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/RootingAPI.h"  // JS::Handle
  16 #include "js/Value.h"       // JS::Value
  17
  18 struct JS_PUBLIC_API JSContext;
  19
  20 namespace JS {
  21
  22 /**
  23  * Store |v1 === v2| to |*equal| -- strict equality, which performs no
  24  * conversions on |v1| or |v2| before comparing.
  25  *
  26  * This operation can fail only if an internal error occurs (e.g. OOM while
  27  * linearizing a string value).
  28  */
  29 extern JS_PUBLIC_API bool StrictlyEqual(JSContext* cx, JS::Handle<JS::Value> v1,
  30                                         JS::Handle<JS::Value> v2, bool* equal);
  31
  32 /**
  33  * Store |v1 == v2| to |*equal| -- loose equality, which may perform
  34  * user-modifiable conversions on |v1| or |v2|.
  35  *
  36  * This operation can fail if a user-modifiable conversion fails *or* if an
  37  * internal error occurs. (e.g. OOM while linearizing a string value).
  38  */
  39 extern JS_PUBLIC_API bool LooselyEqual(JSContext* cx, JS::Handle<JS::Value> v1,
  40                                        JS::Handle<JS::Value> v2, bool* equal);
  41
  42 /**
  43  * Stores |SameValue(v1, v2)| to |*equal| -- using the SameValue operation
  44  * defined in ECMAScript, initially exposed to script as |Object.is|.  SameValue
  45  * behaves identically to strict equality, except that it equates two NaN values
  46  * and does not equate differently-signed zeroes.  It performs no conversions on
  47  * |v1| or |v2| before comparing.
  48  *
  49  * This operation can fail only if an internal error occurs (e.g. OOM while
  50  * linearizing a string value).
  51  */
  52 extern JS_PUBLIC_API bool SameValue(JSContext* cx, JS::Handle<JS::Value> v1,
  53                                     JS::Handle<JS::Value> v2, bool* same);
  54
  55 /**
  56  * Implements |SameValueZero(v1, v2)| for Number values |v1| and |v2|.
  57  * SameValueZero equates NaNs, equal nonzero values, and zeroes without respect
  58  * to their signs.
  59  */
  60 static inline bool SameValueZero(double v1, double v2) {
  61   return mozilla::EqualOrBothNaN(v1, v2);
  62 }
  63
  64 }  // namespace JS
  65
  66 #endif /* js_Equality_h */