private int InternalLastIndexOf(ASCIIString value, int startIndex, int count, bool ignoreCase)
{
Debug.Assert(value != null);
Debug.Assert(startIndex >= 0);
Debug.Assert(count <= this.Length - startIndex);
int matchLength = value.Length;
int matchChars = matchLength - 1;
for (int i = (startIndex + count) - 1; i >= startIndex; i--)
{
ASCIIChar curr = ignoreCase ? ASCIIChar.ToLower(this[i]) : this[i];
ASCIIChar toMatch = ignoreCase ? ASCIIChar.ToLower(value[matchChars]) : value[matchChars];
if (curr == toMatch)
{
matchChars--;
if (matchChars == -1)
{
return(i);
}
continue;
}
matchChars = matchLength - 1;
}
return(-1);
}
private int InternalIndexOf(ASCIIString value, int startIndex, int count, bool ignoreCase)
{
Debug.Assert(value != null);
Debug.Assert(startIndex >= 0 && startIndex < this.Length);
Debug.Assert(count <= this.Length - startIndex);
int matchChars = 0;
int matchLength = value.Length;
for (int i = startIndex; i < startIndex + count; i++)
{
ASCIIChar curr = ignoreCase ? ASCIIChar.ToLower(this[i]) : this[i];
ASCIIChar toMatch = ignoreCase ? ASCIIChar.ToLower(value[matchChars]) : value[matchChars];
if (curr == toMatch)
{
matchChars++;
if (matchChars == matchLength)
{
return(i - (matchLength - 1));
}
continue;
}
matchChars = 0;
}
return(-1);
}
/// <summary>
/// Determines whether the specified substring appears within this string.
/// </summary>
/// <param name="value">The string to seek.</param>
/// <param name="ignoreCase">True to ignore case; otherwise, false.</param>
/// <returns></returns>
public bool Contains(ASCIIString value, bool ignoreCase = false)
{
if (value is null)
{
throw new ArgumentNullException(nameof(value));
}
return(IndexOf(value, ignoreCase) >= 0);
}
/// <summary>
/// Reports the zero-based index position of the last occurence of a specified string within this instance.
/// The search starts at a specified character position and proceeds backwards toward the beginning of the string for the specified number of character positions.
/// </summary>
/// <param name="value">The string to seek.</param>
/// <param name="startIndex">The search starting position. The search proceeds from startIndex toward the beginning of this instance.</param>
/// <param name="count">The number of character positions to examine.</param>
/// <param name="ignoreCase">True to ignore case; otherwise, false.</param>
/// <exception cref="ArgumentNullException"/>
/// <exception cref="ArgumentOutOfRangeException"/>
public int LastIndexOf(ASCIIString value, int startIndex, int count, bool ignoreCase = false)
{
if (startIndex < 0 || startIndex >= this.Length)
{
throw new ArgumentOutOfRangeException(nameof(startIndex));
}
if (count < 0 || count > this.Length - startIndex)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
if (value.Length > this.Length)
{
return(-1);
}
if (count == 0)
{
return(-1);
}
return(InternalLastIndexOf(value, startIndex, count, ignoreCase));
}
/// <summary>
/// Reports the zero-based index of the first occurence of the specified string in the current <see cref="ASCIIString"/> object.
/// Parameters specify the starting search position in the current string and the type of search to use for the specified string.
/// </summary>
/// <param name="value">The string to seek.</param>
/// <param name="ignoreCase">True to ignore case; otherwise, false.</param>
public int IndexOf(ASCIIString value, bool ignoreCase = false)
{
return(IndexOf(value, 0, this.Length, ignoreCase));
}
/// <summary>
/// Reports the zero-based index position of the last occurence of a specified string within this instance.
/// The search starts at a specified character position and proceeds backwards toward the beginning of the string.
/// </summary>
/// <param name="value">The string to seek.</param>
/// <param name="startIndex">The search starting position. The search proceeds from startIndex toward the beginning of this instance.</param>
/// <param name="ignoreCase">True to ignore case; otherwise, false.</param>
/// <exception cref="ArgumentNullException"/>
/// <exception cref="ArgumentOutOfRangeException"/>
public int LastIndexOf(ASCIIString value, int startIndex, bool ignoreCase = false)
{
return(LastIndexOf(value, startIndex, this.Length, ignoreCase));
}