// NameFilter.cs
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//
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// Copyright 2005 John Reilly
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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//
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// Linking this library statically or dynamically with other modules is
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// making a combined work based on this library. Thus, the terms and
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// conditions of the GNU General Public License cover the whole
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// combination.
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//
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// As a special exception, the copyright holders of this library give you
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// permission to link this library with independent modules to produce an
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// executable, regardless of the license terms of these independent
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// modules, and to copy and distribute the resulting executable under
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// terms of your choice, provided that you also meet, for each linked
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// independent module, the terms and conditions of the license of that
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// module. An independent module is a module which is not derived from
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// or based on this library. If you modify this library, you may extend
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// this exception to your version of the library, but you are not
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// obligated to do so. If you do not wish to do so, delete this
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// exception statement from your version.
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// HISTORY
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// 2010-03-03 Z-1654 Fixed bug where escape characters were excluded in SplitQuoted()
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using System;
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using System.Collections;
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using System.Text;
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using System.Text.RegularExpressions;
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namespace ICSharpCode.SharpZipLib.Core
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{
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/// <summary>
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/// NameFilter is a string matching class which allows for both positive and negative
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/// matching.
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/// A filter is a sequence of independant <see cref="Regex">regular expressions</see> separated by semi-colons ';'.
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/// To include a semi-colon it may be quoted as in \;. Each expression can be prefixed by a plus '+' sign or
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/// a minus '-' sign to denote the expression is intended to include or exclude names.
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/// If neither a plus or minus sign is found include is the default.
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/// A given name is tested for inclusion before checking exclusions. Only names matching an include spec
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/// and not matching an exclude spec are deemed to match the filter.
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/// An empty filter matches any name.
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/// </summary>
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/// <example>The following expression includes all name ending in '.dat' with the exception of 'dummy.dat'
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/// "+\.dat$;-^dummy\.dat$"
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/// </example>
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public class NameFilter : IScanFilter
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{
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#region Constructors
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/// <summary>
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/// Construct an instance based on the filter expression passed
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/// </summary>
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/// <param name="filter">The filter expression.</param>
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public NameFilter(string filter)
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{
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filter_ = filter;
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inclusions_ = new ArrayList();
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exclusions_ = new ArrayList();
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Compile();
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}
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#endregion
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/// <summary>
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/// Test a string to see if it is a valid regular expression.
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/// </summary>
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/// <param name="expression">The expression to test.</param>
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/// <returns>True if expression is a valid <see cref="System.Text.RegularExpressions.Regex"/> false otherwise.</returns>
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public static bool IsValidExpression(string expression)
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{
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bool result = true;
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try {
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Regex exp = new Regex(expression, RegexOptions.IgnoreCase | RegexOptions.Singleline);
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}
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catch (ArgumentException) {
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result = false;
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}
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return result;
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}
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/// <summary>
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/// Test an expression to see if it is valid as a filter.
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/// </summary>
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/// <param name="toTest">The filter expression to test.</param>
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/// <returns>True if the expression is valid, false otherwise.</returns>
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public static bool IsValidFilterExpression(string toTest)
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{
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bool result = true;
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try {
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if (toTest != null) {
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string[] items = SplitQuoted(toTest);
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for (int i = 0; i < items.Length; ++i) {
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if ((items[i] != null) && (items[i].Length > 0)) {
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string toCompile;
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if (items[i][0] == '+') {
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toCompile = items[i].Substring(1, items[i].Length - 1);
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}
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else if (items[i][0] == '-') {
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toCompile = items[i].Substring(1, items[i].Length - 1);
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}
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else {
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toCompile = items[i];
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}
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Regex testRegex = new Regex(toCompile, RegexOptions.IgnoreCase | RegexOptions.Singleline);
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}
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}
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}
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}
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catch (ArgumentException) {
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result = false;
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}
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return result;
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}
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/// <summary>
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/// Split a string into its component pieces
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/// </summary>
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/// <param name="original">The original string</param>
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/// <returns>Returns an array of <see cref="T:System.String"/> values containing the individual filter elements.</returns>
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public static string[] SplitQuoted(string original)
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{
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char escape = '\\';
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char[] separators = { ';' };
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ArrayList result = new ArrayList();
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if ((original != null) && (original.Length > 0)) {
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int endIndex = -1;
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StringBuilder b = new StringBuilder();
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while (endIndex < original.Length) {
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endIndex += 1;
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if (endIndex >= original.Length) {
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result.Add(b.ToString());
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}
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else if (original[endIndex] == escape) {
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endIndex += 1;
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if (endIndex >= original.Length) {
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#if NETCF_1_0
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throw new ArgumentException("Missing terminating escape character");
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#else
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throw new ArgumentException("Missing terminating escape character", "original");
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#endif
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}
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// include escape if this is not an escaped separator
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if (Array.IndexOf(separators, original[endIndex]) < 0)
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b.Append(escape);
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b.Append(original[endIndex]);
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}
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else {
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if (Array.IndexOf(separators, original[endIndex]) >= 0) {
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result.Add(b.ToString());
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b.Length = 0;
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}
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else {
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b.Append(original[endIndex]);
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}
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}
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}
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}
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return (string[])result.ToArray(typeof(string));
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}
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/// <summary>
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/// Convert this filter to its string equivalent.
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/// </summary>
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/// <returns>The string equivalent for this filter.</returns>
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public override string ToString()
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{
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return filter_;
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}
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/// <summary>
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/// Test a value to see if it is included by the filter.
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/// </summary>
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/// <param name="name">The value to test.</param>
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/// <returns>True if the value is included, false otherwise.</returns>
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public bool IsIncluded(string name)
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{
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bool result = false;
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if ( inclusions_.Count == 0 ) {
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result = true;
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}
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else {
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foreach ( Regex r in inclusions_ ) {
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if ( r.IsMatch(name) ) {
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result = true;
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break;
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}
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}
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}
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return result;
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}
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/// <summary>
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/// Test a value to see if it is excluded by the filter.
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/// </summary>
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/// <param name="name">The value to test.</param>
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/// <returns>True if the value is excluded, false otherwise.</returns>
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public bool IsExcluded(string name)
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{
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bool result = false;
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foreach ( Regex r in exclusions_ ) {
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if ( r.IsMatch(name) ) {
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result = true;
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break;
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}
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}
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return result;
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}
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#region IScanFilter Members
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/// <summary>
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/// Test a value to see if it matches the filter.
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/// </summary>
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/// <param name="name">The value to test.</param>
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/// <returns>True if the value matches, false otherwise.</returns>
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public bool IsMatch(string name)
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{
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return (IsIncluded(name) && !IsExcluded(name));
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}
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#endregion
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/// <summary>
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/// Compile this filter.
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/// </summary>
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void Compile()
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{
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// TODO: Check to see if combining RE's makes it faster/smaller.
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// simple scheme would be to have one RE for inclusion and one for exclusion.
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if ( filter_ == null ) {
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return;
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}
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string[] items = SplitQuoted(filter_);
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for ( int i = 0; i < items.Length; ++i ) {
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if ( (items[i] != null) && (items[i].Length > 0) ) {
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bool include = (items[i][0] != '-');
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string toCompile;
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if ( items[i][0] == '+' ) {
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toCompile = items[i].Substring(1, items[i].Length - 1);
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}
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else if ( items[i][0] == '-' ) {
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toCompile = items[i].Substring(1, items[i].Length - 1);
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}
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else {
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toCompile = items[i];
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}
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// NOTE: Regular expressions can fail to compile here for a number of reasons that cause an exception
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// these are left unhandled here as the caller is responsible for ensuring all is valid.
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// several functions IsValidFilterExpression and IsValidExpression are provided for such checking
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if ( include ) {
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inclusions_.Add(new Regex(toCompile, RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Singleline));
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}
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else {
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exclusions_.Add(new Regex(toCompile, RegexOptions.IgnoreCase | RegexOptions.Compiled | RegexOptions.Singleline));
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}
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}
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}
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}
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#region Instance Fields
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string filter_;
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ArrayList inclusions_;
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ArrayList exclusions_;
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#endregion
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}
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}
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