From 1a4b2bf52940f1b5f84a6a04402f8ccbad5266bd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=82=B9=E6=99=93=E8=88=AA?= <1210603696@qq.com>
Date: Wed, 24 Sep 2014 12:01:43 +0800
Subject: [PATCH] =?UTF-8?q?=E5=AE=8C=E6=88=90circular=20buffer=E5=88=9D?=
 =?UTF-8?q?=E5=A7=8B=E5=8C=96?=
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---
 TinySTL/CircularBuffer.h | 114 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 113 insertions(+), 1 deletion(-)

diff --git a/TinySTL/CircularBuffer.h b/TinySTL/CircularBuffer.h
index a047605..950bce4 100644
--- a/TinySTL/CircularBuffer.h
+++ b/TinySTL/CircularBuffer.h
@@ -1,8 +1,120 @@
 #ifndef _CIRCULAR_BUFFER_H_
 #define _CIRCULAR_BUFFER_H_
 
-namespace TinySTL{
+#include "Allocator.h"
+#include "Iterator.h"
+#include "UninitializedFunctions.h"
 
+namespace TinySTL{
+	template<class T, size_t N, class Alloc>
+	class circular_buffer;
+	namespace{
+		//the iterator of circular buffer
+		template<class T, size_t N, class Alloc = allocator<T>>
+		class cb_iter:iterator<bidirectional_iterator_tag, T>{
+		private:
+			typedef circular_buffer<T, N, Alloc> cb;
+			typedef cb *cbPtr;
+
+			T *ptr_;
+			int index_;
+			cbPtr container_;
+		public:
+			cb_iter() :ptr_(0), index_(0), container_(0){}
+			explicit cb_iter(T *ptr, cbPtr container) :
+				ptr_(ptr), index_(ptr - container->start_), container_(container){}
+		public:
+			operator T*(){ return ptr_; }
+
+			cb_iter& operator ++(){
+				setIndex_(++index_ % N);
+				setPtr_(container_->start_ + index_);
+				return *this;
+			}
+			cb_iter operator ++(int){
+				cb_iter temp(*this);
+				++(*this);
+				return temp;
+			}
+			cb_iter& operator --(){
+				int index = index_ - 1;
+				index = (index == -1 ? index + N : index);
+				setIndex_(index);
+				setPtr_(container_->start_ + index_);
+				return *this;
+			}
+			cb_iter operator --(int){
+				cb_iter temp(*this);
+				--(*this);
+				return temp;
+			}
+		private:
+			void setIndex_(int index){ index_ = index; }
+			void setPtr_(T *ptr){ ptr_ = ptr; }
+		};
+	}//end of anonymous namespace
+
+	//circular buffer
+	template<class T, size_t N, class Alloc = allocator<T>>
+	class circular_buffer{
+	public:
+		typedef T			value_type;
+		typedef cb_iter<T, N>	iterator;
+		typedef iterator	pointer;
+		typedef T&			reference;
+		typedef int		size_type;
+		typedef ptrdiff_t	difference_type;
+	private:
+		T *start_;
+		T *finish_;
+		int indexOfHead;
+		int indexOfTail;
+
+		typedef Alloc dataAllocator;
+	public:
+		circular_buffer() :
+			start_(0), finish_(0), indexOfHead(0), indexOfTail(0){}
+		explicit circular_buffer(const int& n, const value_type& val = value_type());
+		template<class InputIterator>
+		circular_buffer(InputIterator first, InputIterator last);
+
+		//just for test
+		T *begin(){ return start_; }
+		T *end(){ return finish_; }
+	private:
+		void allocateAndFillN(const int& n, const value_type& val){
+			start_ = dataAllocator::allocate(N);
+			finish_ = start_ + N;
+			indexOfHead = indexOfTail = 0;
+			if (N <= n){
+				finish_ = TinySTL::uninitialized_fill_n(start_, N, val);
+			}else{//N > n
+				finish_ = TinySTL::uninitialized_fill_n(start_, n, val);
+				finish_ = TinySTL::uninitialized_fill_n(finish_, N - n, value_type());
+			}
+		}
+		template<class InputIterator>
+		void allocateAndCopy(InputIterator first, InputIterator last){
+			int n = last - first;
+			start_ = dataAllocator::allocate(N);
+			indexOfHead = indexOfTail = 0;
+			if (N <= n){
+				finish_ = TinySTL::uninitialized_copy(first, first + N, start_);
+			}else{//N > n
+				finish_ = TinySTL::uninitialized_copy(first, last, start_);
+				finish_ = TinySTL::uninitialized_fill_n(finish_, N - n, value_type());
+			}
+		}
+	};
+	template<class T, size_t N, class Alloc>
+	circular_buffer<T, N, Alloc>::circular_buffer(const int& n, const value_type& val = value_type()){
+		allocateAndFillN(n, val);
+	}
+	template<class T, size_t N, class Alloc>
+	template<class InputIterator>
+	circular_buffer<T, N, Alloc>::circular_buffer(InputIterator first, InputIterator last){
+		allocateAndCopy(first, last);
+	}
 }
 
 #endif
\ No newline at end of file