#ifndef KV_PAIR_H
#define KV_PAIR_H

#include "memory.h"
#include <string.h>

/*
 * the key value pair contains a key and a value in a contiguous space.  the
 * key is right after the length fields and the value is right after the key.
 */
struct kv_pair {
    int keylen;
    int vallen;
    char key[];
};

/* return the size of a kv pair */
static inline int kv_pair_size(struct kv_pair *pair) {
    return sizeof (struct kv_pair) + pair->keylen + pair->vallen;
}

static inline void kv_pair_init(struct kv_pair *pair, void *key, int keylen, void *val, int vallen) {

    pair->keylen = keylen;
    memcpy(pair->key, key, keylen);
    pair->vallen = vallen;
    memcpy(pair->key + keylen, val, vallen);
}

static inline struct kv_pair *kv_pair_malloc(void *key, int keylen, void *val, int vallen) {
    struct kv_pair *pair = toku_malloc(sizeof (struct kv_pair) + keylen + vallen);
    if (pair)
        kv_pair_init(pair, key, keylen, val, vallen);
    return pair;
}

/* replace the val, keep the same key */
static inline struct kv_pair *kv_pair_realloc_same_key(struct kv_pair *p, void *newval, int newvallen) {
    struct kv_pair *pair = toku_realloc(p, sizeof (struct kv_pair) + p->keylen + newvallen);
    if (pair) {
	pair->vallen = newvallen;
	memcpy(pair->key + pair->keylen, newval, newvallen);
    }
    return pair;
}

static inline void kv_pair_free(struct kv_pair *pair) {
    toku_free_n(pair, sizeof(struct kv_pair)+pair->keylen+pair->vallen);
}

static inline void *kv_pair_key(struct kv_pair *pair) {
    return pair->key;
}
static inline const void *kv_pair_key_const(const struct kv_pair *pair) {
    return pair->key;
}


static inline int kv_pair_keylen(struct kv_pair *pair) {
    return pair->keylen;
}

static inline void *kv_pair_val(struct kv_pair *pair) {
    return pair->key + pair->keylen;
}
static inline const void *kv_pair_val_const(const struct kv_pair *pair) {
    return pair->key + pair->keylen;
}

static inline int kv_pair_vallen(struct kv_pair *pair) {
    return pair->vallen;
}

/* use the low bit to indicate an inuse pair that is deleted */

static inline int kv_pair_inuse(struct kv_pair *pair) {
    return pair != 0;
}

static inline int kv_pair_deleted(struct kv_pair *pair) {
    return ((long) pair & 1) != 0;
}

static inline int kv_pair_valid(struct kv_pair *pair) {
    return kv_pair_inuse(pair) && !kv_pair_deleted(pair);
}

static inline struct kv_pair *kv_pair_set_deleted(struct kv_pair *pair) {
    return (struct kv_pair *) ((long) pair | 1);
}

static inline struct kv_pair *kv_pair_ptr(struct kv_pair *pair) {
    return (struct kv_pair *) ((long) pair & ~1);
}

struct kv_pair_tag {
    struct kv_pair *pair;
    int oldtag, newtag;
};
#endif