fuchsia-china/third_party.pigweed.src
1
0
Fork 0
mirror of https://fuchsia.googlesource.com/third_party/pigweed.googlesource.com/pigweed/pigweed synced 2024-09-21 06:12:09 +00:00
Code Issues Actions 4 Packages Projects Releases Wiki Activity

pw_containers: Use unsigned short for Vector sizes

Browse Source 
Since pw::Vectors are statically allocated, 65535 is a reasonable upper
limit for the number of entries in the vector.

Change-Id: I5a2fda53d522cffd70138d34b60273c6083ffe41
This commit is contained in:
Wyatt Hepler 2020-02-24 15:11:24 -08:00
parent e79bf9ef46
commit 75ea8dba2f
1 changed files with 27 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

43
pw_containers/public/pw_containers/vector.h
View File

@ -17,6 +17,7 @@
#include <cstddef>
#include <initializer_list>
#include <iterator>
#include <limits>
#include <new>
#include <type_traits>
#include <utility>
@ -46,17 +47,17 @@ inline constexpr size_t kGeneric = size_t(-1);
template <typename T, size_t kMaxSize = vector_impl::kGeneric>
class Vector : public Vector<T, vector_impl::kGeneric> {
public:
using value_type = T;
using size_type = size_t;
using difference_type = ptrdiff_t;
using reference = value_type&;
using const_reference = const value_type&;
using pointer = T*;
using const_pointer = const T*;
using iterator = T*;
using const_iterator = const T*;
using reverse_iterator = std::reverse_iterator<iterator>;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
using typename Vector<T, vector_impl::kGeneric>::value_type;
using typename Vector<T, vector_impl::kGeneric>::size_type;
using typename Vector<T, vector_impl::kGeneric>::difference_type;
using typename Vector<T, vector_impl::kGeneric>::reference;
using typename Vector<T, vector_impl::kGeneric>::const_reference;
using typename Vector<T, vector_impl::kGeneric>::pointer;
using typename Vector<T, vector_impl::kGeneric>::const_pointer;
using typename Vector<T, vector_impl::kGeneric>::iterator;
using typename Vector<T, vector_impl::kGeneric>::const_iterator;
using typename Vector<T, vector_impl::kGeneric>::reverse_iterator;
using typename Vector<T, vector_impl::kGeneric>::const_reverse_iterator;
// Construct
Vector() noexcept : Vector<T, vector_impl::kGeneric>(kMaxSize) {}
@ -117,6 +118,8 @@ class Vector : public Vector<T, vector_impl::kGeneric> {
private:
friend class Vector<T, vector_impl::kGeneric>;
static_assert(kMaxSize <= std::numeric_limits<size_type>::max());
// Provides access to the underlying array as an array of T.
pointer array() { return std::launder(reinterpret_cast<T*>(&array_)); }
const_pointer array() const {
@ -135,7 +138,12 @@ template <typename T>
class Vector<T, vector_impl::kGeneric> {
public:
using value_type = T;
using size_type = size_t;
// Use unsigned short instead of size_t. Since Vectors are statically
// allocated, 65535 entries is a reasonable upper limit. This reduces Vector's
// overhead by packing the size and capacity into 32 bits.
using size_type = unsigned short;
using difference_type = ptrdiff_t;
using reference = value_type&;
using const_reference = const value_type&;
@ -243,11 +251,14 @@ class Vector<T, vector_impl::kGeneric> {
// (push_back, insert, etc.) will fail if full() is true.
[[nodiscard]] bool full() const noexcept { return size() == max_size(); }
size_type size() const noexcept { return size_; }
// Returns the number of elements in the Vector. Uses size_t instead of
// size_type for consistency with other containers.
size_t size() const noexcept { return size_; }
size_type max_size() const noexcept { return max_size_; }
// Returns the maximum number of elements in this Vector.
size_t max_size() const noexcept { return max_size_; }
size_type capacity() const noexcept { return max_size(); }
size_t capacity() const noexcept { return max_size(); }
// Modify
@ -398,7 +409,7 @@ template <typename T>
void Vector<T, vector_impl::kGeneric>::resize(size_type new_size,
const T& value) {
if (size() < new_size) {
Append(std::min(max_size(), new_size) - size(), value);
Append(std::min(max_size(), size_t(new_size)) - size(), value);
} else {
while (size() > new_size) {
pop_back();