1 /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2 *
3 * ***** BEGIN LICENSE BLOCK *****
4 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
5 *
6 * The contents of this file are subject to the Mozilla Public License Version
7 * 1.1 (the "License"); you may not use this file except in compliance with
8 * the License. You may obtain a copy of the License at
9 * http://www.mozilla.org/MPL/
10 *
11 * Software distributed under the License is distributed on an "AS IS" basis,
12 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
13 * for the specific language governing rights and limitations under the
14 * License.
15 *
16 * The Original Code is Mozilla Communicator client code, released
17 * March 31, 1998.
18 *
19 * The Initial Developer of the Original Code is
20 * Netscape Communications Corporation.
21 * Portions created by the Initial Developer are Copyright (C) 1998
22 * the Initial Developer. All Rights Reserved.
23 *
24 * Contributor(s):
25 *
26 * Alternatively, the contents of this file may be used under the terms of
27 * either of the GNU General Public License Version 2 or later (the "GPL"),
28 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
29 * in which case the provisions of the GPL or the LGPL are applicable instead
30 * of those above. If you wish to allow use of your version of this file only
31 * under the terms of either the GPL or the LGPL, and not to allow others to
32 * use your version of this file under the terms of the MPL, indicate your
33 * decision by deleting the provisions above and replace them with the notice
34 * and other provisions required by the GPL or the LGPL. If you do not delete
35 * the provisions above, a recipient may use your version of this file under
36 * the terms of any one of the MPL, the GPL or the LGPL.
37 *
38 * ***** END LICENSE BLOCK ***** */
40 #ifndef jsnum_h___
41 #define jsnum_h___
42 /*
43 * JS number (IEEE double) interface.
44 *
45 * JS numbers are optimistically stored in the top 31 bits of 32-bit integers,
46 * but floating point literals, results that overflow 31 bits, and division and
47 * modulus operands and results require a 64-bit IEEE double. These are GC'ed
48 * and pointed to by 32-bit jsvals on the stack and in object properties.
49 *
50 * When a JS number is treated as an object (followed by . or []), the runtime
51 * wraps it with a JSObject whose valueOf method returns the unwrapped number.
52 */
54 JS_BEGIN_EXTERN_C
56 /*
57 * Stefan Hanske <sh990154@mail.uni-greifswald.de> reports:
58 * ARM is a little endian architecture but 64 bit double words are stored
59 * differently: the 32 bit words are in little endian byte order, the two words
60 * are stored in big endian`s way.
61 */
63 #if defined(__arm) || defined(__arm32__) || defined(__arm26__) || defined(__arm__)
64 #define CPU_IS_ARM
65 #endif
67 typedef union jsdpun {
68 struct {
69 #if defined(IS_LITTLE_ENDIAN) && !defined(CPU_IS_ARM)
70 uint32 lo, hi;
71 #else
72 uint32 hi, lo;
73 #endif
74 } s;
75 jsdouble d;
76 } jsdpun;
78 #if (__GNUC__ == 2 && __GNUC_MINOR__ > 95) || __GNUC__ > 2
79 /*
80 * This version of the macros is safe for the alias optimizations that gcc
81 * does, but uses gcc-specific extensions.
82 */
84 #define JSDOUBLE_HI32(x) (__extension__ ({ jsdpun u; u.d = (x); u.s.hi; }))
85 #define JSDOUBLE_LO32(x) (__extension__ ({ jsdpun u; u.d = (x); u.s.lo; }))
86 #define JSDOUBLE_SET_HI32(x, y) \
87 (__extension__ ({ jsdpun u; u.d = (x); u.s.hi = (y); (x) = u.d; }))
88 #define JSDOUBLE_SET_LO32(x, y) \
89 (__extension__ ({ jsdpun u; u.d = (x); u.s.lo = (y); (x) = u.d; }))
91 #else /* not or old GNUC */
93 /*
94 * We don't know of any non-gcc compilers that perform alias optimization,
95 * so this code should work.
96 */
98 #if defined(IS_LITTLE_ENDIAN) && !defined(CPU_IS_ARM)
99 #define JSDOUBLE_HI32(x) (((uint32 *)&(x))[1])
100 #define JSDOUBLE_LO32(x) (((uint32 *)&(x))[0])
101 #else
102 #define JSDOUBLE_HI32(x) (((uint32 *)&(x))[0])
103 #define JSDOUBLE_LO32(x) (((uint32 *)&(x))[1])
104 #endif
106 #define JSDOUBLE_SET_HI32(x, y) (JSDOUBLE_HI32(x)=(y))
107 #define JSDOUBLE_SET_LO32(x, y) (JSDOUBLE_LO32(x)=(y))
109 #endif /* not or old GNUC */
111 #define JSDOUBLE_HI32_SIGNBIT 0x80000000
112 #define JSDOUBLE_HI32_EXPMASK 0x7ff00000
113 #define JSDOUBLE_HI32_MANTMASK 0x000fffff
115 #define JSDOUBLE_IS_NaN(x) \
116 ((JSDOUBLE_HI32(x) & JSDOUBLE_HI32_EXPMASK) == JSDOUBLE_HI32_EXPMASK && \
117 (JSDOUBLE_LO32(x) || (JSDOUBLE_HI32(x) & JSDOUBLE_HI32_MANTMASK)))
119 #define JSDOUBLE_IS_INFINITE(x) \
120 ((JSDOUBLE_HI32(x) & ~JSDOUBLE_HI32_SIGNBIT) == JSDOUBLE_HI32_EXPMASK && \
121 !JSDOUBLE_LO32(x))
123 #define JSDOUBLE_IS_FINITE(x) \
124 ((JSDOUBLE_HI32(x) & JSDOUBLE_HI32_EXPMASK) != JSDOUBLE_HI32_EXPMASK)
126 #define JSDOUBLE_IS_NEGZERO(d) (JSDOUBLE_HI32(d) == JSDOUBLE_HI32_SIGNBIT && \
127 JSDOUBLE_LO32(d) == 0)
129 /*
130 * JSDOUBLE_IS_INT first checks that d is neither NaN nor infinite, to avoid
131 * raising SIGFPE on platforms such as Alpha Linux, then (only if the cast is
132 * safe) leaves i as (jsint)d. This also avoid anomalous NaN floating point
133 * comparisons under MSVC.
134 */
135 #define JSDOUBLE_IS_INT(d, i) (JSDOUBLE_IS_FINITE(d) \
136 && !JSDOUBLE_IS_NEGZERO(d) \
137 && ((d) == (i = (jsint)(d))))
139 #if defined(XP_WIN)
140 #define JSDOUBLE_COMPARE(LVAL, OP, RVAL, IFNAN) \
141 ((JSDOUBLE_IS_NaN(LVAL) || JSDOUBLE_IS_NaN(RVAL)) \
142 ? (IFNAN) \
143 : (LVAL) OP (RVAL))
144 #else
145 #define JSDOUBLE_COMPARE(LVAL, OP, RVAL, IFNAN) ((LVAL) OP (RVAL))
146 #endif
148 /* Initialize number constants and runtime state for the first context. */
149 extern JSBool
150 js_InitRuntimeNumberState(JSContext *cx);
152 extern void
153 js_FinishRuntimeNumberState(JSContext *cx);
155 /* Initialize the Number class, returning its prototype object. */
156 extern JSClass js_NumberClass;
158 extern JSObject *
159 js_InitNumberClass(JSContext *cx, JSObject *obj);
161 /*
162 * String constants for global function names, used in jsapi.c and jsnum.c.
163 */
164 extern const char js_Infinity_str[];
165 extern const char js_NaN_str[];
166 extern const char js_isNaN_str[];
167 extern const char js_isFinite_str[];
168 extern const char js_parseFloat_str[];
169 extern const char js_parseInt_str[];
171 /* GC-allocate a new JS number. */
172 extern jsdouble *
173 js_NewDouble(JSContext *cx, jsdouble d, uintN gcflag);
175 extern void
176 js_FinalizeDouble(JSContext *cx, jsdouble *dp);
178 extern JSBool
179 js_NewDoubleValue(JSContext *cx, jsdouble d, jsval *rval);
181 extern JSBool
182 js_NewNumberValue(JSContext *cx, jsdouble d, jsval *rval);
184 /* Construct a Number instance that wraps around d. */
185 extern JSObject *
186 js_NumberToObject(JSContext *cx, jsdouble d);
188 /* Convert a number to a GC'ed string. */
189 extern JSString *
190 js_NumberToString(JSContext *cx, jsdouble d);
192 /*
193 * Convert a value to a number, returning false after reporting any error,
194 * otherwise returning true with *dp set.
195 */
196 extern JSBool
197 js_ValueToNumber(JSContext *cx, jsval v, jsdouble *dp);
199 /*
200 * Convert a value or a double to an int32, according to the ECMA rules
201 * for ToInt32.
202 */
203 extern JSBool
204 js_ValueToECMAInt32(JSContext *cx, jsval v, int32 *ip);
206 extern JSBool
207 js_DoubleToECMAInt32(JSContext *cx, jsdouble d, int32 *ip);
209 /*
210 * Convert a value or a double to a uint32, according to the ECMA rules
211 * for ToUint32.
212 */
213 extern JSBool
214 js_ValueToECMAUint32(JSContext *cx, jsval v, uint32 *ip);
216 extern JSBool
217 js_DoubleToECMAUint32(JSContext *cx, jsdouble d, uint32 *ip);
219 /*
220 * Convert a value to a number, then to an int32 if it fits by rounding to
221 * nearest; but failing with an error report if the double is out of range
222 * or unordered.
223 */
224 extern JSBool
225 js_ValueToInt32(JSContext *cx, jsval v, int32 *ip);
227 /*
228 * Convert a value to a number, then to a uint16 according to the ECMA rules
229 * for ToUint16.
230 */
231 extern JSBool
232 js_ValueToUint16(JSContext *cx, jsval v, uint16 *ip);
234 /*
235 * Convert a jsdouble to an integral number, stored in a jsdouble.
236 * If d is NaN, return 0. If d is an infinity, return it without conversion.
237 */
238 extern jsdouble
239 js_DoubleToInteger(jsdouble d);
241 /*
242 * Similar to strtod except that it replaces overflows with infinities of the
243 * correct sign, and underflows with zeros of the correct sign. Guaranteed to
244 * return the closest double number to the given input in dp.
245 *
246 * Also allows inputs of the form [+|-]Infinity, which produce an infinity of
247 * the appropriate sign. The case of the "Infinity" string must match exactly.
248 * If the string does not contain a number, set *ep to s and return 0.0 in dp.
249 * Return false if out of memory.
250 */
251 extern JSBool
252 js_strtod(JSContext *cx, const jschar *s, const jschar **ep, jsdouble *dp);
254 /*
255 * Similar to strtol except that it handles integers of arbitrary size.
256 * Guaranteed to return the closest double number to the given input when radix
257 * is 10 or a power of 2. Callers may see round-off errors for very large
258 * numbers of a different radix than 10 or a power of 2.
259 *
260 * If the string does not contain a number, set *ep to s and return 0.0 in dp.
261 * Return false if out of memory.
262 */
263 extern JSBool
264 js_strtointeger(JSContext *cx, const jschar *s, const jschar **ep, jsint radix, jsdouble *dp);
266 JS_END_EXTERN_C
268 #endif /* jsnum_h___ */