/// <summary>
/// Translates the magic values (End, Beginning, Word) into actual values
/// based on the given count.
/// </summary>
/// <param name="text">The text used for normalizing.</param>
/// <param name="searchPosition">The character position to start searching for words.</param>
/// <param name="direction">The direction to search for Word positions.</param>
/// <returns>
/// The normalized index.
/// </returns>
/// <exception cref="System.IndexOutOfRangeException">Encountered an invalid index: + Index</exception>
public int GetCharacterIndex(
string text,
CharacterPosition searchPosition,
WordSearchDirection direction)
{
return(GetCharacterIndex(
text, searchPosition, direction, DefaultWordTokenizer));
}
/// <summary>
/// Translates the magic values (End, Beginning, Word) into actual values
/// based on the given count.
/// </summary>
/// <param name="text">The text used for normalizing.</param>
/// <param name="searchPosition">The character position to start searching for words.</param>
/// <param name="direction">The direction to search for Word positions.</param>
/// <param name="wordTokenizer">The word tokenizer to use for word positions.</param>
/// <returns>
/// The normalized index.
/// </returns>
/// <exception cref="System.IndexOutOfRangeException">Encountered an invalid index: + Index</exception>
public int GetCharacterIndex(
string text,
CharacterPosition searchPosition,
WordSearchDirection direction,
IWordTokenizer wordTokenizer)
{
// Make sure we have a sane state before we start.
if (wordTokenizer == null)
{
throw new ArgumentNullException("wordTokenizer");
}
// All the magic values are negative, so if we don't have one, there is
// nothing to do.
if (Index >= 0)
{
return(Index);
}
// If we have the end magic number, then the index is equal to the end
// of the text line.
if (Index == EndIndex)
{
return(text.Length);
}
// If we have the word, then we go either left or right.
if (Index == WordIndex)
{
// Perform some additional checks on the range and index.
if (searchPosition.Index == 0 &&
direction == WordSearchDirection.Left)
{
throw new IndexOutOfRangeException(
"Cannot find Word position at beginning of string.");
}
if (searchPosition.Index == text.Length &&
direction == WordSearchDirection.Right)
{
throw new IndexOutOfRangeException(
"Cannot find Word position at end of string.");
}
// Depending on the direction, we use the word tokenizer in
// the appropriate direction. We also have to resolve the
// position because the word tokenizer doesn't know how to handle
// the symbolic constants.
int searchIndex = searchPosition.GetCharacterIndex(text);
if (direction == WordSearchDirection.Right)
{
int index = wordTokenizer.GetNextWordBoundary(text, searchIndex);
return(index);
}
else
{
int index = wordTokenizer.GetPreviousWordBoundary(text, searchIndex);
return(index);
}
}
// If we got this far, we don't know how to process this.
throw new IndexOutOfRangeException("Encountered an invalid index: " + Index);
}