#define __LIBRARY__
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <fcntl.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <asm/segment.h>
#include <sys/stat.h>

#define BUF_MAX  128
#define	DIRBUF  8192
#define NAME_MAX  14

struct dirent {                            /* Ŀ¼��ṹ�� */
	long           d_ino;                  /* i�ڵ� */
	off_t          d_off;                  /* � */
	unsigned short d_reclen;               /* �ļ������� */
	char           d_name[NAME_MAX + 1];   /* �ļ��� */
};

int sys_getdents(unsigned int fd, struct dirent* dirp, unsigned int count) {
	struct file* file;
	struct m_inode* inode;
	struct buffer_head* head;
	struct dir_entry* de_tmp;
	struct dirent* self_tmp;                       /* ָ�������Զ���ṹ�����ʱָ�� */
	char* buf;
	int dir_size, dire_size, read_bytes, addr_off, i;

	dir_size = sizeof(struct dirent);              /* ��ǰĿ¼�ṹ��Ĵ�С */
	dire_size = sizeof(struct dir_entry);          /*  Ŀ¼��ṹ��Ĵ�С  */

	self_tmp = (struct dirent*)malloc(dir_size);       /* �ȷ����ʼ�ռ� */
	buf = (char*)malloc(dir_size);

	file = current->filp[fd];                      /* ��ȡ��ǰĿ¼����Ϣ */
	inode = file->f_inode;
	head = bread(inode->i_dev, inode->i_zone[0]);

	/* �������ѭ������dirpΪ�����ڴ�洢������Ŀ¼����Ϣ��read_bytes�洢�������ֽ��� */
	read_bytes = 0;
	for (addr_off = 0; addr_off < inode->i_size; addr_off += dire_size) {   /* �ӵ�ǰĿ¼����ڿ�ʼ����ȡÿһ��Ŀ¼��Ļ��������� */
		if (read_bytes >= count - dir_size)                                 /* �����ȡ���ֽ����������ƣ�ֱ���˳�ѭ�� */
			break;
		de_tmp = (struct dir_entry*)(head->b_data + addr_off);              /* deָ��Ŀ¼������Ľṹ�� */
		if (!de_tmp->inode)                                                 /* ���������Ŀ¼����� */
			continue;
		self_tmp->d_ino = de_tmp->inode;                                    /* Ŀ¼�����Ϣ����deָ��Ľṹ���У������ǿ�������ʱָ��self_tmpָ��Ľṹ���� */
		self_tmp->d_off = 0;
		self_tmp->d_reclen = dir_size;
		strcpy(self_tmp->d_name, de_tmp->name);
		memcpy(buf, self_tmp, dir_size);                                    /* �Ѹն��������ݿ�������buf�������ڴ��� */
		for (i = 0; i < dir_size; i++)                                      /* ���ڴ��������һ���ֽ�һ���ֽڵؿ�����dirp�������û�һ������ֵ */
			put_fs_byte(*(buf + i), ((char*)dirp) + i + read_bytes);
		read_bytes += dir_size;
	}
	return read_bytes;
}