text: /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
   *
   * ***** 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 Mozilla Communicator client code, released
   * March 31, 1998.
   *
   * The Initial Developer of the Original Code is
   * Netscape Communications Corporation.
   * Portions created by the Initial Developer are Copyright (C) 1998
   * the Initial Developer. All Rights Reserved.
   *
   * Contributor(s):
   *
   * Alternatively, the contents of this file may be used under the terms of
   * either of 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 ***** */
  
  #ifndef jsnum_h___
  #define jsnum_h___
  /*
   * JS number (IEEE double) interface.
   *
   * JS numbers are optimistically stored in the top 31 bits of 32-bit integers,
   * but floating point literals, results that overflow 31 bits, and division and
   * modulus operands and results require a 64-bit IEEE double.  These are GC'ed
   * and pointed to by 32-bit jsvals on the stack and in object properties.
   *
   * When a JS number is treated as an object (followed by . or []), the runtime
   * wraps it with a JSObject whose valueOf method returns the unwrapped number.
   */
  
  JS_BEGIN_EXTERN_C
  
  /*
   * Stefan Hanske <sh990154@mail.uni-greifswald.de> reports:
   *  ARM is a little endian architecture but 64 bit double words are stored
   * differently: the 32 bit words are in little endian byte order, the two words
   * are stored in big endian`s way.
   */
  
  #if defined(__arm) || defined(__arm32__) || defined(__arm26__) || defined(__arm__)
  #define CPU_IS_ARM
  #endif
  
  typedef union jsdpun {
      struct {
  #if defined(IS_LITTLE_ENDIAN) && !defined(CPU_IS_ARM)
          uint32 lo, hi;
  #else
          uint32 hi, lo;
  #endif
      } s;
      jsdouble d;
  } jsdpun;
  
  #if (__GNUC__ == 2 && __GNUC_MINOR__ > 95) || __GNUC__ > 2
  /*
   * This version of the macros is safe for the alias optimizations that gcc
   * does, but uses gcc-specific extensions.
   */
  
  #define JSDOUBLE_HI32(x) (__extension__ ({ jsdpun u; u.d = (x); u.s.hi; }))
  #define JSDOUBLE_LO32(x) (__extension__ ({ jsdpun u; u.d = (x); u.s.lo; }))
  #define JSDOUBLE_SET_HI32(x, y) \
      (__extension__ ({ jsdpun u; u.d = (x); u.s.hi = (y); (x) = u.d; }))
  #define JSDOUBLE_SET_LO32(x, y) \
      (__extension__ ({ jsdpun u; u.d = (x); u.s.lo = (y); (x) = u.d; }))
  
  #else /* not or old GNUC */
  
  /*
   * We don't know of any non-gcc compilers that perform alias optimization,
   * so this code should work.
   */
  
  #if defined(IS_LITTLE_ENDIAN) && !defined(CPU_IS_ARM)
  #define JSDOUBLE_HI32(x)        (((uint32 *)&(x))[1])
  #define JSDOUBLE_LO32(x)        (((uint32 *)&(x))[0])
  #else
  #define JSDOUBLE_HI32(x)        (((uint32 *)&(x))[0])
  #define JSDOUBLE_LO32(x)        (((uint32 *)&(x))[1])
  #endif
  
  #define JSDOUBLE_SET_HI32(x, y) (JSDOUBLE_HI32(x)=(y))
  #define JSDOUBLE_SET_LO32(x, y) (JSDOUBLE_LO32(x)=(y))
  
  #endif /* not or old GNUC */
  
  #define JSDOUBLE_HI32_SIGNBIT   0x80000000
  #define JSDOUBLE_HI32_EXPMASK   0x7ff00000
  #define JSDOUBLE_HI32_MANTMASK  0x000fffff
  
  #define JSDOUBLE_IS_NaN(x)                                                    \
      ((JSDOUBLE_HI32(x) & JSDOUBLE_HI32_EXPMASK) == JSDOUBLE_HI32_EXPMASK &&   \
       (JSDOUBLE_LO32(x) || (JSDOUBLE_HI32(x) & JSDOUBLE_HI32_MANTMASK)))
  
  #define JSDOUBLE_IS_INFINITE(x)                                               \
      ((JSDOUBLE_HI32(x) & ~JSDOUBLE_HI32_SIGNBIT) == JSDOUBLE_HI32_EXPMASK &&  \
       !JSDOUBLE_LO32(x))
  
  #define JSDOUBLE_IS_FINITE(x)                                                 \
      ((JSDOUBLE_HI32(x) & JSDOUBLE_HI32_EXPMASK) != JSDOUBLE_HI32_EXPMASK)
  
  #define JSDOUBLE_IS_NEGZERO(d)  (JSDOUBLE_HI32(d) == JSDOUBLE_HI32_SIGNBIT && \
                                   JSDOUBLE_LO32(d) == 0)
  
  /*
   * JSDOUBLE_IS_INT first checks that d is neither NaN nor infinite, to avoid
   * raising SIGFPE on platforms such as Alpha Linux, then (only if the cast is
   * safe) leaves i as (jsint)d.  This also avoid anomalous NaN floating point
   * comparisons under MSVC.
   */
  #define JSDOUBLE_IS_INT(d, i) (JSDOUBLE_IS_FINITE(d)                          \
                                 && !JSDOUBLE_IS_NEGZERO(d)                     \
                                 && ((d) == (i = (jsint)(d))))
  
  #if defined(XP_WIN)
  #define JSDOUBLE_COMPARE(LVAL, OP, RVAL, IFNAN)                               \
      ((JSDOUBLE_IS_NaN(LVAL) || JSDOUBLE_IS_NaN(RVAL))                         \
       ? (IFNAN)                                                                \
       : (LVAL) OP (RVAL))
  #else
  #define JSDOUBLE_COMPARE(LVAL, OP, RVAL, IFNAN) ((LVAL) OP (RVAL))
  #endif
  
  /* Initialize number constants and runtime state for the first context. */
  extern JSBool
  js_InitRuntimeNumberState(JSContext *cx);
  
  extern void
  js_FinishRuntimeNumberState(JSContext *cx);
  
  /* Initialize the Number class, returning its prototype object. */
  extern JSClass js_NumberClass;
  
  extern JSObject *
  js_InitNumberClass(JSContext *cx, JSObject *obj);
  
  /*
   * String constants for global function names, used in jsapi.c and jsnum.c.
   */
  extern const char js_Infinity_str[];
  extern const char js_NaN_str[];
  extern const char js_isNaN_str[];
  extern const char js_isFinite_str[];
  extern const char js_parseFloat_str[];
  extern const char js_parseInt_str[];
  
  /* GC-allocate a new JS number. */
  extern jsdouble *
  js_NewDouble(JSContext *cx, jsdouble d, uintN gcflag);
  
  extern void
  js_FinalizeDouble(JSContext *cx, jsdouble *dp);
  
  extern JSBool
  js_NewDoubleValue(JSContext *cx, jsdouble d, jsval *rval);
  
  extern JSBool
  js_NewNumberValue(JSContext *cx, jsdouble d, jsval *rval);
  
  /* Construct a Number instance that wraps around d. */
  extern JSObject *
  js_NumberToObject(JSContext *cx, jsdouble d);
  
  /* Convert a number to a GC'ed string. */
  extern JSString *
  js_NumberToString(JSContext *cx, jsdouble d);
  
  /*
   * Convert a value to a number, returning false after reporting any error,
   * otherwise returning true with *dp set.
   */
  extern JSBool
  js_ValueToNumber(JSContext *cx, jsval v, jsdouble *dp);
  
  /*
   * Convert a value or a double to an int32, according to the ECMA rules
   * for ToInt32.
   */
  extern JSBool
  js_ValueToECMAInt32(JSContext *cx, jsval v, int32 *ip);
  
  extern JSBool
  js_DoubleToECMAInt32(JSContext *cx, jsdouble d, int32 *ip);
  
  /*
   * Convert a value or a double to a uint32, according to the ECMA rules
   * for ToUint32.
   */
  extern JSBool
  js_ValueToECMAUint32(JSContext *cx, jsval v, uint32 *ip);
  
  extern JSBool
  js_DoubleToECMAUint32(JSContext *cx, jsdouble d, uint32 *ip);
  
  /*
   * Convert a value to a number, then to an int32 if it fits by rounding to
   * nearest; but failing with an error report if the double is out of range
   * or unordered.
   */
  extern JSBool
  js_ValueToInt32(JSContext *cx, jsval v, int32 *ip);
  
  /*
   * Convert a value to a number, then to a uint16 according to the ECMA rules
   * for ToUint16.
   */
  extern JSBool
  js_ValueToUint16(JSContext *cx, jsval v, uint16 *ip);
  
  /*
   * Convert a jsdouble to an integral number, stored in a jsdouble.
   * If d is NaN, return 0.  If d is an infinity, return it without conversion.
   */
  extern jsdouble
  js_DoubleToInteger(jsdouble d);
  
  /*
   * Similar to strtod except that it replaces overflows with infinities of the
   * correct sign, and underflows with zeros of the correct sign.  Guaranteed to
   * return the closest double number to the given input in dp.
   *
   * Also allows inputs of the form [+|-]Infinity, which produce an infinity of
   * the appropriate sign.  The case of the "Infinity" string must match exactly.
   * If the string does not contain a number, set *ep to s and return 0.0 in dp.
   * Return false if out of memory.
   */
  extern JSBool
  js_strtod(JSContext *cx, const jschar *s, const jschar **ep, jsdouble *dp);
  
  /*
   * Similar to strtol except that it handles integers of arbitrary size.
   * Guaranteed to return the closest double number to the given input when radix
   * is 10 or a power of 2.  Callers may see round-off errors for very large
   * numbers of a different radix than 10 or a power of 2.
   *
   * If the string does not contain a number, set *ep to s and return 0.0 in dp.
   * Return false if out of memory.
   */
  extern JSBool
  js_strtointeger(JSContext *cx, const jschar *s, const jschar **ep, jsint radix, jsdouble *dp);
  
  JS_END_EXTERN_C
  
  #endif /* jsnum_h___ */
  