| #ifndef UTIL_FIXED_ARRAY_H |
| #define UTIL_FIXED_ARRAY_H |
| |
| #include "util/scoped.hh" |
| |
| #include <cstddef> |
| |
| #include <assert.h> |
| #include <stdlib.h> |
| |
| namespace util { |
| |
| /** |
| * Defines a fixed-size collection. |
| * |
| * Ever want an array of things by they don't have a default constructor or are |
| * non-copyable? FixedArray allows constructing one at a time. |
| */ |
| template <class T> class FixedArray { |
| public: |
| /** Initialize with a given size bound but do not construct the objects. */ |
| explicit FixedArray(std::size_t limit) { |
| Init(limit); |
| } |
| |
| /** |
| * Constructs an instance, but does not initialize it. |
| * |
| * Any objects constructed in this manner must be subsequently @ref FixedArray::Init() "initialized" prior to use. |
| * |
| * @see FixedArray::Init() |
| */ |
| FixedArray() |
| : newed_end_(NULL) |
| #ifndef NDEBUG |
| , allocated_end_(NULL) |
| #endif |
| {} |
| |
| /** |
| * Initialize with a given size bound but do not construct the objects. |
| * |
| * This method is responsible for allocating memory. |
| * Objects stored in this array will be constructed in a location within this allocated memory. |
| */ |
| void Init(std::size_t count) { |
| assert(!block_.get()); |
| block_.reset(malloc(sizeof(T) * count)); |
| if (!block_.get()) throw std::bad_alloc(); |
| newed_end_ = begin(); |
| #ifndef NDEBUG |
| allocated_end_ = begin() + count; |
| #endif |
| } |
| |
| /** |
| * Constructs a copy of the provided array. |
| * |
| * @param from Array whose elements should be copied into this newly-constructed data structure. |
| */ |
| FixedArray(const FixedArray &from) { |
| std::size_t size = from.newed_end_ - static_cast<const T*>(from.block_.get()); |
| Init(size); |
| for (std::size_t i = 0; i < size; ++i) { |
| push_back(from[i]); |
| } |
| } |
| |
| /** |
| * Frees the memory held by this object. |
| */ |
| ~FixedArray() { clear(); } |
| |
| /** Gets a pointer to the first object currently stored in this data structure. */ |
| T *begin() { return static_cast<T*>(block_.get()); } |
| |
| /** Gets a const pointer to the last object currently stored in this data structure. */ |
| const T *begin() const { return static_cast<const T*>(block_.get()); } |
| |
| /** Gets a pointer to the last object currently stored in this data structure. */ |
| T *end() { return newed_end_; } |
| |
| /** Gets a const pointer to the last object currently stored in this data structure. */ |
| const T *end() const { return newed_end_; } |
| |
| /** Gets a reference to the last object currently stored in this data structure. */ |
| T &back() { return *(end() - 1); } |
| |
| /** Gets a const reference to the last object currently stored in this data structure. */ |
| const T &back() const { return *(end() - 1); } |
| |
| /** Gets the number of objects currently stored in this data structure. */ |
| std::size_t size() const { return end() - begin(); } |
| |
| /** Returns true if there are no objects currently stored in this data structure. */ |
| bool empty() const { return begin() == end(); } |
| |
| /** |
| * Gets a reference to the object with index i currently stored in this data structure. |
| * |
| * @param i Index of the object to reference |
| */ |
| T &operator[](std::size_t i) { return begin()[i]; } |
| |
| /** |
| * Gets a const reference to the object with index i currently stored in this data structure. |
| * |
| * @param i Index of the object to reference |
| */ |
| const T &operator[](std::size_t i) const { return begin()[i]; } |
| |
| /** |
| * Constructs a new object using the provided parameter, |
| * and stores it in this data structure. |
| * |
| * The memory backing the constructed object is managed by this data structure. |
| */ |
| template <class C> void push_back(const C &c) { |
| new (end()) T(c); // use "placement new" syntax to initalize T in an already-allocated memory location |
| Constructed(); |
| } |
| |
| /** |
| * Removes all elements from this array. |
| */ |
| void clear() { |
| for (T *i = begin(); i != end(); ++i) |
| i->~T(); |
| newed_end_ = begin(); |
| } |
| |
| protected: |
| // Always call Constructed after successful completion of new. |
| void Constructed() { |
| ++newed_end_; |
| #ifndef NDEBUG |
| assert(newed_end_ <= allocated_end_); |
| #endif |
| } |
| |
| private: |
| util::scoped_malloc block_; |
| |
| T *newed_end_; |
| |
| #ifndef NDEBUG |
| T *allocated_end_; |
| #endif |
| }; |
| |
| } // namespace util |
| |
| #endif // UTIL_FIXED_ARRAY_H |