#define _GNU_SOURCE 

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>

#define FILE_SIZE  1024000
#define HOLE_START	409600
#define HOLE_LEN	204800
#define HOLE_SHIFET	102400


int main(int argc, char *argv[])
{
	int fd;
	int ret;
	void* data_foo;
	int fd_bar;
	char bar_path[256];
	
	if (argc != 2) {
		printf("usage: a.out [file Path]\n");
		exit(1);
	}
	sprintf(bar_path,"%s_bar",argv[1]);
	
	printf("file path: %s \n",argv[1]);
	printf("file_bar path: %s \n",bar_path);

	fd =  open(argv[1], O_CREAT | O_RDWR  , 0755);
	if (fd < 0) {
		printf("open err! \n");
		exit(1);
	}
	
	data_foo = malloc(FILE_SIZE);
	if (!data_foo) {
		printf("malloc err! \n");
		exit(1);
	}
	
	int offset_foo = 0;
	int to_write_foo = FILE_SIZE ;
	const char *text_foo  = "ddddddddddklmnopqrstuvwxyz123456";
	while (offset_foo < FILE_SIZE){
		if (to_write_foo < 32){
			memcpy((char *)data_foo+ offset_foo, text_foo, to_write_foo);
			offset_foo += to_write_foo;
		}
		else {
			memcpy((char *)data_foo+ offset_foo,text_foo, 32);
			offset_foo += 32; 
		} 
	} 	

	ret = pwrite(fd, data_foo, FILE_SIZE, 0);
	if (ret != FILE_SIZE) {
		printf("write err! [%d] \n",ret);
		exit(1);
	}	
	
	ret = fallocate( fd , FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE , HOLE_START , HOLE_LEN);
	if ( ret < 0){ 
		printf("fallocate err! [%d] \n",ret);
		exit(1);
	}

	fd_bar = open(bar_path, O_CREAT | O_RDWR , 0755);
	if (fd_bar < 0) {
		printf("open fd_bar err! \n");
		exit(1);			
	}
	fsync(fd_bar);
	close(fd_bar);

	ret = fallocate( fd , FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE , HOLE_START-HOLE_SHIFET , HOLE_LEN);
	if ( ret < 0){ 
		printf("fallocate err! [%d] \n",ret);
		exit(1);
	}
	fsync(fd);
	close(fd);
	exit(0);
}