js/public/Equality.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 /* Equality operations. */
   7
   8 #ifndef js_Equality_h
   9 #define js_Equality_h
  10
  11 #include "mozilla/FloatingPoint.h"
  12
  13 #include "jstypes.h"  // JS_PUBLIC_API
  14
  15 #include "js/TypeDecls.h"
  16
  17 struct JS_PUBLIC_API JSContext;
  18
  19 namespace JS {
  20
  21 /**
  22  * Store |v1 === v2| to |*equal| -- strict equality, which performs no
  23  * conversions on |v1| or |v2| before comparing.
  24  *
  25  * This operation can fail only if an internal error occurs (e.g. OOM while
  26  * linearizing a string value).
  27  */
  28 extern JS_PUBLIC_API bool StrictlyEqual(JSContext* cx, JS::Handle<JS::Value> v1,
  29                                         JS::Handle<JS::Value> v2, bool* equal);
  30
  31 /**
  32  * Store |v1 == v2| to |*equal| -- loose equality, which may perform
  33  * user-modifiable conversions on |v1| or |v2|.
  34  *
  35  * This operation can fail if a user-modifiable conversion fails *or* if an
  36  * internal error occurs. (e.g. OOM while linearizing a string value).
  37  */
  38 extern JS_PUBLIC_API bool LooselyEqual(JSContext* cx, JS::Handle<JS::Value> v1,
  39                                        JS::Handle<JS::Value> v2, bool* equal);
  40
  41 /**
  42  * Stores |SameValue(v1, v2)| to |*equal| -- using the SameValue operation
  43  * defined in ECMAScript, initially exposed to script as |Object.is|.  SameValue
  44  * behaves identically to strict equality, except that it equates two NaN values
  45  * and does not equate differently-signed zeroes.  It performs no conversions on
  46  * |v1| or |v2| before comparing.
  47  *
  48  * This operation can fail only if an internal error occurs (e.g. OOM while
  49  * linearizing a string value).
  50  */
  51 extern JS_PUBLIC_API bool SameValue(JSContext* cx, JS::Handle<JS::Value> v1,
  52                                     JS::Handle<JS::Value> v2, bool* same);
  53
  54 /**
  55  * Implements |SameValueZero(v1, v2)| for Number values |v1| and |v2|.
  56  * SameValueZero equates NaNs, equal nonzero values, and zeroes without respect
  57  * to their signs.
  58  */
  59 static inline bool SameValueZero(double v1, double v2) {
  60   return mozilla::EqualOrBothNaN(v1, v2);
  61 }
  62
  63 }  // namespace JS
  64
  65 #endif /* js_Equality_h */