runtime/JSString.cpp

   1 /*
   2  *  Copyright (C) 1999-2002 Harri Porten (porten@kde.org)
   3  *  Copyright (C) 2001 Peter Kelly (pmk@post.com)
   4  *  Copyright (C) 2004, 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 "JSString.h"
  25
  26 #include "JSGlobalObject.h"
  27 #include "JSObject.h"
  28 #include "StringObject.h"
  29 #include "StringPrototype.h"
  30
  31 namespace JSC {
  32
  33 JSValue JSString::toPrimitive(ExecState*, PreferredPrimitiveType) const
  34 {
  35     return const_cast<JSString*>(this);
  36 }
  37
  38 bool JSString::getPrimitiveNumber(ExecState*, double& number, JSValue& value)
  39 {
  40     value = this;
  41     number = m_value.toDouble();
  42     return false;
  43 }
  44
  45 bool JSString::toBoolean(ExecState*) const
  46 {
  47     return !m_value.isEmpty();
  48 }
  49
  50 double JSString::toNumber(ExecState*) const
  51 {
  52     return m_value.toDouble();
  53 }
  54
  55 UString JSString::toString(ExecState*) const
  56 {
  57     return m_value;
  58 }
  59
  60 UString JSString::toThisString(ExecState*) const
  61 {
  62     return m_value;
  63 }
  64
  65 JSString* JSString::toThisJSString(ExecState*)
  66 {
  67     return this;
  68 }
  69
  70 inline StringObject* StringObject::create(ExecState* exec, JSString* string)
  71 {
  72     return new (exec) StringObject(exec->lexicalGlobalObject()->stringObjectStructure(), string);
  73 }
  74
  75 JSObject* JSString::toObject(ExecState* exec) const
  76 {
  77     return StringObject::create(exec, const_cast<JSString*>(this));
  78 }
  79
  80 JSObject* JSString::toThisObject(ExecState* exec) const
  81 {
  82     return StringObject::create(exec, const_cast<JSString*>(this));
  83 }
  84
  85 bool JSString::getOwnPropertySlot(ExecState* exec, const Identifier& propertyName, PropertySlot& slot)
  86 {
  87     // The semantics here are really getPropertySlot, not getOwnPropertySlot.
  88     // This function should only be called by JSValue::get.
  89     if (getStringPropertySlot(exec, propertyName, slot))
  90         return true;
  91     if (propertyName == exec->propertyNames().underscoreProto) {
  92         slot.setValue(exec->lexicalGlobalObject()->stringPrototype());
  93         return true;
  94     }
  95     slot.setBase(this);
  96     JSObject* object;
  97     for (JSValue prototype = exec->lexicalGlobalObject()->stringPrototype(); !prototype.isNull(); prototype = object->prototype()) {
  98         object = asObject(prototype);
  99         if (object->getOwnPropertySlot(exec, propertyName, slot))
 100             return true;
 101     }
 102     slot.setUndefined();
 103     return true;
 104 }
 105
 106 bool JSString::getOwnPropertySlot(ExecState* exec, unsigned propertyName, PropertySlot& slot)
 107 {
 108     // The semantics here are really getPropertySlot, not getOwnPropertySlot.
 109     // This function should only be called by JSValue::get.
 110     if (getStringPropertySlot(exec, propertyName, slot))
 111         return true;
 112     return JSString::getOwnPropertySlot(exec, Identifier::from(exec, propertyName), slot);
 113 }
 114
 115 JSString* jsString(JSGlobalData* globalData, const UString& s)
 116 {
 117     int size = s.size();
 118     if (!size)
 119         return globalData->smallStrings.emptyString(globalData);
 120     if (size == 1) {
 121         UChar c = s.data()[0];
 122         if (c <= 0xFF)
 123             return globalData->smallStrings.singleCharacterString(globalData, c);
 124     }
 125     return new (globalData) JSString(globalData, s);
 126 }
 127
 128 JSString* jsSubstring(JSGlobalData* globalData, const UString& s, unsigned offset, unsigned length)
 129 {
 130     ASSERT(offset <= static_cast<unsigned>(s.size()));
 131     ASSERT(length <= static_cast<unsigned>(s.size()));
 132     ASSERT(offset + length <= static_cast<unsigned>(s.size()));
 133     if (!length)
 134         return globalData->smallStrings.emptyString(globalData);
 135     if (length == 1) {
 136         UChar c = s.data()[offset];
 137         if (c <= 0xFF)
 138             return globalData->smallStrings.singleCharacterString(globalData, c);
 139     }
 140     return new (globalData) JSString(globalData, UString::Rep::create(s.rep(), offset, length));
 141 }
 142
 143 JSString* jsOwnedString(JSGlobalData* globalData, const UString& s)
 144 {
 145     int size = s.size();
 146     if (!size)
 147         return globalData->smallStrings.emptyString(globalData);
 148     if (size == 1) {
 149         UChar c = s.data()[0];
 150         if (c <= 0xFF)
 151             return globalData->smallStrings.singleCharacterString(globalData, c);
 152     }
 153     return new (globalData) JSString(globalData, s, JSString::HasOtherOwner);
 154 }
 155
 156 } // namespace JSC