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/*
* Copyright 2016 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef GRPC_CORE_LIB_SLICE_SLICE_HASH_TABLE_H
#define GRPC_CORE_LIB_SLICE_SLICE_HASH_TABLE_H
#include "src/core/lib/transport/metadata.h"
#ifdef __cplusplus
extern "C" {
#endif
/** Hash table implementation.
*
* This implementation uses open addressing
* (https://en.wikipedia.org/wiki/Open_addressing) with linear
* probing (https://en.wikipedia.org/wiki/Linear_probing).
*
* The keys are \a grpc_slice objects. The values are arbitrary pointers
* with a common destroy function.
*
* Hash tables are intentionally immutable, to avoid the need for locking.
*/
typedef struct grpc_slice_hash_table grpc_slice_hash_table;
typedef struct grpc_slice_hash_table_entry {
grpc_slice key;
void *value; /* Must not be NULL. */
} grpc_slice_hash_table_entry;
/** Creates a new hash table of containing \a entries, which is an array
of length \a num_entries. Takes ownership of all keys and values in \a
entries. Values will be cleaned up via \a destroy_value(). If not NULL, \a
value_cmp will be used to compare values in the context of \a
grpc_slice_hash_table_cmp. If NULL, raw pointer (\a GPR_ICMP) comparison
will be used. */
grpc_slice_hash_table *grpc_slice_hash_table_create(
size_t num_entries, grpc_slice_hash_table_entry *entries,
void (*destroy_value)(grpc_exec_ctx *exec_ctx, void *value),
int (*value_cmp)(void *a, void *b));
grpc_slice_hash_table *grpc_slice_hash_table_ref(grpc_slice_hash_table *table);
void grpc_slice_hash_table_unref(grpc_exec_ctx *exec_ctx,
grpc_slice_hash_table *table);
/** Returns the value from \a table associated with \a key.
Returns NULL if \a key is not found. */
void *grpc_slice_hash_table_get(const grpc_slice_hash_table *table,
const grpc_slice key);
/** Compares \a a vs. \a b.
* A table is considered "smaller" (resp. "greater") if:
* - GPR_ICMP(a->value_cmp, b->value_cmp) < 1 (resp. > 1),
* - else, it contains fewer (resp. more) entries,
* - else, if strcmp(a_key, b_key) < 1 (resp. > 1),
* - else, if value_cmp(a_value, b_value) < 1 (resp. > 1). */
int grpc_slice_hash_table_cmp(const grpc_slice_hash_table *a,
const grpc_slice_hash_table *b);
#ifdef __cplusplus
}
#endif
#endif /* GRPC_CORE_LIB_SLICE_SLICE_HASH_TABLE_H */
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