/* -*-  Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2; -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is js-ctypes.
 *
 * The Initial Developer of the Original Code is
 * The Mozilla Foundation <http://www.mozilla.org/>.
 * Portions created by the Initial Developer are Copyright (C) 2009
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *  Dan Witte <dwitte@mozilla.com>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#include "CTypes.h"
#include "Library.h"
#include "jsnum.h"
#include "jscompartment.h"
#include "jsobjinlines.h"
#include <limits>

#include <math.h>
#if defined(XP_WIN) || defined(XP_OS2)
#include <float.h>
#endif

#if defined(SOLARIS)
#include <ieeefp.h>
#endif

#ifdef HAVE_SSIZE_T
#include <sys/types.h>
#endif

using namespace std;

namespace js {
namespace ctypes {

/*******************************************************************************
** JSAPI function prototypes
*******************************************************************************/

static JSBool ConstructAbstract(JSContext* cx, uintN argc, jsval* vp);

namespace CType {
  static JSBool ConstructData(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ConstructBasic(JSContext* cx, JSObject* obj, uintN argc, jsval* vp);

  static void Trace(JSTracer* trc, JSObject* obj);
  static void Finalize(JSContext* cx, JSObject* obj);
  static void FinalizeProtoClass(JSContext* cx, JSObject* obj);

  static JSBool PrototypeGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool NameGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool SizeGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool PtrGetter(JSContext* cx, JSObject* obj, jsid idval, jsval* vp);
  static JSBool CreateArray(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ToString(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ToSource(JSContext* cx, uintN argc, jsval* vp);
  static JSBool HasInstance(JSContext* cx, JSObject* obj, const jsval* v, JSBool* bp);
}

namespace PointerType {
  static JSBool Create(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ConstructData(JSContext* cx, JSObject* obj, uintN argc, jsval* vp);

  static JSBool TargetTypeGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool ContentsGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool ContentsSetter(JSContext* cx, JSObject* obj, jsid idval, JSBool strict,
    jsval* vp);
  static JSBool IsNull(JSContext* cx, uintN argc, jsval* vp);
  static JSBool Increment(JSContext* cx, uintN argc, jsval* vp);
  static JSBool Decrement(JSContext* cx, uintN argc, jsval* vp);
  // The following is not an instance function, since we don't want to expose arbitrary
  // pointer arithmetic at this moment.
  static JSBool OffsetBy(JSContext* cx, intN offset, jsval* vp);
}

namespace ArrayType {
  static JSBool Create(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ConstructData(JSContext* cx, JSObject* obj, uintN argc, jsval* vp);

  static JSBool ElementTypeGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool LengthGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool Getter(JSContext* cx, JSObject* obj, jsid idval, jsval* vp);
  static JSBool Setter(JSContext* cx, JSObject* obj, jsid idval, JSBool strict, jsval* vp);
  static JSBool AddressOfElement(JSContext* cx, uintN argc, jsval* vp);
}

namespace StructType {
  static JSBool Create(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ConstructData(JSContext* cx, JSObject* obj, uintN argc, jsval* vp);

  static JSBool FieldsArrayGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool FieldGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool FieldSetter(JSContext* cx, JSObject* obj, jsid idval, JSBool strict,
                            jsval* vp);
  static JSBool AddressOfField(JSContext* cx, uintN argc, jsval* vp);
  static JSBool Define(JSContext* cx, uintN argc, jsval* vp);
}

namespace FunctionType {
  static JSBool Create(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ConstructData(JSContext* cx, JSObject* typeObj,
    JSObject* dataObj, JSObject* fnObj, JSObject* thisObj, jsval errVal);

  static JSBool Call(JSContext* cx, uintN argc, jsval* vp);

  static JSBool ArgTypesGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool ReturnTypeGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
  static JSBool ABIGetter(JSContext* cx, JSObject* obj, jsid idval, jsval* vp);
  static JSBool IsVariadicGetter(JSContext* cx, JSObject* obj, jsid idval,
    jsval* vp);
}

namespace CClosure {
  static void Trace(JSTracer* trc, JSObject* obj);
  static void Finalize(JSContext* cx, JSObject* obj);

  // libffi callback
  static void ClosureStub(ffi_cif* cif, void* result, void** args,
    void* userData);
}

namespace CData {
  static void Finalize(JSContext* cx, JSObject* obj);

  static JSBool ValueGetter(JSContext* cx, JSObject* obj, jsid idval,
                            jsval* vp);
  static JSBool ValueSetter(JSContext* cx, JSObject* obj, jsid idval,
                            JSBool strict, jsval* vp);
  static JSBool Address(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ReadString(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ToSource(JSContext* cx, uintN argc, jsval* vp);
}

// Int64Base provides functions common to Int64 and UInt64.
namespace Int64Base {
  JSObject* Construct(JSContext* cx, JSObject* proto, uint64_t data,
    bool isUnsigned);

  uint64_t GetInt(JSObject* obj);

  JSBool ToString(JSContext* cx, JSObject* obj, uintN argc, jsval* vp,
    bool isUnsigned);

  JSBool ToSource(JSContext* cx, JSObject* obj, uintN argc, jsval* vp,
    bool isUnsigned);

  static void Finalize(JSContext* cx, JSObject* obj);
}

namespace Int64 {
  static JSBool Construct(JSContext* cx, uintN argc, jsval* vp);

  static JSBool ToString(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ToSource(JSContext* cx, uintN argc, jsval* vp);

  static JSBool Compare(JSContext* cx, uintN argc, jsval* vp);
  static JSBool Lo(JSContext* cx, uintN argc, jsval* vp);
  static JSBool Hi(JSContext* cx, uintN argc, jsval* vp);
  static JSBool Join(JSContext* cx, uintN argc, jsval* vp);
}

namespace UInt64 {
  static JSBool Construct(JSContext* cx, uintN argc, jsval* vp);

  static JSBool ToString(JSContext* cx, uintN argc, jsval* vp);
  static JSBool ToSource(JSContext* cx, uintN argc, jsval* vp);

  static JSBool Compare(JSContext* cx, uintN argc, jsval* vp);
  static JSBool Lo(JSContext* cx, uintN argc, jsval* vp);
  static JSBool Hi(JSContext* cx, uintN argc, jsval* vp);
  static JSBool Join(JSContext* cx, uintN argc, jsval* vp);
}

/*******************************************************************************
** JSClass definitions and initialization functions
*******************************************************************************/

// Class representing the 'ctypes' object itself. This exists to contain the
// JSCTypesCallbacks set of function pointers.
static JSClass sCTypesGlobalClass = {
  "ctypes",
  JSCLASS_HAS_RESERVED_SLOTS(CTYPESGLOBAL_SLOTS),
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, JS_FinalizeStub,
  JSCLASS_NO_OPTIONAL_MEMBERS
};

static JSClass sCABIClass = {
  "CABI",
  JSCLASS_HAS_RESERVED_SLOTS(CABI_SLOTS),
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, JS_FinalizeStub,
  JSCLASS_NO_OPTIONAL_MEMBERS
};

// Class representing ctypes.{C,Pointer,Array,Struct,Function}Type.prototype.
// This exists to give said prototypes a class of "CType", and to provide
// reserved slots for stashing various other prototype objects.
static JSClass sCTypeProtoClass = {
  "CType",
  JSCLASS_HAS_RESERVED_SLOTS(CTYPEPROTO_SLOTS),
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, CType::FinalizeProtoClass,
  NULL, NULL, ConstructAbstract, ConstructAbstract, NULL, NULL, NULL, NULL
};

// Class representing ctypes.CData.prototype and the 'prototype' properties
// of CTypes. This exists to give said prototypes a class of "CData".
static JSClass sCDataProtoClass = {
  "CData",
  0,
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, JS_FinalizeStub,
  JSCLASS_NO_OPTIONAL_MEMBERS
};

static JSClass sCTypeClass = {
  "CType",
  JSCLASS_HAS_RESERVED_SLOTS(CTYPE_SLOTS),
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, CType::Finalize,
  NULL, NULL, CType::ConstructData, CType::ConstructData, NULL,
  CType::HasInstance, CType::Trace, NULL
};

static JSClass sCDataClass = {
  "CData",
  JSCLASS_HAS_RESERVED_SLOTS(CDATA_SLOTS),
  JS_PropertyStub, JS_PropertyStub, ArrayType::Getter, ArrayType::Setter,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, CData::Finalize,
  NULL, NULL, FunctionType::Call, FunctionType::Call, NULL, NULL, NULL, NULL
};

static JSClass sCClosureClass = {
  "CClosure",
  JSCLASS_HAS_RESERVED_SLOTS(CCLOSURE_SLOTS),
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, CClosure::Finalize,
  NULL, NULL, NULL, NULL, NULL, NULL, CClosure::Trace, NULL
};

#define CTYPESFN_FLAGS \
  (JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT)

#define CTYPESCTOR_FLAGS \
  (CTYPESFN_FLAGS | JSFUN_CONSTRUCTOR)

#define CTYPESPROP_FLAGS \
  (JSPROP_SHARED | JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT)

#define CDATAFN_FLAGS \
  (JSPROP_READONLY | JSPROP_PERMANENT)

static JSPropertySpec sCTypeProps[] = {
  { "name", 0, CTYPESPROP_FLAGS, CType::NameGetter, NULL },
  { "size", 0, CTYPESPROP_FLAGS, CType::SizeGetter, NULL },
  { "ptr", 0, CTYPESPROP_FLAGS, CType::PtrGetter, NULL },
  { "prototype", 0, CTYPESPROP_FLAGS, CType::PrototypeGetter, NULL },
  { 0, 0, 0, NULL, NULL }
};

static JSFunctionSpec sCTypeFunctions[] = {
  JS_FN("array", CType::CreateArray, 0, CTYPESFN_FLAGS),
  JS_FN("toString", CType::ToString, 0, CTYPESFN_FLAGS),
  JS_FN("toSource", CType::ToSource, 0, CTYPESFN_FLAGS),
  JS_FS_END
};

static JSPropertySpec sCDataProps[] = {
  { "value", 0, JSPROP_SHARED | JSPROP_PERMANENT,
    CData::ValueGetter, CData::ValueSetter },
  { 0, 0, 0, NULL, NULL }
};

static JSFunctionSpec sCDataFunctions[] = {
  JS_FN("address", CData::Address, 0, CDATAFN_FLAGS),
  JS_FN("readString", CData::ReadString, 0, CDATAFN_FLAGS),
  JS_FN("toSource", CData::ToSource, 0, CDATAFN_FLAGS),
  JS_FN("toString", CData::ToSource, 0, CDATAFN_FLAGS),
  JS_FS_END
};

static JSFunctionSpec sPointerFunction =
  JS_FN("PointerType", PointerType::Create, 1, CTYPESCTOR_FLAGS);

static JSPropertySpec sPointerProps[] = {
  { "targetType", 0, CTYPESPROP_FLAGS, PointerType::TargetTypeGetter, NULL },
  { 0, 0, 0, NULL, NULL }
};

static JSFunctionSpec sPointerInstanceFunctions[] = {
  JS_FN("isNull", PointerType::IsNull, 0, CTYPESFN_FLAGS),
  JS_FN("increment", PointerType::Increment, 0, CTYPESFN_FLAGS),
  JS_FN("decrement", PointerType::Decrement, 0, CTYPESFN_FLAGS),
  JS_FS_END
};
  
static JSPropertySpec sPointerInstanceProps[] = {
  { "contents", 0, JSPROP_SHARED | JSPROP_PERMANENT,
    PointerType::ContentsGetter, PointerType::ContentsSetter },
  { 0, 0, 0, NULL, NULL }
};

static JSFunctionSpec sArrayFunction =
  JS_FN("ArrayType", ArrayType::Create, 1, CTYPESCTOR_FLAGS);

static JSPropertySpec sArrayProps[] = {
  { "elementType", 0, CTYPESPROP_FLAGS, ArrayType::ElementTypeGetter, NULL },
  { "length", 0, CTYPESPROP_FLAGS, ArrayType::LengthGetter, NULL },
  { 0, 0, 0, NULL, NULL }
};

static JSFunctionSpec sArrayInstanceFunctions[] = {
  JS_FN("addressOfElement", ArrayType::AddressOfElement, 1, CDATAFN_FLAGS),
  JS_FS_END
};

static JSPropertySpec sArrayInstanceProps[] = {
  { "length", 0, JSPROP_SHARED | JSPROP_READONLY | JSPROP_PERMANENT,
    ArrayType::LengthGetter, NULL },
  { 0, 0, 0, NULL, NULL }
};

static JSFunctionSpec sStructFunction =
  JS_FN("StructType", StructType::Create, 2, CTYPESCTOR_FLAGS);

static JSPropertySpec sStructProps[] = {
  { "fields", 0, CTYPESPROP_FLAGS, StructType::FieldsArrayGetter, NULL },
  { 0, 0, 0, NULL, NULL }
};

static JSFunctionSpec sStructFunctions[] = {
  JS_FN("define", StructType::Define, 1, CDATAFN_FLAGS),
  JS_FS_END
};

static JSFunctionSpec sStructInstanceFunctions[] = {
  JS_FN("addressOfField", StructType::AddressOfField, 1, CDATAFN_FLAGS),
  JS_FS_END
};

static JSFunctionSpec sFunctionFunction =
  JS_FN("FunctionType", FunctionType::Create, 2, CTYPESCTOR_FLAGS);

static JSPropertySpec sFunctionProps[] = {
  { "argTypes", 0, CTYPESPROP_FLAGS, FunctionType::ArgTypesGetter, NULL },
  { "returnType", 0, CTYPESPROP_FLAGS, FunctionType::ReturnTypeGetter, NULL },
  { "abi", 0, CTYPESPROP_FLAGS, FunctionType::ABIGetter, NULL },
  { "isVariadic", 0, CTYPESPROP_FLAGS, FunctionType::IsVariadicGetter, NULL },
  { 0, 0, 0, NULL, NULL }
};

static JSClass sInt64ProtoClass = {
  "Int64",
  0,
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, JS_FinalizeStub,
  JSCLASS_NO_OPTIONAL_MEMBERS
};

static JSClass sUInt64ProtoClass = {
  "UInt64",
  0,
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, JS_FinalizeStub,
  JSCLASS_NO_OPTIONAL_MEMBERS
};

static JSClass sInt64Class = {
  "Int64",
  JSCLASS_HAS_RESERVED_SLOTS(INT64_SLOTS),
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, Int64Base::Finalize,
  JSCLASS_NO_OPTIONAL_MEMBERS
};

static JSClass sUInt64Class = {
  "UInt64",
  JSCLASS_HAS_RESERVED_SLOTS(INT64_SLOTS),
  JS_PropertyStub, JS_PropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
  JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub, Int64Base::Finalize,
  JSCLASS_NO_OPTIONAL_MEMBERS
};

static JSFunctionSpec sInt64StaticFunctions[] = {
  JS_FN("compare", Int64::Compare, 2, CTYPESFN_FLAGS),
  JS_FN("lo", Int64::Lo, 1, CTYPESFN_FLAGS),
  JS_FN("hi", Int64::Hi, 1, CTYPESFN_FLAGS),
  JS_FN("join", Int64::Join, 2, CTYPESFN_FLAGS),
  JS_FS_END
};

static JSFunctionSpec sUInt64StaticFunctions[] = {
  JS_FN("compare", UInt64::Compare, 2, CTYPESFN_FLAGS),
  JS_FN("lo", UInt64::Lo, 1, CTYPESFN_FLAGS),
  JS_FN("hi", UInt64::Hi, 1, CTYPESFN_FLAGS),
  JS_FN("join", UInt64::Join, 2, CTYPESFN_FLAGS),
  JS_FS_END
};

static JSFunctionSpec sInt64Functions[] = {
  JS_FN("toString", Int64::ToString, 0, CTYPESFN_FLAGS),
  JS_FN("toSource", Int64::ToSource, 0, CTYPESFN_FLAGS),
  JS_FS_END
};

static JSFunctionSpec sUInt64Functions[] = {
  JS_FN("toString", UInt64::ToString, 0, CTYPESFN_FLAGS),
  JS_FN("toSource", UInt64::ToSource, 0, CTYPESFN_FLAGS),
  JS_FS_END
};

static JSFunctionSpec sModuleFunctions[] = {
  JS_FN("open", Library::Open, 1, CTYPESFN_FLAGS),
  JS_FN("cast", CData::Cast, 2, CTYPESFN_FLAGS),
  JS_FN("getRuntime", CData::GetRuntime, 1, CTYPESFN_FLAGS),
  JS_FN("libraryName", Library::Name, 1, CTYPESFN_FLAGS),
  JS_FS_END
};

static inline bool FloatIsFinite(jsdouble f) {
#ifdef WIN32
  return _finite(f) != 0;
#else
  return finite(f);
#endif
}

JS_ALWAYS_INLINE JSString*
NewUCString(JSContext* cx, const AutoString& from)
{
  return JS_NewUCStringCopyN(cx, from.begin(), from.length());
}

JS_ALWAYS_INLINE size_t
Align(size_t val, size_t align)
{
  return ((val - 1) | (align - 1)) + 1;
}

static ABICode
GetABICode(JSObject* obj)
{
  // make sure we have an object representing a CABI class,
  // and extract the enumerated class type from the reserved slot.
  if (JS_GetClass(obj) != &sCABIClass)
    return INVALID_ABI;

  jsval result = JS_GetReservedSlot(obj, SLOT_ABICODE);
  return ABICode(JSVAL_TO_INT(result));
}

JSErrorFormatString ErrorFormatString[CTYPESERR_LIMIT] = {
#define MSG_DEF(name, number, count, exception, format) \
  { format, count, exception } ,
#include "ctypes.msg"
#undef MSG_DEF
};

const JSErrorFormatString*
GetErrorMessage(void* userRef, const char* locale, const uintN errorNumber)
{
  if (0 < errorNumber && errorNumber < CTYPESERR_LIMIT)
    return &ErrorFormatString[errorNumber];
  return NULL;
}

JSBool
TypeError(JSContext* cx, const char* expected, jsval actual)
{
  JSString* str = JS_ValueToSource(cx, actual);
  JSAutoByteString bytes;
  
  const char* src;
  if (str) {
    src = bytes.encode(cx, str);
    if (!src)
      return false;
  } else {
    JS_ClearPendingException(cx);
    src = "<<error converting value to string>>";
  }
  JS_ReportErrorNumber(cx, GetErrorMessage, NULL,
                       CTYPESMSG_TYPE_ERROR, expected, src);
  return false;
}

static JSObject*
InitCTypeClass(JSContext* cx, JSObject* parent)
{
  JSFunction* fun = JS_DefineFunction(cx, parent, "CType", ConstructAbstract, 0,
                      CTYPESCTOR_FLAGS);
  if (!fun)
    return NULL;

  JSObject* ctor = JS_GetFunctionObject(fun);
  JSObject* fnproto = JS_GetPrototype(ctor);
  JS_ASSERT(ctor);
  JS_ASSERT(fnproto);

  // Set up ctypes.CType.prototype.
  JSObject* prototype = JS_NewObject(cx, &sCTypeProtoClass, fnproto, parent);
  if (!prototype)
    return NULL;

  if (!JS_DefineProperty(cx, ctor, "prototype", OBJECT_TO_JSVAL(prototype),
         NULL, NULL, JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT))
    return NULL;

  if (!JS_DefineProperty(cx, prototype, "constructor", OBJECT_TO_JSVAL(ctor),
         NULL, NULL, JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT))
    return NULL;

  // Define properties and functions common to all CTypes.
  if (!JS_DefineProperties(cx, prototype, sCTypeProps) ||
      !JS_DefineFunctions(cx, prototype, sCTypeFunctions))
    return NULL;

  if (!JS_FreezeObject(cx, ctor) || !JS_FreezeObject(cx, prototype))
    return NULL;

  return prototype;
}

static JSObject*
InitCDataClass(JSContext* cx, JSObject* parent, JSObject* CTypeProto)
{
  JSFunction* fun = JS_DefineFunction(cx, parent, "CData", ConstructAbstract, 0,
                      CTYPESCTOR_FLAGS);
  if (!fun)
    return NULL;

  JSObject* ctor = JS_GetFunctionObject(fun);
  JS_ASSERT(ctor);

  // Set up ctypes.CData.__proto__ === ctypes.CType.prototype.
  // (Note that 'ctypes.CData instanceof Function' is still true, thanks to the
  // prototype chain.)
  if (!JS_SetPrototype(cx, ctor, CTypeProto))
    return NULL;

  // Set up ctypes.CData.prototype.
  JSObject* prototype = JS_NewObject(cx, &sCDataProtoClass, NULL, parent);
  if (!prototype)
    return NULL;

  if (!JS_DefineProperty(cx, ctor, "prototype", OBJECT_TO_JSVAL(prototype),
         NULL, NULL, JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT))
    return NULL;

  if (!JS_DefineProperty(cx, prototype, "constructor", OBJECT_TO_JSVAL(ctor),
         NULL, NULL, JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT))
    return NULL;

  // Define properties and functions common to all CDatas.
  if (!JS_DefineProperties(cx, prototype, sCDataProps) ||
      !JS_DefineFunctions(cx, prototype, sCDataFunctions))
    return NULL;

  if (//!JS_FreezeObject(cx, prototype) || // XXX fixme - see bug 541212!
      !JS_FreezeObject(cx, ctor))
    return NULL;

  return prototype;
}

static JSBool
DefineABIConstant(JSContext* cx,
                  JSObject* parent,
                  const char* name,
                  ABICode code)
{
  JSObject* obj = JS_DefineObject(cx, parent, name, &sCABIClass, NULL,
                    JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT);
  if (!obj)
    return false;
  JS_SetReservedSlot(obj, SLOT_ABICODE, INT_TO_JSVAL(code));
  return JS_FreezeObject(cx, obj);
}

// Set up a single type constructor for
// ctypes.{Pointer,Array,Struct,Function}Type.
static JSBool
InitTypeConstructor(JSContext* cx,
                    JSObject* parent,
                    JSObject* CTypeProto,
                    JSObject* CDataProto,
                    JSFunctionSpec spec,
                    JSFunctionSpec* fns,
                    JSPropertySpec* props,
                    JSFunctionSpec* instanceFns,
                    JSPropertySpec* instanceProps,
                    JSObject*& typeProto,
                    JSObject*& dataProto)
{
  JSFunction* fun = js::DefineFunctionWithReserved(cx, parent, spec.name, spec.call, 
                      spec.nargs, spec.flags);
  if (!fun)
    return false;

  JSObject* obj = JS_GetFunctionObject(fun);
  if (!obj)
    return false;

  // Set up the .prototype and .prototype.constructor properties.
  typeProto = JS_NewObject(cx, &sCTypeProtoClass, CTypeProto, parent);
  if (!typeProto)
    return false;

  // Define property before proceeding, for GC safety.
  if (!JS_DefineProperty(cx, obj, "prototype", OBJECT_TO_JSVAL(typeProto),
         NULL, NULL, JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT))
    return false;

  if (fns && !JS_DefineFunctions(cx, typeProto, fns))
    return false;

  if (!JS_DefineProperties(cx, typeProto, props))
    return false;

  if (!JS_DefineProperty(cx, typeProto, "constructor", OBJECT_TO_JSVAL(obj),
         NULL, NULL, JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT))
    return false;

  // Stash ctypes.{Pointer,Array,Struct}Type.prototype on a reserved slot of
  // the type constructor, for faster lookup.
  js::SetFunctionNativeReserved(obj, SLOT_FN_CTORPROTO, OBJECT_TO_JSVAL(typeProto));

  // Create an object to serve as the common ancestor for all CData objects
  // created from the given type constructor. This has ctypes.CData.prototype
  // as its prototype, such that it inherits the properties and functions
  // common to all CDatas.
  dataProto = JS_NewObject(cx, &sCDataProtoClass, CDataProto, parent);
  if (!dataProto)
    return false;
  js::AutoObjectRooter protoroot(cx, dataProto);

  // Define functions and properties on the 'dataProto' object that are common
  // to all CData objects created from this type constructor. (These will
  // become functions and properties on CData objects created from this type.)
  if (instanceFns && !JS_DefineFunctions(cx, dataProto, instanceFns))
    return false;

  if (instanceProps && !JS_DefineProperties(cx, dataProto, instanceProps))
    return false;

  // Link the type prototype to the data prototype.
  JS_SetReservedSlot(typeProto, SLOT_OURDATAPROTO, OBJECT_TO_JSVAL(dataProto));

  if (!JS_FreezeObject(cx, obj) ||
      //!JS_FreezeObject(cx, dataProto) || // XXX fixme - see bug 541212!
      !JS_FreezeObject(cx, typeProto))
    return false;

  return true;
}

JSObject*
InitInt64Class(JSContext* cx,
               JSObject* parent,
               JSClass* clasp,
               JSNative construct,
               JSFunctionSpec* fs,
               JSFunctionSpec* static_fs)
{
  // Init type class and constructor
  JSObject* prototype = JS_InitClass(cx, parent, NULL, clasp, construct,
    0, NULL, fs, NULL, static_fs);
  if (!prototype)
    return NULL;

  JSObject* ctor = JS_GetConstructor(cx, prototype);
  if (!ctor)
    return NULL;
  if (!JS_FreezeObject(cx, ctor))
    return NULL;

  // Redefine the 'join' function as an extended native and stash
  // ctypes.{Int64,UInt64}.prototype in a reserved slot of the new function.
  JS_ASSERT(clasp == &sInt64ProtoClass || clasp == &sUInt64ProtoClass);
  JSNative native = (clasp == &sInt64ProtoClass) ? Int64::Join : UInt64::Join;
  JSFunction* fun = js::DefineFunctionWithReserved(cx, ctor, "join", native,
                      2, CTYPESFN_FLAGS);
  if (!fun)
    return NULL;

  js::SetFunctionNativeReserved(fun, SLOT_FN_INT64PROTO,
    OBJECT_TO_JSVAL(prototype));

  if (!JS_FreezeObject(cx, prototype))
    return NULL;

  return prototype;
}

static void
AttachProtos(JSObject* proto, JSObject** protos)
{
  // For a given 'proto' of [[Class]] "CTypeProto", attach each of the 'protos'
  // to the appropriate CTypeProtoSlot. (SLOT_UINT64PROTO is the last slot
  // of [[Class]] "CTypeProto" that we fill in this automated manner.)
  for (uint32_t i = 0; i <= SLOT_UINT64PROTO; ++i)
    JS_SetReservedSlot(proto, i, OBJECT_TO_JSVAL(protos[i]));
}

JSBool
InitTypeClasses(JSContext* cx, JSObject* parent)
{
  // Initialize the ctypes.CType class. This acts as an abstract base class for
  // the various types, and provides the common API functions. It has:
  //   * [[Class]] "Function"
  //   * __proto__ === Function.prototype
  //   * A constructor that throws a TypeError. (You can't construct an
  //     abstract type!)
  //   * 'prototype' property:
  //     * [[Class]] "CTypeProto"
  //     * __proto__ === Function.prototype
  //     * A constructor that throws a TypeError. (You can't construct an
  //       abstract type instance!)
  //     * 'constructor' property === ctypes.CType
  //     * Provides properties and functions common to all CTypes.
  JSObject* CTypeProto = InitCTypeClass(cx, parent);
  if (!CTypeProto)
    return false;

  // Initialize the ctypes.CData class. This acts as an abstract base class for
  // instances of the various types, and provides the common API functions.
  // It has:
  //   * [[Class]] "Function"
  //   * __proto__ === Function.prototype
  //   * A constructor that throws a TypeError. (You can't construct an
  //     abstract type instance!)
  //   * 'prototype' property:
  //     * [[Class]] "CDataProto"
  //     * 'constructor' property === ctypes.CData
  //     * Provides properties and functions common to all CDatas.
  JSObject* CDataProto = InitCDataClass(cx, parent, CTypeProto);
  if (!CDataProto)
    return false;

  // Link CTypeProto to CDataProto.
  JS_SetReservedSlot(CTypeProto, SLOT_OURDATAPROTO,
                     OBJECT_TO_JSVAL(CDataProto));

  // Create and attach the special class constructors: ctypes.PointerType,
  // ctypes.ArrayType, ctypes.StructType, and ctypes.FunctionType.
  // Each of these constructors 'c' has, respectively:
  //   * [[Class]] "Function"
  //   * __proto__ === Function.prototype
  //   * A constructor that creates a user-defined type.
  //   * 'prototype' property:
  //     * [[Class]] "CTypeProto"
  //     * __proto__ === ctypes.CType.prototype
  //     * 'constructor' property === 'c'
  // We also construct an object 'p' to serve, given a type object 't'
  // constructed from one of these type constructors, as
  // 't.prototype.__proto__'. This object has:
  //   * [[Class]] "CDataProto"
  //   * __proto__ === ctypes.CData.prototype
  //   * Properties and functions common to all CDatas.
  // Therefore an instance 't' of ctypes.{Pointer,Array,Struct,Function}Type
  // will have, resp.:
  //   * [[Class]] "CType"
  //   * __proto__ === ctypes.{Pointer,Array,Struct,Function}Type.prototype
  //   * A constructor which creates and returns a CData object, containing
  //     binary data of the given type.
  //   * 'prototype' property:
  //     * [[Class]] "CDataProto"
  //     * __proto__ === 'p', the prototype object from above
  //     * 'constructor' property === 't'
  JSObject* protos[CTYPEPROTO_SLOTS];
  if (!InitTypeConstructor(cx, parent, CTypeProto, CDataProto,
         sPointerFunction, NULL, sPointerProps,
         sPointerInstanceFunctions, sPointerInstanceProps,
         protos[SLOT_POINTERPROTO], protos[SLOT_POINTERDATAPROTO]))
    return false;
  js::AutoObjectRooter proot(cx, protos[SLOT_POINTERDATAPROTO]);

  if (!InitTypeConstructor(cx, parent, CTypeProto, CDataProto,
         sArrayFunction, NULL, sArrayProps,
         sArrayInstanceFunctions, sArrayInstanceProps,
         protos[SLOT_ARRAYPROTO], protos[SLOT_ARRAYDATAPROTO]))
    return false;
  js::AutoObjectRooter aroot(cx, protos[SLOT_ARRAYDATAPROTO]);

  if (!InitTypeConstructor(cx, parent, CTypeProto, CDataProto,
         sStructFunction, sStructFunctions, sStructProps,
         sStructInstanceFunctions, NULL,
         protos[SLOT_STRUCTPROTO], protos[SLOT_STRUCTDATAPROTO]))
    return false;
  js::AutoObjectRooter sroot(cx, protos[SLOT_STRUCTDATAPROTO]);

  if (!InitTypeConstructor(cx, parent, CTypeProto, CDataProto,
         sFunctionFunction, NULL, sFunctionProps, NULL, NULL,
         protos[SLOT_FUNCTIONPROTO], protos[SLOT_FUNCTIONDATAPROTO]))
    return false;
  js::AutoObjectRooter froot(cx, protos[SLOT_FUNCTIONDATAPROTO]);

  protos[SLOT_CDATAPROTO] = CDataProto;

  // Create and attach the ctypes.{Int64,UInt64} constructors.
  // Each of these has, respectively:
  //   * [[Class]] "Function"
  //   * __proto__ === Function.prototype
  //   * A constructor that creates a ctypes.{Int64,UInt64} object, respectively.
  //   * 'prototype' property:
  //     * [[Class]] {"Int64Proto","UInt64Proto"}
  //     * 'constructor' property === ctypes.{Int64,UInt64}
  protos[SLOT_INT64PROTO] = InitInt64Class(cx, parent, &sInt64ProtoClass,
    Int64::Construct, sInt64Functions, sInt64StaticFunctions);
  if (!protos[SLOT_INT64PROTO])
    return false;
  protos[SLOT_UINT64PROTO] = InitInt64Class(cx, parent, &sUInt64ProtoClass,
    UInt64::Construct, sUInt64Functions, sUInt64StaticFunctions);
  if (!protos[SLOT_UINT64PROTO])
    return false;

  // Attach the prototypes just created to each of ctypes.CType.prototype,
  // and the special type constructors, so we can access them when constructing
  // instances of those types. 
  AttachProtos(CTypeProto, protos);
  AttachProtos(protos[SLOT_POINTERPROTO], protos);
  AttachProtos(protos[SLOT_ARRAYPROTO], protos);
  AttachProtos(protos[SLOT_STRUCTPROTO], protos);
  AttachProtos(protos[SLOT_FUNCTIONPROTO], protos);

  // Attach objects representing ABI constants.
  if (!DefineABIConstant(cx, parent, "default_abi", ABI_DEFAULT) ||
      !DefineABIConstant(cx, parent, "stdcall_abi", ABI_STDCALL) ||
      !DefineABIConstant(cx, parent, "winapi_abi", ABI_WINAPI))
    return false;

  // Create objects representing the builtin types, and attach them to the
  // ctypes object. Each type object 't' has:
  //   * [[Class]] "CType"
  //   * __proto__ === ctypes.CType.prototype
  //   * A constructor which creates and returns a CData object, containing
  //     binary data of the given type.
  //   * 'prototype' property:
  //     * [[Class]] "CDataProto"
  //     * __proto__ === ctypes.CData.prototype
  //     * 'constructor' property === 't'
#define DEFINE_TYPE(name, type, ffiType)                                       \
  JSObject* typeObj_##name =                                                   \
    CType::DefineBuiltin(cx, parent, #name, CTypeProto, CDataProto, #name,     \
      TYPE_##name, INT_TO_JSVAL(sizeof(type)),                                 \
      INT_TO_JSVAL(ffiType.alignment), &ffiType);                              \
  if (!typeObj_##name)                                                         \
    return false;
#include "typedefs.h"

  // Alias 'ctypes.unsigned' as 'ctypes.unsigned_int', since they represent
  // the same type in C.
  if (!JS_DefineProperty(cx, parent, "unsigned",
         OBJECT_TO_JSVAL(typeObj_unsigned_int), NULL, NULL,
         JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT))
    return false;

  // Create objects representing the special types void_t and voidptr_t.
  JSObject* typeObj =
    CType::DefineBuiltin(cx, parent, "void_t", CTypeProto, CDataProto, "void",
      TYPE_void_t, JSVAL_VOID, JSVAL_VOID, &ffi_type_void);
  if (!typeObj)
    return false;

  typeObj = PointerType::CreateInternal(cx, typeObj);
  if (!typeObj)
    return false;
  if (!JS_DefineProperty(cx, parent, "voidptr_t", OBJECT_TO_JSVAL(typeObj),
         NULL, NULL, JSPROP_ENUMERATE | JSPROP_READONLY | JSPROP_PERMANENT))
    return false;

  return true;
}

bool
IsCTypesGlobal(JSObject* obj)
{
  return JS_GetClass(obj) == &sCTypesGlobalClass;
}

// Get the JSCTypesCallbacks struct from the 'ctypes' object 'obj'.
JSCTypesCallbacks*
GetCallbacks(JSObject* obj)
{
  JS_ASSERT(IsCTypesGlobal(obj));

  jsval result = JS_GetReservedSlot(obj, SLOT_CALLBACKS);
  if (JSVAL_IS_VOID(result))
    return NULL;

  return static_cast<JSCTypesCallbacks*>(JSVAL_TO_PRIVATE(result));
}

JS_BEGIN_EXTERN_C

JS_PUBLIC_API(JSBool)
JS_InitCTypesClass(JSContext* cx, JSObject* global)
{
  // attach ctypes property to global object
  JSObject* ctypes = JS_NewObject(cx, &sCTypesGlobalClass, NULL, NULL);
  if (!ctypes)
    return false;

  if (!JS_DefineProperty(cx, global, "ctypes", OBJECT_TO_JSVAL(ctypes),
         JS_PropertyStub, JS_StrictPropertyStub, JSPROP_READONLY | JSPROP_PERMANENT)) {
    return false;
  }

  if (!InitTypeClasses(cx, ctypes))
    return false;

  // attach API functions
  if (!JS_DefineFunctions(cx, ctypes, sModuleFunctions))
    return false;

  // Seal the ctypes object, to prevent modification.
  return JS_FreezeObject(cx, ctypes);
}

JS_PUBLIC_API(void)
JS_SetCTypesCallbacks(JSObject* ctypesObj,
                      JSCTypesCallbacks* callbacks)
{
  JS_ASSERT(callbacks);
  JS_ASSERT(IsCTypesGlobal(ctypesObj));

  // Set the callbacks on a reserved slot.
  JS_SetReservedSlot(ctypesObj, SLOT_CALLBACKS, PRIVATE_TO_JSVAL(callbacks));
}

JS_END_EXTERN_C

/*******************************************************************************
** Type conversion functions
*******************************************************************************/

// Enforce some sanity checks on type widths and properties.
// Where the architecture is 64-bit, make sure it's LP64 or LLP64. (ctypes.int
// autoconverts to a primitive JS number; to support ILP64 architectures, it
// would need to autoconvert to an Int64 object instead. Therefore we enforce
// this invariant here.)
JS_STATIC_ASSERT(sizeof(bool) == 1 || sizeof(bool) == 4);
JS_STATIC_ASSERT(sizeof(char) == 1);
JS_STATIC_ASSERT(sizeof(short) == 2);
JS_STATIC_ASSERT(sizeof(int) == 4);
JS_STATIC_ASSERT(sizeof(unsigned) == 4);
JS_STATIC_ASSERT(sizeof(long) == 4 || sizeof(long) == 8);
JS_STATIC_ASSERT(sizeof(long long) == 8);
JS_STATIC_ASSERT(sizeof(size_t) == sizeof(uintptr_t));
JS_STATIC_ASSERT(sizeof(float) == 4);
JS_STATIC_ASSERT(sizeof(PRFuncPtr) == sizeof(void*));
JS_STATIC_ASSERT(numeric_limits<double>::is_signed);

// Templated helper to convert FromType to TargetType, for the default case
// where the trivial POD constructor will do.
template<class TargetType, class FromType>
struct ConvertImpl {
  static JS_ALWAYS_INLINE TargetType Convert(FromType d) {
    return TargetType(d);
  }
};

#ifdef _MSC_VER
// MSVC can't perform double to unsigned __int64 conversion when the
// double is greater than 2^63 - 1. Help it along a little.
template<>
struct ConvertImpl<uint64_t, jsdouble> {
  static JS_ALWAYS_INLINE uint64_t Convert(jsdouble d) {
    return d > 0x7fffffffffffffffui64 ?
           uint64_t(d - 0x8000000000000000ui64) + 0x8000000000000000ui64 :
           uint64_t(d);
  }
};
#endif

// C++ doesn't guarantee that exact values are the only ones that will
// round-trip. In fact, on some platforms, including SPARC, there are pairs of
// values, a uint64_t and a double, such that neither value is exactly
// representable in the other type, but they cast to each other.
#ifdef SPARC
// Simulate x86 overflow behavior
template<>
struct ConvertImpl<uint64_t, jsdouble> {
  static JS_ALWAYS_INLINE uint64_t Convert(jsdouble d) {
    return d >= 0xffffffffffffffff ?
           0x8000000000000000 : uint64_t(d);
  }
};

template<>
struct ConvertImpl<int64_t, jsdouble> {
  static JS_ALWAYS_INLINE int64_t Convert(jsdouble d) {
    return d >= 0x7fffffffffffffff ?
           0x8000000000000000 : int64_t(d);
  }
};
#endif

template<class TargetType, class FromType>
static JS_ALWAYS_INLINE TargetType Convert(FromType d)
{
  return ConvertImpl<TargetType, FromType>::Convert(d);
}

template<class TargetType, class FromType>
static JS_ALWAYS_INLINE bool IsAlwaysExact()
{
  // Return 'true' if TargetType can always exactly represent FromType.
  // This means that:
  // 1) TargetType must be the same or more bits wide as FromType. For integers
  //    represented in 'n' bits, unsigned variants will have 'n' digits while
  //    signed will have 'n - 1'. For floating point types, 'digits' is the
  //    mantissa width.
  // 2) If FromType is signed, TargetType must also be signed. (Floating point
  //    types are always signed.)
  // 3) If TargetType is an exact integral type, FromType must be also.
  if (numeric_limits<TargetType>::digits < numeric_limits<FromType>::digits)
    return false;

  if (numeric_limits<FromType>::is_signed &&
      !numeric_limits<TargetType>::is_signed)
    return false;

  if (!numeric_limits<FromType>::is_exact &&
      numeric_limits<TargetType>::is_exact)
    return false;

  return true;
}

// Templated helper to determine if FromType 'i' converts losslessly to
// TargetType 'j'. Default case where both types are the same signedness.
template<class TargetType, class FromType, bool TargetSigned, bool FromSigned>
struct IsExactImpl {
  static JS_ALWAYS_INLINE bool Test(FromType i, TargetType j) {
    JS_STATIC_ASSERT(numeric_limits<TargetType>::is_exact);
    return FromType(j) == i;
  }
};

// Specialization where TargetType is unsigned, FromType is signed.
template<class TargetType, class FromType>
struct IsExactImpl<TargetType, FromType, false, true> {
  static JS_ALWAYS_INLINE bool Test(FromType i, TargetType j) {
    JS_STATIC_ASSERT(numeric_limits<TargetType>::is_exact);
    return i >= 0 && FromType(j) == i;
  }
};

// Specialization where TargetType is signed, FromType is unsigned.
template<class TargetType, class FromType>
struct IsExactImpl<TargetType, FromType, true, false> {
  static JS_ALWAYS_INLINE bool Test(FromType i, TargetType j) {
    JS_STATIC_ASSERT(numeric_limits<TargetType>::is_exact);
    return TargetType(i) >= 0 && FromType(j) == i;
  }
};

// Convert FromType 'i' to TargetType 'result', returning true iff 'result'
// is an exact representation of 'i'.
template<class TargetType, class FromType>
static JS_ALWAYS_INLINE bool ConvertExact(FromType i, TargetType* result)
{
  // Require that TargetType is integral, to simplify conversion.
  JS_STATIC_ASSERT(numeric_limits<TargetType>::is_exact);

  *result = Convert<TargetType>(i);

  // See if we can avoid a dynamic check.
  if (IsAlwaysExact<TargetType, FromType>())
    return true;

  // Return 'true' if 'i' is exactly representable in 'TargetType'.
  return IsExactImpl<TargetType,
                     FromType,
                     numeric_limits<TargetType>::is_signed,
                     numeric_limits<FromType>::is_signed>::Test(i, *result);
}

// Templated helper to determine if Type 'i' is negative. Default case
// where IntegerType is unsigned.
template<class Type, bool IsSigned>
struct IsNegativeImpl {
  static JS_ALWAYS_INLINE bool Test(Type i) {
    return false;
  }
};

// Specialization where Type is signed.
template<class Type>
struct IsNegativeImpl<Type, true> {
  static JS_ALWAYS_INLINE bool Test(Type i) {
    return i < 0;
  }
};

// Determine whether Type 'i' is negative.
template<class Type>
static JS_ALWAYS_INLINE bool IsNegative(Type i)
{
  return IsNegativeImpl<Type, numeric_limits<Type>::is_signed>::Test(i);
}

// Implicitly convert val to bool, allowing JSBool, jsint, and jsdouble
// arguments numerically equal to 0 or 1.
static bool
jsvalToBool(JSContext* cx, jsval val, bool* result)
{
  if (JSVAL_IS_BOOLEAN(val)) {
    *result = JSVAL_TO_BOOLEAN(val) != JS_FALSE;
    return true;
  }
  if (JSVAL_IS_INT(val)) {
    jsint i = JSVAL_TO_INT(val);
    *result = i != 0;
    return i == 0 || i == 1;
  }
  if (JSVAL_IS_DOUBLE(val)) {
    jsdouble d = JSVAL_TO_DOUBLE(val);
    *result = d != 0;
    // Allow -0.
    return d == 1 || d == 0;
  }
  // Don't silently convert null to bool. It's probably a mistake.
  return false;
}

// Implicitly convert val to IntegerType, allowing JSBool, jsint, jsdouble,
// Int64, UInt64, and CData integer types 't' where all values of 't' are
// representable by IntegerType.
template<class IntegerType>
static bool
jsvalToInteger(JSContext* cx, jsval val, IntegerType* result)
{
  JS_STATIC_ASSERT(numeric_limits<IntegerType>::is_exact);

  if (JSVAL_IS_INT(val)) {
    // Make sure the integer fits in the alotted precision, and has the right
    // sign.
    jsint i = JSVAL_TO_INT(val);
    return ConvertExact(i, result);
  }
  if (JSVAL_IS_DOUBLE(val)) {
    // Don't silently lose bits here -- check that val really is an
    // integer value, and has the right sign.
    jsdouble d = JSVAL_TO_DOUBLE(val);
    return ConvertExact(d, result);
  }
  if (!JSVAL_IS_PRIMITIVE(val)) {
    JSObject* obj = JSVAL_TO_OBJECT(val);
    if (CData::IsCData(obj)) {
      JSObject* typeObj = CData::GetCType(obj);
      void* data = CData::GetData(obj);

      // Check whether the source type is always representable, with exact
      // precision, by the target type. If it is, convert the value.
      switch (CType::GetTypeCode(typeObj)) {
#define DEFINE_INT_TYPE(name, fromType, ffiType)                               \
      case TYPE_##name:                                                        \
        if (!IsAlwaysExact<IntegerType, fromType>())                           \
          return false;                                                        \
        *result = IntegerType(*static_cast<fromType*>(data));                  \
        return true;
#define DEFINE_WRAPPED_INT_TYPE(x, y, z) DEFINE_INT_TYPE(x, y, z)
#include "typedefs.h"
      case TYPE_void_t:
      case TYPE_bool:
      case TYPE_float:
      case TYPE_double:
      case TYPE_float32_t:
      case TYPE_float64_t:
      case TYPE_char:
      case TYPE_signed_char:
      case TYPE_unsigned_char:
      case TYPE_jschar:
      case TYPE_pointer:
      case TYPE_function:
      case TYPE_array:
      case TYPE_struct:
        // Not a compatible number type.
        return false;
      }
    }

    if (Int64::IsInt64(obj)) {
      // Make sure the integer fits in IntegerType.
      int64_t i = Int64Base::GetInt(obj);
      return ConvertExact(i, result);
    }

    if (UInt64::IsUInt64(obj)) {
      // Make sure the integer fits in IntegerType.
      uint64_t i = Int64Base::GetInt(obj);
      return ConvertExact(i, result);
    }

    return false; 
  }
  if (JSVAL_IS_BOOLEAN(val)) {
    // Implicitly promote boolean values to 0 or 1, like C.
    *result = JSVAL_TO_BOOLEAN(val);
    JS_ASSERT(*result == 0 || *result == 1);
    return true;
  }
  // Don't silently convert null to an integer. It's probably a mistake.
  return false;
}

// Implicitly convert val to FloatType, allowing jsint, jsdouble,
// Int64, UInt64, and CData numeric types 't' where all values of 't' are
// representable by FloatType.
template<class FloatType>
static bool
jsvalToFloat(JSContext *cx, jsval val, FloatType* result)
{
  JS_STATIC_ASSERT(!numeric_limits<FloatType>::is_exact);

  // The following casts may silently throw away some bits, but there's
  // no good way around it. Sternly requiring that the 64-bit double
  // argument be exactly representable as a 32-bit float is
  // unrealistic: it would allow 1/2 to pass but not 1/3.
  if (JSVAL_IS_INT(val)) {
    *result = FloatType(JSVAL_TO_INT(val));
    return true;
  }
  if (JSVAL_IS_DOUBLE(val)) {
    *result = FloatType(JSVAL_TO_DOUBLE(val));
    return true;
  }
  if (!JSVAL_IS_PRIMITIVE(val)) {
    JSObject* obj = JSVAL_TO_OBJECT(val);
    if (CData::IsCData(obj)) {
      JSObject* typeObj = CData::GetCType(obj);
      void* data = CData::GetData(obj);

      // Check whether the source type is always representable, with exact
      // precision, by the target type. If it is, convert the value.
      switch (CType::GetTypeCode(typeObj)) {
#define DEFINE_FLOAT_TYPE(name, fromType, ffiType)                             \
      case TYPE_##name:                                                        \
        if (!IsAlwaysExact<FloatType, fromType>())                             \
          return false;                                                        \
        *result = FloatType(*static_cast<fromType*>(data));                    \
        return true;
#define DEFINE_INT_TYPE(x, y, z) DEFINE_FLOAT_TYPE(x, y, z)
#define DEFINE_WRAPPED_INT_TYPE(x, y, z) DEFINE_INT_TYPE(x, y, z)
#include "typedefs.h"
      case TYPE_void_t:
      case TYPE_bool:
      case TYPE_char:
      case TYPE_signed_char:
      case TYPE_unsigned_char:
      case TYPE_jschar:
      case TYPE_pointer:
      case TYPE_function:
      case TYPE_array:
      case TYPE_struct:
        // Not a compatible number type.
        return false;
      }
    }
  }
  // Don't silently convert true to 1.0 or false to 0.0, even though C/C++
  // does it. It's likely to be a mistake.
  return false;
}

template<class IntegerType>
static bool
StringToInteger(JSContext* cx, JSString* string, IntegerType* result)
{
  JS_STATIC_ASSERT(numeric_limits<IntegerType>::is_exact);

  const jschar* cp = string->getChars(NULL);
  if (!cp)
    return false;

  const jschar* end = cp + string->length();
  if (cp == end)
    return false;

  IntegerType sign = 1;
  if (cp[0] == '-') {
    if (!numeric_limits<IntegerType>::is_signed)
      return false;

    sign = -1;
    ++cp;
  }

  // Assume base-10, unless the string begins with '0x' or '0X'.
  IntegerType base = 10;
  if (end - cp > 2 && cp[0] == '0' && (cp[1] == 'x' || cp[1] == 'X')) {
    cp += 2;
    base = 16;
  }

  // Scan the string left to right and build the number,
  // checking for valid characters 0 - 9, a - f, A - F and overflow.
  IntegerType i = 0;
  while (cp != end) {
    jschar c = *cp++;
    if (c >= '0' && c <= '9')
      c -= '0';
    else if (base == 16 && c >= 'a' && c <= 'f')
      c = c - 'a' + 10;
    else if (base == 16 && c >= 'A' && c <= 'F')
      c = c - 'A' + 10;
    else
      return false;

    IntegerType ii = i;
    i = ii * base + sign * c;
    if (i / base != ii) // overflow
      return false;
  }

  *result = i;
  return true;
}

// Implicitly convert val to IntegerType, allowing jsint, jsdouble,
// Int64, UInt64, and optionally a decimal or hexadecimal string argument.
// (This is common code shared by jsvalToSize and the Int64/UInt64 constructors.)
template<class IntegerType>
static bool
jsvalToBigInteger(JSContext* cx,
                  jsval val,
                  bool allowString,
                  IntegerType* result)
{
  JS_STATIC_ASSERT(numeric_limits<IntegerType>::is_exact);

  if (JSVAL_IS_INT(val)) {
    // Make sure the integer fits in the alotted precision, and has the right
    // sign.
    jsint i = JSVAL_TO_INT(val);
    return ConvertExact(i, result);
  }
  if (JSVAL_IS_DOUBLE(val)) {
    // Don't silently lose bits here -- check that val really is an
    // integer value, and has the right sign.
    jsdouble d = JSVAL_TO_DOUBLE(val);
    return ConvertExact(d, result);
  }
  if (allowString && JSVAL_IS_STRING(val)) {
    // Allow conversion from base-10 or base-16 strings, provided the result
    // fits in IntegerType. (This allows an Int64 or UInt64 object to be passed
    // to the JS array element operator, which will automatically call
    // toString() on the object for us.)
    return StringToInteger(cx, JSVAL_TO_STRING(val), result);
  }
  if (!JSVAL_IS_PRIMITIVE(val)) {
    // Allow conversion from an Int64 or UInt64 object directly.
    JSObject* obj = JSVAL_TO_OBJECT(val);

    if (UInt64::IsUInt64(obj)) {
      // Make sure the integer fits in IntegerType.
      uint64_t i = Int64Base::GetInt(obj);
      return ConvertExact(i, result);
    }

    if (Int64::IsInt64(obj)) {
      // Make sure the integer fits in IntegerType.
      int64_t i = Int64Base::GetInt(obj);
      return ConvertExact(i, result);
    }
  }
  return false;
}

// Implicitly convert val to a size value, where the size value is represented
// by size_t but must also fit in a jsdouble.
static bool
jsvalToSize(JSContext* cx, jsval val, bool allowString, size_t* result)
{
  if (!jsvalToBigInteger(cx, val, allowString, result))
    return false;

  // Also check that the result fits in a jsdouble.
  return Convert<size_t>(jsdouble(*result)) == *result;
}

// Implicitly convert val to IntegerType, allowing jsint, jsdouble,
// Int64, UInt64, and optionally a decimal or hexadecimal string argument.
// (This is common code shared by jsvalToSize and the Int64/UInt64 constructors.)
template<class IntegerType>
static bool
jsidToBigInteger(JSContext* cx,
                  jsid val,
                  bool allowSt…