Repository: valkey-io/valkey
File: src/dict.c (C)

Code before:
    return ((uintptr_t)(void *)de & ENTRY_PTR_MASK) == ENTRY_PTR_NORMAL;
}

/* Returns 1 if the entry is a special entry with key and next, but without
 * value. Returns 0 otherwise. */
static inline int entryIsNoValue(const dictEntry *de) {
    return ((uintptr_t)(void *)de & ENTRY_PTR_MASK) == ENTRY_PTR_NO_VALUE;
}


static inline int entryIsEmbedded(const dictEntry *de) {
    return ((uintptr_t)(void *)de & ENTRY_PTR_MASK) == ENTRY_PTR_EMBEDDED;
}

/* Creates an entry without a value field. */
static inline dictEntry *createEntryNoValue(void *key, dictEntry *next) {
    dictEntryNoValue *entry = zmalloc(sizeof(*entry));
    entry->key = key;
    entry->next = next;
    return (dictEntry *)(void *)((uintptr_t)(void *)entry | ENTRY_PTR_NO_VALUE);
}

static inline dictEntry *createEmbeddedEntry(void *key, dictEntry *next, dictType *dt) {
    size_t keylen = dt->keyLen(key);
    embeddedDictEntry *entry = zmalloc(sizeof(*entry) + keylen + ENTRY_METADATA_BYTES);
    size_t bytes_written = dt->keyToBytes(entry->data + ENTRY_METADATA_BYTES, key, &entry->data[0]);
    assert(bytes_written == keylen);
    entry->next = next;
    return (dictEntry *)(void *)((uintptr_t)(void *)entry | ENTRY_PTR_EMBEDDED);
}

static inline dictEntry *encodeMaskedPtr(const void *ptr, unsigned int bits) {
    assert(((uintptr_t)ptr & ENTRY_PTR_MASK) == 0);
    return (dictEntry *)(void *)((uintptr_t)ptr | bits);
}

static inline void *decodeMaskedPtr(const dictEntry *de) {
    assert(!entryIsKey(de));
    return (void *)((uintptr_t)(void *)de & ~ENTRY_PTR_MASK);
}

static inline void *getEmbeddedKey(const dictEntry *de) {
    embeddedDictEntry *entry = (embeddedDictEntry *)decodeMaskedPtr(de);
    return &entry->data[ENTRY_METADATA_BYTES + entry->data[0]];
}

/* Decodes the pointer to an entry without value, when you know it is an entry
 * without value. Hint: Use entryIsNoValue to check. */
static inline dictEntryNoValue *decodeEntryNoValue(const dictEntry *de) {
    return decodeMaskedPtr(de);
}

Review comment (suggestion):
[Readability suggestion]

looks like we are missing `1`. Is it currently used a key flag in `entryIsKey`? If so, it would be good to add it too.

Code after:
}

/* The default hashing function uses SipHash implementation
 * in siphash.c. */

uint64_t siphash(const uint8_t *in, const size_t inlen, const uint8_t *k);
uint64_t siphash_nocase(const uint8_t *in, const size_t inlen, const uint8_t *k);

uint64_t dictGenHashFunction(const void *key, size_t len) {
    return siphash(key, len, dict_hash_function_seed);
}

uint64_t dictGenCaseHashFunction(const unsigned char *buf, size_t len) {
    return siphash_nocase(buf, len, dict_hash_function_seed);
}

/* --------------------- dictEntry pointer bit tricks ----------------------  */

/* The 3 least significant bits in a pointer to a dictEntry determines what the
 * pointer actually points to. If the least bit is set, it's a key. Otherwise,
 * the bit pattern of the least 3 significant bits mark the kind of entry. */

#define ENTRY_PTR_MASK 7     /* 111 */
#define ENTRY_PTR_NORMAL 0   /* 000 */
#define ENTRY_PTR_NO_VALUE 2 /* 010 */
#define ENTRY_PTR_EMBEDDED 4 /* 100 */
/*      ENTRY_PTR_IS_KEY        xx1 */

/* Returns 1 if the entry pointer is a pointer to a key, rather than to an
 * allocated entry. Returns 0 otherwise. */
static inline int entryIsKey(const dictEntry *de) {
    return (uintptr_t)(void *)de & 1;
}

/* Returns 1 if the pointer is actually a pointer to a dictEntry struct. Returns
 * 0 otherwise. */
static inline int entryIsNormal(const dictEntry *de) {
    return ((uintptr_t)(void *)de & ENTRY_PTR_MASK) == ENTRY_PTR_NORMAL;
}

/* Returns 1 if the entry is a special entry with key and next, but without
 * value. Returns 0 otherwise. */
static inline int entryIsNoValue(const dictEntry *de) {
    return ((uintptr_t)(void *)de & ENTRY_PTR_MASK) == ENTRY_PTR_NO_VALUE;
}


static inline int entryIsEmbedded(const dictEntry *de) {
    return ((uintptr_t)(void *)de & ENTRY_PTR_MASK) == ENTRY_PTR_EMBEDDED;
}