1 /*
2 * Copyright (C) 1999-2001 Harri Porten (porten@kde.org)
3 * Copyright (C) 2001 Peter Kelly (pmk@post.com)
4 * Copyright (C) 2003, 2007, 2008 Apple Inc. All rights reserved.
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
15 *
16 * You should have received a copy of the GNU Library General Public License
17 * along with this library; see the file COPYING.LIB. If not, write to
18 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
20 *
21 */
22
23 #include "config.h"
24 #include "JSValue.h"
25
26 #include "BooleanConstructor.h"
27 #include "BooleanPrototype.h"
28 #include "Error.h"
29 #include "ExceptionHelpers.h"
30 #include "JSGlobalObject.h"
31 #include "JSFunction.h"
32 #include "JSNotAnObject.h"
33 #include "NumberObject.h"
34 #include <wtf/MathExtras.h>
35 #include <wtf/StringExtras.h>
36
37 namespace JSC {
38
39 static const double D32 = 4294967296.0;
40
41 // ECMA 9.4
toInteger(ExecState * exec) const42 double JSValue::toInteger(ExecState* exec) const
43 {
44 if (isInt32())
45 return asInt32();
46 double d = toNumber(exec);
47 return isnan(d) ? 0.0 : trunc(d);
48 }
49
toIntegerPreserveNaN(ExecState * exec) const50 double JSValue::toIntegerPreserveNaN(ExecState* exec) const
51 {
52 if (isInt32())
53 return asInt32();
54 return trunc(toNumber(exec));
55 }
56
toObjectSlowCase(ExecState * exec,JSGlobalObject * globalObject) const57 JSObject* JSValue::toObjectSlowCase(ExecState* exec, JSGlobalObject* globalObject) const
58 {
59 ASSERT(!isCell());
60
61 if (isInt32() || isDouble())
62 return constructNumber(exec, globalObject, asValue());
63 if (isTrue() || isFalse())
64 return constructBooleanFromImmediateBoolean(exec, globalObject, asValue());
65
66 ASSERT(isUndefinedOrNull());
67 throwError(exec, createNotAnObjectError(exec, *this));
68 return new (exec) JSNotAnObject(exec);
69 }
70
toThisObjectSlowCase(ExecState * exec) const71 JSObject* JSValue::toThisObjectSlowCase(ExecState* exec) const
72 {
73 ASSERT(!isCell());
74
75 if (isInt32() || isDouble())
76 return constructNumber(exec, exec->lexicalGlobalObject(), asValue());
77 if (isTrue() || isFalse())
78 return constructBooleanFromImmediateBoolean(exec, exec->lexicalGlobalObject(), asValue());
79 ASSERT(isUndefinedOrNull());
80 return exec->globalThisValue();
81 }
82
synthesizeObject(ExecState * exec) const83 JSObject* JSValue::synthesizeObject(ExecState* exec) const
84 {
85 ASSERT(!isCell());
86 if (isNumber())
87 return constructNumber(exec, exec->lexicalGlobalObject(), asValue());
88 if (isBoolean())
89 return constructBooleanFromImmediateBoolean(exec, exec->lexicalGlobalObject(), asValue());
90
91 ASSERT(isUndefinedOrNull());
92 throwError(exec, createNotAnObjectError(exec, *this));
93 return new (exec) JSNotAnObject(exec);
94 }
95
synthesizePrototype(ExecState * exec) const96 JSObject* JSValue::synthesizePrototype(ExecState* exec) const
97 {
98 ASSERT(!isCell());
99 if (isNumber())
100 return exec->lexicalGlobalObject()->numberPrototype();
101 if (isBoolean())
102 return exec->lexicalGlobalObject()->booleanPrototype();
103
104 ASSERT(isUndefinedOrNull());
105 throwError(exec, createNotAnObjectError(exec, *this));
106 return new (exec) JSNotAnObject(exec);
107 }
108
109 #ifndef NDEBUG
description()110 char* JSValue::description()
111 {
112 static const size_t size = 32;
113 static char description[size];
114
115 if (!*this)
116 snprintf(description, size, "<JSValue()>");
117 else if (isInt32())
118 snprintf(description, size, "Int32: %d", asInt32());
119 else if (isDouble())
120 snprintf(description, size, "Double: %lf", asDouble());
121 else if (isCell())
122 snprintf(description, size, "Cell: %p", asCell());
123 else if (isTrue())
124 snprintf(description, size, "True");
125 else if (isFalse())
126 snprintf(description, size, "False");
127 else if (isNull())
128 snprintf(description, size, "Null");
129 else if (isUndefined())
130 snprintf(description, size, "Undefined");
131 else
132 snprintf(description, size, "INVALID");
133
134 return description;
135 }
136 #endif
137
138 // This in the ToInt32 operation is defined in section 9.5 of the ECMA-262 spec.
139 // Note that this operation is identical to ToUInt32 other than to interpretation
140 // of the resulting bit-pattern (as such this metod is also called to implement
141 // ToUInt32).
142 //
143 // The operation can be descibed as round towards zero, then select the 32 least
144 // bits of the resulting value in 2s-complement representation.
toInt32(double number)145 int32_t toInt32(double number)
146 {
147 int64_t bits = WTF::bitwise_cast<int64_t>(number);
148 int32_t exp = (static_cast<int32_t>(bits >> 52) & 0x7ff) - 0x3ff;
149
150 // If exponent < 0 there will be no bits to the left of the decimal point
151 // after rounding; if the exponent is > 83 then no bits of precision can be
152 // left in the low 32-bit range of the result (IEEE-754 doubles have 52 bits
153 // of fractional precision).
154 // Note this case handles 0, -0, and all infinte, NaN, & denormal value.
155 if (exp < 0 || exp > 83)
156 return 0;
157
158 // Select the appropriate 32-bits from the floating point mantissa. If the
159 // exponent is 52 then the bits we need to select are already aligned to the
160 // lowest bits of the 64-bit integer representation of tghe number, no need
161 // to shift. If the exponent is greater than 52 we need to shift the value
162 // left by (exp - 52), if the value is less than 52 we need to shift right
163 // accordingly.
164 int32_t result = (exp > 52)
165 ? static_cast<int32_t>(bits << (exp - 52))
166 : static_cast<int32_t>(bits >> (52 - exp));
167
168 // IEEE-754 double precision values are stored omitting an implicit 1 before
169 // the decimal point; we need to reinsert this now. We may also the shifted
170 // invalid bits into the result that are not a part of the mantissa (the sign
171 // and exponent bits from the floatingpoint representation); mask these out.
172 if (exp < 32) {
173 int32_t missingOne = 1 << exp;
174 result &= missingOne - 1;
175 result += missingOne;
176 }
177
178 // If the input value was negative (we could test either 'number' or 'bits',
179 // but testing 'bits' is likely faster) invert the result appropriately.
180 return bits < 0 ? -result : result;
181 }
182
nonInlineNaN()183 NEVER_INLINE double nonInlineNaN()
184 {
185 #if OS(SYMBIAN)
186 return nanval();
187 #else
188 return std::numeric_limits<double>::quiet_NaN();
189 #endif
190 }
191
isValidCallee()192 bool JSValue::isValidCallee()
193 {
194 return asObject(asObject(asCell())->getAnonymousValue(0))->isGlobalObject();
195 }
196
197 } // namespace JSC
198