libswfdec/js/jsnum.h

   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 ***** */
  39
  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  */
  53
  54 JS_BEGIN_EXTERN_C
  55
  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  */
  62
  63 #if defined(__arm) || defined(__arm32__) || defined(__arm26__) || defined(__arm__)
  64 #define CPU_IS_ARM
  65 #endif
  66
  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;
  77
  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  */
  83
  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; }))
  90
  91 #else /* not or old GNUC */
  92
  93 /*
  94  * We don't know of any non-gcc compilers that perform alias optimization,
  95  * so this code should work.
  96  */
  97
  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
 105
 106 #define JSDOUBLE_SET_HI32(x, y) (JSDOUBLE_HI32(x)=(y))
 107 #define JSDOUBLE_SET_LO32(x, y) (JSDOUBLE_LO32(x)=(y))
 108
 109 #endif /* not or old GNUC */
 110
 111 #define JSDOUBLE_HI32_SIGNBIT   0x80000000
 112 #define JSDOUBLE_HI32_EXPMASK   0x7ff00000
 113 #define JSDOUBLE_HI32_MANTMASK  0x000fffff
 114
 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)))
 118
 119 #define JSDOUBLE_IS_INFINITE(x)                                               \
 120     ((JSDOUBLE_HI32(x) & ~JSDOUBLE_HI32_SIGNBIT) == JSDOUBLE_HI32_EXPMASK &&  \
 121      !JSDOUBLE_LO32(x))
 122
 123 #define JSDOUBLE_IS_FINITE(x)                                                 \
 124     ((JSDOUBLE_HI32(x) & JSDOUBLE_HI32_EXPMASK) != JSDOUBLE_HI32_EXPMASK)
 125
 126 #define JSDOUBLE_IS_NEGZERO(d)  (JSDOUBLE_HI32(d) == JSDOUBLE_HI32_SIGNBIT && \
 127                                  JSDOUBLE_LO32(d) == 0)
 128
 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))) && !((d) < i))
 138
 139 /* Initialize number constants and runtime state for the first context. */
 140 extern JSBool
 141 js_InitRuntimeNumberState(JSContext *cx);
 142
 143 extern void
 144 js_FinishRuntimeNumberState(JSContext *cx);
 145
 146 /* Initialize the Number class, returning its prototype object. */
 147 extern JSObject *
 148 js_InitNumberClass(JSContext *cx, JSObject *obj);
 149
 150 /*
 151  * String constants for global function names, used in jsapi.c and jsnum.c.
 152  */
 153 extern const char js_Infinity_str[];
 154 extern const char js_NaN_str[];
 155 extern const char js_isNaN_str[];
 156 extern const char js_isFinite_str[];
 157 extern const char js_parseFloat_str[];
 158 extern const char js_parseInt_str[];
 159
 160 /* GC-allocate a new JS number. */
 161 extern jsdouble *
 162 js_NewDouble(JSContext *cx, jsdouble d);
 163
 164 extern void
 165 js_FinalizeDouble(JSContext *cx, jsdouble *dp);
 166
 167 extern JSBool
 168 js_NewDoubleValue(JSContext *cx, jsdouble d, jsval *rval);
 169
 170 extern JSBool
 171 js_NewNumberValue(JSContext *cx, jsdouble d, jsval *rval);
 172
 173 /* Construct a Number instance that wraps around d. */
 174 extern JSObject *
 175 js_NumberToObject(JSContext *cx, jsdouble d);
 176
 177 /* Convert a number to a GC'ed string. */
 178 extern JSString *
 179 js_NumberToString(JSContext *cx, jsdouble d);
 180
 181 /*
 182  * Convert a value to a number, returning false after reporting any error,
 183  * otherwise returning true with *dp set.
 184  */
 185 extern JSBool
 186 js_ValueToNumber(JSContext *cx, jsval v, jsdouble *dp);
 187
 188 /*
 189  * Convert a value or a double to an int32, according to the ECMA rules
 190  * for ToInt32.
 191  */
 192 extern JSBool
 193 js_ValueToECMAInt32(JSContext *cx, jsval v, int32 *ip);
 194
 195 extern JSBool
 196 js_DoubleToECMAInt32(JSContext *cx, jsdouble d, int32 *ip);
 197
 198 /*
 199  * Convert a value or a double to a uint32, according to the ECMA rules
 200  * for ToUint32.
 201  */
 202 extern JSBool
 203 js_ValueToECMAUint32(JSContext *cx, jsval v, uint32 *ip);
 204
 205 extern JSBool
 206 js_DoubleToECMAUint32(JSContext *cx, jsdouble d, uint32 *ip);
 207
 208 /*
 209  * Convert a value to a number, then to an int32 if it fits by rounding to
 210  * nearest; but failing with an error report if the double is out of range
 211  * or unordered.
 212  */
 213 extern JSBool
 214 js_ValueToInt32(JSContext *cx, jsval v, int32 *ip);
 215
 216 /*
 217  * Convert a value to a number, then to a uint16 according to the ECMA rules
 218  * for ToUint16.
 219  */
 220 extern JSBool
 221 js_ValueToUint16(JSContext *cx, jsval v, uint16 *ip);
 222
 223 /*
 224  * Convert a jsdouble to an integral number, stored in a jsdouble.
 225  * If d is NaN, return 0.  If d is an infinity, return it without conversion.
 226  */
 227 extern jsdouble
 228 js_DoubleToInteger(jsdouble d);
 229
 230 /*
 231  * Similar to strtod except that it replaces overflows with infinities of the
 232  * correct sign, and underflows with zeros of the correct sign.  Guaranteed to
 233  * return the closest double number to the given input in dp.
 234  *
 235  * Also allows inputs of the form [+|-]Infinity, which produce an infinity of
 236  * the appropriate sign.  The case of the "Infinity" string must match exactly.
 237  * If the string does not contain a number, set *ep to s and return 0.0 in dp.
 238  * Return false if out of memory.
 239  */
 240 extern JSBool
 241 js_strtod(JSContext *cx, const jschar *s, const jschar **ep, jsdouble *dp);
 242
 243 /*
 244  * Similar to strtol except that it handles integers of arbitrary size.
 245  * Guaranteed to return the closest double number to the given input when radix
 246  * is 10 or a power of 2.  Callers may see round-off errors for very large
 247  * numbers of a different radix than 10 or a power of 2.
 248  *
 249  * If the string does not contain a number, set *ep to s and return 0.0 in dp.
 250  * Return false if out of memory.
 251  */
 252 extern JSBool
 253 js_strtointeger(JSContext *cx, const jschar *s, const jschar **ep, jsint radix, jsdouble *dp);
 254
 255 JS_END_EXTERN_C
 256
 257 #endif /* jsnum_h___ */