libc/src/search/hcreate.cpp

   1 //===-- Implementation of hcreate -------------------------------*- 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/hcreate.h"
  10 #include "src/__support/HashTable/randomness.h"
  11 #include "src/__support/HashTable/table.h"
  12 #include "src/__support/macros/config.h"
  13 #include "src/errno/libc_errno.h"
  14 #include "src/search/hsearch/global.h"
  15
  16 namespace LIBC_NAMESPACE_DECL {
  17 LLVM_LIBC_FUNCTION(int, hcreate, (size_t capacity)) {
  18   // We follow FreeBSD's implementation here. If the global_hash_table is
  19   // already initialized, this function will do nothing and return 1.
  20   // https://cgit.freebsd.org/src/tree/lib/libc/stdlib/hcreate.c
  21   if (internal::global_hash_table != nullptr)
  22     return 1;
  23
  24   uint64_t randomness = internal::randomness::next_random_seed();
  25   internal::HashTable *table =
  26       internal::HashTable::allocate(capacity, randomness);
  27   if (table == nullptr) {
  28     libc_errno = ENOMEM;
  29     return 0;
  30   }
  31   internal::global_hash_table = table;
  32   return 1;
  33 }
  34
  35 } // namespace LIBC_NAMESPACE_DECL