comparison core/tools/CStack.m @ 0:e9a9cd732c1e tip

first hg version after svn

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