| 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/errno/libc_errno.h" |
| 13 | #include "src/search/hsearch/global.h" |
| 14 | |
| 15 | namespace LIBC_NAMESPACE { |
| 16 | LLVM_LIBC_FUNCTION(ENTRY *, hsearch, (ENTRY item, ACTION action)) { |
| 17 | ENTRY *result; |
| 18 | if (internal::global_hash_table == nullptr) { |
| 19 | // If global_hash_table is null, we create a new hash table with a minimal |
| 20 | // capacity. Such hashtable will be expanded as needed. |
| 21 | uint64_t randomness = internal::randomness::next_random_seed(); |
| 22 | internal::global_hash_table = internal::HashTable::allocate(capacity: 0, randomness); |
| 23 | } |
| 24 | |
| 25 | // In rare cases, the global hashtable may still fail to allocate. We treat it |
| 26 | // as ESRCH or ENOMEM depending on the action. |
| 27 | switch (action) { |
| 28 | case FIND: |
| 29 | result = internal::global_hash_table |
| 30 | ? internal::global_hash_table->find(key: item.key) |
| 31 | : nullptr; |
| 32 | if (result == nullptr) { |
| 33 | libc_errno = ESRCH; |
| 34 | } |
| 35 | break; |
| 36 | case ENTER: |
| 37 | result = |
| 38 | internal::global_hash_table |
| 39 | ? internal::HashTable::insert(table&: internal::global_hash_table, item) |
| 40 | : nullptr; |
| 41 | if (result == nullptr) { |
| 42 | libc_errno = ENOMEM; |
| 43 | } |
| 44 | break; |
| 45 | } |
| 46 | return result; |
| 47 | } |
| 48 | |
| 49 | } // namespace LIBC_NAMESPACE |
| 50 |