Add CollapseWhitespace string extension

Author: mythz

src/ServiceStack.Text/StreamExtensions.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Text;
 using ServiceStack.Text;
 
 namespace ServiceStack
@@ -242,5 +243,29 @@ private static byte[] ReadExactlyFast(Stream fromStream, byte[] intoBuffer, int
             }
             return intoBuffer;
         }
+
+        public static string CollapseWhitespace(this string str)
+        {
+            if (str == null) 
+                return null;
+
+            var sb = new StringBuilder();
+
+            var lastChar = (char)0;
+            for (var i = 0; i < str.Length; i++)
+            {
+                var c = str[i];
+                if (c < 32) continue; // Skip all these
+                if (c == 32)
+                {
+                    if (lastChar == 32)
+                        continue; // Only write one space character
+                }
+                sb.Append(c);
+                lastChar = c;
+            }
+
+            return sb.ToString();
+        }
     }
 }