using System;
using System.Globalization;
using System.Text;
namespace Knowledge
{
public class StringHelper
{
/// <summary>
/// Intercept a string of the specified length
/// </summary>
/// <param name="value"></param>
/// <param name="len"></param>
/// <returns></returns>
public static string SubStartString(string value, int len)
{
if (string.IsNullOrEmpty(value) || value.Length <= len) return value;
else return value.Substring(0, len);
}
/// <summary>
/// Removes leading specified characters from string.(default ignore case sensitive)
/// </summary>
/// <param name="value">The string to trim</param>
/// <param name="prefix">The characters to trim<</param>
/// <returns></returns>
public static string TrimStart(string value, string prefix)
{
return TrimStart(value, prefix, true);
}
/// <summary>
/// Removes leading specified characters from string.
/// </summary>
/// <param name="value">The string to trim</param>
/// <param name="prefix">The characters to trim</param>
/// <param name="ignoreCase">ignore case sensitive</param>
/// <returns></returns>
public static string TrimStart(string value, string prefix, bool ignoreCase)
{
if (string.IsNullOrEmpty(value)) return string.Empty;
if (string.IsNullOrEmpty(prefix) || value.Length < prefix.Length) return value;
if (ignoreCase)
{
if (value.Substring(0, prefix.Length).ToLower() == prefix.ToLower())
{
value = value.Substring(prefix.Length);
}
}
else
{
if (value.StartsWith(prefix)) value = value.Substring(prefix.Length);
}
return value;
}
/// <summary>
/// Converts the specified string to title case (except for words that are entirely
/// in uppercase, which are considered to be acronyms).
/// </summary>
/// <param name="value">The string to convert to title case.</param>
/// <returns></returns>
public static string TitleCase(string value)
{
if (string.IsNullOrEmpty(value)) return value;
return System.Threading.Thread.CurrentThread.CurrentCulture.TextInfo.ToTitleCase(value);
}
/// <summary>
/// Converts the first character of string to lower case
/// </summary>
/// <param name="value">The string to convert</param>
/// <returns></returns>
public static string LowerFirst(string value)
{
if (string.IsNullOrEmpty(value)) return value;
return Char.ToLowerInvariant(value[0]) + value.Substring(1);
}
/// <summary>
/// Converts the first character of string to upper case.
/// </summary>
/// <param name="value"></param>
/// <returns></returns>
public static string UpperFirst(string value)
{
if (string.IsNullOrEmpty(value)) return value;
return Char.ToUpperInvariant(value[0]) + value.Substring(1);
}
/// <summary>
/// Repeats the given string n times
/// </summary>
/// <param name="value">The string to repeat.</param>
/// <param name="n">The number of times to repeat the string.</param>
/// <returns></returns>
public static string Repeat(string value, int n = 1)
{
return new StringBuilder(value.Length * n)
.AppendJoin(value, new string[n + 1])
.ToString();
}
/// <summary>
/// Truncates string if it's longer than the given maximum string length.
/// The last characters of the truncated string are replaced with the omission string which defaults to "...".
/// </summary>
/// <param name="value">The string to truncate.</param>
/// <param name="maxLength">The maximum string length.</param>
/// <param name="omission">The string to indicate text is omission.</param>
/// <returns></returns>
public static string Truncate(string value, int maxLength, string omission = "...")
{
if (string.IsNullOrEmpty(value)) return value;
return value.Length <= maxLength ? value : value.Substring(0, maxLength) + omission;
}
/// <summary>
/// Splits string by separator
/// </summary>
/// <param name="value">The string to split</param>
/// <param name="separator">The separator pattern to split by</param>
/// <param name="options"></param>
/// <returns></returns>
public static string[] Split(string value, string separator, StringSplitOptions options)
{
return value.Split(new string[] { separator }, options);
}
/// <summary>
/// Remaps international characters to ascii compatible ones
/// based of: https://meta.stackexchange.com/questions/7435/non-us-ascii-characters-dropped-from-full-profile-url/7696#7696
/// </summary>
/// <param name="c">Charcter to remap</param>
/// <returns>Remapped character</returns>
public static string RemapInternationalCharToAscii(char c)
{
string s = c.ToString().ToLowerInvariant();
if ("àåáâäãåą".Contains(s))
{
return "a";
}
else if ("èéêëę".Contains(s))
{
return "e";
}
else if ("ìíîïı".Contains(s))
{
return "i";
}
else if ("òóôõöøőð".Contains(s))
{
return "o";
}
else if ("ùúûüŭů".Contains(s))
{
return "u";
}
else if ("çćčĉ".Contains(s))
{
return "c";
}
else if ("żźž".Contains(s))
{
return "z";
}
else if ("śşšŝ".Contains(s))
{
return "s";
}
else if ("ñń".Contains(s))
{
return "n";
}
else if ("ýÿ".Contains(s))
{
return "y";
}
else if ("ğĝ".Contains(s))
{
return "g";
}
else if (c == 'ř')
{
return "r";
}
else if (c == 'ł')
{
return "l";
}
else if (c == 'đ')
{
return "d";
}
else if (c == 'ß')
{
return "ss";
}
else if (c == 'þ')
{
return "th";
}
else if (c == 'ĥ')
{
return "h";
}
else if (c == 'ĵ')
{
return "j";
}
else
{
return "";
}
}
/// <summary>
/// Slugifies a string
/// </summary>
/// <param name="text">The string to slugify</param>
/// <param name="maxLength">Max length of slug</param>
public static string Slugify(string text, int maxLength = 0)
{
// Return empty value if text is null
if (text == null) return "";
var normalizedString = text
// Make lowercase
.ToLowerInvariant()
// Normalize the text
.Normalize(NormalizationForm.FormD);
var stringBuilder = new StringBuilder();
var stringLength = normalizedString.Length;
var prevdash = false;
var trueLength = 0;
char c;
for (int i = 0; i < stringLength; i++)
{
c = normalizedString[i];
switch (CharUnicodeInfo.GetUnicodeCategory(c))
{
// Check if the character is a letter or a digit if the character is a
// international character remap it to an ascii valid character
case UnicodeCategory.LowercaseLetter:
case UnicodeCategory.UppercaseLetter:
case UnicodeCategory.DecimalDigitNumber:
if (c < 128)
stringBuilder.Append(c);
else
stringBuilder.Append(RemapInternationalCharToAscii(c));
prevdash = false;
trueLength = stringBuilder.Length;
break;
// Check if the character is to be replaced by a hyphen but only if the last character wasn't
case UnicodeCategory.SpaceSeparator:
case UnicodeCategory.ConnectorPunctuation:
case UnicodeCategory.DashPunctuation:
case UnicodeCategory.OtherPunctuation:
case UnicodeCategory.MathSymbol:
if (!prevdash)
{
stringBuilder.Append('-');
prevdash = true;
trueLength = stringBuilder.Length;
}
break;
}
// If we are at max length, stop parsing
if (maxLength > 0 && trueLength >= maxLength)
break;
}
// Trim excess hyphens
var result = stringBuilder.ToString().Trim('-');
// Remove any excess character to meet maxlength criteria
return maxLength <= 0 || result.Length <= maxLength ? result : result.Substring(0, maxLength);
}
public static int GetBytesLength(string value)
{
if (string.IsNullOrEmpty(value)) return 0;
return System.Text.Encoding.Default.GetBytes(value).Length;
}
}
}