zerovec/varzerovec/
owned.rs

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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// The mutation operations in this file should panic to prevent undefined behavior
6#![allow(clippy::unwrap_used)]
7#![allow(clippy::expect_used)]
8#![allow(clippy::indexing_slicing)]
9#![allow(clippy::panic)]
10
11use super::*;
12use crate::ule::*;
13use alloc::vec::Vec;
14use core::any;
15use core::convert::TryInto;
16use core::marker::PhantomData;
17use core::ops::Deref;
18use core::ops::Range;
19use core::{fmt, ptr, slice};
20
21use super::components::IntegerULE;
22
23/// A fully-owned [`VarZeroVec`]. This type has no lifetime but has the same
24/// internal buffer representation of [`VarZeroVec`], making it cheaply convertible to
25/// [`VarZeroVec`] and [`VarZeroSlice`].
26///
27/// The `F` type parameter is a [`VarZeroVecFormat`] (see its docs for more details), which can be used to select the
28/// precise format of the backing buffer with various size and performance tradeoffs. It defaults to [`Index16`].
29pub struct VarZeroVecOwned<T: ?Sized, F = Index16> {
30    marker1: PhantomData<T>,
31    marker2: PhantomData<F>,
32    // safety invariant: must parse into a valid VarZeroVecComponents
33    entire_slice: Vec<u8>,
34}
35
36impl<T: ?Sized, F> Clone for VarZeroVecOwned<T, F> {
37    fn clone(&self) -> Self {
38        VarZeroVecOwned {
39            marker1: PhantomData,
40            marker2: PhantomData,
41            entire_slice: self.entire_slice.clone(),
42        }
43    }
44}
45
46// The effect of a shift on the indices in the varzerovec.
47#[derive(PartialEq)]
48enum ShiftType {
49    Insert,
50    Replace,
51    Remove,
52}
53
54impl<T: VarULE + ?Sized, F: VarZeroVecFormat> Deref for VarZeroVecOwned<T, F> {
55    type Target = VarZeroSlice<T, F>;
56    fn deref(&self) -> &VarZeroSlice<T, F> {
57        self.as_slice()
58    }
59}
60
61impl<T: VarULE + ?Sized, F> VarZeroVecOwned<T, F> {
62    /// Construct an empty VarZeroVecOwned
63    pub fn new() -> Self {
64        Self {
65            marker1: PhantomData,
66            marker2: PhantomData,
67            entire_slice: Vec::new(),
68        }
69    }
70}
71
72impl<T: VarULE + ?Sized, F: VarZeroVecFormat> VarZeroVecOwned<T, F> {
73    /// Construct a VarZeroVecOwned from a [`VarZeroSlice`] by cloning the internal data
74    pub fn from_slice(slice: &VarZeroSlice<T, F>) -> Self {
75        Self {
76            marker1: PhantomData,
77            marker2: PhantomData,
78            entire_slice: slice.as_bytes().into(),
79        }
80    }
81
82    /// Construct a VarZeroVecOwned from a list of elements
83    pub fn try_from_elements<A>(elements: &[A]) -> Result<Self, &'static str>
84    where
85        A: EncodeAsVarULE<T>,
86    {
87        Ok(if elements.is_empty() {
88            Self::from_slice(VarZeroSlice::new_empty())
89        } else {
90            Self {
91                marker1: PhantomData,
92                marker2: PhantomData,
93                // TODO(#1410): Rethink length errors in VZV.
94                entire_slice: components::get_serializable_bytes_non_empty::<T, A, F>(elements)
95                    .ok_or(F::Index::TOO_LARGE_ERROR)?,
96            }
97        })
98    }
99
100    /// Obtain this `VarZeroVec` as a [`VarZeroSlice`]
101    pub fn as_slice(&self) -> &VarZeroSlice<T, F> {
102        let slice: &[u8] = &self.entire_slice;
103        unsafe {
104            // safety: the slice is known to come from a valid parsed VZV
105            VarZeroSlice::from_bytes_unchecked(slice)
106        }
107    }
108
109    /// Try to allocate a buffer with enough capacity for `capacity`
110    /// elements. Since `T` can take up an arbitrary size this will
111    /// just allocate enough space for 4-byte Ts
112    pub(crate) fn with_capacity(capacity: usize) -> Self {
113        Self {
114            marker1: PhantomData,
115            marker2: PhantomData,
116            entire_slice: Vec::with_capacity(capacity * (F::Index::SIZE + 4)),
117        }
118    }
119
120    /// Try to reserve space for `capacity`
121    /// elements. Since `T` can take up an arbitrary size this will
122    /// just allocate enough space for 4-byte Ts
123    pub(crate) fn reserve(&mut self, capacity: usize) {
124        self.entire_slice.reserve(capacity * (F::Index::SIZE + 4))
125    }
126
127    /// Get the position of a specific element in the data segment.
128    ///
129    /// If `idx == self.len()`, it will return the size of the data segment (where a new element would go).
130    ///
131    /// ## Safety
132    /// `idx <= self.len()` and `self.as_encoded_bytes()` is well-formed.
133    unsafe fn element_position_unchecked(&self, idx: usize) -> usize {
134        let len = self.len();
135        let out = if idx == len {
136            self.entire_slice.len() - F::Len::SIZE - (F::Index::SIZE * (len - 1))
137        } else if let Some(idx) = self.index_data(idx) {
138            idx.iule_to_usize()
139        } else {
140            0
141        };
142        debug_assert!(out + F::Len::SIZE + (len - 1) * F::Index::SIZE <= self.entire_slice.len());
143        out
144    }
145
146    /// Get the range of a specific element in the data segment.
147    ///
148    /// ## Safety
149    /// `idx < self.len()` and `self.as_encoded_bytes()` is well-formed.
150    unsafe fn element_range_unchecked(&self, idx: usize) -> core::ops::Range<usize> {
151        let start = self.element_position_unchecked(idx);
152        let end = self.element_position_unchecked(idx + 1);
153        debug_assert!(start <= end, "{start} > {end}");
154        start..end
155    }
156
157    /// Set the number of elements in the list without any checks.
158    ///
159    /// ## Safety
160    /// No safe functions may be called until `self.as_encoded_bytes()` is well-formed.
161    unsafe fn set_len(&mut self, len: usize) {
162        assert!(len <= F::Len::MAX_VALUE as usize);
163        let len_bytes = len.to_le_bytes();
164        let len_ule = F::Len::iule_from_usize(len).expect(F::Len::TOO_LARGE_ERROR);
165        self.entire_slice[0..F::Len::SIZE].copy_from_slice(ULE::slice_as_bytes(&[len_ule]));
166        // Double-check that the length fits in the length field
167        assert_eq!(len_bytes[F::Len::SIZE..].iter().sum::<u8>(), 0);
168    }
169
170    /// Get the range in the full data for a given index. Returns None for index 0
171    /// since there is no stored index for it.
172    fn index_range(index: usize) -> Option<Range<usize>> {
173        let index_minus_one = index.checked_sub(1)?;
174        let pos = F::Len::SIZE + F::Index::SIZE * index_minus_one;
175        Some(pos..pos + F::Index::SIZE)
176    }
177
178    /// Return the raw bytes representing the given `index`. Returns None when given index 0
179    ///
180    /// ## Safety
181    /// The index must be valid, and self.as_encoded_bytes() must be well-formed
182    unsafe fn index_data(&self, index: usize) -> Option<&F::Index> {
183        let index_range = Self::index_range(index)?;
184        Some(&F::Index::slice_from_bytes_unchecked(&self.entire_slice[index_range])[0])
185    }
186
187    /// Return the mutable slice representing the given `index`. Returns None when given index 0
188    ///
189    /// ## Safety
190    /// The index must be valid. self.as_encoded_bytes() must have allocated space
191    /// for this index, but need not have its length appropriately set.
192    unsafe fn index_data_mut(&mut self, index: usize) -> Option<&mut F::Index> {
193        let ptr = self.entire_slice.as_mut_ptr();
194        let range = Self::index_range(index)?;
195
196        // Doing this instead of just `get_unchecked_mut()` because it's unclear
197        // if `get_unchecked_mut()` can be called out of bounds on a slice even
198        // if we know the buffer is larger.
199        let data = slice::from_raw_parts_mut(ptr.add(range.start), F::Index::SIZE);
200        Some(&mut F::Index::iule_from_bytes_unchecked_mut(data)[0])
201    }
202
203    /// Shift the indices starting with and after `starting_index` by the provided `amount`.
204    ///
205    /// ## Panics
206    /// Should never be called with a starting index of 0, since that index cannot be shifted.
207    ///
208    /// ## Safety
209    /// Adding `amount` to each index after `starting_index` must not result in the slice from becoming malformed.
210    /// The length of the slice must be correctly set.
211    unsafe fn shift_indices(&mut self, starting_index: usize, amount: i32) {
212        let normalized_idx = starting_index
213            .checked_sub(1)
214            .expect("shift_indices called with a 0 starting index");
215        let len = self.len();
216        let indices = F::Index::iule_from_bytes_unchecked_mut(
217            &mut self.entire_slice[F::Len::SIZE..F::Len::SIZE + F::Index::SIZE * (len - 1)],
218        );
219        for idx in &mut indices[normalized_idx..] {
220            let mut new_idx = idx.iule_to_usize();
221            if amount > 0 {
222                new_idx = new_idx.checked_add(amount.try_into().unwrap()).unwrap();
223            } else {
224                new_idx = new_idx.checked_sub((-amount).try_into().unwrap()).unwrap();
225            }
226            *idx = F::Index::iule_from_usize(new_idx).expect(F::Index::TOO_LARGE_ERROR);
227        }
228    }
229
230    /// Get this [`VarZeroVecOwned`] as a borrowed [`VarZeroVec`]
231    ///
232    /// If you wish to repeatedly call methods on this [`VarZeroVecOwned`],
233    /// it is more efficient to perform this conversion first
234    pub fn as_varzerovec<'a>(&'a self) -> VarZeroVec<'a, T, F> {
235        self.as_slice().into()
236    }
237
238    /// Empty the vector
239    pub fn clear(&mut self) {
240        self.entire_slice.clear()
241    }
242
243    /// Consume this vector and return the backing buffer
244    #[inline]
245    pub fn into_bytes(self) -> Vec<u8> {
246        self.entire_slice
247    }
248
249    /// Invalidate and resize the data at an index, optionally inserting or removing the index.
250    /// Also updates affected indices and the length.
251    ///
252    /// `new_size` is the encoded byte size of the element that is going to be inserted
253    ///
254    /// Returns a slice to the new element data - it doesn't contain uninitialized data but its value is indeterminate.
255    ///
256    /// ## Safety
257    /// - `index` must be a valid index, or, if `shift_type == ShiftType::Insert`, `index == self.len()` is allowed.
258    /// - `new_size` musn't result in the data segment growing larger than `F::Index::MAX_VALUE`.
259    unsafe fn shift(&mut self, index: usize, new_size: usize, shift_type: ShiftType) -> &mut [u8] {
260        // The format of the encoded data is:
261        //  - four bytes of "len"
262        //  - len*4 bytes for an array of indices
263        //  - the actual data to which the indices point
264        //
265        // When inserting or removing an element, the size of the indices segment must be changed,
266        // so the data before the target element must be shifted by 4 bytes in addition to the
267        // shifting needed for the new element size.
268        let len = self.len();
269        let slice_len = self.entire_slice.len();
270
271        let prev_element = match shift_type {
272            ShiftType::Insert => {
273                let pos = self.element_position_unchecked(index);
274                // In the case of an insert, there's no previous element,
275                // so it's an empty range at the new position.
276                pos..pos
277            }
278            _ => self.element_range_unchecked(index),
279        };
280
281        // How much shifting must be done in bytes due to removal/insertion of an index.
282        let index_shift: i64 = match shift_type {
283            ShiftType::Insert => F::Index::SIZE as i64,
284            ShiftType::Replace => 0,
285            ShiftType::Remove => -(F::Index::SIZE as i64),
286        };
287        // The total shift in byte size of the owned slice.
288        let shift: i64 =
289            new_size as i64 - (prev_element.end - prev_element.start) as i64 + index_shift;
290        let new_slice_len = slice_len.wrapping_add(shift as usize);
291        if shift > 0 {
292            if new_slice_len > F::Index::MAX_VALUE as usize {
293                panic!(
294                    "Attempted to grow VarZeroVec to an encoded size that does not fit within the length size used by {}",
295                    any::type_name::<F>()
296                );
297            }
298            self.entire_slice.resize(new_slice_len, 0);
299        }
300
301        // Now that we've ensured there's enough space, we can shift the data around.
302        {
303            // Note: There are no references introduced between pointer creation and pointer use, and all
304            //       raw pointers are derived from a single &mut. This preserves pointer provenance.
305            let slice_range = self.entire_slice.as_mut_ptr_range();
306            // The start of the indices buffer
307            let indices_start = slice_range.start.add(F::Len::SIZE);
308            let old_slice_end = slice_range.start.add(slice_len);
309            let data_start = indices_start.add((len - 1) * F::Index::SIZE);
310            let prev_element_p =
311                data_start.add(prev_element.start)..data_start.add(prev_element.end);
312
313            // The memory range of the affected index.
314            // When inserting: where the new index goes.
315            // When removing:  where the index being removed is.
316            // When replacing: unused.
317            // Will be None when the affected index is index 0, which is special
318            let index_range = if let Some(index_minus_one) = index.checked_sub(1) {
319                let index_start = indices_start.add(F::Index::SIZE * index_minus_one);
320                Some(index_start..index_start.add(F::Index::SIZE))
321            } else {
322                None
323            };
324
325            unsafe fn shift_bytes(block: Range<*const u8>, to: *mut u8) {
326                debug_assert!(block.end >= block.start);
327                ptr::copy(block.start, to, block.end.offset_from(block.start) as usize);
328            }
329
330            if shift_type == ShiftType::Remove {
331                if let Some(ref index_range) = index_range {
332                    shift_bytes(index_range.end..prev_element_p.start, index_range.start);
333                } else {
334                    // We are removing the first index, so we skip the second index and copy it over. The second index
335                    // is now zero and unnecessary.
336                    shift_bytes(
337                        indices_start.add(F::Index::SIZE)..prev_element_p.start,
338                        indices_start,
339                    )
340                }
341            }
342
343            // Shift data after the element to its new position.
344            shift_bytes(
345                prev_element_p.end..old_slice_end,
346                prev_element_p
347                    .start
348                    .offset((new_size as i64 + index_shift) as isize),
349            );
350
351            let first_affected_index = match shift_type {
352                ShiftType::Insert => {
353                    if let Some(index_range) = index_range {
354                        // Move data before the element forward by 4 to make space for a new index.
355                        shift_bytes(index_range.start..prev_element_p.start, index_range.end);
356                        let index_data = self
357                            .index_data_mut(index)
358                            .expect("If index_range is some, index is > 0 and should not panic in index_data_mut");
359                        *index_data = F::Index::iule_from_usize(prev_element.start)
360                            .expect(F::Index::TOO_LARGE_ERROR);
361                    } else {
362                        // We are adding a new index 0. There's nothing in the indices array for index 0, but the element
363                        // that is currently at index 0 will become index 1 and need a value
364                        // We first shift bytes to make space
365                        shift_bytes(
366                            indices_start..prev_element_p.start,
367                            indices_start.add(F::Index::SIZE),
368                        );
369                        // And then we write a temporary zero to the zeroeth index, which will get shifted later
370                        let index_data = self
371                            .index_data_mut(1)
372                            .expect("Should be able to write to index 1");
373                        *index_data = F::Index::iule_from_usize(0).expect("0 is always valid!");
374                    }
375
376                    self.set_len(len + 1);
377                    index + 1
378                }
379                ShiftType::Remove => {
380                    self.set_len(len - 1);
381                    if index == 0 {
382                        // We don't need to shift index 0 since index 0 is not stored in the indices buffer
383                        index + 1
384                    } else {
385                        index
386                    }
387                }
388                ShiftType::Replace => index + 1,
389            };
390            // No raw pointer use should occur after this point (because of self.index_data and self.set_len).
391
392            // Set the new slice length. This must be done after shifting data around to avoid uninitialized data.
393            self.entire_slice.set_len(new_slice_len);
394            // Shift the affected indices.
395            self.shift_indices(first_affected_index, (shift - index_shift) as i32);
396        };
397
398        debug_assert!(self.verify_integrity());
399
400        // Return a mut slice to the new element data.
401        let element_pos = F::Len::SIZE
402            + (self.len() - 1) * F::Index::SIZE
403            + self.element_position_unchecked(index);
404        &mut self.entire_slice[element_pos..element_pos + new_size]
405    }
406
407    /// Checks the internal invariants of the vec to ensure safe code will not cause UB.
408    /// Returns whether integrity was verified.
409    ///
410    /// Note: an index is valid if it doesn't point to data past the end of the slice and is
411    /// less than or equal to all future indices. The length of the index segment is not part of each index.
412    fn verify_integrity(&self) -> bool {
413        if self.is_empty() {
414            if self.entire_slice.is_empty() {
415                return true;
416            } else {
417                panic!(
418                    "VarZeroVecOwned integrity: Found empty VarZeroVecOwned with a nonempty slice"
419                );
420            }
421        }
422        let len = unsafe {
423            <F::Len as ULE>::slice_from_bytes_unchecked(&self.entire_slice[..F::Len::SIZE])[0]
424                .iule_to_usize()
425        };
426        if len == 0 {
427            // An empty vec must have an empty slice: there is only a single valid byte representation.
428            panic!("VarZeroVecOwned integrity: Found empty VarZeroVecOwned with a nonempty slice");
429        }
430        if self.entire_slice.len() < F::Len::SIZE + (len - 1) * F::Index::SIZE {
431            panic!("VarZeroVecOwned integrity: Not enough room for the indices");
432        }
433        let data_len = self.entire_slice.len() - F::Len::SIZE - (len - 1) * F::Index::SIZE;
434        if data_len > F::Index::MAX_VALUE as usize {
435            panic!("VarZeroVecOwned integrity: Data segment is too long");
436        }
437
438        // Test index validity.
439        let indices = unsafe {
440            F::Index::slice_from_bytes_unchecked(
441                &self.entire_slice[F::Len::SIZE..F::Len::SIZE + (len - 1) * F::Index::SIZE],
442            )
443        };
444        for idx in indices {
445            if idx.iule_to_usize() > data_len {
446                panic!("VarZeroVecOwned integrity: Indices must not point past the data segment");
447            }
448        }
449        for window in indices.windows(2) {
450            if window[0].iule_to_usize() > window[1].iule_to_usize() {
451                panic!("VarZeroVecOwned integrity: Indices must be in non-decreasing order");
452            }
453        }
454        true
455    }
456
457    /// Insert an element at the end of this vector
458    pub fn push<A: EncodeAsVarULE<T> + ?Sized>(&mut self, element: &A) {
459        self.insert(self.len(), element)
460    }
461
462    /// Insert an element at index `idx`
463    pub fn insert<A: EncodeAsVarULE<T> + ?Sized>(&mut self, index: usize, element: &A) {
464        let len = self.len();
465        if index > len {
466            panic!("Called out-of-bounds insert() on VarZeroVec, index {index} len {len}");
467        }
468
469        let value_len = element.encode_var_ule_len();
470
471        if len == 0 {
472            let header_len = F::Len::SIZE; // Index array is size 0 for len = 1
473            let cap = header_len + value_len;
474            self.entire_slice.resize(cap, 0);
475            self.entire_slice[0] = 1; // set length
476            element.encode_var_ule_write(&mut self.entire_slice[header_len..]);
477            return;
478        }
479
480        assert!(value_len < F::Index::MAX_VALUE as usize);
481        unsafe {
482            let place = self.shift(index, value_len, ShiftType::Insert);
483            element.encode_var_ule_write(place);
484        }
485    }
486
487    /// Remove the element at index `idx`
488    pub fn remove(&mut self, index: usize) {
489        let len = self.len();
490        if index >= len {
491            panic!("Called out-of-bounds remove() on VarZeroVec, index {index} len {len}");
492        }
493        if len == 1 {
494            // This is removing the last element. Set the slice to empty to ensure all empty vecs have empty data slices.
495            self.entire_slice.clear();
496            return;
497        }
498        unsafe {
499            self.shift(index, 0, ShiftType::Remove);
500        }
501    }
502
503    /// Replace the element at index `idx` with another
504    pub fn replace<A: EncodeAsVarULE<T> + ?Sized>(&mut self, index: usize, element: &A) {
505        let len = self.len();
506        if index >= len {
507            panic!("Called out-of-bounds replace() on VarZeroVec, index {index} len {len}");
508        }
509
510        let value_len = element.encode_var_ule_len();
511
512        assert!(value_len < F::Index::MAX_VALUE as usize);
513        unsafe {
514            let place = self.shift(index, value_len, ShiftType::Replace);
515            element.encode_var_ule_write(place);
516        }
517    }
518}
519
520impl<T: VarULE + ?Sized, F: VarZeroVecFormat> fmt::Debug for VarZeroVecOwned<T, F>
521where
522    T: fmt::Debug,
523{
524    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
525        VarZeroSlice::fmt(self, f)
526    }
527}
528
529impl<T: VarULE + ?Sized, F> Default for VarZeroVecOwned<T, F> {
530    fn default() -> Self {
531        Self::new()
532    }
533}
534
535impl<T, A, F> PartialEq<&'_ [A]> for VarZeroVecOwned<T, F>
536where
537    T: VarULE + ?Sized,
538    T: PartialEq,
539    A: AsRef<T>,
540    F: VarZeroVecFormat,
541{
542    #[inline]
543    fn eq(&self, other: &&[A]) -> bool {
544        self.iter().eq(other.iter().map(|t| t.as_ref()))
545    }
546}
547
548impl<'a, T: ?Sized + VarULE, F: VarZeroVecFormat> From<&'a VarZeroSlice<T, F>>
549    for VarZeroVecOwned<T, F>
550{
551    fn from(other: &'a VarZeroSlice<T, F>) -> Self {
552        Self::from_slice(other)
553    }
554}
555
556#[cfg(test)]
557mod test {
558    use super::VarZeroVecOwned;
559    #[test]
560    fn test_insert_integrity() {
561        let mut items: Vec<String> = Vec::new();
562        let mut zerovec = VarZeroVecOwned::<str>::new();
563
564        // Insert into an empty vec.
565        items.insert(0, "1234567890".into());
566        zerovec.insert(0, "1234567890");
567        assert_eq!(zerovec, &*items);
568
569        zerovec.insert(1, "foo3");
570        items.insert(1, "foo3".into());
571        assert_eq!(zerovec, &*items);
572
573        // Insert at the end.
574        items.insert(items.len(), "qwertyuiop".into());
575        zerovec.insert(zerovec.len(), "qwertyuiop");
576        assert_eq!(zerovec, &*items);
577
578        items.insert(0, "asdfghjkl;".into());
579        zerovec.insert(0, "asdfghjkl;");
580        assert_eq!(zerovec, &*items);
581
582        items.insert(2, "".into());
583        zerovec.insert(2, "");
584        assert_eq!(zerovec, &*items);
585    }
586
587    #[test]
588    // ensure that inserting empty items works
589    fn test_empty_inserts() {
590        let mut items: Vec<String> = Vec::new();
591        let mut zerovec = VarZeroVecOwned::<str>::new();
592
593        // Insert into an empty vec.
594        items.insert(0, "".into());
595        zerovec.insert(0, "");
596        assert_eq!(zerovec, &*items);
597
598        items.insert(0, "".into());
599        zerovec.insert(0, "");
600        assert_eq!(zerovec, &*items);
601
602        items.insert(0, "1234567890".into());
603        zerovec.insert(0, "1234567890");
604        assert_eq!(zerovec, &*items);
605
606        items.insert(0, "".into());
607        zerovec.insert(0, "");
608        assert_eq!(zerovec, &*items);
609    }
610
611    #[test]
612    fn test_small_insert_integrity() {
613        // Tests that insert() works even when there
614        // is not enough space for the new index in entire_slice.len()
615        let mut items: Vec<String> = Vec::new();
616        let mut zerovec = VarZeroVecOwned::<str>::new();
617
618        // Insert into an empty vec.
619        items.insert(0, "abc".into());
620        zerovec.insert(0, "abc");
621        assert_eq!(zerovec, &*items);
622
623        zerovec.insert(1, "def");
624        items.insert(1, "def".into());
625        assert_eq!(zerovec, &*items);
626    }
627
628    #[test]
629    #[should_panic]
630    fn test_insert_past_end() {
631        VarZeroVecOwned::<str>::new().insert(1, "");
632    }
633
634    #[test]
635    fn test_remove_integrity() {
636        let mut items: Vec<&str> = vec!["apples", "bananas", "eeples", "", "baneenees", "five", ""];
637        let mut zerovec = VarZeroVecOwned::<str>::try_from_elements(&items).unwrap();
638
639        for index in [0, 2, 4, 0, 1, 1, 0] {
640            items.remove(index);
641            zerovec.remove(index);
642            assert_eq!(zerovec, &*items, "index {}, len {}", index, items.len());
643        }
644    }
645
646    #[test]
647    fn test_removing_last_element_clears() {
648        let mut zerovec = VarZeroVecOwned::<str>::try_from_elements(&["buy some apples"]).unwrap();
649        assert!(!zerovec.as_bytes().is_empty());
650        zerovec.remove(0);
651        assert!(zerovec.as_bytes().is_empty());
652    }
653
654    #[test]
655    #[should_panic]
656    fn test_remove_past_end() {
657        VarZeroVecOwned::<str>::new().remove(0);
658    }
659
660    #[test]
661    fn test_replace_integrity() {
662        let mut items: Vec<&str> = vec!["apples", "bananas", "eeples", "", "baneenees", "five", ""];
663        let mut zerovec = VarZeroVecOwned::<str>::try_from_elements(&items).unwrap();
664
665        // Replace with an element of the same size (and the first element)
666        items[0] = "blablah";
667        zerovec.replace(0, "blablah");
668        assert_eq!(zerovec, &*items);
669
670        // Replace with a smaller element
671        items[1] = "twily";
672        zerovec.replace(1, "twily");
673        assert_eq!(zerovec, &*items);
674
675        // Replace an empty element
676        items[3] = "aoeuidhtns";
677        zerovec.replace(3, "aoeuidhtns");
678        assert_eq!(zerovec, &*items);
679
680        // Replace the last element
681        items[6] = "0123456789";
682        zerovec.replace(6, "0123456789");
683        assert_eq!(zerovec, &*items);
684
685        // Replace with an empty element
686        items[2] = "";
687        zerovec.replace(2, "");
688        assert_eq!(zerovec, &*items);
689    }
690
691    #[test]
692    #[should_panic]
693    fn test_replace_past_end() {
694        VarZeroVecOwned::<str>::new().replace(0, "");
695    }
696}
zerovec/varzerovec/owned.rs

zerovec/varzerovec/
owned.rs
