X-Git-Url: https://git.saurik.com/apple/javascriptcore.git/blobdiff_plain/b5422865f473faf3977f31b96a635c4c8c4ede09..9dae56ea45a0f5f8136a5c93d6f3a7f99399ca73:/kjs/JSImmediate.h diff --git a/kjs/JSImmediate.h b/kjs/JSImmediate.h deleted file mode 100644 index bc0cb16..0000000 --- a/kjs/JSImmediate.h +++ /dev/null @@ -1,278 +0,0 @@ -/* - * Copyright (C) 2003, 2004, 2005, 2006, 2007 Apple Inc. All rights reserved. - * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org) - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Library General Public - * License as published by the Free Software Foundation; either - * version 2 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Library General Public License for more details. - * - * You should have received a copy of the GNU Library General Public License - * along with this library; see the file COPYING.LIB. If not, write to - * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, - * Boston, MA 02110-1301, USA. - * - */ - -#ifndef KJS_JS_IMMEDIATE_H -#define KJS_JS_IMMEDIATE_H - -#include "JSType.h" -#include -#include -#include -#include -#include -#include -#include - -namespace KJS { - -class ExecState; -class JSObject; -class JSValue; -class UString; - -/* - * A JSValue* is either a pointer to a cell (a heap-allocated object) or an immediate (a type-tagged - * signed int masquerading as a pointer). The low two bits in a JSValue* are available - * for type tagging because allocator alignment guarantees they will be 00 in cell pointers. - * - * For example, on a 32 bit system: - * - * JSCell*: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 00 - * [ high 30 bits: pointer address ] [ low 2 bits -- always 0 ] - * - * JSImmediate: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXX TT - * [ high 30 bits: signed int ] [ low 2 bits -- type tag ] - * - * The bit "payload" (the high 30 bits) is a 30 bit signed int for immediate numbers, a flag to distinguish true/false - * and undefined/null. - * - * Notice that the JSType value of NullType is 4, which requires 3 bits to encode. Since we only have 2 bits - * available for type tagging, we tag the null immediate with UndefinedType, and JSImmediate::type() has - * to sort them out. - */ - -class JSImmediate { -public: - static ALWAYS_INLINE bool isImmediate(const JSValue* v) - { - return getTag(v) != 0; - } - - static ALWAYS_INLINE bool isNumber(const JSValue* v) - { - return (getTag(v) == NumberType); - } - - static ALWAYS_INLINE bool isBoolean(const JSValue* v) - { - return (getTag(v) == BooleanType); - } - - // Since we have room for only 3 unique tags, null and undefined have to share. - static ALWAYS_INLINE bool isUndefinedOrNull(const JSValue* v) - { - return (getTag(v) == UndefinedType); - } - - static JSValue* from(char); - static JSValue* from(signed char); - static JSValue* from(unsigned char); - static JSValue* from(short); - static JSValue* from(unsigned short); - static JSValue* from(int); - static JSValue* from(unsigned); - static JSValue* from(long); - static JSValue* from(unsigned long); - static JSValue* from(long long); - static JSValue* from(unsigned long long); - static JSValue* from(double); - - static ALWAYS_INLINE bool areBothImmediateNumbers(const JSValue* v1, const JSValue* v2) - { - return (reinterpret_cast(v1) & reinterpret_cast(v2) & TagMask) == NumberType; - } - - static ALWAYS_INLINE JSValue* andImmediateNumbers(const JSValue* v1, const JSValue* v2) - { - ASSERT(areBothImmediateNumbers(v1, v2)); - return reinterpret_cast(reinterpret_cast(v1) & reinterpret_cast(v2)); - } - - static double toDouble(const JSValue*); - static bool toBoolean(const JSValue*); - static JSObject* toObject(const JSValue*, ExecState*); - static UString toString(const JSValue*); - static JSType type(const JSValue*); - - static bool getUInt32(const JSValue*, uint32_t&); - static bool getTruncatedInt32(const JSValue*, int32_t&); - static bool getTruncatedUInt32(const JSValue*, uint32_t&); - - static int32_t getTruncatedInt32(const JSValue*); - - static JSValue* trueImmediate(); - static JSValue* falseImmediate(); - static JSValue* undefinedImmediate(); - static JSValue* nullImmediate(); - -private: - static const uintptr_t TagMask = 3; // type tags are 2 bits long - - // Immediate values are restricted to a 30 bit signed value. - static const int minImmediateInt = -(1 << 29); - static const int maxImmediateInt = (1 << 29) - 1; - static const unsigned maxImmediateUInt = maxImmediateInt; - - static ALWAYS_INLINE JSValue* tag(uintptr_t bits, uintptr_t tag) - { - return reinterpret_cast(bits | tag); - } - - static ALWAYS_INLINE uintptr_t unTag(const JSValue* v) - { - return reinterpret_cast(v) & ~TagMask; - } - - static ALWAYS_INLINE uintptr_t getTag(const JSValue* v) - { - return reinterpret_cast(v) & TagMask; - } -}; - -ALWAYS_INLINE JSValue* JSImmediate::trueImmediate() { return tag(1 << 2, BooleanType); } -ALWAYS_INLINE JSValue* JSImmediate::falseImmediate() { return tag(0, BooleanType); } -ALWAYS_INLINE JSValue* JSImmediate::undefinedImmediate() { return tag(1 << 2, UndefinedType); } -ALWAYS_INLINE JSValue* JSImmediate::nullImmediate() { return tag(0, UndefinedType); } - -ALWAYS_INLINE bool JSImmediate::toBoolean(const JSValue* v) -{ - ASSERT(isImmediate(v)); - uintptr_t bits = unTag(v); - return (bits != 0) & (JSImmediate::getTag(v) != UndefinedType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(char i) -{ - return tag(i << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(signed char i) -{ - return tag(i << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(unsigned char i) -{ - return tag(i << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(short i) -{ - return tag(i << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(unsigned short i) -{ - return tag(i << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(int i) -{ - if ((i < minImmediateInt) | (i > maxImmediateInt)) - return 0; - return tag(i << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(unsigned i) -{ - if (i > maxImmediateUInt) - return 0; - return tag(i << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(long i) -{ - if ((i < minImmediateInt) | (i > maxImmediateInt)) - return 0; - return tag(i << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(unsigned long i) -{ - if (i > maxImmediateUInt) - return 0; - return tag(i << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(long long i) -{ - if ((i < minImmediateInt) | (i > maxImmediateInt)) - return 0; - return tag(static_cast(i) << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(unsigned long long i) -{ - if (i > maxImmediateUInt) - return 0; - return tag(static_cast(i) << 2, NumberType); -} - -ALWAYS_INLINE JSValue* JSImmediate::from(double d) -{ - const int intVal = static_cast(d); - - if ((intVal < minImmediateInt) | (intVal > maxImmediateInt)) - return 0; - - // Check for data loss from conversion to int. - if ((intVal != d) || (!intVal && signbit(d))) - return 0; - - return tag(intVal << 2, NumberType); -} - -ALWAYS_INLINE int32_t JSImmediate::getTruncatedInt32(const JSValue* v) -{ - ASSERT(isNumber(v)); - return static_cast(unTag(v)) >> 2; -} - -ALWAYS_INLINE double JSImmediate::toDouble(const JSValue* v) -{ - ASSERT(isImmediate(v)); - const int32_t i = static_cast(unTag(v)) >> 2; - if (JSImmediate::getTag(v) == UndefinedType && i) - return std::numeric_limits::quiet_NaN(); - return i; -} - -ALWAYS_INLINE bool JSImmediate::getUInt32(const JSValue* v, uint32_t& i) -{ - const int32_t si = static_cast(unTag(v)) >> 2; - i = si; - return isNumber(v) & (si >= 0); -} - -ALWAYS_INLINE bool JSImmediate::getTruncatedInt32(const JSValue* v, int32_t& i) -{ - i = static_cast(unTag(v)) >> 2; - return isNumber(v); -} - -ALWAYS_INLINE bool JSImmediate::getTruncatedUInt32(const JSValue* v, uint32_t& i) -{ - return getUInt32(v, i); -} - -} // namespace KJS - -#endif