Rewrite of name capitalization routine 'UnderscoresToPascalOrCamelCase'

1 files changed, 47 insertions, 41 deletions

diff --git a/src/ProtocolBuffers/NameHelpers.cs b/src/ProtocolBuffers/NameHelpers.cs
index cd8f2a79..40231147 100644
--- a/src/ProtocolBuffers/NameHelpers.cs
+++ b/src/ProtocolBuffers/NameHelpers.cs
@@ -34,8 +34,10 @@
 

 #endregion

 

+using System;

 using System.Globalization;

 using System.Text;

+using System.Text.RegularExpressions;

 

 namespace Google.ProtocolBuffers

 {

@@ -64,49 +66,14 @@ namespace Google.ProtocolBuffers
         /// </summary>

         private static string UnderscoresToPascalOrCamelCase(string input, bool pascal)

         {

-            StringBuilder result = new StringBuilder();

-            bool capitaliseNext = pascal;

-            for (int i = 0; i < input.Length; i++)

+            string name = Transform(input, pascal ? UnderlineToPascal : UnderlineToCamel, x => x.Value.TrimStart('_').ToUpper());

+            if (!pascal && name.Length > 0 && Char.IsUpper(name[0]))

             {

-                char c = input[i];

-                if ('a' <= c && c <= 'z')

-                {

-                    if (capitaliseNext)

-                    {

-                        result.Append(char.ToUpper(c, CultureInfo.InvariantCulture));

-                    }

-                    else

-                    {

-                        result.Append(c);

-                    }

-                    capitaliseNext = false;

-                }

-                else if ('A' <= c && c <= 'Z')

-                {

-                    if (i == 0 && !pascal)

-                    {

-                        // Force first letter to lower-case unless explicitly told to

-                        // capitalize it.

-                        result.Append(char.ToLower(c, CultureInfo.InvariantCulture));

-                    }

-                    else

-                    {

-                        // Capital letters after the first are left as-is.

-                        result.Append(c);

-                    }

-                    capitaliseNext = false;

-                }

-                else if ('0' <= c && c <= '9')

-                {

-                    result.Append(c);

-                    capitaliseNext = true;

-                }

-                else

-                {

-                    capitaliseNext = true;

-                }

+                char[] chars = name.ToCharArray();

+                chars[0] = char.ToLower(chars[0]);

+                return new string(chars);

             }

-            return result.ToString();

+            return name;

         }

 

         internal static string StripProto(string text)

@@ -131,5 +98,44 @@ namespace Google.ProtocolBuffers
             }

             return false;

         }

+

+        /// <summary>

+        /// Similar to UnderlineToCamel, but also matches the first character if it is lower-case

+        /// </summary>

+        private static Regex UnderlineToPascal = new Regex(@"(?:^|[0-9_])[a-z]");

+

+        /// <summary>

+        /// Matches lower-case character that follow either an underscore, or a number

+        /// </summary>

+        private static Regex UnderlineToCamel = new Regex(@"[0-9_][a-z]");

+

+        /// <summary>

+        /// Used for text-template transformation where a regex match is replaced in the input string.

+        /// </summary>

+        /// <param name="input">The text to perform the replacement upon</param>

+        /// <param name="pattern">The regex used to perform the match</param>

+        /// <param name="fnReplace">A delegate that selects the appropriate replacement text</param>

+        /// <returns>The newly formed text after all replacements are made</returns>

+        /// <remarks>

+        /// Originally found at http://csharptest.net/browse/src/Library/Utils/StringUtils.cs#120

+        /// Republished here by the original author under this project's licensing.

+        /// </remarks>

+        private static string Transform(string input, Regex pattern, Converter<Match, string> fnReplace)

+        {

+            int currIx = 0;

+            StringBuilder sb = new StringBuilder();

+

+            foreach (Match match in pattern.Matches(input))

+            {

+                sb.Append(input, currIx, match.Index - currIx);

+                string replace = fnReplace(match);

+                sb.Append(replace);

+

+                currIx = match.Index + match.Length;

+            }

+

+            sb.Append(input, currIx, input.Length - currIx);

+            return sb.ToString();

+        }

     }

 }
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