universe@549: /*
universe@549:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
universe@549:  *
universe@549:  * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
universe@549:  *
universe@549:  * Redistribution and use in source and binary forms, with or without
universe@549:  * modification, are permitted provided that the following conditions are met:
universe@549:  *
universe@549:  *   1. Redistributions of source code must retain the above copyright
universe@549:  *      notice, this list of conditions and the following disclaimer.
universe@549:  *
universe@549:  *   2. Redistributions in binary form must reproduce the above copyright
universe@549:  *      notice, this list of conditions and the following disclaimer in the
universe@549:  *      documentation and/or other materials provided with the distribution.
universe@549:  *
universe@549:  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
universe@549:  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
universe@549:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
universe@549:  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
universe@549:  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
universe@549:  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
universe@549:  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
universe@549:  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
universe@549:  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
universe@549:  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
universe@549:  * POSSIBILITY OF SUCH DAMAGE.
universe@549:  */
universe@549: 
universe@549: #include <string.h>
universe@549: #include "cx/hash_map.h"
universe@550: #include "cx/utils.h"
universe@549: 
universe@550: static void cx_hash_map_clear(struct cx_map_s *map) {
universe@550:     struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
universe@550:     cx_for_n(i, hash_map->bucket_count) {
universe@550:         struct cx_hash_map_element_s *elem = hash_map->buckets[i];
universe@550:         if (elem != NULL) {
universe@550:             do {
universe@550:                 struct cx_hash_map_element_s *next = elem->next;
universe@550:                 // free the key data
universe@563:                 cxFree(map->allocator, elem->key.data.obj);
universe@550:                 // free the node
universe@550:                 cxFree(map->allocator, elem);
universe@550:                 // proceed
universe@550:                 elem = next;
universe@550:             } while (elem != NULL);
universe@550: 
universe@550:             // do not leave a dangling pointer
universe@550:             hash_map->buckets[i] = NULL;
universe@550:         }
universe@550:     }
universe@550:     map->size = 0;
universe@550: }
universe@550: 
universe@550: static void cx_hash_map_destructor(struct cx_map_s *map) {
universe@550:     struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
universe@550: 
universe@550:     // free the buckets
universe@550:     cx_hash_map_clear(map);
universe@550:     cxFree(map->allocator, hash_map->buckets);
universe@550: 
universe@550:     // free the map structure
universe@550:     cxFree(map->allocator, map);
universe@550: }
universe@550: 
universe@550: static int cx_hash_map_put(
universe@550:         CxMap *map,
universe@563:         CxHashKey key,
universe@550:         void *value
universe@550: ) {
universe@550:     struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
universe@550:     CxAllocator *allocator = map->allocator;
universe@550: 
universe@563:     unsigned hash = key.hash;
universe@563:     if (hash == 0) {
universe@563:         cx_hash_murmur(&key);
universe@563:         hash = key.hash;
universe@563:     }
universe@550: 
universe@550:     size_t slot = hash % hash_map->bucket_count;
universe@550:     struct cx_hash_map_element_s *elm = hash_map->buckets[slot];
universe@550:     struct cx_hash_map_element_s *prev = NULL;
universe@550: 
universe@550:     while (elm != NULL && elm->key.hash < hash) {
universe@550:         prev = elm;
universe@550:         elm = elm->next;
universe@550:     }
universe@550: 
universe@550:     if (elm == NULL || elm->key.hash != hash) {
universe@550:         struct cx_hash_map_element_s *e = cxMalloc(allocator, sizeof(struct cx_hash_map_element_s));
universe@550:         if (e == NULL) {
universe@550:             return -1;
universe@550:         }
universe@550: 
universe@550:         // write the value
universe@550:         // TODO: depending on future map features, we may want to copy here
universe@550:         e->data = value;
universe@550: 
universe@550:         // copy the key
universe@550:         void *kd = cxMalloc(allocator, key.len);
universe@550:         if (kd == NULL) {
universe@550:             return -1;
universe@550:         }
universe@563:         memcpy(kd, key.data.obj, key.len);
universe@563:         e->key.data.obj = kd;
universe@550:         e->key.len = key.len;
universe@550:         e->key.hash = hash;
universe@550: 
universe@550:         // insert the element into the linked list
universe@550:         if (prev == NULL) {
universe@550:             hash_map->buckets[slot] = e;
universe@550:         } else {
universe@550:             prev->next = e;
universe@550:         }
universe@550:         e->next = elm;
universe@550: 
universe@550:         // increase the size
universe@550:         map->size++;
universe@550:     } else {
universe@550:         // (elem != NULL && elem->key.hash == hash) - overwrite value of existing element
universe@550:         elm->data = value;
universe@550:     }
universe@550: 
universe@550:     return 0;
universe@550: }
universe@549: 
universe@551: static void cx_hash_map_unlink(
universe@551:         struct cx_hash_map_s *hash_map,
universe@551:         size_t slot,
universe@551:         struct cx_hash_map_element_s *prev,
universe@551:         struct cx_hash_map_element_s *elm
universe@551: ) {
universe@551:     // unlink
universe@551:     if (prev == NULL) {
universe@551:         hash_map->buckets[slot] = elm->next;
universe@551:     } else {
universe@551:         prev->next = elm->next;
universe@551:     }
universe@551:     // free element
universe@563:     cxFree(hash_map->base.allocator, elm->key.data.obj);
universe@551:     cxFree(hash_map->base.allocator, elm);
universe@551:     // decrease size
universe@551:     hash_map->base.size--;
universe@551: }
universe@551: 
universe@549: /**
universe@550:  * Helper function to avoid code duplication.
universe@549:  *
universe@550:  * @param map the map
universe@550:  * @param key the key to look up
universe@550:  * @param remove flag indicating whether the looked up entry shall be removed
universe@550:  * @return the value corresponding to the key or \c NULL
universe@549:  */
universe@550: static void *cx_hash_map_get_remove(
universe@550:         CxMap *map,
universe@563:         CxHashKey key,
universe@550:         bool remove
universe@550: ) {
universe@550:     struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
universe@550: 
universe@563:     unsigned hash = key.hash;
universe@563:     if (hash == 0) {
universe@563:         cx_hash_murmur(&key);
universe@563:         hash = key.hash;
universe@563:     }
universe@550: 
universe@550:     size_t slot = hash % hash_map->bucket_count;
universe@550:     struct cx_hash_map_element_s *elm = hash_map->buckets[slot];
universe@550:     struct cx_hash_map_element_s *prev = NULL;
universe@550:     while (elm && elm->key.hash <= hash) {
universe@550:         if (elm->key.hash == hash && elm->key.len == key.len) {
universe@563:             if (memcmp(elm->key.data.obj, key.data.obj, key.len) == 0) {
universe@550:                 void *data = elm->data;
universe@550:                 if (remove) {
universe@551:                     cx_hash_map_unlink(hash_map, slot, prev, elm);
universe@550:                 }
universe@550:                 return data;
universe@550:             }
universe@550:         }
universe@550:         prev = elm;
universe@550:         elm = prev->next;
universe@550:     }
universe@550: 
universe@550:     return NULL;
universe@549: }
universe@550: 
universe@550: static void *cx_hash_map_get(
universe@550:         CxMap const *map,
universe@563:         CxHashKey key
universe@550: ) {
universe@550:     // we can safely cast, because we know when remove=false, the map stays untouched
universe@550:     return cx_hash_map_get_remove((CxMap *) map, key, false);
universe@550: }
universe@550: 
universe@550: static void *cx_hash_map_remove(
universe@550:         CxMap *map,
universe@563:         CxHashKey key
universe@550: ) {
universe@550:     return cx_hash_map_get_remove(map, key, true);
universe@550: }
universe@550: 
universe@551: static void *cx_hash_map_iter_current_entry(CxIterator const *iter) {
universe@551:     // struct has to have a compatible signature
universe@573:     return (struct cx_map_entry_s *) &(iter->kv_data);
universe@551: }
universe@551: 
universe@551: static void *cx_hash_map_iter_current_key(CxIterator const *iter) {
universe@551:     struct cx_hash_map_element_s *elm = iter->elem_handle;
universe@551:     return &elm->key;
universe@551: }
universe@551: 
universe@551: static void *cx_hash_map_iter_current_value(CxIterator const *iter) {
universe@551:     struct cx_hash_map_element_s *elm = iter->elem_handle;
universe@551:     // TODO: return a pointer to data if this map is storing copies
universe@551:     return elm->data;
universe@551: }
universe@551: 
universe@551: static bool cx_hash_map_iter_valid(CxIterator const *iter) {
universe@551:     return iter->elem_handle != NULL;
universe@551: }
universe@551: 
universe@551: static void cx_hash_map_iter_next(CxIterator *iter) {
universe@551:     struct cx_hash_map_s *map = iter->src_handle;
universe@551:     struct cx_hash_map_element_s *elm = iter->elem_handle;
universe@551: 
universe@551:     // remove current element, if asked
universe@551:     if (iter->remove) {
universe@551:         // clear the flag
universe@551:         iter->remove = false;
universe@551: 
universe@551:         // determine the next element
universe@551:         struct cx_hash_map_element_s *next = elm->next;
universe@551: 
universe@551:         // search the previous element
universe@551:         struct cx_hash_map_element_s *prev = NULL;
universe@551:         if (map->buckets[iter->slot] != elm) {
universe@551:             prev = map->buckets[iter->slot];
universe@551:             while (prev->next != elm) {
universe@551:                 prev = prev->next;
universe@551:             }
universe@551:         }
universe@551: 
universe@551:         // unlink
universe@551:         cx_hash_map_unlink(map, iter->slot, prev, elm);
universe@551: 
universe@551:         // advance
universe@551:         elm = next;
universe@551:     } else {
universe@551:         // just advance
universe@551:         elm = elm->next;
universe@560:         iter->index++;
universe@551:     }
universe@551: 
universe@560:     // search the next bucket, if required
universe@560:     while (elm == NULL && ++iter->slot < map->bucket_count) {
universe@560:         elm = map->buckets[iter->slot];
universe@551:     }
universe@551: 
universe@560:     // fill the struct with the next element
universe@551:     iter->elem_handle = elm;
universe@551:     if (elm == NULL) {
universe@551:         iter->kv_data.key = NULL;
universe@551:         iter->kv_data.value = NULL;
universe@551:     } else {
universe@551:         iter->kv_data.key = &elm->key;
universe@551:         // TODO: pointer to data if this map is storing copies
universe@551:         iter->kv_data.value = elm->data;
universe@551:     }
universe@551: }
universe@551: 
universe@551: static CxIterator cx_hash_map_iterator(CxMap *map) {
universe@550:     CxIterator iter;
universe@551: 
universe@551:     iter.src_handle = map;
universe@551:     iter.valid = cx_hash_map_iter_valid;
universe@551:     iter.next = cx_hash_map_iter_next;
universe@551:     iter.current = cx_hash_map_iter_current_entry;
universe@551: 
universe@551:     iter.slot = 0;
universe@551:     iter.index = 0;
universe@551:     iter.remove = false;
universe@551: 
universe@551:     if (map->size > 0) {
universe@551:         struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
universe@560:         struct cx_hash_map_element_s *elm = hash_map->buckets[0];
universe@554:         for (; elm == NULL; iter.slot++) {
universe@554:             elm = hash_map->buckets[iter.slot];
universe@551:         }
universe@554:         iter.elem_handle = elm;
universe@554:         iter.kv_data.key = &elm->key;
universe@554:         // TODO: pointer to data if this map is storing copies
universe@554:         iter.kv_data.value = elm->data;
universe@551:     } else {
universe@551:         iter.elem_handle = NULL;
universe@551:         iter.kv_data.key = NULL;
universe@551:         iter.kv_data.value = NULL;
universe@551:     }
universe@551: 
universe@550:     return iter;
universe@550: }
universe@550: 
universe@551: static CxIterator cx_hash_map_iterator_keys(CxMap *map) {
universe@551:     CxIterator iter = cx_hash_map_iterator(map);
universe@551:     iter.current = cx_hash_map_iter_current_key;
universe@550:     return iter;
universe@550: }
universe@550: 
universe@551: static CxIterator cx_hash_map_iterator_values(CxMap *map) {
universe@551:     CxIterator iter = cx_hash_map_iterator(map);
universe@551:     iter.current = cx_hash_map_iter_current_value;
universe@550:     return iter;
universe@550: }
universe@550: 
universe@550: static cx_map_class cx_hash_map_class = {
universe@550:         cx_hash_map_destructor,
universe@550:         cx_hash_map_clear,
universe@550:         cx_hash_map_put,
universe@550:         cx_hash_map_get,
universe@550:         cx_hash_map_remove,
universe@550:         cx_hash_map_iterator,
universe@550:         cx_hash_map_iterator_keys,
universe@550:         cx_hash_map_iterator_values,
universe@550: };
universe@550: 
universe@550: CxMap *cxHashMapCreate(
universe@550:         CxAllocator *allocator,
universe@550:         size_t buckets
universe@550: ) {
universe@550:     if (buckets == 0) {
universe@550:         // implementation defined default
universe@550:         buckets = 16;
universe@550:     }
universe@550: 
universe@550:     struct cx_hash_map_s *map = cxMalloc(allocator, sizeof(struct cx_hash_map_s));
universe@550:     if (map == NULL) return NULL;
universe@550: 
universe@550:     // initialize hash map members
universe@550:     map->bucket_count = buckets;
universe@550:     map->buckets = cxCalloc(allocator, buckets, sizeof(struct cx_hash_map_element_s *));
universe@550:     if (map->buckets == NULL) {
universe@550:         cxFree(allocator, map);
universe@550:         return NULL;
universe@550:     }
universe@550: 
universe@550:     // initialize base members
universe@550:     map->base.cl = &cx_hash_map_class;
universe@550:     map->base.allocator = allocator;
universe@550:     map->base.size = 0;
universe@550: 
universe@550:     return (CxMap *) map;
universe@550: }
universe@562: 
universe@562: int cxMapRehash(CxMap *map) {
universe@562:     struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
universe@562:     if (map->size > ((hash_map->bucket_count * 3) >> 2)) {
universe@562: 
universe@562:         size_t new_bucket_count = (map->size * 5) >> 1;
universe@562:         struct cx_hash_map_element_s **new_buckets = cxCalloc(map->allocator,
universe@562:                                                               new_bucket_count, sizeof(struct cx_hash_map_element_s *));
universe@562: 
universe@562:         if (new_buckets == NULL) {
universe@562:             return 1;
universe@562:         }
universe@562: 
universe@562:         // iterate through the elements and assign them to their new slots
universe@562:         cx_for_n(slot, hash_map->bucket_count) {
universe@562:             struct cx_hash_map_element_s *elm = hash_map->buckets[slot];
universe@562:             while (elm != NULL) {
universe@562:                 struct cx_hash_map_element_s *next = elm->next;
universe@562:                 size_t new_slot = elm->key.hash % new_bucket_count;
universe@562: 
universe@562:                 // find position where to insert
universe@562:                 struct cx_hash_map_element_s *bucket_next = new_buckets[new_slot];
universe@562:                 struct cx_hash_map_element_s *bucket_prev = NULL;
universe@562:                 while (bucket_next != NULL && bucket_next->key.hash < elm->key.hash) {
universe@562:                     bucket_prev = bucket_next;
universe@562:                     bucket_next = bucket_next->next;
universe@562:                 }
universe@562: 
universe@562:                 // insert
universe@562:                 if (bucket_prev == NULL) {
universe@562:                     elm->next = new_buckets[new_slot];
universe@562:                     new_buckets[new_slot] = elm;
universe@562:                 } else {
universe@562:                     bucket_prev->next = elm;
universe@562:                     elm->next = bucket_next;
universe@562:                 }
universe@562: 
universe@562:                 // advance
universe@562:                 elm = next;
universe@562:             }
universe@562:         }
universe@562: 
universe@562:         // assign result to the map
universe@562:         hash_map->bucket_count = new_bucket_count;
universe@562:         cxFree(map->allocator, hash_map->buckets);
universe@562:         hash_map->buckets = new_buckets;
universe@562:     }
universe@562:     return 0;
universe@562: }