fs/ceph/decode.h

#ifndef __CEPH_DECODE_H
#define __CEPH_DECODE_H

#include <asm/unaligned.h>

/*
 * in all cases,
 *   void **p     pointer to position pointer
 *   void *end    pointer to end of buffer (last byte + 1)
 */

/*
 * bounds check input.
 */
#define ceph_decode_need(p, end, n, bad)		\
	do {						\
		if (unlikely(*(p) + (n) > (end))) 	\
			goto bad;			\
	} while (0)

#define ceph_decode_64(p, v)					\
	do {							\
		v = get_unaligned_le64(*(p));			\
		*(p) += sizeof(u64);				\
	} while (0)
#define ceph_decode_32(p, v)					\
	do {							\
		v = get_unaligned_le32(*(p));			\
		*(p) += sizeof(u32);				\
	} while (0)
#define ceph_decode_16(p, v)					\
	do {							\
		v = get_unaligned_le16(*(p));			\
		*(p) += sizeof(u16);				\
	} while (0)
#define ceph_decode_8(p, v)				\
	do {						\
		v = *(u8 *)*(p);			\
		(*p)++;					\
	} while (0)

#define ceph_decode_copy(p, pv, n)			\
	do {						\
		memcpy(pv, *(p), n);			\
		*(p) += n;				\
	} while (0)

/* bounds check too */
#define ceph_decode_64_safe(p, end, v, bad)			\
	do {							\
		ceph_decode_need(p, end, sizeof(u64), bad);	\
		ceph_decode_64(p, v);				\
	} while (0)
#define ceph_decode_32_safe(p, end, v, bad)			\
	do {							\
		ceph_decode_need(p, end, sizeof(u32), bad);	\
		ceph_decode_32(p, v);				\
	} while (0)
#define ceph_decode_16_safe(p, end, v, bad)			\
	do {							\
		ceph_decode_need(p, end, sizeof(u16), bad);	\
		ceph_decode_16(p, v);				\
	} while (0)

#define ceph_decode_copy_safe(p, end, pv, n, bad)		\
	do {							\
		ceph_decode_need(p, end, n, bad);		\
		ceph_decode_copy(p, pv, n);			\
	} while (0)

/*
 * struct ceph_timespec <-> struct timespec
 */
#define ceph_decode_timespec(ts, tv)					\
	do {								\
		(ts)->tv_sec = le32_to_cpu((tv)->tv_sec);		\
		(ts)->tv_nsec = le32_to_cpu((tv)->tv_nsec);		\
	} while (0)
#define ceph_encode_timespec(tv, ts)				\
	do {							\
		(tv)->tv_sec = cpu_to_le32((ts)->tv_sec);	\
		(tv)->tv_nsec = cpu_to_le32((ts)->tv_nsec);	\
	} while (0)


/*
 * encoders
 */
#define ceph_encode_64(p, v)						\
	do {								\
		put_unaligned_le64(v, (__le64 *)*(p));			\
		*(p) += sizeof(u64);					\
	} while (0)
#define ceph_encode_32(p, v)					\
	do {							\
		put_unaligned_le32(v, (__le32 *)*(p));		\
		*(p) += sizeof(u32);				\
	} while (0)
#define ceph_encode_16(p, v)					\
	do {							\
		put_unaligned_le16(v), (__le16 *)*(p));		\
	*(p) += sizeof(u16);					\
	} while (0)
#define ceph_encode_8(p, v)			  \
	do {					  \
		*(u8 *)*(p) = v;		  \
		(*(p))++;			  \
	} while (0)

/*
 * filepath, string encoders
 */
static inline void ceph_encode_filepath(void **p, void *end,
					u64 ino, const char *path)
{
	u32 len = path ? strlen(path) : 0;
	BUG_ON(*p + sizeof(ino) + sizeof(len) + len > end);
	ceph_encode_64(p, ino);
	ceph_encode_32(p, len);
	if (len)
		memcpy(*p, path, len);
	*p += len;
}

static inline void ceph_encode_string(void **p, void *end,
				      const char *s, u32 len)
{
	BUG_ON(*p + sizeof(len) + len > end);
	ceph_encode_32(p, len);
	if (len)
		memcpy(*p, s, len);
	*p += len;
}


#endif