1 files changed, 37 insertions, 1 deletions
diff --git a/Source/WebCore/html/canvas/ArrayBuffer.cpp b/Source/WebCore/html/canvas/ArrayBuffer.cpp
index 4f75cc3..9c072ed 100644
--- a/Source/WebCore/html/canvas/ArrayBuffer.cpp
+++ b/Source/WebCore/html/canvas/ArrayBuffer.cpp
@@ -1,5 +1,7 @@
 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
+ * Copyright (C) 2012 Sony Ericsson Mobile Communications AB
+ * Copyright (C) 2012 Sony Mobile Communications AB
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
@@ -30,6 +32,16 @@
 
 namespace WebCore {
 
+static int clampValue(int x, int left, int right)
+{
+    ASSERT(left <= right);
+    if (x < left)
+        x = left;
+    if (right < x)
+        x = right;
+    return x;
+}
+
 PassRefPtr<ArrayBuffer> ArrayBuffer::create(unsigned numElements, unsigned elementByteSize)
 {
     void* data = tryAllocate(numElements, elementByteSize);
@@ -43,7 +55,7 @@ PassRefPtr<ArrayBuffer> ArrayBuffer::create(ArrayBuffer* other)
     return ArrayBuffer::create(other->data(), other->byteLength());
 }
 
-PassRefPtr<ArrayBuffer> ArrayBuffer::create(void* source, unsigned byteLength)
+PassRefPtr<ArrayBuffer> ArrayBuffer::create(const void* source, unsigned byteLength)
 {
     void* data = tryAllocate(byteLength, 1);
     if (!data)
@@ -74,6 +86,30 @@ unsigned ArrayBuffer::byteLength() const
     return m_sizeInBytes;
 }
 
+PassRefPtr<ArrayBuffer> ArrayBuffer::slice(int begin, int end) const
+{
+    return sliceImpl(clampIndex(begin), clampIndex(end));
+}
+
+PassRefPtr<ArrayBuffer> ArrayBuffer::slice(int begin) const
+{
+    return sliceImpl(clampIndex(begin), byteLength());
+}
+
+PassRefPtr<ArrayBuffer> ArrayBuffer::sliceImpl(unsigned begin, unsigned end) const
+{
+    unsigned size = begin <= end ? end - begin : 0;
+    return ArrayBuffer::create(static_cast<const char*>(data()) + begin, size);
+}
+
+unsigned ArrayBuffer::clampIndex(int index) const
+{
+    unsigned currentLength = byteLength();
+    if (index < 0)
+        index = currentLength + index;
+    return clampValue(index, 0, currentLength);
+}
+
 ArrayBuffer::~ArrayBuffer()
 {
     WTF::fastFree(m_data);