urho3d/Engine/Script/RegisterArray.cpp

//
// Urho3D Engine
// Copyright (c) 2008-2011 Lasse Öörni
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#include "Precompiled.h"
#include "Exception.h"
#include "RegisterArray.h"

#include <cstring>

#include "DebugNew.h"

// Adapted from Angelscript's scriptarray add-on, but with garbage collection disabled, and method names changed
// to a kind of a C++ / JavaScript hybrid

//! Script array buffer
struct SArrayBuffer
{
    asDWORD numElements;
    asBYTE data[1];
};

static CScriptArray* ScriptArrayFactory2(asIObjectType* ot, asUINT length)
{
    CScriptArray* a = new CScriptArray(length, ot);
    
    // It's possible the constructor raised a script exception, in which case we 
    // need to free the memory and return null instead, else we get a memory leak.
    asIScriptContext* context = asGetActiveContext();
    if (context && context->GetState() == asEXECUTION_EXCEPTION)
    {
        delete a;
        return 0;
    }
    
    return a;
}

static CScriptArray* ScriptArrayFactoryDefVal(asIObjectType* ot, asUINT length, void* defVal)
{
    CScriptArray* a = new CScriptArray(length, defVal, ot);
    
    // It's possible the constructor raised a script exception, in which case we 
    // need to free the memory and return null instead, else we get a memory leak.
    asIScriptContext* context = asGetActiveContext();
    if (context && context->GetState() == asEXECUTION_EXCEPTION)
    {
        delete a;
        return 0;
    }
    
    return a;
}

static CScriptArray* ScriptArrayFactory(asIObjectType* ot)
{
    return ScriptArrayFactory2(ot, 0);
}

// This optional callback is called when the template type is first used by the compiler.
// It allows the application to validate if the template can be instanciated for the requested 
// subtype at compile time, instead of at runtime.
static bool ScriptArrayTemplateCallback(asIObjectType* ot)
{
    // Make sure the subtype can be instanciated with a default factory/constructor, 
    // otherwise we won't be able to instanciate the elements. Script classes always
    // have default factories, so we don't have to worry about those.
    int typeId = ot->GetSubTypeId();
    if ((typeId & asTYPEID_MASK_OBJECT) && !(typeId & asTYPEID_OBJHANDLE) && !(typeId & asTYPEID_SCRIPTOBJECT))
    {
        asIObjectType *subtype = ot->GetEngine()->GetObjectTypeById(typeId);
        asDWORD flags = subtype->GetFlags();
        if ((flags & asOBJ_VALUE) && !(flags & asOBJ_POD))
        {
            // Verify that there is a default constructor
            for (int n = 0; n < subtype->GetBehaviourCount(); ++n)
            {
                asEBehaviours beh;
                int funcId = subtype->GetBehaviourByIndex(n, &beh);
                if (beh != asBEHAVE_CONSTRUCT)
                    continue;
                
                asIScriptFunction* func = ot->GetEngine()->GetFunctionDescriptorById(funcId);
                if (func->GetParamCount() == 0)
                {
                    // Found the default constructor
                    return true;
                }
            }
            
            // There is no default constructor
            return false;
        }
        else if ((flags & asOBJ_REF))
        {
            // Verify that there is a default factory
            for (int n = 0; n < subtype->GetFactoryCount(); ++n)
            {
                int funcId = subtype->GetFactoryIdByIndex(n);
                asIScriptFunction* func = ot->GetEngine()->GetFunctionDescriptorById(funcId);
                if (func->GetParamCount() == 0)
                {
                    // Found the default factory
                    return true;
                }
            }
            
            // No default factory
            return false;
        }
    }
    
    // The type is ok
    return true;
}

CScriptArray& CScriptArray::operator = (const CScriptArray &other)
{
    // Only perform the copy if the array types are the same
    if (&other != this && other.GetArrayObjectType() == GetArrayObjectType())
    {
        if (buffer)
        {
            DeleteBuffer(buffer);
            buffer = 0;
        }
        
        // Copy all elements from the other array
        CreateBuffer(&buffer, other.buffer->numElements);
        CopyBuffer(buffer, other.buffer);
    }
    
    return *this;
}

CScriptArray::CScriptArray(asUINT length, asIObjectType* ot)
{
    refCount = 1;
    gcFlag = false;
    objType = ot;
    objType->AddRef();
    buffer = 0;
    
    // Determine element size
    // TODO: Should probably store the template sub type id as well
    int typeId = objType->GetSubTypeId();
    if (typeId & asTYPEID_MASK_OBJECT)
        elementSize = sizeof(asPWORD);
    else
        elementSize = objType->GetEngine()->GetSizeOfPrimitiveType(typeId);
    
    isArrayOfHandles = typeId & asTYPEID_OBJHANDLE ? true : false;
    
    // Make sure the array size isn't too large for us to handle
    if (!CheckMaxSize(length))
    {
        // Don't continue with the initialization
        return;
    }
    
    CreateBuffer(&buffer, length);
}

CScriptArray::CScriptArray(asUINT length, void *defVal, asIObjectType *ot)
{
    refCount = 1;
    gcFlag = false;
    objType = ot;
    objType->AddRef();
    buffer = 0;
    
    // Determine element size
    // TODO: Should probably store the template sub type id as well
    int typeId = objType->GetSubTypeId();
    if (typeId & asTYPEID_MASK_OBJECT)
        elementSize = sizeof(asPWORD);
    else
        elementSize = objType->GetEngine()->GetSizeOfPrimitiveType(typeId);
    
    isArrayOfHandles = typeId & asTYPEID_OBJHANDLE ? true : false;
    
    // Make sure the array size isn't too large for us to handle
    if (!CheckMaxSize(length))
    {
        // Don't continue with the initialization
        return;
    }
    
    CreateBuffer(&buffer, length);
    
    // Initialize the elements with the default value
    for (asUINT n = 0; n < GetSize(); ++n)
        SetValue(n, defVal);
}

// Internal
void CScriptArray::SetValue(asUINT index, void *value)
{
    int typeId = objType->GetSubTypeId();
    
    if ((typeId & ~0x03FFFFFF) && !(typeId & asTYPEID_OBJHANDLE))
        objType->GetEngine()->CopyScriptObject(At(index), value, typeId);
    else if (typeId & asTYPEID_OBJHANDLE)
    {
        *(void**)At(index) = *(void**)value;
        objType->GetEngine()->AddRefScriptObject(*(void**)value, typeId);
    }
    else if (typeId == asTYPEID_BOOL || typeId == asTYPEID_INT8 || typeId == asTYPEID_UINT8)
        *(char*)At(index) = *(char*)value;
    else if (typeId == asTYPEID_INT16 || typeId == asTYPEID_UINT16)
        *(short*)At(index) = *(short*)value;
    else if (typeId == asTYPEID_INT32 || typeId == asTYPEID_UINT32 || typeId == asTYPEID_FLOAT)
        *(int*)At(index) = *(int*)value;
    else if (typeId == asTYPEID_INT64 || typeId == asTYPEID_UINT64 || typeId == asTYPEID_DOUBLE)
        *(double*)At(index) = *(double*)value;
}

CScriptArray::~CScriptArray()
{
    if (buffer)
    {
        DeleteBuffer(buffer);
        buffer = 0;
    }
    if (objType)
        objType->Release();
}

asUINT CScriptArray::GetSize() const
{
    return buffer->numElements;
}

void CScriptArray::Resize(asUINT numElements)
{
    if (numElements & 0x80000000)
    {
        CheckMaxSize(numElements);
        return;
    }
    
    Resize((int)numElements - (int)buffer->numElements, -1);
}

// Internal
void CScriptArray::Resize(int delta, asUINT at)
{
    if (delta < 0)
    {
        if (-delta > (int)buffer->numElements)
            delta = -(int)buffer->numElements;
        if (at > buffer->numElements + delta)
            at = buffer->numElements + delta;
    }
    else if (delta > 0)
    {
        // Make sure the array size isn't too large for us to handle
        if (delta > 0 && !CheckMaxSize(buffer->numElements + delta))
            return;
        
        if (at > buffer->numElements)
            at = buffer->numElements;
    }
    
    if (delta == 0)
        return;
    
    // Allocate memory for the buffer
    SArrayBuffer *newBuffer;
    newBuffer = (SArrayBuffer*)new asBYTE[sizeof(SArrayBuffer)-1 + elementSize*(buffer->numElements + delta)];
    newBuffer->numElements = buffer->numElements + delta;
    
    int c = newBuffer->numElements > buffer->numElements ? buffer->numElements : newBuffer->numElements;
    memcpy(newBuffer->data, buffer->data, at*elementSize);
    if (delta > 0 && at < buffer->numElements)
        memcpy(newBuffer->data + (at+delta)*elementSize, buffer->data + at*elementSize, (buffer->numElements-at)*elementSize);
    else if (delta < 0 && at < buffer->numElements)
        memcpy(newBuffer->data + at*elementSize, buffer->data + (at-delta)*elementSize, (buffer->numElements-at+delta)*elementSize);
    
    int typeId = objType->GetSubTypeId();
    if (typeId & asTYPEID_MASK_OBJECT)
    {
        if (delta > 0)
            Construct(newBuffer, at, at+delta);
        else if (delta < 0)
            Destruct(buffer, at, at-delta);
    }
    
    // Release the old buffer
    delete[] (asBYTE*)buffer;
    
    buffer = newBuffer;
}

// internal
bool CScriptArray::CheckMaxSize(asUINT numElements)
{
    // This code makes sure the size of the buffer that is allocated 
    // for the array doesn't overflow and becomes smaller than requested
    
    asUINT maxSize = 0xFFFFFFFFul - sizeof(SArrayBuffer) + 1;
    if (objType->GetSubTypeId() & asTYPEID_MASK_OBJECT)
        maxSize /= sizeof(void*);
    else
        maxSize /= elementSize;
    
    if (numElements > maxSize)
        SAFE_EXCEPTION_RET("Too large array size", false);
    
    // OK
    return true;
}

asIObjectType *CScriptArray::GetArrayObjectType() const
{
    return objType;
}

int CScriptArray::GetArrayTypeId() const
{
    return objType->GetTypeId();
}

int CScriptArray::GetElementTypeId() const
{
    return objType->GetSubTypeId();
}

void CScriptArray::InsertAt(asUINT index, void *value)
{
    if (index > buffer->numElements)
        SAFE_EXCEPTION("Index out of bounds");
    
    // Make room for the new element
    Resize(1, index);
    
    // Set the value of the new element
    SetValue(index, value);
}

void CScriptArray::InsertLast(void *value)
{
    InsertAt(buffer->numElements, value);
}

void CScriptArray::RemoveAt(asUINT index)
{
    if (index >= buffer->numElements)
        SAFE_EXCEPTION("Index out of bounds");
    
    // Remove the element
    Resize(-1, index);
}

void CScriptArray::RemoveLast()
{
    RemoveAt(buffer->numElements-1);
}

// Return a pointer to the array element. Returns 0 if the index is out of bounds
void *CScriptArray::At(asUINT index)
{
    if (index >= buffer->numElements)
    {
        SAFE_EXCEPTION_RET("Index out of bounds", 0);
    }
    else
    {
        int typeId = objType->GetSubTypeId();
        if ((typeId & asTYPEID_MASK_OBJECT) && !isArrayOfHandles)
            return (void*)((size_t*)buffer->data)[index];
        else
            return buffer->data + elementSize*index;
    }
}

// internal
void CScriptArray::CreateBuffer(SArrayBuffer **buf, asUINT numElements)
{
    int typeId = objType->GetSubTypeId();
    if (typeId & asTYPEID_MASK_OBJECT)
    {
        *buf = (SArrayBuffer*)new asBYTE[sizeof(SArrayBuffer)-1+sizeof(void*)*numElements];
        (*buf)->numElements = numElements;
    }
    else
    {
        *buf = (SArrayBuffer*)new asBYTE[sizeof(SArrayBuffer)-1+elementSize*numElements];
        (*buf)->numElements = numElements;
    }
    
    Construct(*buf, 0, numElements);
}

// internal
void CScriptArray::DeleteBuffer(SArrayBuffer *buf)
{
    Destruct(buf, 0, buf->numElements);
    
    // Free the buffer
    delete[] (asBYTE*)buf;
}

// internal
void CScriptArray::Construct(SArrayBuffer *buf, asUINT start, asUINT end)
{
    int typeId = objType->GetSubTypeId();
    if (isArrayOfHandles)
    {
        // Set all object handles to null
        void* d = (void*)(buf->data + start * sizeof(void*));
        memset(d, 0, (end-start)*sizeof(void*));
    }
    else if (typeId & asTYPEID_MASK_OBJECT)
    {
        void** max = (void**)(buf->data + end * sizeof(void*));
        void** d = (void**)(buf->data + start * sizeof(void*));
        
        asIScriptEngine* engine = objType->GetEngine();
        
        for (; d < max; d++)
            *d = (void*)engine->CreateScriptObject(typeId);
    }
}

// internal
void CScriptArray::Destruct(SArrayBuffer *buf, asUINT start, asUINT end)
{
    int typeId = objType->GetSubTypeId();
    if (typeId & asTYPEID_MASK_OBJECT)
    {
        asIScriptEngine* engine = objType->GetEngine();
        
        void** max = (void**)(buf->data + end * sizeof(void*));
        void** d = (void**)(buf->data + start * sizeof(void*));
        
        for(; d < max; d++ )
        {
            if( *d )
                engine->ReleaseScriptObject(*d, typeId);
        }
    }
}

// internal
void CScriptArray::CopyBuffer(SArrayBuffer *dst, SArrayBuffer *src)
{
    asIScriptEngine* engine = objType->GetEngine();
    if(isArrayOfHandles)
    {
        // Copy the references and increase the reference counters
        if (dst->numElements > 0 && src->numElements > 0)
        {
            int typeId = objType->GetSubTypeId();
            int count = dst->numElements > src->numElements ? src->numElements : dst->numElements;
            
            void** max = (void**)(dst->data + count * sizeof(void*));
            void** d = (void**)dst->data;
            void** s = (void**)src->data;
            
            for (; d < max; d++, s++)
            {
                *d = *s;
                if (*d)
                    engine->AddRefScriptObject(*d, typeId);
            }
        }
    }
    else
    {
        int typeId = objType->GetSubTypeId();
        
        if (dst->numElements > 0 && src->numElements > 0)
        {
            int count = dst->numElements > src->numElements ? src->numElements : dst->numElements;
            if (typeId & asTYPEID_MASK_OBJECT)
            {
                // Call the assignment operator on all of the objects
                void** max = (void**)(dst->data + count * sizeof(void*));
                void** d = (void**)dst->data;
                void** s = (void**)src->data;
                
                for(; d < max; d++, s++)
                    engine->CopyScriptObject(*d, *s, typeId);
            }
            else
            {
                // Primitives are copied byte for byte
                memcpy(dst->data, src->data, count*elementSize);
            }
        }
    }
}

void CScriptArray::AddRef() const
{
    // Clear the GC flag then increase the counter
    gcFlag = false;
    refCount++;
}

void CScriptArray::Release() const
{
    // Now do the actual releasing (clearing the flag set by GC)
    gcFlag = false;
    if (--refCount == 0)
        delete this;
}

// Registers the template array type
void registerArray(asIScriptEngine* engine)
{
    engine->RegisterObjectType("array<class T>", 0, asOBJ_REF | asOBJ_TEMPLATE);
    engine->RegisterObjectBehaviour("array<T>", asBEHAVE_TEMPLATE_CALLBACK, "bool f(int&in)", asFUNCTION(ScriptArrayTemplateCallback), asCALL_CDECL);
    engine->RegisterObjectBehaviour("array<T>", asBEHAVE_FACTORY, "array<T>@ f(int& in)", asFUNCTIONPR(ScriptArrayFactory, (asIObjectType*), CScriptArray*), asCALL_CDECL);
    engine->RegisterObjectBehaviour("array<T>", asBEHAVE_FACTORY, "array<T>@ f(int& in, uint)", asFUNCTIONPR(ScriptArrayFactory2, (asIObjectType*, asUINT), CScriptArray*), asCALL_CDECL);
    engine->RegisterObjectBehaviour("array<T>", asBEHAVE_FACTORY, "array<T>@ f(int& in, uint, const T& in)", asFUNCTIONPR(ScriptArrayFactoryDefVal, (asIObjectType*, asUINT, void *), CScriptArray*), asCALL_CDECL);
    engine->RegisterObjectBehaviour("array<T>", asBEHAVE_LIST_FACTORY, "array<T>@ f(int& in, uint)", asFUNCTIONPR(ScriptArrayFactory2, (asIObjectType*, asUINT), CScriptArray*), asCALL_CDECL);
    engine->RegisterObjectBehaviour("array<T>", asBEHAVE_ADDREF, "void f()", asMETHOD(CScriptArray,AddRef), asCALL_THISCALL);
    engine->RegisterObjectBehaviour("array<T>", asBEHAVE_RELEASE, "void f()", asMETHOD(CScriptArray,Release), asCALL_THISCALL);
    engine->RegisterObjectMethod("array<T>", "T& opIndex(uint)", asMETHOD(CScriptArray, At), asCALL_THISCALL);
    engine->RegisterObjectMethod("array<T>", "const T& opIndex(uint) const", asMETHOD(CScriptArray, At), asCALL_THISCALL);
    engine->RegisterObjectMethod("array<T>", "array<T> &opAssign(const array<T>& in)", asMETHOD(CScriptArray, operator=), asCALL_THISCALL);
    engine->RegisterObjectMethod("array<T>", "void insert(uint, const T& in)", asMETHOD(CScriptArray, InsertAt), asCALL_THISCALL);
    engine->RegisterObjectMethod("array<T>", "void remove(uint)", asMETHOD(CScriptArray, RemoveAt), asCALL_THISCALL);
    engine->RegisterObjectMethod("array<T>", "void push(const T& in)", asMETHOD(CScriptArray, InsertLast), asCALL_THISCALL);
    engine->RegisterObjectMethod("array<T>", "void pop()", asMETHOD(CScriptArray, RemoveLast), asCALL_THISCALL);
    engine->RegisterObjectMethod("array<T>", "uint size() const", asMETHOD(CScriptArray, GetSize), asCALL_THISCALL);
    engine->RegisterObjectMethod("array<T>", "void resize(uint)", asMETHODPR(CScriptArray, Resize, (asUINT), void), asCALL_THISCALL);
    engine->RegisterDefaultArrayType("array<T>");
}