From 2772dfe8a1eae7c942bb50d84bda3f45b5d7b683 Mon Sep 17 00:00:00 2001
From: csharptest <roger@csharptest.net>
Date: Wed, 8 Jun 2011 15:50:58 -0500
Subject: Performance fix for float/double write bytes.  Performance fix, do
 not use Array.Copy.

---
 src/ProtocolBuffers/Bytes.cs | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 src/ProtocolBuffers/Bytes.cs

(limited to 'src/ProtocolBuffers/Bytes.cs')

diff --git a/src/ProtocolBuffers/Bytes.cs b/src/ProtocolBuffers/Bytes.cs
new file mode 100644
index 00000000..88bc16f8
--- /dev/null
+++ b/src/ProtocolBuffers/Bytes.cs
@@ -0,0 +1,32 @@
+namespace Google.ProtocolBuffers
+{
+    /// <summary>
+    /// Provides a utility routine to copy small arrays much more quickly than Buffer.BlockCopy
+    /// </summary>
+    static class Bytes
+    {
+        /// <summary>
+        /// The threshold above which you should use Buffer.BlockCopy rather than Bytes.Copy
+        /// </summary>
+        const int CopyThreshold = 12;
+        /// <summary>
+        /// Determines which copy routine to use based on the number of bytes to be copied.
+        /// </summary>
+        public static void Copy(byte[] src, int srcOffset, byte[] dst, int dstOffset, int count)
+        {
+            if (count > CopyThreshold)
+                global::System.Buffer.BlockCopy(src, srcOffset, dst, dstOffset, count);
+            else
+                ByteCopy(src, srcOffset, dst, dstOffset, count);
+        }
+        /// <summary>
+        /// Copyies the bytes provided with a for loop, faster when there are only a few bytes to copy
+        /// </summary>
+        public static void ByteCopy(byte[] src, int srcOffset, byte[] dst, int dstOffset, int count)
+        {
+            int stop = srcOffset + count;
+            for (int i = srcOffset; i < stop; i++)
+                dst[dstOffset++] = src[i];
+        }
+    }
+}
\ No newline at end of file
-- 
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