StringBuilder - ExtractStringDoubleQuote
A StringBuilder extension method that extracts the string double quote described by @this.
public static void Main() { int endIndex; // C# Extension Method: StringBuilder - ExtractStringDoubleQuote Console.WriteLine(new StringBuilder(" ").ExtractStringDoubleQuote()); Console.WriteLine(new StringBuilder("\"z\"").ExtractStringDoubleQuote().ToString()); Console.WriteLine(new StringBuilder("-\"z\"z").ExtractStringDoubleQuote(1, out endIndex).ToString()); Console.WriteLine(endIndex); }
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using System; using System.Text; public static partial class Extensions { /// <summary> /// A StringBuilder extension method that extracts the string double quote described by /// @this. /// </summary> /// <param name="this">The @this to act on.</param> /// <returns>The extracted string double quote.</returns> public static StringBuilder ExtractStringDoubleQuote(this StringBuilder @this) { return @this.ExtractStringDoubleQuote(0); } /// <summary>A StringBuilder extension method that extracts the string double quote described by /// @this.</summary> /// <param name="this">The @this to act on.</param> /// <param name="endIndex">[out] The end index.</param> /// <returns>The extracted string double quote.</returns> public static StringBuilder ExtractStringDoubleQuote(this StringBuilder @this, out int endIndex) { return @this.ExtractStringDoubleQuote(0, out endIndex); } /// <summary> /// A StringBuilder extension method that extracts the string double quote described by /// @this. /// </summary> /// <exception cref="Exception">Thrown when an exception error condition occurs.</exception> /// <param name="this">The @this to act on.</param> /// <param name="startIndex">The start index.</param> /// <returns>The extracted string double quote.</returns> public static StringBuilder ExtractStringDoubleQuote(this StringBuilder @this, int startIndex) { int endIndex; return @this.ExtractStringDoubleQuote(startIndex, out endIndex); } /// <summary>A StringBuilder extension method that extracts the string double quote described by /// @this.</summary> /// <exception cref="Exception">Thrown when an exception error condition occurs.</exception> /// <param name="this">The @this to act on.</param> /// <param name="startIndex">The start index.</param> /// <param name="endIndex">[out] The end index.</param> /// <returns>The extracted string double quote.</returns> public static StringBuilder ExtractStringDoubleQuote(this StringBuilder @this, int startIndex, out int endIndex) { var sb = new StringBuilder(); if (@this.Length > startIndex + 1) { var ch1 = @this[startIndex]; if (ch1 == '"') { // "my string" var pos = startIndex + 1; while (pos < @this.Length) { var ch = @this[pos]; pos++; char nextChar; if (ch == '\\' && pos < @this.Length && ((nextChar = @this[pos]) == '\\' || nextChar == '"')) { sb.Append(nextChar); pos++; // Treat as escape character for \\ or \" } else if (ch == '"') { endIndex = pos; return sb; } else { sb.Append(ch); } } throw new Exception("Unclosed string starting at position: " + startIndex); } } endIndex = -1; return null; } }