/[jscoverage]/trunk/js/jsnum.h
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1 siliconforks 332 /* -*- 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 ***** */
39    
40     #ifndef jsnum_h___
41     #define jsnum_h___
42 siliconforks 399
43 siliconforks 507 #include <math.h>
44     #if defined(XP_WIN) || defined(XP_OS2)
45     #include <float.h>
46     #endif
47     #ifdef SOLARIS
48     #include <ieeefp.h>
49     #endif
50    
51 siliconforks 332 /*
52     * JS number (IEEE double) interface.
53     *
54     * JS numbers are optimistically stored in the top 31 bits of 32-bit integers,
55     * but floating point literals, results that overflow 31 bits, and division and
56     * modulus operands and results require a 64-bit IEEE double. These are GC'ed
57     * and pointed to by 32-bit jsvals on the stack and in object properties.
58     */
59    
60     JS_BEGIN_EXTERN_C
61    
62     /*
63     * The ARM architecture supports two floating point models: VFP and FPA. When
64     * targetting FPA, doubles are mixed-endian on little endian ARMs (meaning that
65     * the high and low words are in big endian order).
66     */
67     #if defined(__arm) || defined(__arm32__) || defined(__arm26__) || defined(__arm__)
68     #if !defined(__VFP_FP__)
69     #define FPU_IS_ARM_FPA
70     #endif
71     #endif
72    
73     typedef union jsdpun {
74     struct {
75     #if defined(IS_LITTLE_ENDIAN) && !defined(FPU_IS_ARM_FPA)
76     uint32 lo, hi;
77     #else
78     uint32 hi, lo;
79     #endif
80     } s;
81     uint64 u64;
82     jsdouble d;
83     } jsdpun;
84    
85 siliconforks 507 static inline int
86     JSDOUBLE_IS_NaN(jsdouble d)
87     {
88     #ifdef WIN32
89     return _isnan(d);
90     #else
91     return isnan(d);
92     #endif
93     }
94 siliconforks 332
95 siliconforks 507 static inline int
96     JSDOUBLE_IS_FINITE(jsdouble d)
97     {
98     #ifdef WIN32
99     return _finite(d);
100     #else
101     return finite(d);
102     #endif
103     }
104 siliconforks 332
105 siliconforks 507 static inline int
106     JSDOUBLE_IS_INFINITE(jsdouble d)
107     {
108     #ifdef WIN32
109     int c = _fpclass(d);
110     return c == _FPCLASS_NINF || c == _FPCLASS_PINF;
111     #elif defined(SOLARIS)
112     return !finite(d) && !isnan(d);
113     #else
114     return isinf(d);
115     #endif
116     }
117 siliconforks 332
118 siliconforks 507 static inline int
119     JSDOUBLE_IS_NEGZERO(jsdouble d)
120     {
121     #ifdef WIN32
122     return (d == 0 && (_fpclass(d) & _FPCLASS_NZ));
123     #elif defined(SOLARIS)
124     return (d == 0 && copysign(1, d) < 0);
125 siliconforks 332 #else
126 siliconforks 507 return (d == 0 && signbit(d));
127 siliconforks 332 #endif
128 siliconforks 507 }
129 siliconforks 332
130     #define JSDOUBLE_HI32_SIGNBIT 0x80000000
131     #define JSDOUBLE_HI32_EXPMASK 0x7ff00000
132     #define JSDOUBLE_HI32_MANTMASK 0x000fffff
133    
134 siliconforks 507 static inline int
135     JSDOUBLE_IS_INT(jsdouble d, jsint& i)
136     {
137     if (JSDOUBLE_IS_NEGZERO(d))
138     return false;
139     return d == (i = jsint(d));
140     }
141 siliconforks 332
142 siliconforks 507 static inline int
143     JSDOUBLE_IS_NEG(jsdouble d)
144     {
145     #ifdef WIN32
146     return JSDOUBLE_IS_NEGZERO(d) || d < 0;
147     #elif defined(SOLARIS)
148     return copysign(1, d) < 0;
149     #else
150     return signbit(d);
151     #endif
152     }
153 siliconforks 332
154 siliconforks 507 static inline uint32
155     JS_HASH_DOUBLE(jsdouble d)
156     {
157     jsdpun u;
158     u.d = d;
159     return u.s.lo ^ u.s.hi;
160     }
161 siliconforks 332
162     #if defined(XP_WIN)
163     #define JSDOUBLE_COMPARE(LVAL, OP, RVAL, IFNAN) \
164     ((JSDOUBLE_IS_NaN(LVAL) || JSDOUBLE_IS_NaN(RVAL)) \
165     ? (IFNAN) \
166     : (LVAL) OP (RVAL))
167     #else
168     #define JSDOUBLE_COMPARE(LVAL, OP, RVAL, IFNAN) ((LVAL) OP (RVAL))
169     #endif
170    
171     extern jsdouble js_NaN;
172    
173     /* Initialize number constants and runtime state for the first context. */
174     extern JSBool
175     js_InitRuntimeNumberState(JSContext *cx);
176    
177     extern void
178     js_TraceRuntimeNumberState(JSTracer *trc);
179    
180     extern void
181     js_FinishRuntimeNumberState(JSContext *cx);
182    
183     /* Initialize the Number class, returning its prototype object. */
184     extern JSClass js_NumberClass;
185    
186     extern JSObject *
187     js_InitNumberClass(JSContext *cx, JSObject *obj);
188    
189     /*
190     * String constants for global function names, used in jsapi.c and jsnum.c.
191     */
192     extern const char js_Infinity_str[];
193     extern const char js_NaN_str[];
194     extern const char js_isNaN_str[];
195     extern const char js_isFinite_str[];
196     extern const char js_parseFloat_str[];
197     extern const char js_parseInt_str[];
198    
199     /*
200     * vp must be a root.
201     */
202     extern JSBool
203     js_NewNumberInRootedValue(JSContext *cx, jsdouble d, jsval *vp);
204    
205 siliconforks 460 /*
206     * Create a weakly rooted integer or double jsval as appropriate for the given
207     * jsdouble.
208     */
209     extern JSBool
210     js_NewWeaklyRootedNumber(JSContext *cx, jsdouble d, jsval *vp);
211    
212 siliconforks 332 /* Convert a number to a GC'ed string. */
213     extern JSString * JS_FASTCALL
214     js_NumberToString(JSContext *cx, jsdouble d);
215    
216     /*
217 siliconforks 507 * Convert an integer or double (contained in the given jsval) to a string and
218     * append to the given buffer.
219     */
220     extern JSBool JS_FASTCALL
221     js_NumberValueToCharBuffer(JSContext *cx, jsval v, JSCharBuffer &cb);
222    
223     /*
224 siliconforks 332 * Convert a value to a number. On exit JSVAL_IS_NULL(*vp) iff there was an
225     * error. If on exit JSVAL_IS_NUMBER(*vp), then *vp holds the jsval that
226     * matches the result. Otherwise *vp is JSVAL_TRUE indicating that the jsval
227     * for result has to be created explicitly using, for example, the
228     * js_NewNumberInRootedValue function.
229     */
230     extern jsdouble
231     js_ValueToNumber(JSContext *cx, jsval* vp);
232    
233     /*
234     * Convert a value to an int32 or uint32, according to the ECMA rules for
235     * ToInt32 and ToUint32. On exit JSVAL_IS_NULL(*vp) iff there was an error. If
236     * on exit JSVAL_IS_INT(*vp), then *vp holds the jsval matching the result.
237     * Otherwise *vp is JSVAL_TRUE indicating that the jsval for result has to be
238     * created explicitly using, for example, the js_NewNumberInRootedValue
239     * function.
240     */
241     extern int32
242     js_ValueToECMAInt32(JSContext *cx, jsval *vp);
243    
244     extern uint32
245     js_ValueToECMAUint32(JSContext *cx, jsval *vp);
246    
247     /*
248     * Specialized ToInt32 and ToUint32 converters for doubles.
249     */
250 siliconforks 507 /*
251     * From the ES3 spec, 9.5
252     * 2. If Result(1) is NaN, +0, -0, +Inf, or -Inf, return +0.
253     * 3. Compute sign(Result(1)) * floor(abs(Result(1))).
254     * 4. Compute Result(3) modulo 2^32; that is, a finite integer value k of Number
255     * type with positive sign and less than 2^32 in magnitude such the mathematical
256     * difference of Result(3) and k is mathematically an integer multiple of 2^32.
257     * 5. If Result(4) is greater than or equal to 2^31, return Result(4)- 2^32,
258     * otherwise return Result(4).
259     */
260     static inline int32
261     js_DoubleToECMAInt32(jsdouble d)
262     {
263     #ifdef __i386__
264     jsdpun du, duh, two32;
265     uint32 di_h, u_tmp, expon, shift_amount;
266     int32 mask32;
267 siliconforks 332
268 siliconforks 507 /*
269     * Algorithm Outline
270     * Step 1. If d is NaN, +/-Inf or |d|>=2^84 or |d|<1, then return 0
271     * All of this is implemented based on an exponent comparison.
272     * Step 2. If |d|<2^31, then return (int)d
273     * The cast to integer (conversion in RZ mode) returns the correct result.
274     * Step 3. If |d|>=2^32, d:=fmod(d, 2^32) is taken -- but without a call
275     * Step 4. If |d|>=2^31, then the fractional bits are cleared before
276     * applying the correction by 2^32: d - sign(d)*2^32
277     * Step 5. Return (int)d
278     */
279    
280     du.d = d;
281     di_h = du.s.hi;
282    
283     u_tmp = (di_h & 0x7ff00000) - 0x3ff00000;
284     if (u_tmp >= (0x45300000-0x3ff00000)) {
285     // d is Nan, +/-Inf or +/-0, or |d|>=2^(32+52) or |d|<1, in which case result=0
286     return 0;
287     }
288    
289     if (u_tmp < 0x01f00000) {
290     // |d|<2^31
291     return int32_t(d);
292     }
293    
294     if (u_tmp > 0x01f00000) {
295     // |d|>=2^32
296     expon = u_tmp >> 20;
297     shift_amount = expon - 21;
298     duh.u64 = du.u64;
299     mask32 = 0x80000000;
300     if (shift_amount < 32) {
301     mask32 >>= shift_amount;
302     duh.s.hi = du.s.hi & mask32;
303     duh.s.lo = 0;
304     } else {
305     mask32 >>= (shift_amount-32);
306     duh.s.hi = du.s.hi;
307     duh.s.lo = du.s.lo & mask32;
308     }
309     du.d -= duh.d;
310     }
311    
312     di_h = du.s.hi;
313    
314     // eliminate fractional bits
315     u_tmp = (di_h & 0x7ff00000);
316     if (u_tmp >= 0x41e00000) {
317     // |d|>=2^31
318     expon = u_tmp >> 20;
319     shift_amount = expon - (0x3ff - 11);
320     mask32 = 0x80000000;
321     if (shift_amount < 32) {
322     mask32 >>= shift_amount;
323     du.s.hi &= mask32;
324     du.s.lo = 0;
325     } else {
326     mask32 >>= (shift_amount-32);
327     du.s.lo &= mask32;
328     }
329     two32.s.hi = 0x41f00000 ^ (du.s.hi & 0x80000000);
330     two32.s.lo = 0;
331     du.d -= two32.d;
332     }
333    
334     return int32(du.d);
335     #else
336     int32 i;
337     jsdouble two32, two31;
338    
339     if (!JSDOUBLE_IS_FINITE(d))
340     return 0;
341    
342     i = (int32) d;
343     if ((jsdouble) i == d)
344     return i;
345    
346     two32 = 4294967296.0;
347     two31 = 2147483648.0;
348     d = fmod(d, two32);
349     d = (d >= 0) ? floor(d) : ceil(d) + two32;
350     return (int32) (d >= two31 ? d - two32 : d);
351     #endif
352     }
353    
354 siliconforks 332 extern uint32
355     js_DoubleToECMAUint32(jsdouble d);
356    
357     /*
358     * Convert a value to a number, then to an int32 if it fits by rounding to
359     * nearest; but failing with an error report if the double is out of range
360     * or unordered. On exit JSVAL_IS_NULL(*vp) iff there was an error. If on exit
361     * JSVAL_IS_INT(*vp), then *vp holds the jsval matching the result. Otherwise
362     * *vp is JSVAL_TRUE indicating that the jsval for result has to be created
363     * explicitly using, for example, the js_NewNumberInRootedValue function.
364     */
365     extern int32
366     js_ValueToInt32(JSContext *cx, jsval *vp);
367    
368     /*
369     * Convert a value to a number, then to a uint16 according to the ECMA rules
370     * for ToUint16. On exit JSVAL_IS_NULL(*vp) iff there was an error, otherwise
371     * vp is jsval matching the result.
372     */
373     extern uint16
374     js_ValueToUint16(JSContext *cx, jsval *vp);
375    
376     /*
377     * Convert a jsdouble to an integral number, stored in a jsdouble.
378     * If d is NaN, return 0. If d is an infinity, return it without conversion.
379     */
380 siliconforks 507 static inline jsdouble
381     js_DoubleToInteger(jsdouble d)
382     {
383     if (d == 0)
384     return d;
385 siliconforks 332
386 siliconforks 507 if (!JSDOUBLE_IS_FINITE(d)) {
387     if (JSDOUBLE_IS_NaN(d))
388     return 0;
389     return d;
390     }
391    
392     JSBool neg = (d < 0);
393     d = floor(neg ? -d : d);
394    
395     return neg ? -d : d;
396     }
397    
398 siliconforks 332 /*
399     * Similar to strtod except that it replaces overflows with infinities of the
400     * correct sign, and underflows with zeros of the correct sign. Guaranteed to
401     * return the closest double number to the given input in dp.
402     *
403     * Also allows inputs of the form [+|-]Infinity, which produce an infinity of
404     * the appropriate sign. The case of the "Infinity" string must match exactly.
405     * If the string does not contain a number, set *ep to s and return 0.0 in dp.
406     * Return false if out of memory.
407     */
408     extern JSBool
409     js_strtod(JSContext *cx, const jschar *s, const jschar *send,
410     const jschar **ep, jsdouble *dp);
411    
412     /*
413     * Similar to strtol except that it handles integers of arbitrary size.
414     * Guaranteed to return the closest double number to the given input when radix
415     * is 10 or a power of 2. Callers may see round-off errors for very large
416     * numbers of a different radix than 10 or a power of 2.
417     *
418     * If the string does not contain a number, set *ep to s and return 0.0 in dp.
419     * Return false if out of memory.
420     */
421     extern JSBool
422     js_strtointeger(JSContext *cx, const jschar *s, const jschar *send,
423     const jschar **ep, jsint radix, jsdouble *dp);
424    
425     JS_END_EXTERN_C
426    
427     #endif /* jsnum_h___ */

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