--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/hash_map.c Fri Apr 21 21:25:32 2023 +0200
@@ -0,0 +1,509 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <string.h>
+#include "cx/hash_map.h"
+#include "cx/utils.h"
+
+struct cx_hash_map_element_s {
+ /** A pointer to the next element in the current bucket. */
+ struct cx_hash_map_element_s *next;
+
+ /** The corresponding key. */
+ CxHashKey key;
+
+ /** The value data. */
+ char data[];
+};
+
+static void cx_hash_map_clear(struct cx_map_s *map) {
+ struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
+ cx_for_n(i, hash_map->bucket_count) {
+ struct cx_hash_map_element_s *elem = hash_map->buckets[i];
+ if (elem != NULL) {
+ do {
+ struct cx_hash_map_element_s *next = elem->next;
+ // invoke the destructor
+ cx_invoke_destructor(map, elem->data);
+ // free the key data
+ cxFree(map->allocator, (void *) elem->key.data);
+ // free the node
+ cxFree(map->allocator, elem);
+ // proceed
+ elem = next;
+ } while (elem != NULL);
+
+ // do not leave a dangling pointer
+ hash_map->buckets[i] = NULL;
+ }
+ }
+ map->size = 0;
+}
+
+static void cx_hash_map_destructor(struct cx_map_s *map) {
+ struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
+
+ // free the buckets
+ cx_hash_map_clear(map);
+ cxFree(map->allocator, hash_map->buckets);
+
+ // free the map structure
+ cxFree(map->allocator, map);
+}
+
+static int cx_hash_map_put(
+ CxMap *map,
+ CxHashKey key,
+ void *value
+) {
+ struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
+ CxAllocator const *allocator = map->allocator;
+
+ unsigned hash = key.hash;
+ if (hash == 0) {
+ cx_hash_murmur(&key);
+ hash = key.hash;
+ }
+
+ size_t slot = hash % hash_map->bucket_count;
+ struct cx_hash_map_element_s *elm = hash_map->buckets[slot];
+ struct cx_hash_map_element_s *prev = NULL;
+
+ while (elm != NULL && elm->key.hash < hash) {
+ prev = elm;
+ elm = elm->next;
+ }
+
+ if (elm != NULL && elm->key.hash == hash && elm->key.len == key.len &&
+ memcmp(elm->key.data, key.data, key.len) == 0) {
+ // overwrite existing element
+ if (map->store_pointer) {
+ memcpy(elm->data, &value, sizeof(void *));
+ } else {
+ memcpy(elm->data, value, map->item_size);
+ }
+ } else {
+ // allocate new element
+ struct cx_hash_map_element_s *e = cxMalloc(
+ allocator,
+ sizeof(struct cx_hash_map_element_s) + map->item_size
+ );
+ if (e == NULL) {
+ return -1;
+ }
+
+ // write the value
+ if (map->store_pointer) {
+ memcpy(e->data, &value, sizeof(void *));
+ } else {
+ memcpy(e->data, value, map->item_size);
+ }
+
+ // copy the key
+ void *kd = cxMalloc(allocator, key.len);
+ if (kd == NULL) {
+ return -1;
+ }
+ memcpy(kd, key.data, key.len);
+ e->key.data = kd;
+ e->key.len = key.len;
+ e->key.hash = hash;
+
+ // insert the element into the linked list
+ if (prev == NULL) {
+ hash_map->buckets[slot] = e;
+ } else {
+ prev->next = e;
+ }
+ e->next = elm;
+
+ // increase the size
+ map->size++;
+ }
+
+ return 0;
+}
+
+static void cx_hash_map_unlink(
+ struct cx_hash_map_s *hash_map,
+ size_t slot,
+ struct cx_hash_map_element_s *prev,
+ struct cx_hash_map_element_s *elm
+) {
+ // unlink
+ if (prev == NULL) {
+ hash_map->buckets[slot] = elm->next;
+ } else {
+ prev->next = elm->next;
+ }
+ // free element
+ cxFree(hash_map->base.allocator, (void *) elm->key.data);
+ cxFree(hash_map->base.allocator, elm);
+ // decrease size
+ hash_map->base.size--;
+}
+
+/**
+ * Helper function to avoid code duplication.
+ *
+ * @param map the map
+ * @param key the key to look up
+ * @param remove flag indicating whether the looked up entry shall be removed
+ * @param destroy flag indicating whether the destructor shall be invoked
+ * @return a pointer to the value corresponding to the key or \c NULL
+ */
+static void *cx_hash_map_get_remove(
+ CxMap *map,
+ CxHashKey key,
+ bool remove,
+ bool destroy
+) {
+ struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
+
+ unsigned hash = key.hash;
+ if (hash == 0) {
+ cx_hash_murmur(&key);
+ hash = key.hash;
+ }
+
+ size_t slot = hash % hash_map->bucket_count;
+ struct cx_hash_map_element_s *elm = hash_map->buckets[slot];
+ struct cx_hash_map_element_s *prev = NULL;
+ while (elm && elm->key.hash <= hash) {
+ if (elm->key.hash == hash && elm->key.len == key.len) {
+ if (memcmp(elm->key.data, key.data, key.len) == 0) {
+ void *data = NULL;
+ if (destroy) {
+ cx_invoke_destructor(map, elm->data);
+ } else {
+ if (map->store_pointer) {
+ data = *(void **) elm->data;
+ } else {
+ data = elm->data;
+ }
+ }
+ if (remove) {
+ cx_hash_map_unlink(hash_map, slot, prev, elm);
+ }
+ return data;
+ }
+ }
+ prev = elm;
+ elm = prev->next;
+ }
+
+ return NULL;
+}
+
+static void *cx_hash_map_get(
+ CxMap const *map,
+ CxHashKey key
+) {
+ // we can safely cast, because we know the map stays untouched
+ return cx_hash_map_get_remove((CxMap *) map, key, false, false);
+}
+
+static void *cx_hash_map_remove(
+ CxMap *map,
+ CxHashKey key,
+ bool destroy
+) {
+ return cx_hash_map_get_remove(map, key, true, destroy);
+}
+
+static void *cx_hash_map_iter_current_entry(void const *it) {
+ struct cx_iterator_s const *iter = it;
+ // struct has to have a compatible signature
+ return (struct cx_map_entry_s *) &(iter->kv_data);
+}
+
+static void *cx_hash_map_iter_current_key(void const *it) {
+ struct cx_iterator_s const *iter = it;
+ struct cx_hash_map_element_s *elm = iter->elem_handle;
+ return &elm->key;
+}
+
+static void *cx_hash_map_iter_current_value(void const *it) {
+ struct cx_iterator_s const *iter = it;
+ struct cx_hash_map_s const *map = iter->src_handle;
+ struct cx_hash_map_element_s *elm = iter->elem_handle;
+ if (map->base.store_pointer) {
+ return *(void **) elm->data;
+ } else {
+ return elm->data;
+ }
+}
+
+static bool cx_hash_map_iter_valid(void const *it) {
+ struct cx_iterator_s const *iter = it;
+ return iter->elem_handle != NULL;
+}
+
+static void cx_hash_map_iter_next(void *it) {
+ struct cx_iterator_s *iter = it;
+ struct cx_hash_map_element_s *elm = iter->elem_handle;
+
+ // remove current element, if asked
+ if (iter->base.remove) {
+ // obtain mutable pointer to the map
+ struct cx_mut_iterator_s *miter = it;
+ struct cx_hash_map_s *map = miter->src_handle;
+
+ // clear the flag
+ iter->base.remove = false;
+
+ // determine the next element
+ struct cx_hash_map_element_s *next = elm->next;
+
+ // search the previous element
+ struct cx_hash_map_element_s *prev = NULL;
+ if (map->buckets[iter->slot] != elm) {
+ prev = map->buckets[iter->slot];
+ while (prev->next != elm) {
+ prev = prev->next;
+ }
+ }
+
+ // destroy
+ cx_invoke_destructor((struct cx_map_s *) map, elm->data);
+
+ // unlink
+ cx_hash_map_unlink(map, iter->slot, prev, elm);
+
+ // advance
+ elm = next;
+ } else {
+ // just advance
+ elm = elm->next;
+ iter->index++;
+ }
+
+ // search the next bucket, if required
+ struct cx_hash_map_s const *map = iter->src_handle;
+ while (elm == NULL && ++iter->slot < map->bucket_count) {
+ elm = map->buckets[iter->slot];
+ }
+
+ // fill the struct with the next element
+ iter->elem_handle = elm;
+ if (elm == NULL) {
+ iter->kv_data.key = NULL;
+ iter->kv_data.value = NULL;
+ } else {
+ iter->kv_data.key = &elm->key;
+ if (map->base.store_pointer) {
+ iter->kv_data.value = *(void **) elm->data;
+ } else {
+ iter->kv_data.value = elm->data;
+ }
+ }
+}
+
+static bool cx_hash_map_iter_flag_rm(void *it) {
+ struct cx_iterator_base_s *iter = it;
+ if (iter->mutating) {
+ iter->remove = true;
+ return true;
+ } else {
+ return false;
+ }
+}
+
+static CxIterator cx_hash_map_iterator(CxMap const *map) {
+ CxIterator iter;
+
+ iter.src_handle = map;
+ iter.base.valid = cx_hash_map_iter_valid;
+ iter.base.next = cx_hash_map_iter_next;
+ iter.base.current = cx_hash_map_iter_current_entry;
+ iter.base.flag_removal = cx_hash_map_iter_flag_rm;
+ iter.base.remove = false;
+ iter.base.mutating = false;
+
+ iter.slot = 0;
+ iter.index = 0;
+
+ if (map->size > 0) {
+ struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
+ struct cx_hash_map_element_s *elm = hash_map->buckets[0];
+ while (elm == NULL) {
+ elm = hash_map->buckets[++iter.slot];
+ }
+ iter.elem_handle = elm;
+ iter.kv_data.key = &elm->key;
+ if (map->store_pointer) {
+ iter.kv_data.value = *(void **) elm->data;
+ } else {
+ iter.kv_data.value = elm->data;
+ }
+ } else {
+ iter.elem_handle = NULL;
+ iter.kv_data.key = NULL;
+ iter.kv_data.value = NULL;
+ }
+
+ return iter;
+}
+
+static CxIterator cx_hash_map_iterator_keys(CxMap const *map) {
+ CxIterator iter = cx_hash_map_iterator(map);
+ iter.base.current = cx_hash_map_iter_current_key;
+ return iter;
+}
+
+static CxIterator cx_hash_map_iterator_values(CxMap const *map) {
+ CxIterator iter = cx_hash_map_iterator(map);
+ iter.base.current = cx_hash_map_iter_current_value;
+ return iter;
+}
+
+static CxMutIterator cx_hash_map_mut_iterator(CxMap *map) {
+ CxIterator it = cx_hash_map_iterator(map);
+ it.base.mutating = true;
+
+ // we know the iterators share the same memory layout
+ CxMutIterator iter;
+ memcpy(&iter, &it, sizeof(CxMutIterator));
+ return iter;
+}
+
+static CxMutIterator cx_hash_map_mut_iterator_keys(CxMap *map) {
+ CxMutIterator iter = cx_hash_map_mut_iterator(map);
+ iter.base.current = cx_hash_map_iter_current_key;
+ return iter;
+}
+
+static CxMutIterator cx_hash_map_mut_iterator_values(CxMap *map) {
+ CxMutIterator iter = cx_hash_map_mut_iterator(map);
+ iter.base.current = cx_hash_map_iter_current_value;
+ return iter;
+}
+
+static cx_map_class cx_hash_map_class = {
+ cx_hash_map_destructor,
+ cx_hash_map_clear,
+ cx_hash_map_put,
+ cx_hash_map_get,
+ cx_hash_map_remove,
+ cx_hash_map_iterator,
+ cx_hash_map_iterator_keys,
+ cx_hash_map_iterator_values,
+ cx_hash_map_mut_iterator,
+ cx_hash_map_mut_iterator_keys,
+ cx_hash_map_mut_iterator_values,
+};
+
+CxMap *cxHashMapCreate(
+ CxAllocator const *allocator,
+ size_t itemsize,
+ size_t buckets
+) {
+ if (buckets == 0) {
+ // implementation defined default
+ buckets = 16;
+ }
+
+ struct cx_hash_map_s *map = cxCalloc(allocator, 1,
+ sizeof(struct cx_hash_map_s));
+ if (map == NULL) return NULL;
+
+ // initialize hash map members
+ map->bucket_count = buckets;
+ map->buckets = cxCalloc(allocator, buckets,
+ sizeof(struct cx_hash_map_element_s *));
+ if (map->buckets == NULL) {
+ cxFree(allocator, map);
+ return NULL;
+ }
+
+ // initialize base members
+ map->base.cl = &cx_hash_map_class;
+ map->base.allocator = allocator;
+
+ if (itemsize > 0) {
+ map->base.store_pointer = false;
+ map->base.item_size = itemsize;
+ } else {
+ map->base.store_pointer = true;
+ map->base.item_size = sizeof(void *);
+ }
+
+ return (CxMap *) map;
+}
+
+int cxMapRehash(CxMap *map) {
+ struct cx_hash_map_s *hash_map = (struct cx_hash_map_s *) map;
+ if (map->size > ((hash_map->bucket_count * 3) >> 2)) {
+
+ size_t new_bucket_count = (map->size * 5) >> 1;
+ struct cx_hash_map_element_s **new_buckets = cxCalloc(
+ map->allocator,
+ new_bucket_count, sizeof(struct cx_hash_map_element_s *)
+ );
+
+ if (new_buckets == NULL) {
+ return 1;
+ }
+
+ // iterate through the elements and assign them to their new slots
+ cx_for_n(slot, hash_map->bucket_count) {
+ struct cx_hash_map_element_s *elm = hash_map->buckets[slot];
+ while (elm != NULL) {
+ struct cx_hash_map_element_s *next = elm->next;
+ size_t new_slot = elm->key.hash % new_bucket_count;
+
+ // find position where to insert
+ struct cx_hash_map_element_s *bucket_next = new_buckets[new_slot];
+ struct cx_hash_map_element_s *bucket_prev = NULL;
+ while (bucket_next != NULL &&
+ bucket_next->key.hash < elm->key.hash) {
+ bucket_prev = bucket_next;
+ bucket_next = bucket_next->next;
+ }
+
+ // insert
+ if (bucket_prev == NULL) {
+ elm->next = new_buckets[new_slot];
+ new_buckets[new_slot] = elm;
+ } else {
+ bucket_prev->next = elm;
+ elm->next = bucket_next;
+ }
+
+ // advance
+ elm = next;
+ }
+ }
+
+ // assign result to the map
+ hash_map->bucket_count = new_bucket_count;
+ cxFree(map->allocator, hash_map->buckets);
+ hash_map->buckets = new_buckets;
+ }
+ return 0;
+}