StringBuilderExtensions.cs

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// Copyright 2005-2015 Giacomo Stelluti Scala & Contributors. All rights reserved. See License.md in the project root for license information.
 
using System;
using System.Text;
 
namespace CommandLine.Infrastructure
{
    internal static class StringBuilderExtensions
    {
        public static StringBuilder AppendWhen(this StringBuilder builder, bool condition, params string[] values)
        {
            if (condition)
            {
                foreach (string value in values)
                {
                    builder.Append(value);
                }
            }
 
            return builder;
        }
 
        public static StringBuilder AppendWhen(this StringBuilder builder, bool condition, params char[] values)
        {
            if (condition)
            {
                foreach (char value in values)
                {
                    builder.Append(value);
                }
            }
 
            return builder;
        }
 
        public static StringBuilder AppendFormatWhen(this StringBuilder builder,
                                                     bool condition,
                                                     string format,
                                                     params object[] args)
        {
            return condition
                       ? builder.AppendFormat(format, args)
                       : builder;
        }
 
        public static StringBuilder AppendIf(this StringBuilder builder, bool condition, string ifTrue, string ifFalse)
        {
            return condition
                       ? builder.Append(ifTrue)
                       : builder.Append(ifFalse);
        }
 
        public static StringBuilder BimapIf(this StringBuilder builder,
                                            bool condition,
                                            Func<StringBuilder, StringBuilder> ifTrue,
                                            Func<StringBuilder, StringBuilder> ifFalse)
        {
            return condition
                       ? ifTrue(builder)
                       : ifFalse(builder);
        }
 
        public static StringBuilder MapIf(this StringBuilder builder,
                                          bool condition,
                                          Func<StringBuilder, StringBuilder> ifTrue)
        {
            return condition
                       ? ifTrue(builder)
                       : builder;
        }
 
        public static StringBuilder AppendIfNotEmpty(this StringBuilder builder, params string[] values)
        {
            foreach (string value in values)
            {
                if (value.Length > 0)
                {
                    builder.Append(value);
                }
            }
 
            return builder;
        }
 
        public static string SafeToString(this StringBuilder builder)
        {
            return builder == null
                       ? string.Empty
                       : builder.ToString();
        }
 
        public static int SafeLength(this StringBuilder builder)
        {
            return builder == null ? 0 : builder.Length;
        }
 
        public static StringBuilder TrimEnd(this StringBuilder builder, char c)
        {
            return builder.Length > 0
                       ? builder.Remove(builder.Length - 1, 1)
                       : builder;
        }
 
        public static StringBuilder TrimEndIfMatch(this StringBuilder builder, char c)
        {
            if (builder.Length > 0)
            {
                if (builder[builder.Length - 1] == c)
                {
                    builder.Remove(builder.Length - 1, 1);
                }
            }
 
            return builder;
        }
 
        public static StringBuilder TrimEndIfMatchWhen(this StringBuilder builder, bool condition, char c)
        {
            return condition
                       ? builder.TrimEndIfMatch(c)
                       : builder;
        }
 
        public static int TrailingSpaces(this StringBuilder builder)
        {
            int bound = builder.Length - 1;
 
            if (builder.Length == 0)
            {
                return 0;
            }
 
            if (builder[bound] != ' ')
            {
                return 0;
            }
 
            int c = 0;
 
            for (int i = bound; i <= bound; i--)
            {
                if (i < 0)
                {
                    break;
                }
 
                if (builder[i] != ' ')
                {
                    break;
                }
 
                c++;
            }
 
            return c;
        }
 
        public static bool SafeStartsWith(this StringBuilder builder, string s)
        {
            if (string.IsNullOrEmpty(s))
            {
                return false;
            }
 
            return builder?.Length >= s.Length && builder.ToString(0, s.Length) == s;
        }
 
        public static bool SafeEndsWith(this StringBuilder builder, string s)
        {
            if (string.IsNullOrEmpty(s))
            {
                return false;
            }
 
            return builder?.Length >= s.Length && builder.ToString(builder.Length - s.Length, s.Length) == s;
        }
    }
}