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Diffstat (limited to 'src/prevector.h')
| -rw-r--r-- | src/prevector.h | 486 |
1 files changed, 486 insertions, 0 deletions
diff --git a/src/prevector.h b/src/prevector.h new file mode 100644 index 0000000000..3e80ef5d33 --- /dev/null +++ b/src/prevector.h @@ -0,0 +1,486 @@ +#ifndef _BITCOIN_PREVECTOR_H_ +#define _BITCOIN_PREVECTOR_H_ + +#include <stdlib.h> +#include <stdint.h> +#include <string.h> + +#include <iterator> + +#pragma pack(push, 1) +/** Implements a drop-in replacement for std::vector<T> which stores up to N + * elements directly (without heap allocation). The types Size and Diff are + * used to store element counts, and can be any unsigned + signed type. + * + * Storage layout is either: + * - Direct allocation: + * - Size _size: the number of used elements (between 0 and N) + * - T direct[N]: an array of N elements of type T + * (only the first _size are initialized). + * - Indirect allocation: + * - Size _size: the number of used elements plus N + 1 + * - Size capacity: the number of allocated elements + * - T* indirect: a pointer to an array of capacity elements of type T + * (only the first _size are initialized). + * + * The data type T must be movable by memmove/realloc(). Once we switch to C++, + * move constructors can be used instead. + */ +template<unsigned int N, typename T, typename Size = uint32_t, typename Diff = int32_t> +class prevector { +public: + typedef Size size_type; + typedef Diff difference_type; + typedef T value_type; + typedef value_type& reference; + typedef const value_type& const_reference; + typedef value_type* pointer; + typedef const value_type* const_pointer; + + class iterator { + T* ptr; + public: + typedef Diff difference_type; + typedef T value_type; + typedef T* pointer; + typedef T& reference; + typedef std::random_access_iterator_tag iterator_category; + iterator(T* ptr_) : ptr(ptr_) {} + T& operator*() const { return *ptr; } + T* operator->() const { return ptr; } + T& operator[](size_type pos) { return ptr[pos]; } + const T& operator[](size_type pos) const { return ptr[pos]; } + iterator& operator++() { ptr++; return *this; } + iterator& operator--() { ptr--; return *this; } + iterator operator++(int) { iterator copy(*this); ++(*this); return copy; } + iterator operator--(int) { iterator copy(*this); --(*this); return copy; } + difference_type friend operator-(iterator a, iterator b) { return (&(*a) - &(*b)); } + iterator operator+(size_type n) { return iterator(ptr + n); } + iterator& operator+=(size_type n) { ptr += n; return *this; } + iterator operator-(size_type n) { return iterator(ptr - n); } + iterator& operator-=(size_type n) { ptr -= n; return *this; } + bool operator==(iterator x) const { return ptr == x.ptr; } + bool operator!=(iterator x) const { return ptr != x.ptr; } + bool operator>=(iterator x) const { return ptr >= x.ptr; } + bool operator<=(iterator x) const { return ptr <= x.ptr; } + bool operator>(iterator x) const { return ptr > x.ptr; } + bool operator<(iterator x) const { return ptr < x.ptr; } + }; + + class reverse_iterator { + T* ptr; + public: + typedef Diff difference_type; + typedef T value_type; + typedef T* pointer; + typedef T& reference; + typedef std::bidirectional_iterator_tag iterator_category; + reverse_iterator(T* ptr_) : ptr(ptr_) {} + T& operator*() { return *ptr; } + const T& operator*() const { return *ptr; } + T* operator->() { return ptr; } + const T* operator->() const { return ptr; } + reverse_iterator& operator--() { ptr++; return *this; } + reverse_iterator& operator++() { ptr--; return *this; } + reverse_iterator operator++(int) { reverse_iterator copy(*this); ++(*this); return copy; } + reverse_iterator operator--(int) { reverse_iterator copy(*this); --(*this); return copy; } + bool operator==(reverse_iterator x) const { return ptr == x.ptr; } + bool operator!=(reverse_iterator x) const { return ptr != x.ptr; } + }; + + class const_iterator { + const T* ptr; + public: + typedef Diff difference_type; + typedef const T value_type; + typedef const T* pointer; + typedef const T& reference; + typedef std::random_access_iterator_tag iterator_category; + const_iterator(const T* ptr_) : ptr(ptr_) {} + const_iterator(iterator x) : ptr(&(*x)) {} + const T& operator*() const { return *ptr; } + const T* operator->() const { return ptr; } + const T& operator[](size_type pos) const { return ptr[pos]; } + const_iterator& operator++() { ptr++; return *this; } + const_iterator& operator--() { ptr--; return *this; } + const_iterator operator++(int) { const_iterator copy(*this); ++(*this); return copy; } + const_iterator operator--(int) { const_iterator copy(*this); --(*this); return copy; } + difference_type friend operator-(const_iterator a, const_iterator b) { return (&(*a) - &(*b)); } + const_iterator operator+(size_type n) { return const_iterator(ptr + n); } + const_iterator& operator+=(size_type n) { ptr += n; return *this; } + const_iterator operator-(size_type n) { return const_iterator(ptr - n); } + const_iterator& operator-=(size_type n) { ptr -= n; return *this; } + bool operator==(const_iterator x) const { return ptr == x.ptr; } + bool operator!=(const_iterator x) const { return ptr != x.ptr; } + bool operator>=(const_iterator x) const { return ptr >= x.ptr; } + bool operator<=(const_iterator x) const { return ptr <= x.ptr; } + bool operator>(const_iterator x) const { return ptr > x.ptr; } + bool operator<(const_iterator x) const { return ptr < x.ptr; } + }; + + class const_reverse_iterator { + const T* ptr; + public: + typedef Diff difference_type; + typedef const T value_type; + typedef const T* pointer; + typedef const T& reference; + typedef std::bidirectional_iterator_tag iterator_category; + const_reverse_iterator(T* ptr_) : ptr(ptr_) {} + const_reverse_iterator(reverse_iterator x) : ptr(&(*x)) {} + const T& operator*() const { return *ptr; } + const T* operator->() const { return ptr; } + const_reverse_iterator& operator--() { ptr++; return *this; } + const_reverse_iterator& operator++() { ptr--; return *this; } + const_reverse_iterator operator++(int) { const_reverse_iterator copy(*this); ++(*this); return copy; } + const_reverse_iterator operator--(int) { const_reverse_iterator copy(*this); --(*this); return copy; } + bool operator==(const_reverse_iterator x) const { return ptr == x.ptr; } + bool operator!=(const_reverse_iterator x) const { return ptr != x.ptr; } + }; + +private: + size_type _size; + union { + char direct[sizeof(T) * N]; + struct { + size_type capacity; + char* indirect; + }; + } _union; + + T* direct_ptr(difference_type pos) { return reinterpret_cast<T*>(_union.direct) + pos; } + const T* direct_ptr(difference_type pos) const { return reinterpret_cast<const T*>(_union.direct) + pos; } + T* indirect_ptr(difference_type pos) { return reinterpret_cast<T*>(_union.indirect) + pos; } + const T* indirect_ptr(difference_type pos) const { return reinterpret_cast<const T*>(_union.indirect) + pos; } + bool is_direct() const { return _size <= N; } + + void change_capacity(size_type new_capacity) { + if (new_capacity <= N) { + if (!is_direct()) { + T* indirect = indirect_ptr(0); + T* src = indirect; + T* dst = direct_ptr(0); + memcpy(dst, src, size() * sizeof(T)); + free(indirect); + _size -= N + 1; + } + } else { + if (!is_direct()) { + _union.indirect = static_cast<char*>(realloc(_union.indirect, ((size_t)sizeof(T)) * new_capacity)); + _union.capacity = new_capacity; + } else { + char* new_indirect = static_cast<char*>(malloc(((size_t)sizeof(T)) * new_capacity)); + T* src = direct_ptr(0); + T* dst = reinterpret_cast<T*>(new_indirect); + memcpy(dst, src, size() * sizeof(T)); + _union.indirect = new_indirect; + _union.capacity = new_capacity; + _size += N + 1; + } + } + } + + T* item_ptr(difference_type pos) { return is_direct() ? direct_ptr(pos) : indirect_ptr(pos); } + const T* item_ptr(difference_type pos) const { return is_direct() ? direct_ptr(pos) : indirect_ptr(pos); } + +public: + void assign(size_type n, const T& val) { + clear(); + if (capacity() < n) { + change_capacity(n); + } + while (size() < n) { + _size++; + new(static_cast<void*>(item_ptr(size() - 1))) T(val); + } + } + + template<typename InputIterator> + void assign(InputIterator first, InputIterator last) { + size_type n = last - first; + clear(); + if (capacity() < n) { + change_capacity(n); + } + while (first != last) { + _size++; + new(static_cast<void*>(item_ptr(size() - 1))) T(*first); + ++first; + } + } + + prevector() : _size(0) {} + + explicit prevector(size_type n) : _size(0) { + resize(n); + } + + explicit prevector(size_type n, const T& val = T()) : _size(0) { + change_capacity(n); + while (size() < n) { + _size++; + new(static_cast<void*>(item_ptr(size() - 1))) T(val); + } + } + + template<typename InputIterator> + prevector(InputIterator first, InputIterator last) : _size(0) { + size_type n = last - first; + change_capacity(n); + while (first != last) { + _size++; + new(static_cast<void*>(item_ptr(size() - 1))) T(*first); + ++first; + } + } + + prevector(const prevector<N, T, Size, Diff>& other) : _size(0) { + change_capacity(other.size()); + const_iterator it = other.begin(); + while (it != other.end()) { + _size++; + new(static_cast<void*>(item_ptr(size() - 1))) T(*it); + ++it; + } + } + + prevector& operator=(const prevector<N, T, Size, Diff>& other) { + if (&other == this) { + return *this; + } + resize(0); + change_capacity(other.size()); + const_iterator it = other.begin(); + while (it != other.end()) { + _size++; + new(static_cast<void*>(item_ptr(size() - 1))) T(*it); + ++it; + } + return *this; + } + + size_type size() const { + return is_direct() ? _size : _size - N - 1; + } + + bool empty() const { + return size() == 0; + } + + iterator begin() { return iterator(item_ptr(0)); } + const_iterator begin() const { return const_iterator(item_ptr(0)); } + iterator end() { return iterator(item_ptr(size())); } + const_iterator end() const { return const_iterator(item_ptr(size())); } + + reverse_iterator rbegin() { return reverse_iterator(item_ptr(size() - 1)); } + const_reverse_iterator rbegin() const { return const_reverse_iterator(item_ptr(size() - 1)); } + reverse_iterator rend() { return reverse_iterator(item_ptr(-1)); } + const_reverse_iterator rend() const { return const_reverse_iterator(item_ptr(-1)); } + + size_t capacity() const { + if (is_direct()) { + return N; + } else { + return _union.capacity; + } + } + + T& operator[](size_type pos) { + return *item_ptr(pos); + } + + const T& operator[](size_type pos) const { + return *item_ptr(pos); + } + + void resize(size_type new_size) { + while (size() > new_size) { + item_ptr(size() - 1)->~T(); + _size--; + } + if (new_size > capacity()) { + change_capacity(new_size); + } + while (size() < new_size) { + _size++; + new(static_cast<void*>(item_ptr(size() - 1))) T(); + } + } + + void reserve(size_type new_capacity) { + if (new_capacity > capacity()) { + change_capacity(new_capacity); + } + } + + void shrink_to_fit() { + change_capacity(size()); + } + + void clear() { + resize(0); + } + + iterator insert(iterator pos, const T& value) { + size_type p = pos - begin(); + size_type new_size = size() + 1; + if (capacity() < new_size) { + change_capacity(new_size + (new_size >> 1)); + } + memmove(item_ptr(p + 1), item_ptr(p), (size() - p) * sizeof(T)); + _size++; + new(static_cast<void*>(item_ptr(p))) T(value); + return iterator(item_ptr(p)); + } + + void insert(iterator pos, size_type count, const T& value) { + size_type p = pos - begin(); + size_type new_size = size() + count; + if (capacity() < new_size) { + change_capacity(new_size + (new_size >> 1)); + } + memmove(item_ptr(p + count), item_ptr(p), (size() - p) * sizeof(T)); + _size += count; + for (size_type i = 0; i < count; i++) { + new(static_cast<void*>(item_ptr(p + i))) T(value); + } + } + + template<typename InputIterator> + void insert(iterator pos, InputIterator first, InputIterator last) { + size_type p = pos - begin(); + difference_type count = last - first; + size_type new_size = size() + count; + if (capacity() < new_size) { + change_capacity(new_size + (new_size >> 1)); + } + memmove(item_ptr(p + count), item_ptr(p), (size() - p) * sizeof(T)); + _size += count; + while (first != last) { + new(static_cast<void*>(item_ptr(p))) T(*first); + ++p; + ++first; + } + } + + iterator erase(iterator pos) { + (*pos).~T(); + memmove(&(*pos), &(*pos) + 1, ((char*)&(*end())) - ((char*)(1 + &(*pos)))); + _size--; + return pos; + } + + iterator erase(iterator first, iterator last) { + iterator p = first; + char* endp = (char*)&(*end()); + while (p != last) { + (*p).~T(); + _size--; + ++p; + } + memmove(&(*first), &(*last), endp - ((char*)(&(*last)))); + return first; + } + + void push_back(const T& value) { + size_type new_size = size() + 1; + if (capacity() < new_size) { + change_capacity(new_size + (new_size >> 1)); + } + new(item_ptr(size())) T(value); + _size++; + } + + void pop_back() { + _size--; + } + + T& front() { + return *item_ptr(0); + } + + const T& front() const { + return *item_ptr(0); + } + + T& back() { + return *item_ptr(size() - 1); + } + + const T& back() const { + return *item_ptr(size() - 1); + } + + void swap(prevector<N, T, Size, Diff>& other) { + if (_size & other._size & 1) { + std::swap(_union.capacity, other._union.capacity); + std::swap(_union.indirect, other._union.indirect); + } else { + std::swap(_union, other._union); + } + std::swap(_size, other._size); + } + + ~prevector() { + clear(); + if (!is_direct()) { + free(_union.indirect); + _union.indirect = NULL; + } + } + + bool operator==(const prevector<N, T, Size, Diff>& other) const { + if (other.size() != size()) { + return false; + } + const_iterator b1 = begin(); + const_iterator b2 = other.begin(); + const_iterator e1 = end(); + while (b1 != e1) { + if ((*b1) != (*b2)) { + return false; + } + ++b1; + ++b2; + } + return true; + } + + bool operator!=(const prevector<N, T, Size, Diff>& other) const { + return !(*this == other); + } + + bool operator<(const prevector<N, T, Size, Diff>& other) const { + if (size() < other.size()) { + return true; + } + if (size() > other.size()) { + return false; + } + const_iterator b1 = begin(); + const_iterator b2 = other.begin(); + const_iterator e1 = end(); + while (b1 != e1) { + if ((*b1) < (*b2)) { + return true; + } + if ((*b2) < (*b1)) { + return false; + } + ++b1; + ++b2; + } + return false; + } + + size_t allocated_memory() const { + if (is_direct()) { + return 0; + } else { + return ((size_t)(sizeof(T))) * _union.capacity; + } + } +}; +#pragma pack(pop) + +#endif |