1//===-- Implementation of hsearch -------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "src/search/hsearch.h"
10#include "src/__support/HashTable/randomness.h"
11#include "src/__support/HashTable/table.h"
12#include "src/__support/libc_errno.h"
13#include "src/__support/macros/config.h"
14#include "src/search/hsearch/global.h"
15
16namespace LIBC_NAMESPACE_DECL {
17LLVM_LIBC_FUNCTION(ENTRY *, hsearch, (ENTRY item, ACTION action)) {
18 ENTRY *result = nullptr;
19 if (internal::global_hash_table == nullptr) {
20 // If global_hash_table is null, we create a new hash table with a minimal
21 // capacity. Such hashtable will be expanded as needed.
22 uint64_t randomness = internal::randomness::next_random_seed();
23 internal::global_hash_table = internal::HashTable::allocate(0, randomness);
24 }
25
26 // In rare cases, the global hashtable may still fail to allocate. We treat it
27 // as ESRCH or ENOMEM depending on the action.
28 switch (action) {
29 case FIND:
30 result = internal::global_hash_table
31 ? internal::global_hash_table->find(item.key)
32 : nullptr;
33 if (result == nullptr) {
34 libc_errno = ESRCH;
35 }
36 break;
37 case ENTER:
38 result =
39 internal::global_hash_table
40 ? internal::HashTable::insert(internal::global_hash_table, item)
41 : nullptr;
42 if (result == nullptr) {
43 libc_errno = ENOMEM;
44 }
45 break;
46 }
47 return result;
48}
49
50} // namespace LIBC_NAMESPACE_DECL
51

source code of libc/src/search/hsearch.cpp