Daniel@0: classdef CStack < handle
Daniel@0: % CStack define a stack data strcuture
Daniel@0: % 
Daniel@0: % It likes java.util.Stack, however, it could use CStack.content() to
Daniel@0: % return all the data (in cells) of the Stack, and it is a litter faster
Daniel@0: % than java's Stack.
Daniel@0: % 
Daniel@0: %   s = CStack(c);  c is a cells, and could be omitted
Daniel@0: %   s.size() return the numble of element
Daniel@0: %   s.isempty() return true when the stack is empty
Daniel@0: %   s.empty() delete the content of the stack
Daniel@0: %   s.push(el) push el to the top of stack
Daniel@0: %   s.pop() pop out the top of the stack, and return the element
Daniel@0: %   s.top() return the top element of the stack
Daniel@0: %   s.remove() remove all the elements in the stack
Daniel@0: %   s.content() return all the data of the stack (in the form of a
Daniel@0: %   cells with size [s.size(), 1]
Daniel@0: %   
Daniel@0: % See also CList, CQueue
Daniel@0: %
Daniel@0: % Copyright: zhang@zhiqiang.org, 2010.
Daniel@0: % url: http://zhiqiang.org/blog/it/matlab-data-structures.html
Daniel@0: 
Daniel@0:     properties (Access = private)
Daniel@0:         buffer      % 一个cell数组，保存栈的数据
Daniel@0:         cur         % 当前元素位置, or the length of the stack
Daniel@0:         capacity    % 栈的容量，当容量不够时，容量扩充为2倍。
Daniel@0:     end
Daniel@0:     
Daniel@0:     methods
Daniel@0:         function obj = CStack(c)
Daniel@0:             if nargin >= 1 && iscell(c)
Daniel@0:                 obj.buffer = c(:);
Daniel@0:                 obj.cur = numel(c);
Daniel@0:                 obj.capacity = obj.cur;
Daniel@0:             elseif nargin >= 1
Daniel@0:                 obj.buffer = cell(100, 1);
Daniel@0:                 obj.cur = 1;
Daniel@0:                 obj.capacity =100;
Daniel@0:                 obj.buffer{1} = c;
Daniel@0:             else
Daniel@0:                 obj.buffer = cell(100, 1);
Daniel@0:                 obj.capacity = 100;
Daniel@0:                 obj.cur = 0;
Daniel@0:             end
Daniel@0:         end
Daniel@0:         
Daniel@0:         function s = size(obj)
Daniel@0:             s = obj.cur;
Daniel@0:         end
Daniel@0:         
Daniel@0:         function remove(obj)
Daniel@0:             obj.cur = 0;
Daniel@0:         end
Daniel@0:         
Daniel@0:         function b = empty(obj)
Daniel@0:             b = obj.cur;
Daniel@0:             obj.cur = 0;
Daniel@0:         end
Daniel@0:         
Daniel@0:         function b = isempty(obj)            
Daniel@0:             b = ~logical(obj.cur);
Daniel@0:         end
Daniel@0: 
Daniel@0:         function push(obj, el)
Daniel@0:             if obj.cur >= obj.capacity
Daniel@0:                 obj.buffer(obj.capacity+1:2*obj.capacity) = cell(obj.capacity, 1);
Daniel@0:                 obj.capacity = 2*obj.capacity;
Daniel@0:             end
Daniel@0:             obj.cur = obj.cur + 1;
Daniel@0:             obj.buffer{obj.cur} = el;
Daniel@0:         end
Daniel@0:         
Daniel@0:         function el = top(obj)
Daniel@0:             if obj.cur == 0
Daniel@0:                 el = [];
Daniel@0:                 warning('CStack:No_Data', 'trying to get top element of an emtpy stack');
Daniel@0:             else
Daniel@0:                 el = obj.buffer{obj.cur};
Daniel@0:             end
Daniel@0:         end
Daniel@0:         
Daniel@0:         function el = pop(obj)
Daniel@0:             if obj.cur == 0
Daniel@0:                 el = [];
Daniel@0:                 warning('CStack:No_Data', 'trying to pop element of an emtpy stack');
Daniel@0:             else
Daniel@0:                 el = obj.buffer{obj.cur};
Daniel@0:                 obj.cur = obj.cur - 1;
Daniel@0:             end        
Daniel@0:         end
Daniel@0:         
Daniel@0:         function display(obj)
Daniel@0:             if obj.cur
Daniel@0:                 for i = 1:obj.cur
Daniel@0:                     disp([num2str(i) '-th element of the stack:']);
Daniel@0:                     disp(obj.buffer{i});
Daniel@0:                 end
Daniel@0:             else
Daniel@0:                 disp('The stack is empty');
Daniel@0:             end
Daniel@0:         end
Daniel@0:         
Daniel@0:         function c = content(obj)
Daniel@0:             c = obj.buffer(1:obj.cur);
Daniel@0:         end
Daniel@0:     end
Daniel@0: end