此程序给出3个实用和高速的内存分配函数。这3个函数组成的内存分配体系在以下两种情况下使用可以获得较高的性能和速度：（1）要分配的内存块是同样大小；（2）要分配的内存都小于某个数量。-This procedure gives three practical and high-speed memory allocation function. This is composed of three function memory allocation system in the following two cases can be high performance and speed: (1) to be allocated memory block is the same size　(2) of memory to be allocated are less than a certain quality