/* Copyright (C) 2026 Wildfire Games.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

#include "precompiled.h"

#include "lib/sysdep/os_cpu.h"

#include "lib/alignment.h"
#include "lib/bits.h"
#include "lib/config2.h"
#include "lib/debug.h"
#include "lib/module_init.h"
#include "lib/posix/posix_pthread.h"
#include "lib/posix/posix_types.h"
#include "lib/status.h"
#include "lib/sysdep/os.h"

#include <cerrno>
#include <cstddef>
#include <cstdint>

#if CONFIG2_VALGRIND
# include "valgrind.h"
#endif


size_t os_cpu_NumProcessors()
{
	static size_t numProcessors;

	if(numProcessors == 0)
	{
#if CONFIG2_VALGRIND
		// Valgrind reports the number of real CPUs, but only emulates a single CPU.
		// That causes problems when we expect all those CPUs to be distinct, so
		// just pretend there's only one CPU
		if (RUNNING_ON_VALGRIND)
			numProcessors = 1;
		else
#endif
		{
			long res = sysconf(_SC_NPROCESSORS_CONF);
			ENSURE(res != -1);
			numProcessors = (size_t)res;
		}
	}

	return numProcessors;
}


uintptr_t os_cpu_ProcessorMask()
{
	static uintptr_t processorMask;

	if(!processorMask)
		processorMask = bit_mask<uintptr_t>(os_cpu_NumProcessors());

	return processorMask;
}


size_t os_cpu_PageSize()
{
	static size_t pageSize;

	if(!pageSize)
		pageSize = (size_t)sysconf(_SC_PAGESIZE);

	return pageSize;
}


size_t os_cpu_LargePageSize()
{
	// assume they're unsupported.
	return 0;
}


size_t os_cpu_MemoryAvailable()
{
	const uint64_t memoryAvailableBytes = (uint64_t)sysconf(_SC_AVPHYS_PAGES) * os_cpu_PageSize();
	const size_t memoryAvailable = size_t(memoryAvailableBytes / MiB);
	return memoryAvailable;
}