#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#undef 	NULL
#define NULL	0
#define EOF	(-1)
#define BUFSIZ	8192
#define OPN_MAX	20

struct flag_field {
	unsigned int is_read	: 1;
	unsigned int is_write	: 1;
	unsigned int is_unbuf	: 1;
	unsigned int is_buf	: 1;
	unsigned int is_eof	: 1;
	unsigned int is_err	: 1;
};

typedef struct _iobuff {
	int cnt;
	char *ptr;
	char *base;
	struct flag_field flag;
	int fd;
} FILE;

extern FILE _iob[OPN_MAX];

#define stdin	(&_iob[0]);
#define stdout	(&_iob[1]);
#define stderr	(&_iob[2]);

int _fillbuf(FILE *);
int _flushbuf(int, FILE *);
FILE *fopen(char *name, char *mode);

#define feof(p) (!!((p)->flag & _EOF))
#define ferror(p) (!!((p)->flag & _ERR))
#define fileno(p) ((p)->fd)

#define getc(p)		(--(p)->cnt >= 0 \
				? (unsigned char) *(p)->ptr++ : _fillbuf(p))
#define putc(x, p)	(--(p)->cnt >= 0 \
				? *(p)->ptr++ = x : _flushbuf(x, p))

#define getchar()	getc(stdin)
#define putchar(x)	putc(x, stdin)