/* 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 "Array.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 alignment of all primitive storage is 4 bytes,

        // and that all need <= 4 bytes of storage.

        assert(type->isInt32() ||

               type->isFloat() ||

               type->isBool() ||

               type->isChar() ||

               type->isEnum());

        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)

{

    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_ = unsigned(-1);

    return desc;

}

StructMap *

StructMap::New(Zone *zone, const StructureBufferBuilder &builder, Handle<StructType> type)

{

    Vector<unsigned> composedIndexes;

    for (size_t i = 0; i < type->fields()->length(); i++) {

        Descriptor *desc = Descriptor::cast(type->fields()->at(i));

        if (desc->type()->isArray() || desc->type()->isStruct()) {

            if (!composedIndexes.append(i))

                return NULL;

        }

    }

    Local<FixedArray> composed(zone, FixedArray::New(zone, composedIndexes.length(), Heap::Tenure_Old));

    if (!composed)

        return NULL;

    for (size_t i = 0; i < composedIndexes.length(); i++) {

        Descriptor *desc = Descriptor::cast(type->fields()->at(composedIndexes[i]));

        composed->set(zone, i, desc);

    }

    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_ = type;

    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<Object> child(zone);

        Local<StructMap> childStructMap(zone);

        Local<ArrayMap> childArrayMap(zone);

        for (unsigned i = 0; i < map->composed()->length(); i++) {

            desc = Descriptor::cast(map->composed()->at(i));

            if (desc->type()->isStruct()) {

                childStructMap = StructMap::cast(StructType::cast(desc->type())->newMap());

                child = Struct::New(zone, childStructMap, tenure);

            } else if (desc->type()->isArray()) {

                // :TODO: don't create empty arrays for ref slots here.

                // Instead, make a separate Initialize function, so we

                // can avoid double-creating arrays for module globals.

                //  (const char:x[] = "x")

                ArrayType *type = ArrayType::cast(desc->type());

                childArrayMap = ArrayMap::cast(type->newMap());

                if (type->isFixedLength())

                    child = Array::NewFixed(zone, childArrayMap, tenure);

                else

                    child = Array::NewEmpty(zone, childArrayMap, tenure);

            }

            if (!child)

                return NULL;

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

        }

    }

    return obj;

}

bool

Struct::Copy(Zone *zone, Handle<Struct> left, Handle<Struct> right)

{

    assert(left->map()->type() == right->map()->type());

    Local<StructType> type(zone, StructType::cast(left->map()->type()));

    Local<Struct> leftStruct(zone);

    Local<Struct> rightStruct(zone);

    Local<Array> leftArray(zone);

    Local<Array> rightArray(zone);

    for (unsigned i = 0; i < type->fields()->length(); i++) {

        Descriptor *desc = Descriptor::cast(type->fields()->at(i));

        // If the field is a struct, we need to deep-copy.

        if (desc->type()->isStruct()) {

            leftStruct = Struct::cast(left->get<Object *>(desc));

            rightStruct = Struct::cast(right->get<Object *>(desc));

            if (!Struct::Copy(zone, leftStruct, rightStruct))

                return false;

        } else if (desc->type()->isArray()) {

            leftArray = Array::cast(left->get<Object *>(desc));

            rightArray = Array::cast(right->get<Object *>(desc));

            if (!Array::ShallowCopy(zone, leftArray, rightArray))

                return false;

        } else if (desc->type()->isTraceable()) {

            Object *obj = right->get<Object *>(desc);

            left->set(zone, desc, obj);

        } else {

            switch (desc->type()->pod()) {

              case PrimitiveType_Int32:

              case PrimitiveType_Char:

              case PrimitiveType_Bool:

                left->set(desc, right->get<int>(desc));

                break;

              case PrimitiveType_Float:

                left->set(desc, right->get<float>(desc));

                break;

              default:

                assert(false);

            }

        }

    }

    return true;

}