nullnulllinux动态异长存储资源分配算法的实现

发一下牢骚和主题无关：

    每日一道理
坚持的昨天叫立足，坚持的今天叫进取，坚持的明天叫成功。

#ifdef HAVA_CONFIG_H
#include <config.h>
#endif

#include<stdio.h>
#include<stdlib.h>
#define MAPSIZE 100

struct map//store resoure table'struct
{
	int m_addr;
	int m_size;
}
;
struct map map[MAPSIZE];

//best fit
int BF_malloc(struct map *mp,int size)
{
	register int a,s;
/*these var is recommend to be saved in register,so it can be vary fast
 *but only if its size is not bigger thar 'int' can be declared as 'register type'
 *more over,this var may not be in memory,so you can not use a '&' to get its address
 */
	register struct map *bp,*bpp;

	for(bp=mp;bp->m_size;bp++)
	{
		if(bp->m_size >=size)
		{
			a=bp->m_addr;
			s=bp->m_size;
			for(bpp=bp;bpp->m_size;bpp++)
			{
				if(bpp->m_size >=size && bpp->m_size <s)
				{
					a=bpp->m_addr;
					s=bpp->m_size;
					bp=bpp;
				}
			}
			bp->m_addr +=size;
			if((bp->m_size -= size) ==0)
				do{
					bp++;
					(bp-1)->m_addr=bp->m_addr;
				}while( (bp-1)->m_size=bp->m_size ); //while not null
			return(a);
		}
	}
	return(-1);
}

//worst fit
int WF_malloc(struct map *mp,int size)
{
	register int a,s;
	register struct map *bp,*bpp;
	for(bp=mp;bp->m_size;bp++)
	{
		if(bp->m_size >= size)
		{
			a=bp->m_addr;
			s=bp->m_size;
			for(bpp=bp;bpp->m_size;bpp++)
			{
				if(bpp->m_size>s)
				{
					a=bpp->m_addr;
					s=bpp->m_size;
					bp=bpp;
				}
			}
			bp->m_addr += size;
			if((bp->m_size -= size) ==0)
				do{
					bp++;
					(bp-1)->m_addr=bp->m_addr;
				}while( (bp-1)->m_size=bp->m_size);
			return(a);
		}
	}
	return(-1);
}

void mfree(struct map *mp,int aa,int size)
{
	register struct map *bp;
	register int t;
	register int a;

	a=aa;
	for(bp=mp; bp->m_addr <= a && bp->m_size!=0;bp++);
	
	if(bp>mp && (bp-1)->m_addr+(bp-1)->m_size==a)
	{
		//if the point has moved and can combine with forword one
		//combine forword
		(bp-1)->m_size+=size;
		if(a+size==bp->m_addr)
		{ //combine backword
			(bp-1)->m_size+=bp->m_size;
			while(bp->m_size)
			{
				bp++;
				(bp-1)->m_addr=bp->m_addr;
				(bp-1)->m_size=bp->m_size;
			}
		}
	}else{
		if(a+size==bp->m_addr && bp->m_size)
		{
			//combine backword
			bp->m_addr-=size;
			bp->m_size+=size;
		}else if(size)
			do
			{
				//no combination
				//move each one towards the tail
				t=bp->m_addr;
				bp->m_addr=a;
				a=t;
				t=bp->m_size;
				bp->m_size=size;
				bp++;
			}while(size=t);
	}
}

void init()
{
	struct map *bp; //not register
	int addr,size;
	int i=0;
	bp=map;
	printf("Please input starting addr and total size:");
	scanf("%d,%d",&addr,&size);
	bp->m_addr=addr;
	bp->m_size=size;
	(++bp)->m_size=0;//table's tail
}

void show_map()
{
	int i=0;
	struct map *bp;
	bp=map;
	printf("\nCurrent memory map...\n");
	printf("Address\t\tSize\n");
	while(bp->m_size!=0)
	{
		printf("<%d\t\t%d>\n",bp->m_addr,bp->m_size);
		bp++;
	}
	printf("\n");
}

main()
{
	int a,s;
	char c;
	int i;
	init();
	printf("Please input, b for BF, w for WF:");
	scanf("\n%c",&c);
	do
	{
		show_map();
		printf("Please input,1 for request,2for release,0 for exit:");
		scanf("%d",&i);
		switch(i)
		{
		case 1:
			printf("Please input size:");
			scanf("%d",&s);
			if(c=='b')//BF
				a=BF_malloc(map,s);
			else
				a=WF_malloc(map,s);
			if(a==-1)
				printf("request can't be satisfied\n");
			else
				printf("alloc memory at address:%d,siz:%d\n",a,s);
			break;
		case 2:
			printf("Please input addr and size:");
			scanf("%d,%d",&a,&s);
			mfree(map,a,s);
			break;
		case 0:
			exit(0);	
		}
	}while(1);
}

文章结束给大家分享下程序员的一些笑话语录： 一个程序员对自己的未来很迷茫，于是去问上帝。
"万能的上帝呀，请你告诉我，我的未来会怎样？"
上帝说"我的孩子，你去问Lippman，他现在领导的程序员的队伍可能是地球上最大的"
于是他去问Lippman。
Lippman说"程序员的未来就是驾驭程序员"
这个程序员对这个未来不满意，于是他又去问上帝。
"万能的上帝呀，请你告诉我，我的未来会怎样？"
上帝说"我的孩子，你去问Gates，他现在所拥有的财产可能是地球上最多的"
于是他去问Gates。
Gates说"程序员的未来就是榨取程序员"
这个程序员对这个未来不满意，于是他又去问上帝。
"万能的上帝呀，请你告诉我，我的未来会怎样？"
上帝说"我的孩子，你去问侯捷，他写的计算机书的读者可能是地球上最多的"
于是他去问侯捷。
侯捷说"程序员的未来就是诱惑程序员"
这个程序员对这个未来不满意，于是他又去问上帝。
"万能的上帝呀，请你告诉我，我的未来会怎样？"
上帝摇摇头"唉，我的孩子，你还是别当程序员了"）