xenadmin/XenModel/Utils/StringExtensions.cs

/* Copyright (c) Cloud Software Group, Inc. 
 * 
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 * with or without modification, are permitted provided 
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 *     following disclaimer. 
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 *     copyright notice, this list of conditions and the 
 *     following disclaimer in the documentation and/or other 
 *     materials provided with the distribution. 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
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 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
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using System;
using System.Collections.Generic;
using System.Linq;

namespace XenAdmin
{
    public static class StringExtensions
    {
        public static string[] SplitInChunks(this string input, int chunkSize)
        {
            if (input == null)
                throw new NullReferenceException();

            if (chunkSize < 1)
                throw new ArgumentException("ChunkSize cannot be less than 1");

            if (input == "")
                return new string[] { };

            int numberOfChunks = input.Length / chunkSize;
            if (input.Length % chunkSize > 0)
                numberOfChunks++;

            var result = new string[numberOfChunks];
            for (int i = 0; i < numberOfChunks; i++)
            {
                if (i < numberOfChunks - 1)
                    result[i] = input.Substring(i * chunkSize, chunkSize);
                else
                    result[i] = input.Substring(i * chunkSize);
            }

            return result;
        }

        public static Dictionary<string, string> SplitToDictionary(this string input, char pairDelimiter)
        {
            return input.Split(new[] {pairDelimiter}, StringSplitOptions.RemoveEmptyEntries)
                .Select(o => o.Split(new[] {'='}, 2)) //2 is used in case the delimiter appears within the string
                .ToDictionary(o => o.FirstOrDefault(), o => o.LastOrDefault());
        }

        /// <summary>
        /// Ellipsise string by appending the ellipsis - no truncation is performed
        /// </summary>
        /// <param name="input"></param>
        /// <returns></returns>
        public static string AddEllipsis(this string input)
        {
            return String.Concat(input, Messages.ELLIPSIS);
        }

        /// <summary>
        /// If input is longer than maxLength, returns a string of length maxLength consisting of a truncated
        /// version of the input string with an i18n'd ellipsis character appended. Otherwise returns input.
        /// </summary>
        /// <param name="input">May be null, in which case the empty string is returned.</param>
        /// <param name="maxLength">Must be >= Messages.ELLIPSIS.Length.</param>
        /// <returns></returns>
        public static string Ellipsise(this string input, int maxLength)
        {
            if (maxLength < Messages.ELLIPSIS.Length)
                return ".";
            if (input == null)
                return "";
            if (input.Length < maxLength)
                return input;
            else
                return input.Truncate(maxLength - Messages.ELLIPSIS.Length) + Messages.ELLIPSIS;
        }

        /// <summary>
        /// Truncate string to a fixed number of characters, but not cutting it in the middle of a UTF-16 surrogate pair:
        /// shorten it by one if necessary. The "number of characters" is actually "number of UTF-16 double bytes", not
        /// the number of true Unicode characters. In other words, this a safe replacement for s.Substring(0, len).
        /// </summary>
        /// <reference>CA-89876</reference>
        /// <param name="s">The string to be truncated</param>
        /// <param name="len">The length of the resultant string</param>
        /// <returns>A truncated copy of the string</returns>
        public static string Truncate(this string s, int len)
        {
            if (len > 0 && Char.IsSurrogatePair(s, len - 1))
                return s.Substring(0, len - 1);
            else
                return s.Substring(0, len);
        }

        /// <summary>
        /// Escapes ampersands by doubling them up. Will return null if passed null.
        /// </summary>
        /// <param name="s"></param>
        /// <returns></returns>
        public static string EscapeAmpersands(this string s)
        {
            if (s == null)
                return null;
            else
                return s.Replace("&", "&&");
        }

        public static string EscapeQuotes(this string s)
        {
            return s == null ? null : s.Replace("\"", "\"\"");
        }
    }
}