as_callfunc.h

/*
   AngelCode Scripting Library
   Copyright (c) 2003-2021 Andreas Jonsson

   This software is provided 'as-is', without any express or implied
   warranty. In no event will the authors be held liable for any
   damages arising from the use of this software.

   Permission is granted to anyone to use this software for any
   purpose, including commercial applications, and to alter it and
   redistribute it freely, subject to the following restrictions:

   1. The origin of this software must not be misrepresented; you
      must not claim that you wrote the original software. If you use
      this software in a product, an acknowledgment in the product
      documentation would be appreciated but is not required.

   2. Altered source versions must be plainly marked as such, and
      must not be misrepresented as being the original software.

   3. This notice may not be removed or altered from any source
      distribution.

   The original version of this library can be located at:
   http://www.angelcode.com/angelscript/

   Andreas Jonsson
   andreas@angelcode.com
*/


//
// as_callfunc.h
//
// These functions handle the actual calling of system functions
//


#ifndef AS_CALLFUNC_H
#define AS_CALLFUNC_H

#include "as_memory.h"

BEGIN_AS_NAMESPACE

class asCContext;
class asCScriptEngine;
class asCScriptFunction;
class asCObjectType;
struct asSSystemFunctionInterface;

int DetectCallingConvention(bool isMethod, const asSFuncPtr &ptr, int callConv, void *auxiliary, asSSystemFunctionInterface *internal);

int PrepareSystemFunctionGeneric(asCScriptFunction *func, asSSystemFunctionInterface *internal, asCScriptEngine *engine);

int PrepareSystemFunction(asCScriptFunction *func, asSSystemFunctionInterface *internal, asCScriptEngine *engine);

int CallSystemFunction(int id, asCContext *context);

inline asPWORD FuncPtrToUInt(asFUNCTION_t func) {
    // A little trickery as the C++ standard doesn't allow direct
    // conversion between function pointer and data pointer
    union {
        asFUNCTION_t func;
        asPWORD idx;
    } u;
    u.func = func;

    return u.idx;
}

enum internalCallConv {
    ICC_GENERIC_FUNC,
    ICC_GENERIC_FUNC_RETURNINMEM, // never used
    ICC_CDECL,
    ICC_CDECL_RETURNINMEM,
    ICC_STDCALL,
    ICC_STDCALL_RETURNINMEM,
    ICC_THISCALL,
    ICC_THISCALL_RETURNINMEM,
    ICC_VIRTUAL_THISCALL,
    ICC_VIRTUAL_THISCALL_RETURNINMEM,
    ICC_CDECL_OBJLAST,
    ICC_CDECL_OBJLAST_RETURNINMEM,
    ICC_CDECL_OBJFIRST,
    ICC_CDECL_OBJFIRST_RETURNINMEM,
    ICC_GENERIC_METHOD,
    ICC_GENERIC_METHOD_RETURNINMEM, // never used
    ICC_THISCALL_OBJLAST,
    ICC_THISCALL_OBJLAST_RETURNINMEM,
    ICC_VIRTUAL_THISCALL_OBJLAST,
    ICC_VIRTUAL_THISCALL_OBJLAST_RETURNINMEM,
    ICC_THISCALL_OBJFIRST,
    ICC_THISCALL_OBJFIRST_RETURNINMEM,
    ICC_VIRTUAL_THISCALL_OBJFIRST,
    ICC_VIRTUAL_THISCALL_OBJFIRST_RETURNINMEM
};

struct asSSystemFunctionInterface {
    asFUNCTION_t         func;
    int                  baseOffset;
    internalCallConv     callConv;
    bool                 hostReturnInMemory;
    bool                 hostReturnFloat;
    int                  hostReturnSize;
    int                  paramSize;
    bool                 takesObjByVal;
    asCArray<bool>       paramAutoHandles; // TODO: Should be able to remove this array. Perhaps the flags can be stored together with the inOutFlags in asCScriptFunction?
    bool                 returnAutoHandle;
    int                  compositeOffset;
    bool                 isCompositeIndirect;
    void                *auxiliary; // can be used for functors, e.g. by asCALL_THISCALL_ASGLOBAL or asCALL_THISCALL_OBJFIRST

    struct SClean {
        asCObjectType *ot; // argument type for clean up
        short op;          // clean up operation: 0 = release, 1 = free, 2 = destruct then free
        short off;         // argument offset on the stack
    };
    asCArray<SClean>     cleanArgs;

    asSSystemFunctionInterface() {
        Clear();
    }

    asSSystemFunctionInterface(const asSSystemFunctionInterface &in) {
        *this = in;
    }

    void Clear() {
        func                = 0;
        baseOffset          = 0;
        callConv            = ICC_GENERIC_FUNC;
        hostReturnInMemory  = false;
        hostReturnFloat     = false;
        hostReturnSize      = 0;
        paramSize           = 0;
        takesObjByVal       = false;
        returnAutoHandle    = false;
        compositeOffset     = 0;
        isCompositeIndirect = false;
        auxiliary           = 0;

        paramAutoHandles.SetLength(0);
        cleanArgs.SetLength(0);
    }

    asSSystemFunctionInterface &operator=(const asSSystemFunctionInterface &in) {
        func                = in.func;
        baseOffset          = in.baseOffset;
        callConv            = in.callConv;
        hostReturnInMemory  = in.hostReturnInMemory;
        hostReturnFloat     = in.hostReturnFloat;
        hostReturnSize      = in.hostReturnSize;
        paramSize           = in.paramSize;
        takesObjByVal       = in.takesObjByVal;
        returnAutoHandle    = in.returnAutoHandle;
        compositeOffset     = in.compositeOffset;
        isCompositeIndirect = in.isCompositeIndirect;
        auxiliary           = in.auxiliary;

        cleanArgs           = in.cleanArgs;
        paramAutoHandles    = in.paramAutoHandles;

        return *this;
    }
};

END_AS_NAMESPACE

#endif