/*
============================================================================
Name : homework1_tcp.c
Author :
Version :
Copyright : Your copyright notice
Description : Hello World in C, ANSI-style
============================================================================
*/
#include "stdio.h"
#include <sys/types.h>
#include <sys/stat.h>
#include "fcntl.h"
#include <unistd.h>
#include <sys/mman.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <sys/time.h>
#include <string.h>
#define BUFFER_SIZE 1
void my_copy1()
{
int fin,fout;
void *start;
void *end;
struct stat sf;
if((fin = open("file.in",O_RDONLY)) < 0)
{
perror("open error");
exit(EXIT_FAILURE);
}
if((fout = open( "file.out",O_RDWR | O_CREAT | O_TRUNC,00600)) < 0 )
{
perror( "write error" );
exit( EXIT_FAILURE );
}
fstat(fin,&sf);
start = mmap(NULL,sf.st_size,PROT_READ,MAP_PRIVATE,fin,0);
if(start == MAP_FAILED)
return;
end = mmap(0,(size_t)sf.st_size,PROT_WRITE,MAP_SHARED,fout,0);
if(end == MAP_FAILED)
{
return ;
}
memcpy(end,start,(size_t)sf.st_size);
munmap(start,sf.st_size);
munmap(end,sf.st_size);
close(fin);
close(fout);
return;
}
void my_copy2()
{
int fin,fout;
int bytes_read,bytes_write;
char buffer[BUFFER_SIZE];
char *ptr;
bytes_read=0;
for(;;bytes_read=read(fin,buffer,BUFFER_SIZE)){
if((bytes_read==-1)&&(errno!=EINTR))
break;
else
{
ptr=buffer;
while(bytes_write=write(fout,ptr,bytes_read))
{
if((bytes_write==-1)&&(errno!=EINTR))
break;
else if(bytes_write==bytes_read)
break;
else if(bytes_write>0)
{
ptr+=bytes_write;
bytes_read-=bytes_write;
}
}
if(bytes_write==-1)
break;
}
}
close(fin);
close(fout);
return;
}
main()
{
struct timeval tv;
struct timezone tz;
long time_start,time_end;
gettimeofday(&tv,&tz);
time_start = tv.tv_sec*1000000 + tv.tv_usec;
my_copy1();
printf("\n done.\n\n");
gettimeofday(&tv,&tz);
time_end = tv.tv_sec*1000000 + tv.tv_usec;
printf("using \"mmap()\" to copy costs %ld microseconds \n",time_end - time_start);
gettimeofday(&tv,&tz);
time_start = tv.tv_sec*1000000 + tv.tv_usec;
my_copy2();
gettimeofday(&tv,&tz);
time_end = tv.tv_sec*1000000 + tv.tv_usec;
printf("using \"read() and write()\" to copy costs %ld microseconds \n",time_end - time_start);
}
