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[libc++] Turn pre/post-condition comments in vector.h into actual asserts #129536

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[libc++] Turn pre/post-condition comments in vector.h into actual asserts #129536

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34 changes: 21 additions & 13 deletions libcxx/include/__vector/vector.h
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Original file line number Diff line number Diff line change
Expand Up @@ -549,18 +549,18 @@ class _LIBCPP_TEMPLATE_VIS vector {
// Allocate space for __n objects
// throws length_error if __n > max_size()
// throws (probably bad_alloc) if memory run out
// Precondition: __begin_ == __end_ == __cap_ == nullptr
// Precondition: __n > 0
// Postcondition: capacity() >= __n
// Postcondition: size() == 0
_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __vallocate(size_type __n) {
_LIBCPP_ASSERT_INTERNAL(!__begin_ && !__end_ && !__cap_, "Trying to __vallocate on non-empty vector!");
_LIBCPP_ASSERT_INTERNAL(__n >= 0, "Trying to __vallocate zero elements!");
if (__n > max_size())
this->__throw_length_error();
auto __allocation = std::__allocate_at_least(this->__alloc_, __n);
__begin_ = __allocation.ptr;
__end_ = __allocation.ptr;
__cap_ = __begin_ + __allocation.count;
__annotate_new(0);
_LIBCPP_ASSERT_INTERNAL(capacity() >= __n, "Allocated too few elements!");
_LIBCPP_ASSERT_INTERNAL(size() == 0, "vector isn't empty after __vallocate()!");
}

_LIBCPP_CONSTEXPR_SINCE_CXX20 _LIBCPP_HIDE_FROM_ABI void __vdeallocate() _NOEXCEPT;
Expand Down Expand Up @@ -877,10 +877,11 @@ _LIBCPP_CONSTEXPR_SINCE_CXX20 void vector<_Tp, _Allocator>::__vdeallocate() _NOE
}
}

// Precondition: __new_size > capacity()
template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 inline _LIBCPP_HIDE_FROM_ABI typename vector<_Tp, _Allocator>::size_type
vector<_Tp, _Allocator>::__recommend(size_type __new_size) const {
_LIBCPP_ASSERT_INTERNAL(
__new_size > capacity(), "Asking for a new capacity, but there are still enough elements available!");
const size_type __ms = max_size();
if (__new_size > __ms)
this->__throw_length_error();
Expand All @@ -892,32 +893,36 @@ vector<_Tp, _Allocator>::__recommend(size_type __new_size) const {

// Default constructs __n objects starting at __end_
// throws if construction throws
// Precondition: __n > 0
// Precondition: size() + __n <= capacity()
// Postcondition: size() == size() + __n
template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 void vector<_Tp, _Allocator>::__construct_at_end(size_type __n) {
_LIBCPP_ASSERT_INTERNAL(__n > 0, "Trying to construct zero elements!");
_LIBCPP_ASSERT_INTERNAL(
size() + __n <= capacity(), "Trying to __construct_at_end more elements than there is space available!");
[[__maybe_unused__]] auto __old_size = size();
_ConstructTransaction __tx(*this, __n);
const_pointer __new_end = __tx.__new_end_;
for (pointer __pos = __tx.__pos_; __pos != __new_end; __tx.__pos_ = ++__pos) {
__alloc_traits::construct(this->__alloc_, std::__to_address(__pos));
}
_LIBCPP_ASSERT_INTERNAL(size() == __old_size + __n, "Too few elements constructed!");
}

// Copy constructs __n objects starting at __end_ from __x
// throws if construction throws
// Precondition: __n > 0
// Precondition: size() + __n <= capacity()
// Postcondition: size() == old size() + __n
// Postcondition: [i] == __x for all i in [size() - __n, __n)
template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 inline void
vector<_Tp, _Allocator>::__construct_at_end(size_type __n, const_reference __x) {
_LIBCPP_ASSERT_INTERNAL(__n > 0, "Trying to construct zero elements!");
_LIBCPP_ASSERT_INTERNAL(
size() + __n <= capacity(), "Trying to __construct_at_end more elements than there is space available!");
[[__maybe_unused__]] auto __old_size = size();
_ConstructTransaction __tx(*this, __n);
const_pointer __new_end = __tx.__new_end_;
for (pointer __pos = __tx.__pos_; __pos != __new_end; __tx.__pos_ = ++__pos) {
__alloc_traits::construct(this->__alloc_, std::__to_address(__pos), __x);
}
_LIBCPP_ASSERT_INTERNAL(size() == __old_size + __n, "Too few elements constructed!");
// Postcondition: [i] == __x for all i in [size() - __n, __n)
}

template <class _Tp, class _Allocator>
Expand All @@ -930,17 +935,18 @@ vector<_Tp, _Allocator>::__construct_at_end(_InputIterator __first, _Sentinel __

// Default constructs __n objects starting at __end_
// throws if construction throws
// Postcondition: size() == size() + __n
// Exception safety: strong.
template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 void vector<_Tp, _Allocator>::__append(size_type __n) {
[[__maybe_unused__]] auto __old_size = size();
if (static_cast<size_type>(this->__cap_ - this->__end_) >= __n)
this->__construct_at_end(__n);
else {
__split_buffer<value_type, allocator_type&> __v(__recommend(size() + __n), size(), this->__alloc_);
__v.__construct_at_end(__n);
__swap_out_circular_buffer(__v);
}
_LIBCPP_ASSERT_INTERNAL(size() == __old_size + __n, "Too few elements constructed!");
}

// Default constructs __n objects starting at __end_
Expand All @@ -949,13 +955,15 @@ _LIBCPP_CONSTEXPR_SINCE_CXX20 void vector<_Tp, _Allocator>::__append(size_type _
// Exception safety: strong.
template <class _Tp, class _Allocator>
_LIBCPP_CONSTEXPR_SINCE_CXX20 void vector<_Tp, _Allocator>::__append(size_type __n, const_reference __x) {
[[__maybe_unused__]] auto __old_size = size();
if (static_cast<size_type>(this->__cap_ - this->__end_) >= __n)
this->__construct_at_end(__n, __x);
else {
__split_buffer<value_type, allocator_type&> __v(__recommend(size() + __n), size(), this->__alloc_);
__v.__construct_at_end(__n, __x);
__swap_out_circular_buffer(__v);
}
_LIBCPP_ASSERT_INTERNAL(size() == __old_size + __n, "Too few elements constructed!");
}

template <class _Tp, class _Allocator>
Expand Down
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