SubtitleEdit/libse/StringExtensions.cs
2015-10-05 21:18:41 +02:00

202 lines
7.1 KiB
C#

using System;
using System.Globalization;
using System.Text;
namespace Nikse.SubtitleEdit.Core
{
public static class StringExtensions
{
public static bool LineStartsWithHtmlTag(this string text, bool threeLengthTag, bool includeFont = false)
{
if (text == null || (!threeLengthTag && !includeFont))
return false;
return StartsWithHtmlTag(text, threeLengthTag, includeFont);
}
public static bool LineEndsWithHtmlTag(this string text, bool threeLengthTag, bool includeFont = false)
{
if (text == null)
return false;
var len = text.Length;
if (len < 6 || text[len - 1] != '>')
return false;
// </font> </i>
if (threeLengthTag && len > 3 && text[len - 4] == '<' && text[len - 3] == '/')
return true;
if (includeFont && len > 8 && text[len - 7] == '<' && text[len - 6] == '/')
return true;
return false;
}
public static bool LineBreakStartsWithHtmlTag(this string text, bool threeLengthTag, bool includeFont = false)
{
if (text == null || (!threeLengthTag && !includeFont))
return false;
var newLineIdx = text.IndexOf(Environment.NewLine, StringComparison.Ordinal);
if (newLineIdx < 0 || text.Length < newLineIdx + 5)
return false;
text = text.Substring(newLineIdx + 2);
return StartsWithHtmlTag(text, threeLengthTag, includeFont);
}
private static bool StartsWithHtmlTag(string text, bool threeLengthTag, bool includeFont)
{
if (threeLengthTag && text.Length >= 3 && text[0] == '<' && text[2] == '>' && (text[1] == 'i' || text[1] == 'I' || text[1] == 'u' || text[1] == 'U' || text[1] == 'b' || text[1] == 'B'))
return true;
if (includeFont && text.Length > 5 && text.StartsWith("<font", StringComparison.OrdinalIgnoreCase))
return text.IndexOf('>', 5) >= 5; // <font> or <font color="#000000">
return false;
}
public static bool StartsWith(this string s, char c)
{
return s.Length > 0 && s[0] == c;
}
public static bool StartsWith(this StringBuilder sb, char c)
{
return sb.Length > 0 && sb[0] == c;
}
public static bool EndsWith(this string s, char c)
{
return s.Length > 0 && s[s.Length - 1] == c;
}
public static bool EndsWith(this StringBuilder sb, char c)
{
return sb.Length > 0 && sb[sb.Length - 1] == c;
}
public static bool Contains(this string source, char value)
{
return source.IndexOf(value) >= 0;
}
public static bool Contains(this string source, char[] value)
{
return source.IndexOfAny(value) >= 0;
}
public static bool Contains(this string source, string value, StringComparison comparisonType)
{
return source.IndexOf(value, comparisonType) >= 0;
}
public static string[] SplitToLines(this string source)
{
return source.Replace("\r\n", "\n").Replace('\r', '\n').Replace('\u2028', '\n').Split('\n');
}
// http://www.codeproject.com/Articles/43726/Optimizing-string-operations-in-C
public static int FastIndexOf(this string source, string pattern)
{
if (pattern == null) throw new ArgumentNullException();
if (pattern.Length == 0) return 0;
if (pattern.Length == 1) return source.IndexOf(pattern[0]);
int limit = source.Length - pattern.Length + 1;
if (limit < 1) return -1;
// Store the first 2 characters of "pattern"
char c0 = pattern[0];
char c1 = pattern[1];
// Find the first occurrence of the first character
int first = source.IndexOf(c0, 0, limit);
while (first != -1)
{
// Check if the following character is the same like
// the 2nd character of "pattern"
if (source[first + 1] != c1)
{
first = source.IndexOf(c0, ++first, limit - first);
continue;
}
// Check the rest of "pattern" (starting with the 3rd character)
bool found = true;
for (var j = 2; j < pattern.Length; j++)
if (source[first + j] != pattern[j])
{
found = false;
break;
}
// If the whole word was found, return its index, otherwise try again
if (found) return first;
first = source.IndexOf(c0, ++first, limit - first);
}
return -1;
}
public static int IndexOfAny(this string s, string[] words, StringComparison comparionType)
{
if (words == null || string.IsNullOrEmpty(s))
return -1;
for (int i = 0; i < words.Length; i++)
{
var idx = s.IndexOf(words[i], comparionType);
if (idx >= 0)
return idx;
}
return -1;
}
public static string FixExtraSpaces(this string s)
{
if (string.IsNullOrEmpty(s))
return s;
while (s.Contains(" "))
s = s.Replace(" ", " ");
s = s.Replace(" " + Environment.NewLine, Environment.NewLine);
return s.Replace(Environment.NewLine + " ", Environment.NewLine);
}
public static bool ContainsLetter(this string s)
{
if (string.IsNullOrWhiteSpace(s))
return false;
foreach (var c in s)
{
if (char.IsLetter(c))
return true;
}
return false;
}
public static string RemoveControlCharacters(this string s)
{
var sb = new StringBuilder(s.Length);
foreach (var ch in s)
{
if (!Char.IsControl(ch))
sb.Append(ch);
}
return sb.ToString();
}
public static string RemoveControlCharactersButWhiteSpace(this string s)
{
var sb = new StringBuilder(s.Length);
foreach (var ch in s)
{
if (!Char.IsControl(ch) || ch == '\u000d' || ch == '\u000a' || ch == '\u0009')
sb.Append(ch);
}
return sb.ToString();
}
public static string CapitalizeFirstLetter(this string s, CultureInfo ci = null)
{
var si = new StringInfo(s);
if (ci == null)
ci = CultureInfo.CurrentCulture;
if (si.LengthInTextElements > 0)
s = si.SubstringByTextElements(0, 1).ToUpper(ci);
if (si.LengthInTextElements > 1)
s += si.SubstringByTextElements(1);
return s;
}
}
}