Wildcard.cs source code in C# .NET

                        Code:
                         / FXUpdate3074 / FXUpdate3074 / 1.1 / untmp / whidbey / QFE / ndp / fx / src / xsp / System / Web / Util / Wildcard.cs / 1 / Wildcard.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

/* 
 * Wildcard 
 *
 * wildcard wrappers for Regex 
 *
 * (1) Wildcard does straight string wildcarding with no path separator awareness
 * (2) WildcardUrl recognizes that forward / slashes are special and can't match * or ?
 * (3) WildcardDos recognizes that backward \ and : are special and can't match * or ? 
 *
 * Copyright (c) 1999, Microsoft Corporation 
 */ 
namespace System.Web.Util {
    using System.Runtime.Serialization.Formatters; 
    using System.Text.RegularExpressions;

    /*
     * Wildcard 
     *
     * Wildcard patterns have three metacharacters: 
     * 
     * A ? is equivalent to .
     * A * is equivalent to .* 
     * A , is equivalent to |
     *
     * Note that by each alternative is surrounded by \A...\z to anchor
     * at the edges of the string. 
     */
    internal class Wildcard { 
#if NOT_USED 
        internal /*public*/ Wildcard(String pattern) : this (pattern, false) {
        } 
#endif

        internal /*public*/ Wildcard(String pattern, bool caseInsensitive) {
            _pattern = pattern; 
            _caseInsensitive = caseInsensitive;
        } 
 
        internal String _pattern;
        internal bool _caseInsensitive; 
        internal Regex _regex;

        protected static Regex metaRegex = new Regex("[\\+\\{\\\\\\[\\|\\(\\)\\.\\^\\$]");
        protected static Regex questRegex = new Regex("\\?"); 
        protected static Regex starRegex = new Regex("\\*");
        protected static Regex commaRegex = new Regex(","); 
        protected static Regex slashRegex = new Regex("(?=/)"); 
        protected static Regex backslashRegex = new Regex("(?=[\\\\:])");
 
        /*
         * IsMatch returns true if the input is an exact match for the
         * wildcard pattern.
         */ 
        internal /*public*/ bool IsMatch(String input) {
            EnsureRegex(); 
 
            bool result =  _regex.IsMatch(input);
 
            return result;
        }
#if DONT_COMPILE
        internal /*public*/ String Pattern { 
            get {
                return _pattern; 
            } 
        }
#endif 
        /*
         * Builds the matching regex when needed
         */
        protected void EnsureRegex() { 
            // threadsafe without protection because of gc
 
            if (_regex != null) 
                return;
 
            _regex = RegexFromWildcard(_pattern, _caseInsensitive);
        }

        /* 
         * Basic wildcard -> Regex conversion, no slashes
         */ 
        protected virtual Regex RegexFromWildcard(String pattern, bool caseInsensitive) { 
            RegexOptions options = RegexOptions.None;
 
            // match right-to-left (for speed) if the pattern starts with a *

            if (pattern.Length > 0 && pattern[0] == '*')
                options = RegexOptions.RightToLeft | RegexOptions.Singleline; 
            else
                options = RegexOptions.Singleline; 
 
            // case insensitivity
 
            if (caseInsensitive)
                options |= RegexOptions.IgnoreCase | RegexOptions.CultureInvariant;

            // Remove regex metacharacters 

            pattern = metaRegex.Replace(pattern, "\\$0"); 
 
            // Replace wildcard metacharacters with regex codes
 
            pattern = questRegex.Replace(pattern, ".");
            pattern = starRegex.Replace(pattern, ".*");
            pattern = commaRegex.Replace(pattern, "\\z|\\A");
 
            // anchor the pattern at beginning and end, and return the regex
 
            return new Regex("\\A" + pattern + "\\z", options); 
        }
    } 

    abstract internal class WildcardPath : Wildcard {
#if NOT_USED
        internal /*public*/ WildcardPath(String pattern) : base(pattern) { 
        }
 
        private Regex[][] _dirs; 
#endif
 
        internal /*public*/ WildcardPath(String pattern, bool caseInsensitive) : base(pattern, caseInsensitive) {
        }

        private Regex _suffix; 

        /* 
         * IsSuffix returns true if a suffix of the input is an exact 
         * match for the wildcard pattern.
         */ 
        internal /*public*/ bool IsSuffix(String input) {
            EnsureSuffix();
            return _suffix.IsMatch(input);
        } 

#if NOT_USED 
        /* 
         * AllowPrefix returns true if the input is an exact match for
         * a prefix-directory of the wildcard pattern (i.e., if it 
         * is possible to match the wildcard pattern by adding
         * more subdirectories or a filename at the end of the path).
         */
        internal /*public*/ bool AllowPrefix(String prefix) { 
            String[] dirs = SplitDirs(prefix);
 
            EnsureDirs(); 

            for (int i = 0; i < _dirs.Length; i++) { 
                // pattern is shorter than prefix: reject
                if (_dirs[i].Length < dirs.Length)
                    goto NextAlt;
 
                for (int j = 0; j < dirs.Length; j++) {
                    // the jth directory doesn't match; path is not a prefix 
                    if (!_dirs[i][j].IsMatch(dirs[j])) 
                        goto NextAlt;
                } 

                // one alternative passed: we pass.

                return true; 

                NextAlt: 
                ; 
            }
 
            return false;
        }

        /* 
         * Builds the matching regex array when needed
         */ 
        protected void EnsureDirs() { 
            // threadsafe without protection because of gc
 
            if (_dirs != null)
                return;

            _dirs = DirsFromWildcard(_pattern); 
        }
#endif 
 
        /*
         * Builds the matching regex when needed 
         */
        protected void EnsureSuffix() {
            // threadsafe without protection because of gc
 
            if (_suffix != null)
                return; 
 
            _suffix = SuffixFromWildcard(_pattern, _caseInsensitive);
        } 


        /*
         * Specialize for forward-slash and backward-slash cases 
         */
        protected abstract Regex SuffixFromWildcard(String pattern, bool caseInsensitive); 
        protected abstract Regex[][] DirsFromWildcard(String pattern); 
        protected abstract String[] SplitDirs(String input);
    } 

    /*
     * WildcardUrl
     * 
     * The twist is that * and ? cannot match forward slashes,
     * and we can do an exact suffix match that starts after 
     * any /, and we can also do a prefix prune. 
     */
    internal class WildcardUrl : WildcardPath { 
#if NOT_USED
        internal /*public*/ WildcardUrl(String pattern) : base(pattern) {
        }
#endif 
        internal /*public*/ WildcardUrl(String pattern, bool caseInsensitive) : base(pattern, caseInsensitive) {
        } 
 
        protected override String[] SplitDirs(String input) {
            return slashRegex.Split(input); 
        }

        protected override Regex RegexFromWildcard(String pattern, bool caseInsensitive) {
            RegexOptions options; 

            // match right-to-left (for speed) if the pattern starts with a * 
 
            if (pattern.Length > 0 && pattern[0] == '*')
                options = RegexOptions.RightToLeft; 
            else
                options = RegexOptions.None;

            // case insensitivity 

            if (caseInsensitive) 
                options |= RegexOptions.IgnoreCase | RegexOptions.CultureInvariant; 

            // Remove regex metacharacters 

            pattern = metaRegex.Replace(pattern, "\\$0");

            // Replace wildcard metacharacters with regex codes 

            pattern = questRegex.Replace(pattern, "[^/]"); 
            pattern = starRegex.Replace(pattern, "[^/]*"); 
            pattern = commaRegex.Replace(pattern, "\\z|\\A");
 
            // anchor the pattern at beginning and end, and return the regex

            return new Regex("\\A" + pattern + "\\z", options);
        } 

        protected override Regex SuffixFromWildcard(String pattern, bool caseInsensitive) { 
            RegexOptions options; 

            // match right-to-left (for speed) 

            options = RegexOptions.RightToLeft;

            // case insensitivity 

            if (caseInsensitive) 
                options |= RegexOptions.IgnoreCase | RegexOptions.CultureInvariant; 

            // Remove regex metacharacters 

            pattern = metaRegex.Replace(pattern, "\\$0");

            // Replace wildcard metacharacters with regex codes 

            pattern = questRegex.Replace(pattern, "[^/]"); 
            pattern = starRegex.Replace(pattern, "[^/]*"); 
            pattern = commaRegex.Replace(pattern, "\\z|(?:\\A|(?<=/))");
 
            // anchor the pattern at beginning and end, and return the regex

            return new Regex("(?:\\A|(?<=/))" + pattern + "\\z", options);
        } 

        protected override Regex[][] DirsFromWildcard(String pattern) { 
            String[] alts = commaRegex.Split(pattern); 
            Regex[][] dirs = new Regex[alts.Length][];
 
            for (int i = 0; i < alts.Length; i++) {
                String[] dirpats = slashRegex.Split(alts[i]);

                Regex[] dirregex = new Regex[dirpats.Length]; 

                if (alts.Length == 1 && dirpats.Length == 1) { 
                    // common case: no commas, no slashes: dir regex is same as top regex. 

                    EnsureRegex(); 
                    dirregex[0] = _regex;
                }
                else {
                    for (int j = 0; j < dirpats.Length; j++) { 
                        dirregex[j] = RegexFromWildcard(dirpats[j], _caseInsensitive);
                    } 
                } 

                dirs[i] = dirregex; 
            }

            return dirs;
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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