/************************************************************************************

Filename    :   OVR_Allocator.cpp
Content     :   Installable memory allocator implementation
Created     :   September 19, 2012
Notes       : 

Copyright   :   Copyright 2014 Oculus VR, LLC All Rights reserved.

Licensed under the Oculus VR Rift SDK License Version 3.2 (the "License"); 
you may not use the Oculus VR Rift SDK except in compliance with the License, 
which is provided at the time of installation or download, or which 
otherwise accompanies this software in either electronic or hard copy form.

You may obtain a copy of the License at

http://www.oculusvr.com/licenses/LICENSE-3.2 

Unless required by applicable law or agreed to in writing, the Oculus VR SDK 
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

************************************************************************************/

#include "OVR_Allocator.h"
#ifdef OVR_OS_MAC
 #include <stdlib.h>
#else
 #include <malloc.h>
#endif

#if defined(OVR_OS_MS)
 #include <Windows.h>
#elif defined(OVR_OS_MAC) || defined(OVR_OS_UNIX)
 #include <unistd.h>
 #include <sys/mman.h>
#endif


namespace OVR {

//-----------------------------------------------------------------------------------
// ***** Allocator

Allocator* Allocator::pInstance = 0;

// Default AlignedAlloc implementation will delegate to Alloc/Free after doing rounding.
void* Allocator::AllocAligned(size_t size, size_t align)
{
    OVR_ASSERT((align & (align-1)) == 0);
    align = (align > sizeof(size_t)) ? align : sizeof(size_t);
    size_t p = (size_t)Alloc(size+align);
    size_t aligned = 0;
    if (p)
    {
        aligned = (size_t(p) + align-1) & ~(align-1);
        if (aligned == p) 
            aligned += align;
        *(((size_t*)aligned)-1) = aligned-p;
    }
    return (void*)aligned;
}

void Allocator::FreeAligned(void* p)
{
    size_t src = size_t(p) - *(((size_t*)p)-1);
    Free((void*)src);
}


//------------------------------------------------------------------------
// ***** Default Allocator

// This allocator is created and used if no other allocator is installed.
// Default allocator delegates to system malloc.

void* DefaultAllocator::Alloc(size_t size)
{
    return malloc(size);
}
void* DefaultAllocator::AllocDebug(size_t size, const char* file, unsigned line)
{
	OVR_UNUSED2(file, line); // should be here for debugopt config
#if defined(OVR_CC_MSVC) && defined(_CRTDBG_MAP_ALLOC)
    return _malloc_dbg(size, _NORMAL_BLOCK, file, line);
#else
    return malloc(size);
#endif
}

void* DefaultAllocator::Realloc(void* p, size_t newSize)
{
    return realloc(p, newSize);
}
void DefaultAllocator::Free(void *p)
{
    return free(p);
}




void* MMapAlloc(size_t size)
{
    #if defined(OVR_OS_MS)
        return VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE); // size is rounded up to a page. // Returned memory is 0-filled.

    #elif defined(OVR_OS_MAC) || defined(OVR_OS_UNIX)
        #if !defined(MAP_FAILED)
            #define MAP_FAILED ((void*)-1)
        #endif

        void* result = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); // Returned memory is 0-filled.
        if(result == MAP_FAILED) // mmap returns MAP_FAILED (-1) upon failure.
            result = NULL;
        return result;
    #endif
}




void MMapFree(void* memory, size_t size)
{
    #if defined(OVR_OS_MS)
        OVR_UNUSED(size);
        VirtualFree(memory, 0, MEM_RELEASE);

    #elif defined(OVR_OS_MAC) || defined(OVR_OS_UNIX)
        size_t pageSize = getpagesize();
        size = (((size + (pageSize - 1)) / pageSize) * pageSize);
        munmap(memory, size); // Must supply the size to munmap.
    #endif
}




} // OVR