {
    /// Sets a value at the given position.
    ///
    /// The provided position must be greater than the last position
    /// set.
    pub fn set(&mut self, position: usize, value: T) {
        if position < self.min_next_pos {
            panic!(
                "Positions must be set in increasing order: got {} after {}",
                position,
                self.min_next_pos - 1
            );
        }
        panic_if_out_of_bounds!(position, self.len);
        // SAFETY: conditions have been just checked
        unsafe { self.builder.push_unchecked(position as u64) };
        self.values.push(value);
        self.min_next_pos = position + 1;
    }

    /// Builds the immutable sparse partial array.
    pub fn build(self) -> PartialArray<T, SparseIndex<Box<[usize]>>> {
        let (builder, values) = (self.builder, self.values);
        let ef_dict = builder.build_with_dict();
        let values = values.into_boxed_slice();

        PartialArray {
            index: SparseIndex {
                ef: ef_dict,
                first_invalid_pos: self.min_next_pos,
            },
            values,
            _marker: PhantomData,
        }
    }
}

/// Extends the builder with an iterator of (position, value) pairs.
///
/// Position must be in strictly increasing order. The first returned
/// position must be greater than the last position set.
impl<T> Extend<(usize, T)> for PartialArrayBuilder<T, BitVec<Box<[u64]>>> {
    fn extend<I: IntoIterator<Item = (usize, T)>>(&mut self, iter: I) {
        for (pos, val) in iter {
            self.set(pos, val);
        }
    }
}

/// Extends the builder with an iterator of (position, value) pairs.
///
/// Position must be in strictly increasing order. The first returned
/// position must be greater than the last position set.
impl<T> Extend<(usize, T)> for PartialArrayBuilder<T, EliasFanoBuilder<u64>> {
    fn extend<I: IntoIterator<Item = (usize, T)>>(&mut self, iter: I) {
        for (pos, val) in iter {
            self.set(pos, val);
        }
    }
}

/// An immutable partial array that supports efficient queries
/// in compacted storage.
///
/// This structure stores a *partial array*—an array in which only
/// some positions contain values. There is a [dense](new_dense)
/// and a [sparse](new_sparse) implementation with different
/// space/time trade-offs.
///
/// For convenience, this structure implements [`SliceByValue`].
///
/// When the index structure `P` supports it, this structure implements the
/// [`TryIntoUnaligned`] trait, allowing it
/// to be converted into (usually faster) structures using unaligned access.
///
/// See [`PartialArrayBuilder`] for details on how to create a partial array.
#[derive(Debug, Clone, MemDbg, MemSize)]
#[cfg_attr(feature = "epserde", derive(epserde::Epserde))]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub struct PartialArray<T, P, V = Box<[T]>> {
    index: P,
    values: V,
    _marker: PhantomData<T>,
}

impl<T, P, V: AsRef<[T]>> PartialArray<T, P, V> {
    /// Returns the number of values stored in the array.
    #[inline(always)]
    pub fn num_values(&self) -> usize {
        self.values.as_ref().len()
    }
}

impl<T, V: AsRef<[T]>> PartialArray<T, DenseIndex, V> {
    /// Returns the total length of the array.
    ///
    /// This is the length that was specified when creating the builder,
    /// not the number of values actually stored.
    #[inline(always)]
    pub fn len(&self) -> usize {
        self.index.len()
    }

    /// Returns `true` if the array has no elements.
    #[inline(always)]
    pub fn is_empty(&self) -> bool {
        self.len() == 0
    }

    /// Gets a reference to the value at the given position.
    ///
    /// Returns `Some(&value)` if a value is present at the position,
    /// or `None` if no value was stored there.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use sux::array::partial_array;
    /// let mut builder = partial_array::new_dense(10);
    /// builder.set(5, 42);
    ///
    /// let array = builder.build();
    /// assert_eq!(array.get(5), Some(&42));
    /// assert_eq!(array.get(6), None);
    /// ```
    pub fn get(&self, position: usize) -> Option<&T> {
        panic_if_out_of_bounds!(position, self.len());

        // SAFETY: we just checked
        unsafe { self.get_unchecked(position) }
    }

    /// # Safety
    ///
    /// position < len()
    pub unsafe fn get_unchecked(&self, position: usize) -> Option<&T> {
        // Check if there's a value at this position
        // SAFETY: position < len() guaranteed by caller
        if !unsafe { self.index.get_unchecked(position) } {
            return None;
        }

        // Use ranking to find the index in the values array
        // SAFETY: position < len() guaranteed by caller
        let value_index = unsafe { self.index.rank_unchecked(position) };

        // SAFETY: necessarily value_index < num_values().
        Some(unsafe { self.values.as_ref().get_unchecked(value_index) })
    }
}

impl<T, D: Backend<Word = usize> + AsRef<[usize]>, L: SliceByValue<Value = u64>, V: AsRef<[T]>>
    PartialArray<T, SparseIndex<D, L>, V>
where
    for<'b> &'b L: crate::traits::IntoUncheckedIterator<Item = u64>,
{
    /// Returns the total length of the array.
    ///
    /// This is the length that was specified when creating the builder,
    /// not the number of values actually stored.
    #[inline(always)]
    pub fn len(&self) -> usize {
        self.index.ef.upper_bound() as usize
    }

    /// Returns `true` if the array has no elements.
    #[inline(always)]
    pub fn is_empty(&self) -> bool {
        self.index.ef.upper_bound() == 0
    }

    /// Gets a reference to the value at the given position.
    ///
    /// Returns `Some(&value)` if a value is present at the position,
    /// or `None` if no value was stored there.
    ///
    /// # Examples
    ///
    /// ```rust
    /// # use sux::array::partial_array;
    /// let mut builder = partial_array::new_sparse(10, 1);
    /// builder.set(5, 42);
    ///
    /// let array = builder.build();
    /// assert_eq!(array.get(5), Some(&42));
    /// assert_eq!(array.get(6), None);
    /// ```
    pub fn get(&self, position: usize) -> Option<&T> {
        panic_if_out_of_bounds!(position, self.len());

        // SAFETY: we just checked
        unsafe { self.get_unchecked(position) }
    }

    /// # Safety
    ///
    /// position < len()
    pub unsafe fn get_unchecked(&self, position: usize) -> Option<&T> {
        if position >= self.index.first_invalid_pos {
            return None;
        }
        // Check if there's a value at this position
        // SAFETY: position <= last set position
        let (index, pos) = unsafe { self.index.ef.succ_unchecked::<false>(position as u64) };

        if pos != position as u64 {
            None
        } else {
            // SAFETY: necessarily value_index < num values.
            Some(unsafe { self.values.as_ref().get_unchecked(index) })
        }
    }
}

/// Returns an option even when using `get_value_unchecked` because it should be safe to call
/// whenever `position < len()`.
impl<T: Clone, V: AsRef<[T]>> SliceByValue for PartialArray<T, DenseIndex, V> {
    type Value = Option<T>;

    fn len(&self) -> usize {
        self.len()
    }

    unsafe fn get_value_unchecked(&self, position: usize) -> Self::Value {
        // SAFETY: position < len() guaranteed by caller
        unsafe { self.get_unchecked(position) }.cloned()
    }
}

/// Returns an option even when using `get_value_unchecked` because it should be safe to call
/// whenever `position < len()`.
impl<
    T: Clone,
    D: Backend<Word = usize> + AsRef<[usize]>,
    L: SliceByValue<Value = u64>,
    V: AsRef<[T]>,
> SliceByValue for PartialArray<T, SparseIndex<D, L>, V>
where
    for<'b> &'b L: crate::traits::IntoUncheckedIterator<Item = u64>,
{
    type Value = Option<T>;

    fn len(&self) -> usize {
        self.len()
    }

    unsafe fn get_value_unchecked(&self, position: usize) -> Self::Value {
        // SAFETY: position < len() guaranteed by caller
        unsafe { self.get_unchecked(position) }.cloned()
    }
}

// ── Aligned ↔ Unaligned conversion ──────────────────────────────────

impl<D> TryIntoUnaligned for SparseIndex<D> {
    type Unaligned = SparseIndex<D, Unaligned<BitFieldVec<Box<[u64]>>>>;
    fn try_into_unaligned(
        self,
    ) -> Result<Self::Unaligned, crate::traits::UnalignedConversionError> {
        Ok(SparseIndex {
            ef: self.ef.try_into_unaligned()?,
            first_invalid_pos: self.first_invalid_pos,
        })
    }
}

impl<T, P: TryIntoUnaligned, V> TryIntoUnaligned for PartialArray<T, P, V> {
    type Unaligned = PartialArray<T, P::Unaligned, V>;
    fn try_into_unaligned(
        self,
    ) -> Result<Self::Unaligned, crate::traits::UnalignedConversionError> {
        Ok(PartialArray {
            index: self.index.try_into_unaligned()?,
            values: self.values,
            _marker: PhantomData,
        })
    }
}

1	/*
2	* SPDX-FileCopyrightText: 2025 Sebastiano Vigna
3	*
4	* SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
5	*/
6
7	//! Immutable [partial array](PartialArray) implementations.
8
9	use std::marker::PhantomData;
10
11	use mem_dbg::*;
12	use value_traits::slices::SliceByValue;
13
14	use crate::bits::{BitFieldVec, BitVec};
15	use crate::dict::EliasFanoBuilder;
16	use crate::dict::elias_fano::EliasFano;
17	use crate::panic_if_out_of_bounds;
18	use crate::rank_sel::{Rank9, SelectZeroAdaptConst};
19	use crate::traits::Backend;
20	use crate::traits::TryIntoUnaligned;
21	use crate::traits::Unaligned;
22	use crate::traits::{BitVecOps, BitVecOpsMut};
23	use crate::traits::{RankUnchecked, SuccUnchecked};
24
25	// Rank9 is inherently u64-based, so the dense index must use u64 backing
26	// regardless of usize.
27	type DenseIndex = Rank9<BitVec<Box<[u64]>>>;
28
29	/// An internal index for sparse partial arrays.
30	///
31	/// We cannot use directly an [Elias–Fano](crate::dict::EliasFano) structure
32	/// because we need to keep track of the first invalid position; and we need to
33	/// keep track of the first invalid position because we want to implement just
34	/// [`SuccUnchecked`](crate::traits::SuccUnchecked) on the Elias–Fano structure,
35	/// because it requires just
36	/// [`SelectZeroUnchecked`](crate::traits::SelectZeroUnchecked), whereas
37	/// [`Succ`](crate::traits::Succ) would require
38	/// [`SelectUnchecked`](crate::traits::SelectUnchecked) as well.
39	#[doc(hidden)]
40	#[derive(Debug, Clone, MemDbg, MemSize)]
41	#[cfg_attr(feature = "epserde", derive(epserde::Epserde))]
42	#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
43	pub struct SparseIndex<D, L = BitFieldVec<Box<[u64]>>> {
44	ef: EliasFano<u64, SelectZeroAdaptConst<BitVec<D>, Box<[usize]>, 12, 3>, L>,
45	/// self.ef should not be queried for values >= self.first_invalid_position
46	first_invalid_pos: usize,
47	}
48
49	/// Builder for creating an immutable partial array.
50	///
51	/// The builder allows you to specify the array length and then add
52	/// (position, value) pairs. Positions must be added in strictly
53	/// increasing order.
54	///
55	/// To get a builder you can use either [new_dense] or [new_sparse].
56	#[derive(Debug, Clone, MemDbg, MemSize)]
57	pub struct PartialArrayBuilder<T, B> {
58	builder: B,
59	values: Vec<T>,
60	len: usize,
61	min_next_pos: usize,
62	}
63
64	/// Creates a new builder for a dense partial array of the given length.
65	///
66	/// A dense partial array stores a bit vector of the given length to mark
67	/// which positions contain values, and uses ranking on this bit vector to
68	/// map positions to indices in a contiguous value array.
69	///
70	/// If your set of values is really sparse, consider using a
71	/// [sparse partial array](new_sparse).
72	///
73	/// # Examples
74	///
75	/// ```rust
76	/// # use sux::array::partial_array;
77	/// let mut builder = partial_array::new_dense(10);
78	/// builder.set(1, "foo");
79	/// builder.set(2, "hello");
80	/// builder.set(7, "world");
81	///
82	/// let array = builder.build();
83	/// assert_eq!(array.get(1), Some(&"foo"));
84	/// assert_eq!(array.get(2), Some(&"hello"));
85	/// assert_eq!(array.get(3), None);
86	/// assert_eq!(array.get(7), Some(&"world"));
87	/// ```
88	pub fn new_dense<T>(len: usize) -> PartialArrayBuilder<T, BitVec<Box<[u64]>>> {	8✔
89	let n_of_words = len.div_ceil(64);	24✔
90	// SAFETY: the backing has exactly enough words for len bits
91	let bit_vec = unsafe { BitVec::from_raw_parts(vec![0u64; n_of_words].into_boxed_slice(), len) };	48✔
92	PartialArrayBuilder {
93	builder: bit_vec,
94	values: vec![],	8✔
95	len,
96	min_next_pos: 0,
97	}
98	}
99
100	impl<T> PartialArrayBuilder<T, BitVec<Box<[u64]>>> {
101	/// Sets a value at the given position.
102	///
103	/// The provided position must be greater than the last position set.
104	pub fn set(&mut self, position: usize, value: T) {	13✔
105	if position < self.min_next_pos {	13✔
106	panic!(	1✔
107	"Positions must be set in increasing order: got {} after {}",	×
108	position,	×
109	self.min_next_pos - 1	1✔
110	);
111	}
112	panic_if_out_of_bounds!(position, self.len);	36✔
113
114	// SAFETY: position < len
115	unsafe {
116	self.builder.set_unchecked(position, true);	22✔
117	}
118	self.values.push(value);	33✔
119	self.min_next_pos = position + 1;	11✔
120	}
121
122	/// Builds the immutable dense partial array.
123	pub fn build(self) -> PartialArray<T, Rank9<BitVec<Box<[u64]>>>> {	6✔
124	let (bit_vec, values) = (self.builder, self.values);	18✔
125	let rank9 = Rank9::new(bit_vec);	18✔
126	let values = values.into_boxed_slice();	18✔
127
128	PartialArray {
129	index: rank9,
130	values,
131	_marker: PhantomData,
132	}
133	}
134	}
135
136	/// Creates a new builder for a sparse partial array of the given length.
137	///
138	/// A sparse partial array stores the non-empty positions of the array in an
139	/// [Elias-Fano](crate::dict::EliasFano) structure.
140	///
141	/// If your set of values is really dense, consider using a [dense partial
142	/// array](new_dense).
143	///
144	/// # Examples
145	///
146	/// ```rust
147	/// # use sux::array::partial_array;
148	/// let mut builder = partial_array::new_sparse(10, 3);
149	/// builder.set(1, "foo");
150	/// builder.set(2, "hello");
151	/// builder.set(7, "world");
152	///
153	/// let array = builder.build();
154	/// assert_eq!(array.get(1), Some(&"foo"));
155	/// assert_eq!(array.get(2), Some(&"hello"));
156	/// assert_eq!(array.get(3), None);
157	/// assert_eq!(array.get(7), Some(&"world"));
158	/// ```
159	///
160	/// Note that you must specify the number of values in advance.
161	pub fn new_sparse<T>(	9✔
162	len: usize,
163	num_values: usize,
164	) -> PartialArrayBuilder<T, EliasFanoBuilder<u64>> {
165	PartialArrayBuilder {
166	builder: EliasFanoBuilder::<u64>::new(num_values, len as u64),	36✔
167	values: vec![],	9✔
168	len,
169	min_next_pos: 0,
170	}
171	}
172
173	impl<T> PartialArrayBuilder<T, EliasFanoBuilder<u64>> {
174	/// Sets a value at the given position.
175	///
176	/// The provided position must be greater than the last position
177	/// set.
178	pub fn set(&mut self, position: usize, value: T) {	16✔
179	if position < self.min_next_pos {	16✔
180	panic!(	1✔
181	"Positions must be set in increasing order: got {} after {}",	×
182	position,	×
183	self.min_next_pos - 1	1✔
184	);
185	}
186	panic_if_out_of_bounds!(position, self.len);	45✔
187	// SAFETY: conditions have been just checked
188	unsafe { self.builder.push_unchecked(position as u64) };	42✔
189	self.values.push(value);	42✔
190	self.min_next_pos = position + 1;	14✔
191	}
192
193	/// Builds the immutable sparse partial array.
194	pub fn build(self) -> PartialArray<T, SparseIndex<Box<[usize]>>> {	7✔
195	let (builder, values) = (self.builder, self.values);	21✔
196	let ef_dict = builder.build_with_dict();	21✔
197	let values = values.into_boxed_slice();	21✔
198
199	PartialArray {
200	index: SparseIndex {	14✔
201	ef: ef_dict,
202	first_invalid_pos: self.min_next_pos,
203	},
204	values,
205	_marker: PhantomData,
206	}
207	}
208	}
209
210	/// Extends the builder with an iterator of (position, value) pairs.
211	///
212	/// Position must be in strictly increasing order. The first returned
213	/// position must be greater than the last position set.
214	impl<T> Extend<(usize, T)> for PartialArrayBuilder<T, BitVec<Box<[u64]>>> {
215	fn extend<I: IntoIterator<Item = (usize, T)>>(&mut self, iter: I) {	×
216	for (pos, val) in iter {	×
217	self.set(pos, val);	×
218	}
219	}
220	}
221
222	/// Extends the builder with an iterator of (position, value) pairs.
223	///
224	/// Position must be in strictly increasing order. The first returned
225	/// position must be greater than the last position set.
226	impl<T> Extend<(usize, T)> for PartialArrayBuilder<T, EliasFanoBuilder<u64>> {
227	fn extend<I: IntoIterator<Item = (usize, T)>>(&mut self, iter: I) {	×
228	for (pos, val) in iter {	×
229	self.set(pos, val);	×
230	}
231	}
232	}
233
234	/// An immutable partial array that supports efficient queries
235	/// in compacted storage.
236	///
237	/// This structure stores a partial array—an array in which only
238	/// some positions contain values. There is a [dense](new_dense)
239	/// and a [sparse](new_sparse) implementation with different
240	/// space/time trade-offs.
241	///
242	/// For convenience, this structure implements [`SliceByValue`].
243	///
244	/// When the index structure `P` supports it, this structure implements the
245	/// [`TryIntoUnaligned`] trait, allowing it
246	/// to be converted into (usually faster) structures using unaligned access.
247	///
248	/// See [`PartialArrayBuilder`] for details on how to create a partial array.
249	#[derive(Debug, Clone, MemDbg, MemSize)]
250	#[cfg_attr(feature = "epserde", derive(epserde::Epserde))]
251	#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
252	pub struct PartialArray<T, P, V = Box<[T]>> {
253	index: P,
254	values: V,
255	_marker: PhantomData<T>,
256	}
257
258	impl<T, P, V: AsRef<[T]>> PartialArray<T, P, V> {
259	/// Returns the number of values stored in the array.
260	#[inline(always)]
261	pub fn num_values(&self) -> usize {	14✔
262	self.values.as_ref().len()	28✔
263	}
264	}
265
266	impl<T, V: AsRef<[T]>> PartialArray<T, DenseIndex, V> {
267	/// Returns the total length of the array.
268	///
269	/// This is the length that was specified when creating the builder,
270	/// not the number of values actually stored.
271	#[inline(always)]
272	pub fn len(&self) -> usize {	1,044✔
273	self.index.len()	2,088✔
274	}
275
276	/// Returns `true` if the array has no elements.
277	#[inline(always)]
278	pub fn is_empty(&self) -> bool {	1✔
279	self.len() == 0	1✔
280	}
281
282	/// Gets a reference to the value at the given position.
283	///
284	/// Returns `Some(&value)` if a value is present at the position,
285	/// or `None` if no value was stored there.
286	///
287	/// # Examples
288	///
289	/// ```rust
290	/// # use sux::array::partial_array;
291	/// let mut builder = partial_array::new_dense(10);
292	/// builder.set(5, 42);
293	///
294	/// let array = builder.build();
295	/// assert_eq!(array.get(5), Some(&42));
296	/// assert_eq!(array.get(6), None);
297	/// ```
298	pub fn get(&self, position: usize) -> Option<&T> {	1,041✔
299	panic_if_out_of_bounds!(position, self.len());	2,084✔
300
301	// SAFETY: we just checked
302	unsafe { self.get_unchecked(position) }	3,120✔
303	}
304
305	/// # Safety
306	///
307	/// position < len()
308	pub unsafe fn get_unchecked(&self, position: usize) -> Option<&T> {	1,040✔
309	// Check if there's a value at this position
310	// SAFETY: position < len() guaranteed by caller
311	if !unsafe { self.index.get_unchecked(position) } {	2,080✔
312	return None;	1,027✔
313	}
314
315	// Use ranking to find the index in the values array
316	// SAFETY: position < len() guaranteed by caller
317	let value_index = unsafe { self.index.rank_unchecked(position) };	52✔
318
319	// SAFETY: necessarily value_index < num_values().
320	Some(unsafe { self.values.as_ref().get_unchecked(value_index) })	26✔
321	}
322	}
323
324	impl<T, D: Backend<Word = usize> + AsRef<[usize]>, L: SliceByValue<Value = u64>, V: AsRef<[T]>>
325	PartialArray<T, SparseIndex<D, L>, V>
326	where
327	for<'b> &'b L: crate::traits::IntoUncheckedIterator<Item = u64>,
328	{
329	/// Returns the total length of the array.
330	///
331	/// This is the length that was specified when creating the builder,
332	/// not the number of values actually stored.
333	#[inline(always)]
334	pub fn len(&self) -> usize {	1,063✔
335	self.index.ef.upper_bound() as usize	1,063✔
336	}
337
338	/// Returns `true` if the array has no elements.
339	#[inline(always)]
340	pub fn is_empty(&self) -> bool {	1✔
341	self.index.ef.upper_bound() == 0	1✔
342	}
343
344	/// Gets a reference to the value at the given position.
345	///
346	/// Returns `Some(&value)` if a value is present at the position,
347	/// or `None` if no value was stored there.
348	///
349	/// # Examples
350	///
351	/// ```rust
352	/// # use sux::array::partial_array;
353	/// let mut builder = partial_array::new_sparse(10, 1);
354	/// builder.set(5, 42);
355	///
356	/// let array = builder.build();
357	/// assert_eq!(array.get(5), Some(&42));
358	/// assert_eq!(array.get(6), None);
359	/// ```
360	pub fn get(&self, position: usize) -> Option<&T> {	1,061✔
361	panic_if_out_of_bounds!(position, self.len());	2,124✔
362
363	// SAFETY: we just checked
364	unsafe { self.get_unchecked(position) }	3,180✔
365	}
366
367	/// # Safety
368	///
369	/// position < len()
370	pub unsafe fn get_unchecked(&self, position: usize) -> Option<&T> {	1,060✔
371	if position >= self.index.first_invalid_pos {	1,060✔
372	return None;	505✔
373	}
374	// Check if there's a value at this position
375	// SAFETY: position <= last set position
376	let (index, pos) = unsafe { self.index.ef.succ_unchecked::<false>(position as u64) };	2,220✔
377
378	if pos != position as u64 {	555✔
379	None	536✔
380	} else {
381	// SAFETY: necessarily value_index < num values.
382	Some(unsafe { self.values.as_ref().get_unchecked(index) })	38✔
383	}
384	}
385	}
386
387	/// Returns an option even when using `get_value_unchecked` because it should be safe to call
388	/// whenever `position < len()`.
389	impl<T: Clone, V: AsRef<[T]>> SliceByValue for PartialArray<T, DenseIndex, V> {
390	type Value = Option<T>;
391
392	fn len(&self) -> usize {	×
393	self.len()	×
394	}
395
396	unsafe fn get_value_unchecked(&self, position: usize) -> Self::Value {	×
397	// SAFETY: position < len() guaranteed by caller
398	unsafe { self.get_unchecked(position) }.cloned()	×
399	}
400	}
401
402	/// Returns an option even when using `get_value_unchecked` because it should be safe to call
403	/// whenever `position < len()`.
404	impl<
405	T: Clone,
406	D: Backend<Word = usize> + AsRef<[usize]>,
407	L: SliceByValue<Value = u64>,
408	V: AsRef<[T]>,
409	> SliceByValue for PartialArray<T, SparseIndex<D, L>, V>
410	where
411	for<'b> &'b L: crate::traits::IntoUncheckedIterator<Item = u64>,
412	{
413	type Value = Option<T>;
414
415	fn len(&self) -> usize {	×
416	self.len()	×
417	}
418
419	unsafe fn get_value_unchecked(&self, position: usize) -> Self::Value {	×
420	// SAFETY: position < len() guaranteed by caller
421	unsafe { self.get_unchecked(position) }.cloned()	×
422	}
423	}
424
425	// ── Aligned ↔ Unaligned conversion ──────────────────────────────────
426
427	impl<D> TryIntoUnaligned for SparseIndex<D> {
428	type Unaligned = SparseIndex<D, Unaligned<BitFieldVec<Box<[u64]>>>>;
429	fn try_into_unaligned(	×
430	self,
431	) -> Result<Self::Unaligned, crate::traits::UnalignedConversionError> {
432	Ok(SparseIndex {	×
433	ef: self.ef.try_into_unaligned()?,	×
434	first_invalid_pos: self.first_invalid_pos,	×
435	})
436	}
437	}
438
439	impl<T, P: TryIntoUnaligned, V> TryIntoUnaligned for PartialArray<T, P, V> {
440	type Unaligned = PartialArray<T, P::Unaligned, V>;
441	fn try_into_unaligned(	×
442	self,
443	) -> Result<Self::Unaligned, crate::traits::UnalignedConversionError> {
444	Ok(PartialArray {	×
445	index: self.index.try_into_unaligned()?,	×
446	values: self.values,	×
447	_marker: PhantomData,	×
448	})
449	}
450	}

vigna / sux-rs / 24195165729

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