auto import from //depot/cupcake/@135843

1 files changed, 112 insertions, 0 deletions

diff --git a/JavaScriptCore/runtime/SmallStrings.cpp b/JavaScriptCore/runtime/SmallStrings.cpp
new file mode 100644
index 0000000..06811b9
--- /dev/null
+++ b/JavaScriptCore/runtime/SmallStrings.cpp
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2008 Apple Inc. All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+#include "SmallStrings.h"
+
+#include "JSGlobalObject.h"
+#include "JSString.h"
+
+namespace JSC {
+
+class SmallStringsStorage {
+public:
+    SmallStringsStorage();
+    ~SmallStringsStorage();
+
+    UString::Rep* rep(unsigned char character) { return &reps[character]; }
+
+private:
+    UChar characters[0x100];
+    UString::Rep* reps;
+};
+
+SmallStringsStorage::SmallStringsStorage()
+    : reps(static_cast<UString::Rep*>(fastZeroedMalloc(sizeof(UString::Rep) * 0x100)))
+{
+    for (unsigned i = 0; i < 0x100; ++i) {
+        characters[i] = i;
+        reps[i].offset = i;
+        reps[i].len = 1;
+        reps[i].rc = 1;
+        reps[i].baseString = &reps[0];
+    }
+    reps[0].rc = 0x101;
+    reps[0].buf = characters;
+
+    // make sure UString doesn't try to reuse the buffer by pretending we have one more character in it
+    reps[0].usedCapacity = 0x101;
+    reps[0].capacity = 0x101;
+}
+
+SmallStringsStorage::~SmallStringsStorage()
+{
+    fastFree(reps);
+}
+
+SmallStrings::SmallStrings()
+    : m_emptyString(0)
+    , m_storage(0)
+{
+    for (unsigned i = 0; i < 0x100; ++i)
+        m_singleCharacterStrings[i] = 0;
+}
+
+SmallStrings::~SmallStrings()
+{
+}
+
+void SmallStrings::mark()
+{
+    if (m_emptyString && !m_emptyString->marked())
+        m_emptyString->mark();
+    for (unsigned i = 0; i < 0x100; ++i) {
+        if (m_singleCharacterStrings[i] && !m_singleCharacterStrings[i]->marked())
+            m_singleCharacterStrings[i]->mark();
+    }
+}
+    
+void SmallStrings::createEmptyString(JSGlobalData* globalData)
+{
+    ASSERT(!m_emptyString);
+    m_emptyString = new (globalData) JSString(globalData, "", JSString::HasOtherOwner);
+}
+
+void SmallStrings::createSingleCharacterString(JSGlobalData* globalData, unsigned char character)
+{
+    if (!m_storage)
+        m_storage.set(new SmallStringsStorage);
+    ASSERT(!m_singleCharacterStrings[character]);
+    m_singleCharacterStrings[character] = new (globalData) JSString(globalData, m_storage->rep(character), JSString::HasOtherOwner);
+}
+
+UString::Rep* SmallStrings::singleCharacterStringRep(unsigned char character)
+{
+    if (!m_storage)
+        m_storage.set(new SmallStringsStorage);
+    return m_storage->rep(character);
+}
+
+}