Fix for bug 6100:...

webkit/port/bindings/v8/CanvasPixelArray.cpp

Index: webkit/port/bindings/v8/CanvasPixelArray.cpp
===================================================================
--- webkit/port/bindings/v8/CanvasPixelArray.cpp	(revision 0)
+++ webkit/port/bindings/v8/CanvasPixelArray.cpp	(revision 0)
@@ -0,0 +1,82 @@
+/*
+ * Copyright (c) 2009, Google 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:
+ * 
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * 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.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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 THE COPYRIGHT
+ * OWNER 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 <CanvasPixelArray.h>
+
+#include <v8_proxy.h>
+#include <wtf/Assertions.h>
+
+namespace WebCore {
+
+    CanvasPixelArray::CanvasPixelArray(size_t length)
+    {
+        ASSERT((length & 3) == 0);  // Length must be a multiple of 4.
+        m_length = length;
+        m_data = static_cast<unsigned char*>(fastMalloc(m_length));
+    }
+
+    CanvasPixelArray::~CanvasPixelArray()
+    {
+        fastFree(m_data);
+        // Ensure that accesses after destruction will fail. In case there is a
+        // dangling reference.
+        m_length = 0;
+        m_data = reinterpret_cast<unsigned char*>(-1);

[Feng Qian, 2009/01/20 18:01:08]

I am curious why it is -1? not a usual null pointer value?

+    }
+
+    size_t CanvasPixelArray::length() const
+    {
+        return m_length;
+    }
+
+    unsigned char* CanvasPixelArray::data()
+    {
+        return m_data;
+    }
+
+    unsigned char CanvasPixelArray::get(size_t index)
+    {
+        ASSERT(index < m_length);
+        return m_data[index];
+    }
+
+    void CanvasPixelArray::set(size_t index, double value)
+    {
+        ASSERT(index < m_length);
+        if (!(value > 0)) {  // Test for NaN and less than zero in one go.
+            value = 0;
+        } else if (value > 255) {
+            value = 255;
+        }
+        m_data[index] = static_cast<unsigned char>(value + 0.5);
+    }
+
+}  // namespace WebCore