gecko-dev/js/ref/jsnum.h

168 строки
5.7 KiB
C

/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#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.
*/
PR_BEGIN_EXTERN_C
#ifdef IS_LITTLE_ENDIAN
#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_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))))
/* Initialize the Number class, returning its prototype object. */
extern JSObject *
js_InitNumberClass(JSContext *cx, JSObject *obj);
/* GC-allocate a new JS number. */
extern jsdouble *
js_NewDouble(JSContext *cx, jsdouble d);
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 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.
* If the string does not have a number in it, 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 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.
* May experience roundoff errors for very large numbers of a different radix.
* If the string does not have a number in it, 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);
PR_END_EXTERN_C
#endif /* jsnum_h___ */