mirror of
https://github.com/LadybirdBrowser/ladybird.git
synced 2024-11-29 02:50:26 +00:00
1cdd3bb74f
This implements a shuffle function in AK/Random.h which works on any container with size() and curly brace operators. It uses fisher-yates shuffle.
73 lines
1.5 KiB
C++
73 lines
1.5 KiB
C++
/*
|
|
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <AK/Platform.h>
|
|
#include <AK/StdLibExtras.h>
|
|
#include <AK/Types.h>
|
|
|
|
#if defined(AK_OS_SERENITY) || defined(AK_OS_ANDROID)
|
|
# include <stdlib.h>
|
|
#endif
|
|
|
|
#if defined(__unix__)
|
|
# include <unistd.h>
|
|
#endif
|
|
|
|
#if defined(AK_OS_MACOS)
|
|
# include <sys/random.h>
|
|
#endif
|
|
|
|
#if defined(AK_OS_WINDOWS)
|
|
# include <stdlib.h>
|
|
#endif
|
|
|
|
namespace AK {
|
|
|
|
inline void fill_with_random([[maybe_unused]] void* buffer, [[maybe_unused]] size_t length)
|
|
{
|
|
#if defined(AK_OS_SERENITY) || defined(AK_OS_ANDROID)
|
|
arc4random_buf(buffer, length);
|
|
#elif defined(OSS_FUZZ)
|
|
#elif defined(__unix__) or defined(AK_OS_MACOS)
|
|
[[maybe_unused]] int rc = getentropy(buffer, length);
|
|
#else
|
|
char* char_buffer = static_cast<char*>(buffer);
|
|
for (size_t i = 0; i < length; i++) {
|
|
char_buffer[i] = rand();
|
|
}
|
|
#endif
|
|
}
|
|
|
|
template<typename T>
|
|
inline T get_random()
|
|
{
|
|
T t;
|
|
fill_with_random(&t, sizeof(T));
|
|
return t;
|
|
}
|
|
|
|
u32 get_random_uniform(u32 max_bounds);
|
|
|
|
template<typename Collection>
|
|
inline void shuffle(Collection& collection)
|
|
{
|
|
// Fisher-Yates shuffle
|
|
for (size_t i = collection.size() - 1; i >= 1; --i) {
|
|
size_t j = get_random_uniform(i + 1);
|
|
AK::swap(collection[i], collection[j]);
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
#if USING_AK_GLOBALLY
|
|
using AK::fill_with_random;
|
|
using AK::get_random;
|
|
using AK::get_random_uniform;
|
|
using AK::shuffle;
|
|
#endif
|