/* 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 "Array.h"

#include "FixedArray.h"

#include "Heap.h"

#include "Zone.h"

#include "Structures.h"

#include "Heap-inl.h"

using namespace ke;

ArrayMap *

ArrayMap::New(Zone *zone, Handle<ArrayType> type)

{

    Local<Map> obj(zone, zone->allocateMap(MapKind_Array, sizeof(ArrayMap), MapKind_MetaArray));

    if (!obj)

        return NULL;

    Local<ArrayMap> map(zone, ArrayMap::cast(obj));

    map->type_ = type;

    return map;

}

ArrayMap *

ArrayMap::NewDependent(Zone *zone, Handle<ArrayType> type)

{

    Local<Map> obj(zone, zone->allocateMap(MapKind_DependentArray, sizeof(ArrayMap), MapKind_MetaArray));

    if (!obj)

        return NULL;

    Local<ArrayMap> map(zone, ArrayMap::cast(obj));

    map->type_ = type;

    return map;

}

Array *

Array::NewRaw(Zone *zone, Handle<ArrayMap> map, unsigned nelements, Heap::Tenure tenure)

{

    assert(!map->type()->isFixedLength() || nelements == map->type()->fixedLength());

    if (nelements > (INT_MAX / SizeForElement(map->type()))) {

        zone->reportError(Message_ArraySizeTooBig);

        return NULL;

    }

    size_t bytes = sizeof(Array);

    if (map->type()->hasInlineElements())

        bytes += SizeForElement(map->type()) * nelements;

    Local<Array> array(zone, Array::cast(zone->allocate(map, bytes, tenure)));

    if (!array)

        return NULL;

    array->length_ = 0;

    array->elements_ = NULL;

    if (map->type()->hasInlineElements()) {

        // This must be a fixed array containing no traceables.

        assert(nelements > 0);

        assert(map->type()->isFixedLength());

        assert(!map->type()->contained()->isTraceable());

        // Compute an interior |elements_| pointer, such that if elements_

        // is accessed like a FixedArray, we reach the appropriate vector.

        array->elements_ = Address((Array *)array + 1) - ByteArray::offsetToElements();

        array->length_ = nelements;

        memset(array->bytes(), 0, SizeForElement(map->type()) * nelements);

        return array;

    }

    // If there is nothing to allocate, we don't bother creating elements yet.

    if (!nelements)

        return array;

    if (!map->type()->contained()->isTraceable()) {

        size_t nbytes = SizeForElement(map->type()) * nelements;

        Local<ByteArray> elements(zone, ByteArray::New(zone, nbytes, tenure));

        if (!elements)

            return NULL;

        array->updateLengthAndElements(zone, nelements, elements);

        return array;

    }

    Local<FixedArray> elements(zone, FixedArray::New(zone, nelements, tenure));

    if (!elements)

        return NULL;

    array->updateLengthAndElements(zone, nelements, elements);

    // If this is an array of structs, we're required to allocate those structs now.

    if (map->type()->contained()->isStruct()) {

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

        Local<StructMap> childMap(zone, childType->newMap());

        Local<Struct> child(zone);

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

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

            if (!child)

                return NULL;

            elements->set(zone, i, child);

        }

    }

    return array;

}

static Array *

ConstructSizedArray(Zone *zone, Handle<ArrayMap> map, int dims[MAX_ARRAY_DEPTH],

                    unsigned level, Heap::Tenure tenure)

{

    Local<Array> array(zone, Array::NewRaw(zone, map, dims[level], tenure));

    if (!array)

        return NULL;

    if (map->type()->contained()->isArray()) {

        Local<ArrayType> childType(zone, ArrayType::cast(map->type()->contained()));

        Local<ArrayMap> childMap(zone, childType->newMap());

        Local<Array> child(zone);

        for (unsigned i = 0; i < unsigned(dims[level]); i++) {

            child = ConstructSizedArray(zone, childMap, dims, level + 1, tenure);

            if (!child)

                return NULL;

            array->writeObject(zone, i, child);

        }

    }

    return array;

}

Array *

Array::NewSized(Zone *zone, Handle<ArrayMap> map, int dims[MAX_ARRAY_DEPTH], Heap::Tenure tenure)

{

    for (size_t i = 0; i < map->type()->levels(); i++) {

        if (dims[i] < 0) {

            zone->reportError(Message_InvalidDimensionSize, dims[i], i);

            return NULL;

        }

    }

    return ConstructSizedArray(zone, map, dims, 0, tenure);

}

static Array *

ConstructFixedArray(Zone *zone, Handle<ArrayMap> map, Heap::Tenure tenure)

{

    unsigned length = map->type()->fixedLength();

    Local<Array> array(zone, Array::NewRaw(zone, map, length, tenure));

    if (!array)

        return NULL;

    if (map->type()->contained()->isArray()) {

        Local<ArrayType> childType(zone, ArrayType::cast(map->type()->contained()));

        Local<ArrayMap> childMap(zone, childType->newMap());

        Local<Array> child(zone);

        if (childMap->type()->isFixedLength()) {

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

                child = ConstructFixedArray(zone, childMap, tenure);

                if (!child)

                    return NULL;

                array->writeObject(zone, i, child);

            }

        } else {

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

                child = Array::NewRaw(zone, childMap, 0, tenure);

                if (!child)

                    return NULL;

                array->writeObject(zone, i, child);

            }

        }

    }

    return array;

}

Array *

Array::NewFixed(Zone *zone, Handle<ArrayMap> map, Heap::Tenure tenure)

{

    return ConstructFixedArray(zone, map, tenure);

}

Array *

Array::NewString(Zone *zone, Handle<ArrayMap> map, char *buffer, size_t length, Heap::Tenure tenure)

{

    assert(map->type()->isCharArray());

    Local<Array> array(zone);

    if (map->type()->isFixedLength())

        array = Array::NewFixed(zone, map, tenure);

    else

        array = Array::New1D(zone, map, length + 1, tenure);

    if (!array)

        return NULL;

    assert(array->length() >= length + 1);

    memcpy(array->chars(), buffer, length + 1);

    return array;

}

Array *

Array::New1D(Zone *zone, Handle<ArrayMap> map, uint32 elements, Heap::Tenure tenure)

{

    assert(map->type()->levels());

    return Array::NewRaw(zone, map, elements, tenure);

}

Array *

Array::NewEmpty(Zone *zone, Handle<ArrayMap> map, Heap::Tenure tenure)

{

    assert(!map->type()->isFixedLength());

    return Array::NewRaw(zone, map, 0, tenure);

}

Array *

Array::NewExternal(Zone *zone, Handle<ArrayMap> map, void *buffer, unsigned length,

                   Heap::Tenure tenure)

{

    Local<Array> array(zone, Array::cast(zone->allocate(map, sizeof(Array), tenure)));

    if (!array)

        return NULL;

    array->length_ = length;

    array->elements_ = Address(buffer) - ByteArray::offsetToElements();

    return array;

}

static bool

CopyArrayElements(Zone *zone, Handle<Type> contained, Handle<Array> dest, Handle<Array> source)

{

    if (contained->isTraceable()) {

        if (contained->isStruct()) {

            assert(dest->type()->contained() == contained);

            assert(source->length() == dest->length());

            Local<Struct> left(zone);

            Local<Struct> right(zone);

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

                left = Struct::cast(dest->readObject(i));

                right = Struct::cast(source->readObject(i));

                if (!Struct::Copy(zone, left, right))

                    return false;

            }

        } else if (contained->isArray() && ArrayType::cast(contained)->isFixedLength()) {

            assert(ArrayType::cast(source->type())->fixedLength() ==

                   ArrayType::cast(contained)->fixedLength());

            Local<Array> left(zone);

            Local<Array> right(zone);

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

                left = Array::cast(dest->readObject(i));

                right = Array::cast(source->readObject(i));

                if (!Array::ShallowCopy(zone, left, right))

                    return false;

            }

        } else {

            assert(dest->length() == source->length());

            for (unsigned i = 0; i < source->length(); i++)

                dest->writeObject(zone, i, source->readObject(i));

        }

    } else {

        assert(contained->pod() == dest->type()->contained()->pod());

        assert(contained->pod() == PrimitiveType_Char

               ? source->length() <= dest->length()

               : source->length() == dest->length());

        assert(dest->length());

        memcpy(dest->bytes(), source->bytes(), source->length() * Array::SizeForElement(dest->type()));

    }

    return true;

}

// Shallow copy an array. Fixed slots in the destination are copied from

// the source, but otherwise, references are assigned.

bool

Array::ShallowCopy(Zone *zone, Handle<Array> dest, Handle<Array> source)

{

    Local<Type> contained(zone, dest->type()->contained());

    return CopyArrayElements(zone, contained, dest, source);

}

Array *

Array::DeepCopy(Zone *zone, Handle<Array> source, Heap::Tenure tenure)

{

    Local<ArrayMap> map(zone, ArrayMap::cast(source->map()));

    Local<Array> dest(zone, Array::NewRaw(zone, map, source->length(), tenure));

    if (!dest)

        return NULL;

    Local<Type> contained(zone, source->type()->contained());

    if (contained->isArray()) {

        assert(false);

        Local<Array> sub(zone);

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

            sub = Array::cast(source->readObject(i));

            sub = DeepCopy(zone, sub, tenure);

            if (!sub)

                return NULL;

            dest->writeObject(zone, i, sub);

        }

    } else {

        if (!CopyArrayElements(zone, contained, dest, source))

            return NULL;

    }

    return dest;

}

Array *

DependentArray::New(Zone *zone, Handle<Array> source, Handle<ArrayMap> map, unsigned index)

{

    Local<ArrayType> sourcetype(zone, source->type());

    // Right now we only support char arrays, to avoid nasty deep cloning

    // and to maybe cut off this feature as far as we can.

    assert(sourcetype->isCharArray());

    assert(map->type()->isCharArray());

    // We allow taking 0-length dependent strings. It's safe because any reads

    // or writes will fail.

    assert(index <= source->length());

    unsigned newlen = source->length() - index;

    unsigned eltsize = SizeForElement(sourcetype);

    if (!sourcetype->isFixedLength()) {

        // Simple case, just copy the array.

        Local<ArrayMap> map(zone, sourcetype->newMap());

        Local<Array> dest(zone, Array::NewRaw(zone, map, newlen, Heap::Tenure_Default));

        if (!dest)

            return NULL;

        memcpy(dest->bytes(),

               (Address)source->bytes() + (index * eltsize),

               newlen * eltsize);

        return dest;

    }

    Local<DependentArray> array(zone, DependentArray::cast(zone->allocate(map, sizeof(DependentArray), Heap::Tenure_Default)));

    if (!array)

        return NULL;

    // :GC: This is currently not safe for moving GC! Although we will mark

    // the object owning the interior pointer, the interior pointer could be

    // moved later. We will eventually need some way of dealing with this.

    Address elements = Address(source->bytes()) + (index * eltsize);

    array->root_ = source;

    array->length_ = newlen;

    array->elements_ = elements - ByteArray::offsetToElements();

    return array;

}