// Look for ".piece".
private static bool FindPieceExtension(string path, ref int position, ref ScanStepDelegate nextStep,
ref PieceNameInfo parseResults)
{
if (!FindString(path, ref position, ".piece"))
{
return(false);
}
nextStep = FindIsLast;
return(true);
}
// Retrieve part name. The position points to the slash past the part name.
// So simply return the prefix up to that slash.
private static bool FindPartName(string path, ref int position, ref ScanStepDelegate nextStep,
ref PieceNameInfo parseResults)
{
parseResults.PrefixName = path.Substring(0, position);
// Subtract the length of the part name from position.
position = 0;
if (parseResults.PrefixName.Length == 0)
{
return(false);
}
Uri partUri = new Uri(ZipPackage.GetOpcNameFromZipItemName(parseResults.PrefixName), UriKind.Relative);
PackUriHelper.TryValidatePartUri(partUri, out parseResults.PartUri);
return(true);
}
// Look for "]" or "].last".
private static bool FindIsLast(string path, ref int position, ref ScanStepDelegate nextStep,
ref PieceNameInfo parseResults)
{
// Case of no ".last" member:
if (path[position - 1] == ']')
{
parseResults.IsLastPiece = false;
--position;
nextStep = FindPieceNumber;
return(true);
}
// There has to be "].last".
if (!FindString(path, ref position, "].last"))
{
return(false);
}
parseResults.IsLastPiece = true;
nextStep = FindPieceNumber;
return(true);
}
/// <summary>
/// Attempts to parse a name as a piece name. Returns true and places the
/// output in pieceNameConstituents. Otherwise, returns false and returns
/// the default constituent values pieceName, 0, and false.
/// </summary>
/// <param name="path">The input string.</param>
/// <param name="parseResults">An object containing the prefix name (i.e. generally the part name), the 0-based order number of the piece, and whether the piece is last in the part.</param>
/// <returns>True for parse success.</returns>
/// <remarks>
/// Syntax of a piece name:
/// piece_name = part_name "/" "[" 1*digit "]" [".last"] ".piece"
/// </remarks>
private static bool TryParseAsPieceName(string path, out PieceNameInfo parseResults)
{
parseResults = new PieceNameInfo(); // initialize to CLR default values
// Start from the end and look for ".piece".
int position = path.Length;
ScanStepDelegate nextStep = new ScanStepDelegate(FindPieceExtension);
// Scan backward until the whole path has been scanned.
while (position > 0)
{
if (!nextStep.Invoke(path, ref position, ref nextStep, ref parseResults))
{
// Scan step failed. Return false.
parseResults.IsLastPiece = false;
parseResults.PieceNumber = 0;
parseResults.PrefixName = path;
parseResults.PartUri = null;
return(false);
}
}
return(true);
}
// Look for "/[" followed by decimal digits.
private static bool FindPieceNumber(string path, ref int position, ref ScanStepDelegate nextStep,
ref PieceNameInfo parseResults)
{
if (!char.IsDigit(path[position - 1]))
{
return(false);
}
int pieceNumber = 0;
int multiplier = 1; // rightmost digit is for units
--position;
do
{
pieceNumber += multiplier * (int)char.GetNumericValue(path[position]);
multiplier *= 10;
} while (char.IsDigit(path[--position]));
// Point to the last digit found.
++position;
//If we have a leading 0, then its not correct piecename syntax
if (multiplier > 10 && (int)char.GetNumericValue(path[position]) == 0)
{
return(false);
}
if (!FindString(path, ref position, "/["))
{
return(false);
}
parseResults.PieceNumber = pieceNumber;
nextStep = FindPartName;
return(true);
}