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：
#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"）
