/*

  * Copyright (C) 2012 David Anderson

  *

  * This file is part of JITCraft.

  *

  * JITCraft is free software: you can redistribute it and/or modify it under

  * the terms of the GNU General Public License as published by the Free

  * Software Foundation, either version 3 of the License, or (at your option)

  * any later version.

  * 

  * Foobar 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 General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License along with

  * JITCraft. If not, see http://www.gnu.org/licenses/.

  */

 #include "Utility.h"

 #include "Environments.h"

 #include "Structures.h"

 #include "FixedArray.h"

 #include "Zone.h"

 #include "NameBinding.h"

 using namespace ke;

 EnvironmentSlotDescriptorArray *

 EnvironmentSlotDescriptorArray::New(Zone *zone, unsigned nslots)

 {

     size_t bytesNeeded = sizeof(EnvironmentSlotDescriptorArray) +

                          sizeof(EnvironmentSlotDescriptor) * nslots;

     Local<EnvironmentSlotDescriptorArray> array(zone);

     Local<Map> map(zone, zone->getMap(MapKind_EnvironmentSlotDescriptorArray));

     array = EnvironmentSlotDescriptorArray::cast(zone->allocate(map, bytesNeeded, Heap::Tenure_Old));

     if (!array)

         return NULL;

     // We zero the array for safety, since we could GC or fail before initialization.

     array->length_ = nslots;

     memset(array->slots(), 0, sizeof(EnvironmentSlotDescriptor) * nslots);

     return array;

 }

 Environment *

 Environment::New(Zone *zone, Handle<EnvironmentMap> map, Heap::Tenure tenure)

 {

     size_t bytesNeeded = sizeof(Environment) + map->structureSize();

     Local<Environment> env(zone, Environment::cast(zone->allocate(map, bytesNeeded, tenure)));

     if (!env)

         return NULL;

     // Initialize when called from C++, to make sure object slots are NULL.

     memset((Object *)env + 1, 0, map->structureSize());

     return env;

 }

 EnvironmentMap *

 EnvironmentMap::New(Zone *zone, unsigned nvars, Variable **vars)

 {

     StructureBufferBuilder structure;

     Local<EnvironmentSlotDescriptorArray> slots(zone);

     slots = EnvironmentSlotDescriptorArray::New(zone, nvars);

     if (!slots)

         return NULL;

     // Build the descriptor table, mapping each slot to an offset and type.

     Local<Type> type(zone);

     for (unsigned i = 0; i < nvars; i++) {

         assert(vars[i]->slot() == i);

         type = vars[i]->type();

         EnvironmentSlotDescriptor &desc = slots->slots()[i];

         if (!structure.add(type, &desc.offset))

             return NULL;

         desc.type = type;

     }

     // Allocate the actual map now.

     size_t bytesNeeded = sizeof(EnvironmentMap) + structure.traceableOffsetCount() * sizeof(unsigned);

     Local<EnvironmentMap> map(zone);

     map = EnvironmentMap::cast(zone->allocateMap(MapKind_Environment, bytesNeeded, MapKind_MetaEnvironment));

     if (!map)

         return NULL;

     // Fill in the map fields, and copy the traceable offsets structure.

     map->structureSize_ = structure.structureSize();

     map->traceOffsetCount_ = structure.traceableOffsetCount();

     map->slots_ = slots;

     memcpy(const_cast<unsigned *>(map->traceOffsets()), structure.offsets(), sizeof(unsigned) * structure.traceableOffsetCount());

     return map;

 }