/* vim: set ts=4 sw=4 tw=99 et:
 *
 * Copyright (C) 2012 David Anderson
 *
 * This file is part of SourcePawn.
 *
 * SourcePawn 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.
 * 
 * SourcePawn 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
 * SourcePawn. If not, see http://www.gnu.org/licenses/.
 */
#include <string.h>
#include "Structures.h"
#include "Zone.h"
#include "Types.h"
#include "Spaces-inl.h"
#include "Heap-inl.h"

using namespace ke;

StructureBufferBuilder::StructureBufferBuilder()
  : size_(0)
{
}

bool
StructureBufferBuilder::add(Handle<Type> type, unsigned *offset)
{
    *offset = size_;

    if (!type->isTraceable()) {
        // For now, assume the size of primitives is 4-byte.
        assert(type->isInt32() || type->isFloat());
        size_ += 4;
        return true;
    }

    if (!offsets_.append(size_))
        return false;

    size_ += sizeof(Object *);
    return true;
}

Descriptor *
Descriptor::New(Zone *zone, Handle<String> name, Handle<Type> type, unsigned offset)
{
    Local<Descriptor> desc(zone,
        Descriptor::cast(zone->allocate(MapKind_Descriptor, sizeof(Descriptor), Heap::Tenure_Old)));
    if (!desc)
        return NULL;

    desc->name_ = name;
    desc->type_ = type;
    desc->offset_ = offset;
    return desc;
}

StructMap *
StructMap::New(Zone *zone, const StructureBufferBuilder &builder, Handle<FixedArray> composed)
{
    size_t bytesNeeded = sizeof(StructMap) +
                         (builder.traceableOffsetCount() * sizeof(unsigned));

    Local<StructMap> map(zone);
    map = StructMap::cast(zone->allocateMap(MapKind_Struct, bytesNeeded, MapKind_MetaStruct));
    if (!map)
        return NULL;

    map->structureSize_ = builder.structureSize();
    map->traceOffsetCount_ = builder.traceableOffsetCount();
    map->type_ = NULL;
    map->composed_ = composed;
    memcpy(const_cast<unsigned *>(map->traceOffsets()), builder.offsets(),
           sizeof(unsigned) * builder.traceableOffsetCount());

    return map;
}

Struct *
Struct::New(Zone *zone, Handle<StructMap> map, Heap::Tenure tenure)
{
    size_t bytesNeeded = sizeof(Struct) + map->structureSize();
    Local<Struct> obj(zone, Struct::cast(zone->allocate(map, bytesNeeded, tenure)));
    if (!obj)
        return NULL;

    memset((Struct *)obj + 1, 0, map->structureSize());

    // Initialize any sub-structures. Right now, this is performed as part of
    // struct allocation, rather than inlined in bytecode, for simplicity.
    if (map->composed()) {
        Local<Descriptor> desc(zone);
        Local<Struct> child(zone);
        Local<StructMap> childMap(zone);
        for (unsigned i = 0; i < map->composed()->length(); i++) {
            desc = Descriptor::cast(map->composed()->at(i));

            // We don't support composing arrays yet.
            assert(desc->type()->isStruct());

            childMap = StructMap::cast(desc->type()->newMap());
            child = Struct::New(zone, childMap, tenure);
            if (!child)
                return NULL;

            obj->set(zone, desc, child);
        }
    }

    return obj;
}