/* StarPU --- Runtime system for heterogeneous multicore architectures.
 *
 * Copyright (C) 2011-2013                                Inria
 * Copyright (C) 2012,2017                                CNRS
 * Copyright (C) 2010-2011,2013, 2018                           Université de Bordeaux
 *
 * StarPU is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or (at
 * your option) any later version.
 *
 * StarPU is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 * See the GNU Lesser General Public License in COPYING.LGPL for more details.
 */

#include "socl.h"

static void release_callback_memobject(void * e)
{
	cl_mem mem = (cl_mem)e;

	/* Release references */
	gc_entity_unstore(&mem->context);

	//Delete this mem_object from the mem_object list
	mem_object_release(mem);

	/* Destruct object */
	starpu_data_unregister_submit(mem->handle);

	if (!(mem->flags & CL_MEM_USE_HOST_PTR))
		free(mem->ptr);
}

/**
 * \brief Create a buffer
 *
 * A buffer has always an allocated region in host memory. If CL_MEM_USE_HOST_PTR
 * is set, we use memory pointed by host_ptr, otherwise some host memory is
 * allocated.
 *
 * If CL_MEM_USE_HOST_PTR or CL_MEM_ALLOC_HOST_PTR are set, memory pointed by host_ptr
 * is not coherent. To enforce coherency, you have to map the buffer (clEnqueueMapBuffer).
 *
 * If CL_MEM_COPY_HOST_PTR is set, the buffer will be duplicated in host memory. You
 * should avoid it.
 *
 */
CL_API_SUFFIX__VERSION_1_0
CL_API_ENTRY cl_mem CL_API_CALL
soclCreateBuffer(cl_context   context,
		 cl_mem_flags flags,
		 size_t       size,
		 void *       host_ptr,
		 cl_int *     errcode_ret)
{
	cl_mem mem;

	if (errcode_ret != NULL)
		*errcode_ret = CL_SUCCESS;

	//Check flags
	if (((flags & CL_MEM_READ_ONLY) && (flags & CL_MEM_WRITE_ONLY))
	    || ((flags & CL_MEM_READ_WRITE) && (flags & CL_MEM_READ_ONLY))
	    || ((flags & CL_MEM_READ_WRITE) && (flags & CL_MEM_WRITE_ONLY))
	    || ((flags & CL_MEM_USE_HOST_PTR) && (flags & CL_MEM_ALLOC_HOST_PTR))
	    || ((flags & CL_MEM_USE_HOST_PTR) && (flags & CL_MEM_COPY_HOST_PTR)))
	{
		if (errcode_ret != NULL)
			*errcode_ret = CL_INVALID_VALUE;
		return NULL;
	}

	if (size == 0)
	{
		if (errcode_ret != NULL)
			*errcode_ret = CL_INVALID_BUFFER_SIZE;
		return NULL;
	}

	if ((host_ptr == NULL && (flags & (CL_MEM_USE_HOST_PTR | CL_MEM_COPY_HOST_PTR)))
	    || (host_ptr != NULL && !(flags & (CL_MEM_USE_HOST_PTR | CL_MEM_COPY_HOST_PTR))))
	{
		if (errcode_ret != NULL)
			*errcode_ret = CL_INVALID_HOST_PTR;
		return NULL;
	}

	//Alloc cl_mem structure
	mem = (cl_mem)gc_entity_alloc(sizeof(struct _cl_mem), release_callback_memobject, "buffer");
	if (mem == NULL)
	{
		if (errcode_ret != NULL)
			*errcode_ret = CL_OUT_OF_HOST_MEMORY;
		return NULL;
	}

	mem->ptr = NULL;
	mem->map_count = 0;
	gc_entity_store(&mem->context, context);
	mem->flags = flags;
	mem->size = size;
	mem->host_ptr = host_ptr;

#ifdef DEBUG
	static int id = 0;
	mem->id = id++;
#endif

	mem_object_store(mem);

	//TODO: we shouldn't allocate the buffer ourselves. StarPU allocates it if a NULL pointer is given

	// If not MEM_USE_HOST_PTR, we need to alloc the buffer ourselves
	if (!(flags & CL_MEM_USE_HOST_PTR))
	{
		mem->ptr = valloc(size);
		if (mem->ptr == NULL)
		{
			if (errcode_ret != NULL)
				*errcode_ret = CL_MEM_OBJECT_ALLOCATION_FAILURE;
			free(mem);
			return NULL;
		}
		//The buffer doesn't contain meaningful data
		mem->scratch = 1;
	}
	else
	{
		//The buffer may contain meaningful data
		mem->scratch = 0;
		mem->ptr = host_ptr;
	}

	// Access mode
	mem->mode = (flags & CL_MEM_READ_ONLY) ? CL_MEM_READ_ONLY :
		(flags & CL_MEM_WRITE_ONLY) ? CL_MEM_WRITE_ONLY : CL_MEM_READ_WRITE;

	// Perform data copy if necessary
	if (flags & CL_MEM_COPY_HOST_PTR)
		memcpy(mem->ptr, host_ptr, size);

	// Create StarPU buffer (on home node? what's this?)
	starpu_variable_data_register(&mem->handle, STARPU_MAIN_RAM, (uintptr_t)mem->ptr, size);

	DEBUG_MSG("[Buffer %d] Initialized (cl_mem %p handle %p)\n", mem->id, mem, mem->handle);

	return mem;
}