dir.h

这是一个同样来自贝尔实验室的和UNIX有着渊源的操作系统, 其简洁的设计和实现易于我们学习和理解

typedef	long	long	vlong;
typedef	unsigned long long uvlong;
typedef 	unsigned char uchar;
typedef	unsigned short ushort;
typedef 	unsigned int uint;
typedef	unsigned long ulong;

#define	GBIT8(p)	((p)[0])
#define	GBIT16(p)	((p)[0]|((p)[1]<<8))
#define	GBIT32(p)	((p)[0]|((p)[1]<<8)|((p)[2]<<16)|((p)[3]<<24))
#define	GBIT64(p)	((vlong)((p)[0]|((p)[1]<<8)|((p)[2]<<16)|((p)[3]<<24)) |\
				((vlong)((p)[4]|((p)[5]<<8)|((p)[6]<<16)|((p)[7]<<24)) << 32))

#define	PBIT8(p,v)	(p)[0]=(v)
#define	PBIT16(p,v)	(p)[0]=(v);(p)[1]=(v)>>8
#define	PBIT32(p,v)	(p)[0]=(v);(p)[1]=(v)>>8;(p)[2]=(v)>>16;(p)[3]=(v)>>24
#define	PBIT64(p,v)	(p)[0]=(v);(p)[1]=(v)>>8;(p)[2]=(v)>>16;(p)[3]=(v)>>24;\
			(p)[4]=(v)>>32;(p)[5]=(v)>>40;(p)[6]=(v)>>48;(p)[7]=(v)>>56

#define	BIT8SZ		1
#define	BIT16SZ		2
#define	BIT32SZ		4
#define	BIT64SZ		8
#define	QIDSZ	(BIT8SZ+BIT32SZ+BIT64SZ)

/* STATFIXLEN includes leading 16-bit count */
/* The count, however, excludes itself; total size is BIT16SZ+count */
#define STATFIXLEN	(BIT16SZ+QIDSZ+5*BIT16SZ+4*BIT32SZ+1*BIT64SZ)	/* amount of fixed length data in a stat buffer */

typedef union
{
	char	clength[8];
	vlong	vlength;
	struct
	{
		long	hlength;
		long	length;
	};
} Length;

typedef
struct Qid
{
	uvlong	path;
	ulong	vers;
	uchar	type;
} Qid;

typedef
struct Dir {
	/* system-modified data */
	ushort	type;	/* server type */
	uint	dev;	/* server subtype */
	/* file data */
	Qid	qid;	/* unique id from server */
	ulong	mode;	/* permissions */
	ulong	atime;	/* last read time */
	ulong	mtime;	/* last write time */
	vlong	length;	/* file length: see <u.h> */
	char	*name;	/* last element of path */
	char	*uid;	/* owner name */
	char	*gid;	/* group name */
	char	*muid;	/* last modifier name */
} Dir;

void	_dirtostat(struct stat *, Dir*, Fdinfo*);
uint	_convM2D(uchar*, uint, Dir*, char*);
uint	_convD2M(Dir*, uchar*, uint);
Dir	*_dirstat(char*);
int	_dirwstat(char*, Dir*);
Dir	*_dirfstat(int);
int	_dirfwstat(int, Dir*);
long	_dirread(int, Dir**);
long _dirreadall(int, Dir**);
void _nulldir(Dir*);
uint _sizeD2M(Dir*);

#ifndef nil
#define nil ((void*)0)
#endif