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Using SHORT version of the *_SAFE loops makes the code cleaner and less error prone. So, use the SHORT version and remove the extra variable when possible for hmap and all its derived types. In order to be able to use both long and short versions without changing the name of the macro for all the clients, overload the existing name and select the appropriate version depending on the number of arguments. Acked-by: Dumitru Ceara <dceara@redhat.com> Acked-by: Eelco Chaudron <echaudro@redhat.com> Signed-off-by: Adrian Moreno <amorenoz@redhat.com> Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
440 lines
17 KiB
C
440 lines
17 KiB
C
/*
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* Copyright (c) 2008, 2009, 2010, 2012, 2013, 2015, 2016 Nicira, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef HMAP_H
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#define HMAP_H 1
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#include <stdbool.h>
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#include <stdlib.h>
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#include "openvswitch/util.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* A hash map node, to be embedded inside the data structure being mapped. */
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struct hmap_node {
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size_t hash; /* Hash value. */
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struct hmap_node *next; /* Next in linked list. */
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};
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/* Returns the hash value embedded in 'node'. */
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static inline size_t hmap_node_hash(const struct hmap_node *node)
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{
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return node->hash;
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}
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#define HMAP_NODE_NULL ((struct hmap_node *) 1)
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#define HMAP_NODE_NULL_INITIALIZER { 0, HMAP_NODE_NULL }
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/* Returns true if 'node' has been set to null by hmap_node_nullify() and has
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* not been un-nullified by being inserted into an hmap. */
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static inline bool
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hmap_node_is_null(const struct hmap_node *node)
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{
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return node->next == HMAP_NODE_NULL;
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}
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/* Marks 'node' with a distinctive value that can be tested with
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* hmap_node_is_null(). */
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static inline void
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hmap_node_nullify(struct hmap_node *node)
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{
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node->next = HMAP_NODE_NULL;
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}
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/* A hash map. */
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struct hmap {
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struct hmap_node **buckets; /* Must point to 'one' iff 'mask' == 0. */
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struct hmap_node *one;
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size_t mask;
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size_t n;
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};
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/* Initializer for an empty hash map. */
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#define HMAP_INITIALIZER(HMAP) \
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{ (struct hmap_node **const) &(HMAP)->one, NULL, 0, 0 }
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/* Initializer for an immutable struct hmap 'HMAP' that contains 'N' nodes
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* linked together starting at 'NODE'. The hmap only has a single chain of
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* hmap_nodes, so 'N' should be small. */
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#define HMAP_CONST(HMAP, N, NODE) { \
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CONST_CAST(struct hmap_node **, &(HMAP)->one), NODE, 0, N }
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/* Initialization. */
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void hmap_init(struct hmap *);
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void hmap_destroy(struct hmap *);
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void hmap_clear(struct hmap *);
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void hmap_swap(struct hmap *a, struct hmap *b);
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void hmap_moved(struct hmap *hmap);
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static inline size_t hmap_count(const struct hmap *);
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static inline bool hmap_is_empty(const struct hmap *);
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/* Adjusting capacity. */
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void hmap_expand_at(struct hmap *, const char *where);
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#define hmap_expand(HMAP) hmap_expand_at(HMAP, OVS_SOURCE_LOCATOR)
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void hmap_shrink_at(struct hmap *, const char *where);
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#define hmap_shrink(HMAP) hmap_shrink_at(HMAP, OVS_SOURCE_LOCATOR)
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void hmap_reserve_at(struct hmap *, size_t capacity, const char *where);
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#define hmap_reserve(HMAP, CAPACITY) \
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hmap_reserve_at(HMAP, CAPACITY, OVS_SOURCE_LOCATOR)
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/* Insertion and deletion. */
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static inline void hmap_insert_at(struct hmap *, struct hmap_node *,
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size_t hash, const char *where);
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#define hmap_insert(HMAP, NODE, HASH) \
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hmap_insert_at(HMAP, NODE, HASH, OVS_SOURCE_LOCATOR)
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static inline void hmap_insert_fast(struct hmap *,
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struct hmap_node *, size_t hash);
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static inline void hmap_remove(struct hmap *, struct hmap_node *);
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void hmap_node_moved(struct hmap *, struct hmap_node *, struct hmap_node *);
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static inline void hmap_replace(struct hmap *, const struct hmap_node *old,
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struct hmap_node *new_node);
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struct hmap_node *hmap_random_node(const struct hmap *);
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/* Search.
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*
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* HMAP_FOR_EACH_WITH_HASH iterates NODE over all of the nodes in HMAP that
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* have hash value equal to HASH. HMAP_FOR_EACH_IN_BUCKET iterates NODE over
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* all of the nodes in HMAP that would fall in the same bucket as HASH. MEMBER
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* must be the name of the 'struct hmap_node' member within NODE.
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*
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* These macros may be used interchangeably to search for a particular value in
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* an hmap, see, e.g. shash_find() for an example. Usually, using
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* HMAP_FOR_EACH_WITH_HASH provides an optimization, because comparing a hash
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* value is usually cheaper than comparing an entire hash map key. But for
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* simple hash map keys, it makes sense to use HMAP_FOR_EACH_IN_BUCKET because
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* it avoids doing two comparisons when a single simple comparison suffices.
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*
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* The loop should not change NODE to point to a different node or insert or
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* delete nodes in HMAP (unless it "break"s out of the loop to terminate
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* iteration).
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*
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* HASH is only evaluated once.
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*
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* When the loop terminates normally, meaning the iteration has completed
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* without using 'break', NODE will be NULL. This is true for all of the
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* HMAP_FOR_EACH_*() macros.
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*/
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#define HMAP_FOR_EACH_WITH_HASH(NODE, MEMBER, HASH, HMAP) \
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for (INIT_MULTIVAR(NODE, MEMBER, hmap_first_with_hash(HMAP, HASH), \
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struct hmap_node); \
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CONDITION_MULTIVAR(NODE, MEMBER, ITER_VAR(NODE) != NULL); \
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UPDATE_MULTIVAR(NODE, hmap_next_with_hash(ITER_VAR(NODE))))
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#define HMAP_FOR_EACH_IN_BUCKET(NODE, MEMBER, HASH, HMAP) \
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for (INIT_MULTIVAR(NODE, MEMBER, hmap_first_in_bucket(HMAP, HASH), \
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struct hmap_node); \
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CONDITION_MULTIVAR(NODE, MEMBER, ITER_VAR(NODE) != NULL); \
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UPDATE_MULTIVAR(NODE, hmap_next_in_bucket(ITER_VAR(NODE))))
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static inline struct hmap_node *hmap_first_with_hash(const struct hmap *,
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size_t hash);
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static inline struct hmap_node *hmap_next_with_hash(const struct hmap_node *);
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static inline struct hmap_node *hmap_first_in_bucket(const struct hmap *,
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size_t hash);
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static inline struct hmap_node *hmap_next_in_bucket(const struct hmap_node *);
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bool hmap_contains(const struct hmap *, const struct hmap_node *);
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/* Iteration.
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*
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* The *_INIT variants of these macros additionally evaluate the expressions
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* supplied following the HMAP argument once during the loop initialization.
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* This makes it possible for data structures that wrap around hmaps to insert
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* additional initialization into their iteration macros without having to
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* completely rewrite them. In particular, it can be a good idea to insert
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* BUILD_ASSERT_TYPE checks for map and node types that wrap hmap, since
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* otherwise it is possible for clients to accidentally confuse two derived
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* data structures that happen to use the same member names for struct hmap and
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* struct hmap_node. */
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/* Iterates through every node in HMAP. */
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#define HMAP_FOR_EACH(NODE, MEMBER, HMAP) \
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HMAP_FOR_EACH_INIT(NODE, MEMBER, HMAP, (void) 0)
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#define HMAP_FOR_EACH_INIT(NODE, MEMBER, HMAP, ...) \
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for (INIT_MULTIVAR_EXP(NODE, MEMBER, hmap_first(HMAP), struct hmap_node, \
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__VA_ARGS__); \
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CONDITION_MULTIVAR(NODE, MEMBER, ITER_VAR(NODE) != NULL); \
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UPDATE_MULTIVAR(NODE, hmap_next(HMAP, ITER_VAR(NODE))))
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/* Safe when NODE may be freed (not needed when NODE may be removed from the
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* hash map but its members remain accessible and intact). */
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#define HMAP_FOR_EACH_SAFE_LONG(NODE, NEXT, MEMBER, HMAP) \
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HMAP_FOR_EACH_SAFE_LONG_INIT (NODE, NEXT, MEMBER, HMAP, (void) NEXT)
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#define HMAP_FOR_EACH_SAFE_LONG_INIT(NODE, NEXT, MEMBER, HMAP, ...) \
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for (INIT_MULTIVAR_SAFE_LONG_EXP(NODE, NEXT, MEMBER, hmap_first(HMAP), \
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struct hmap_node, __VA_ARGS__); \
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CONDITION_MULTIVAR_SAFE_LONG(NODE, NEXT, MEMBER, \
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ITER_VAR(NODE) != NULL, \
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ITER_VAR(NEXT) = hmap_next(HMAP, ITER_VAR(NODE)), \
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ITER_VAR(NEXT) != NULL); \
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UPDATE_MULTIVAR_SAFE_LONG(NODE, NEXT))
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/* Short versions of HMAP_FOR_EACH_SAFE. */
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#define HMAP_FOR_EACH_SAFE_SHORT(NODE, MEMBER, HMAP) \
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HMAP_FOR_EACH_SAFE_SHORT_INIT (NODE, MEMBER, HMAP, (void) 0)
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#define HMAP_FOR_EACH_SAFE_SHORT_INIT(NODE, MEMBER, HMAP, ...) \
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for (INIT_MULTIVAR_SAFE_SHORT_EXP(NODE, MEMBER, hmap_first(HMAP), \
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struct hmap_node, __VA_ARGS__); \
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CONDITION_MULTIVAR_SAFE_SHORT(NODE, MEMBER, \
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ITER_VAR(NODE) != NULL, \
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ITER_NEXT_VAR(NODE) = hmap_next(HMAP, ITER_VAR(NODE))); \
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UPDATE_MULTIVAR_SAFE_SHORT(NODE))
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#define HMAP_FOR_EACH_SAFE(...) \
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OVERLOAD_SAFE_MACRO(HMAP_FOR_EACH_SAFE_LONG, \
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HMAP_FOR_EACH_SAFE_SHORT, \
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4, __VA_ARGS__)
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/* Continues an iteration from just after NODE. */
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#define HMAP_FOR_EACH_CONTINUE(NODE, MEMBER, HMAP) \
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HMAP_FOR_EACH_CONTINUE_INIT(NODE, MEMBER, HMAP, (void) 0)
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#define HMAP_FOR_EACH_CONTINUE_INIT(NODE, MEMBER, HMAP, ...) \
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for (INIT_MULTIVAR_EXP(NODE, MEMBER, hmap_next(HMAP, &(NODE)->MEMBER), \
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struct hmap_node, __VA_ARGS__); \
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CONDITION_MULTIVAR(NODE, MEMBER, ITER_VAR(NODE) != NULL); \
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UPDATE_MULTIVAR(NODE, hmap_next(HMAP, ITER_VAR(NODE))))
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struct hmap_pop_helper_iter__ {
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size_t bucket;
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struct hmap_node *node;
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};
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static inline void
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hmap_pop_helper__(struct hmap *hmap, struct hmap_pop_helper_iter__ *iter) {
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for (; iter->bucket <= hmap->mask; (iter->bucket)++) {
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struct hmap_node *node = hmap->buckets[iter->bucket];
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if (node) {
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hmap_remove(hmap, node);
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iter->node = node;
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return;
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}
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}
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iter->node = NULL;
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}
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#define HMAP_FOR_EACH_POP(NODE, MEMBER, HMAP) \
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for (struct hmap_pop_helper_iter__ ITER_VAR(NODE) = { 0, NULL }; \
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hmap_pop_helper__(HMAP, &ITER_VAR(NODE)), \
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(ITER_VAR(NODE).node != NULL) ? \
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(((NODE) = OBJECT_CONTAINING(ITER_VAR(NODE).node, \
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NODE, MEMBER)),1): \
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(((NODE) = NULL), 0);)
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static inline struct hmap_node *hmap_first(const struct hmap *);
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static inline struct hmap_node *hmap_next(const struct hmap *,
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const struct hmap_node *);
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struct hmap_position {
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unsigned int bucket;
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unsigned int offset;
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};
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struct hmap_node *hmap_at_position(const struct hmap *,
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struct hmap_position *);
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/* Returns the number of nodes currently in 'hmap'. */
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static inline size_t
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hmap_count(const struct hmap *hmap)
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{
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return hmap->n;
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}
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/* Returns the maximum number of nodes that 'hmap' may hold before it should be
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* rehashed. */
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static inline size_t
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hmap_capacity(const struct hmap *hmap)
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{
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return hmap->mask * 2 + 1;
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}
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/* Returns true if 'hmap' currently contains no nodes,
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* false otherwise.
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* Note: While hmap in general is not thread-safe without additional locking,
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* hmap_is_empty() is. */
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static inline bool
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hmap_is_empty(const struct hmap *hmap)
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{
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return hmap->n == 0;
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}
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/* Inserts 'node', with the given 'hash', into 'hmap'. 'hmap' is never
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* expanded automatically. */
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static inline void
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hmap_insert_fast(struct hmap *hmap, struct hmap_node *node, size_t hash)
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{
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struct hmap_node **bucket = &hmap->buckets[hash & hmap->mask];
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node->hash = hash;
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node->next = *bucket;
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*bucket = node;
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hmap->n++;
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}
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/* Inserts 'node', with the given 'hash', into 'hmap', and expands 'hmap' if
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* necessary to optimize search performance.
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*
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* ('where' is used in debug logging. Commonly one would use hmap_insert() to
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* automatically provide the caller's source file and line number for
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* 'where'.) */
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static inline void
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hmap_insert_at(struct hmap *hmap, struct hmap_node *node, size_t hash,
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const char *where)
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{
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hmap_insert_fast(hmap, node, hash);
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if (hmap->n / 2 > hmap->mask) {
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hmap_expand_at(hmap, where);
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}
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}
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/* Removes 'node' from 'hmap'. Does not shrink the hash table; call
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* hmap_shrink() directly if desired. */
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static inline void
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hmap_remove(struct hmap *hmap, struct hmap_node *node)
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{
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struct hmap_node **bucket = &hmap->buckets[node->hash & hmap->mask];
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while (*bucket != node) {
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bucket = &(*bucket)->next;
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}
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*bucket = node->next;
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hmap->n--;
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}
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/* Puts 'new_node' in the position in 'hmap' currently occupied by 'old_node'.
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* The 'new_node' must hash to the same value as 'old_node'. The client is
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* responsible for ensuring that the replacement does not violate any
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* client-imposed invariants (e.g. uniqueness of keys within a map).
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*
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* Afterward, 'old_node' is not part of 'hmap', and the client is responsible
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* for freeing it (if this is desirable). */
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static inline void
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hmap_replace(struct hmap *hmap,
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const struct hmap_node *old_node, struct hmap_node *new_node)
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{
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struct hmap_node **bucket = &hmap->buckets[old_node->hash & hmap->mask];
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while (*bucket != old_node) {
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bucket = &(*bucket)->next;
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}
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*bucket = new_node;
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new_node->hash = old_node->hash;
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new_node->next = old_node->next;
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}
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static inline struct hmap_node *
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hmap_next_with_hash__(const struct hmap_node *node, size_t hash)
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{
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while (node != NULL && node->hash != hash) {
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node = node->next;
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}
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return CONST_CAST(struct hmap_node *, node);
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}
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/* Returns the first node in 'hmap' with the given 'hash', or a null pointer if
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* no nodes have that hash value. */
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static inline struct hmap_node *
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hmap_first_with_hash(const struct hmap *hmap, size_t hash)
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{
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return hmap_next_with_hash__(hmap->buckets[hash & hmap->mask], hash);
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}
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/* Returns the first node in 'hmap' in the bucket in which the given 'hash'
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* would land, or a null pointer if that bucket is empty. */
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static inline struct hmap_node *
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hmap_first_in_bucket(const struct hmap *hmap, size_t hash)
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{
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return hmap->buckets[hash & hmap->mask];
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}
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/* Returns the next node in the same bucket as 'node', or a null pointer if
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* there are no more nodes in that bucket.
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*
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* If the hash map has been reallocated since 'node' was visited, some nodes
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* may be skipped; if new nodes with the same hash value have been added, they
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* will be skipped. (Removing 'node' from the hash map does not prevent
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* calling this function, since node->next is preserved, although freeing
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* 'node' of course does.) */
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static inline struct hmap_node *
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hmap_next_in_bucket(const struct hmap_node *node)
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{
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return node->next;
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}
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/* Returns the next node in the same hash map as 'node' with the same hash
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* value, or a null pointer if no more nodes have that hash value.
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*
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* If the hash map has been reallocated since 'node' was visited, some nodes
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* may be skipped; if new nodes with the same hash value have been added, they
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* will be skipped. (Removing 'node' from the hash map does not prevent
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* calling this function, since node->next is preserved, although freeing
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* 'node' of course does.) */
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static inline struct hmap_node *
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hmap_next_with_hash(const struct hmap_node *node)
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{
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return hmap_next_with_hash__(node->next, node->hash);
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}
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static inline struct hmap_node *
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hmap_next__(const struct hmap *hmap, size_t start)
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{
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size_t i;
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for (i = start; i <= hmap->mask; i++) {
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struct hmap_node *node = hmap->buckets[i];
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if (node) {
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return node;
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}
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}
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return NULL;
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}
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/* Returns the first node in 'hmap', in arbitrary order, or a null pointer if
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* 'hmap' is empty. */
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static inline struct hmap_node *
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hmap_first(const struct hmap *hmap)
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{
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return hmap_next__(hmap, 0);
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}
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/* Returns the next node in 'hmap' following 'node', in arbitrary order, or a
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* null pointer if 'node' is the last node in 'hmap'.
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*
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* If the hash map has been reallocated since 'node' was visited, some nodes
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* may be skipped or visited twice. (Removing 'node' from the hash map does
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* not prevent calling this function, since node->next is preserved, although
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* freeing 'node' of course does.) */
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static inline struct hmap_node *
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hmap_next(const struct hmap *hmap, const struct hmap_node *node)
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{
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return (node->next
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? node->next
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: hmap_next__(hmap, (node->hash & hmap->mask) + 1));
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* hmap.h */
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