/* BEGIN_ICS_COPYRIGHT5 ****************************************

Copyright (c) 2015-2017, Intel Corporation

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 * ** END_ICS_COPYRIGHT5   ****************************************/

#define INLINE

#include "cs_hashtable.h"

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <math.h>

/*

 * prime table

 */

static const uint32_t primes[] = {

53, 97, 193, 389,

769, 1543, 3079, 6151,

12289, 24593, 49157, 98317,

196613, 393241, 786433, 1572869,

3145739, 6291469, 12582917, 25165843,

50331653, 100663319, 201326611, 402653189,

805306457, 1610612741

};

const uint32_t prime_table_length = sizeof(primes)/sizeof(primes[0]);

#define MAX_LOAD_FACTOR_NUMERATOR 8

#define MAX_LOAD_FACTOR_DENOMINATOR 10

static int32_t cs_hashtable_expand(struct cs_hashtable *h);

/*

 * cs_create_hashtable

 */

struct cs_hashtable *

cs_create_hashtable(const char *name,

                    uint32_t minsize,

                    uint64_t (*hashf) (void*),

                    int32_t (*eqf) (void*,void*),

                    CS_Hash_KeyType_t keytype)

{

    struct cs_hashtable *h;

    uint32_t pindex;

    /* Check requested hashtable isn't too large */

    if (minsize > (1u << 30)) return NULL;

    /* Enforce size as prime */

    for (pindex=0; pindex < prime_table_length; pindex++) {

        if (primes[pindex] > minsize) break;

    }

    h = (struct cs_hashtable *)malloc(sizeof(struct cs_hashtable));

    if (NULL == h) return NULL;

    memset(h, 0, sizeof(*h));

    h->name = name;

    h->primeindex   = pindex - 1;

    h->hashfn       = hashf;

    h->eqfn         = eqf;

    h->keyType      = keytype;

    if (cs_hashtable_expand(h) == 0) {

        free(h);

        return NULL;

    }

    return h;

}

/*

 * hash

 */

static uint64_t 

_hash(struct cs_hashtable *h, void *k)

{

    /* 

     * Aim to protect against poor hash functions by adding logic here

     * - logic taken from java 1.4 hashtable source 

     */

    uint64_t i = h->hashfn(k);

    i += ~(i << 9);

    i ^=  ((i >> 14) | (i << 18)); /* >>> */

    i +=  (i << 4);

    i ^=  ((i >> 10) | (i << 22)); /* >>> */

    return i;

}

/*

 * cs_hashtable_expand

 */

static int32_t

cs_hashtable_expand(struct cs_hashtable *h)

{

    /* Double the size of the table to accomodate more entries */

    struct hash_entry **newtable;

    struct hash_entry *e;

    uint32_t newsize;

    uint32_t index;

    /* Check we're not hitting max capacity */

    if (h->primeindex == (prime_table_length - 1)) 

        return 0;

    newsize = primes[++(h->primeindex)];

//  sysPrintf("%s h=%p(%s) primeindex=%lu newsize=%lu\n", __FUNCTION__, h, h->name, h->primeindex, newsize);

    /* malloc table */

    newtable = (struct hash_entry **)malloc(newsize * sizeof(struct hash_entry *));

    if (NULL == newtable) { 

        (h->primeindex)--; 

        return 0;

    }

    memset(newtable, 0, newsize * sizeof(struct hash_entry *));

    for (e = h->listHead; e != NULL; e = e->listNext) {

        index = indexFor(newsize, e->h);

        e->hashNext = newtable[index];

        newtable[index] = e;

    }

    if (h->table)

        free(h->table);

    h->table = newtable;

    h->tablelength = newsize;

    h->loadlimit = ((uint64_t)newsize * MAX_LOAD_FACTOR_NUMERATOR) / MAX_LOAD_FACTOR_DENOMINATOR;

    return -1;

}

/*

 * cs_hashtable_insert

 */

int32_t

cs_hashtable_insert(struct cs_hashtable *h, void *k, void *v)

{

    /* This method allows duplicate keys - but they shouldn't be used */

    uint32_t index;

    struct hash_entry *e;

//  sysPrintf("%s h=%p(%s) k=%p v=%p ra=%p\n", __FUNCTION__, h, h->name, k, v, __builtin_return_address(0));

    if (++h->entrycount > h->loadlimit) {

        /* Ignore the return value. If expand fails, we should

         * still try cramming just this value into the existing table

         * -- we may not have memory for a larger table, but one more

         * element may be ok. Next time we insert, we'll try expanding again.*/

        cs_hashtable_expand(h);

    }

    /* retrieve a free hash_entry or allocate a new one */

    if ((e = h->freeHead) == NULL) {

        e = (struct hash_entry *)malloc(sizeof(struct hash_entry));

        if (NULL == e) { /* out of memory */

            --h->entrycount; 

            return 0;

        }

    } else

        h->freeHead = e->listNext;

    e->h = _hash(h,k);

    //IB_LOG_INFINI_INFOLX("key is", e->h);

    index = indexFor(h->tablelength,e->h);

    e->k = k;

    e->v = v;

    e->hashNext = h->table[index];

    h->table[index] = e;

    e->listNext = NULL;

    if (h->listHead == NULL) {

        h->listHead = h->listTail = e;

        e->listPrev = NULL;

    } else {

        e->listPrev = h->listTail;

        h->listTail = h->listTail->listNext = e;

    }

    return -1;

}

/*

 * cs_hashtable_search

 */

void *cs_hashtable_search(struct cs_hashtable *h, void *k)

{

    struct hash_entry *e;

    uint64_t hashvalue = _hash(h,k);

    for(e = h->table[indexFor(h->tablelength,hashvalue)]; e != NULL; e = e->hashNext) {

        /* Check hash value to short circuit heavier comparison */

        if ((hashvalue == e->h) && (h->eqfn(k, e->k))) 

            return e->v;

    }

    return NULL;

}

void cs_hashentry_delete(struct cs_hashtable *h, struct hash_entry *e) {

    h->entrycount--;

    if (e == h->listHead) 

        h->listHead = e->listNext;

    if (e == h->listTail)

        h->listTail = e->listPrev;

    if (e->listPrev != NULL)

        e->listPrev->listNext = e->listNext;

    if (e->listNext != NULL)

        e->listNext->listPrev = e->listPrev;

    if (h->keyType == CS_HASH_KEY_ALLOCATED) freekey(e->k);

    e->listNext = h->freeHead;

    h->freeHead = e;

}

/*

 * cs_hashtable_remove

 * returns value associated with key 

 */

void *cs_hashtable_remove(struct cs_hashtable *h, void *k) {

    /* TODO: consider compacting the table when the load factor drops enough,

     *       or provide a 'compact' method. */

    struct hash_entry *e;

    struct hash_entry **pE;

    void *v;

    uint64_t hashvalue = _hash(h,k);

    pE = &(h->table[indexFor(h->tablelength,hashvalue)]);

    for(e = *pE; e != NULL; e = e->hashNext) {

        /* Check hash value to short circuit heavier comparison */

        if ((hashvalue == e->h) && (h->eqfn(k, e->k))) {

            *pE = e->hashNext;

            v = e->v;

            cs_hashentry_delete(h, e);

            return v;

        }

        pE = &(e->hashNext);

    }

    return NULL;

}

/*

 * cs_hashtable_destroy

 */

void cs_hashtable_destroy(struct cs_hashtable *h, int32_t free_values)

{

    struct hash_entry *e;

    struct hash_entry *listNext;

    for(e = h->freeHead; e != NULL; e = listNext) {

        listNext = e->listNext;

        free(e);

    }

    for(e = h->listHead; e != NULL; e = listNext) {

        listNext = e->listNext;

        if (h->keyType == CS_HASH_KEY_ALLOCATED) freekey(e->k);

        if (free_values)

            free(e->v);

        free(e);

    }

    free(h->table);

    free(h);

}

/*

 * cs_hashtable_change

 *

 * function to change the value associated with a key, where there already

 * exists a value bound to the key in the hashtable.

 * Source due to Holger Schemel.

 * 

 */

int32_t 

cs_hashtable_change(struct cs_hashtable *h, void *k, void *v)

{

    struct hash_entry *e;

    uint64_t hashvalue = _hash(h,k);

    for(e = h->table[indexFor(h->tablelength,hashvalue)]; e != NULL; e = e->hashNext) {

        /* Check hash value to short circuit heavier comparison */

        if ((hashvalue == e->h) && (h->eqfn(k, e->k))) {

            free(e->v);

            e->v = v;

            return -1;

        }

    }

    return 0;

}

/*

 * remove - remove the entry at the current iterator position

 *          and advance the iterator, if there is a successive

 *          element.

 *          If you want the value, read it before you remove:

 *          beware memory leaks if you don't.

 *          Returns zero if end of iteration. 

 */

int32_t 

cs_hashtable_iterator_remove(struct cs_hashtable_itr *itr) {

    struct cs_hashtable *h = itr->h;

    struct hash_entry *removeEntry = itr->e;

    struct hash_entry *e;

    struct hash_entry **pE;

    int32_t ret;

    ret = cs_hashtable_iterator_advance(itr);

    pE = &(h->table[indexFor(h->tablelength,_hash(h,removeEntry->k))]);

    for(e = *pE; e != NULL; e = e->hashNext) {

        if (e == removeEntry) {

            *pE = e->hashNext;

            cs_hashentry_delete(h, e);

            break;

        }

        pE = &(e->hashNext);

    }

    return ret;

}

/* 

 * cs_hashtable_iterator_search

 * returns zero if not found 

 */

int32_t 

cs_hashtable_iterator_search(struct cs_hashtable_itr *itr,

                                     struct cs_hashtable *h, void *k) {

    struct hash_entry *e;

    uint64_t hashvalue = _hash(h,k);

    for(e = h->table[indexFor(h->tablelength,hashvalue)]; e != NULL; e = e->hashNext) {

        /* Check hash value to short circuit heavier comparison */

        if ((hashvalue == e->h) && (h->eqfn(k, e->k))) {

            itr->e = e;

            itr->h = h;

            return -1;

        }

    }

    return 0;

}