//
// RegularExpression.h
//
// Library: Foundation
// Package: RegExp
// Module:  RegularExpression
//
// Definitions of class RegularExpression.
//
// A wrapper class for Philip Hazel's PCRE - Perl Compatible Regular Expressions
// library (http://www.pcre.org).
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_RegularExpression_INCLUDED
#define Foundation_RegularExpression_INCLUDED


#include <vector>
#include "Poco/Foundation.h"


namespace Poco
{


class Foundation_API RegularExpression
/// A class for working with regular expressions.
/// Implemented using PCRE, the Perl Compatible
/// Regular Expressions library by Philip Hazel
/// (see http://www.pcre.org).
{
public:
    enum Options // These must match the corresponding options in pcre.h!
    /// Some of the following options can only be passed to the constructor;
    /// some can be passed only to matching functions, and some can be used
    /// everywhere.
    ///
    ///   * Options marked [ctor] can be passed to the constructor.
    ///   * Options marked [match] can be passed to match, extract, split and subst.
    ///   * Options marked [subst] can be passed to subst.
    ///
    /// See the PCRE documentation for more information.
    {
        RE_CASELESS = 0x00000001, /// case insensitive matching (/i) [ctor]
        RE_MULTILINE = 0x00000002, /// enable multi-line mode; affects ^ and $ (/m) [ctor]
        RE_DOTALL = 0x00000004, /// dot matches all characters, including newline (/s) [ctor]
        RE_EXTENDED = 0x00000008, /// totally ignore whitespace (/x) [ctor]
        RE_ANCHORED = 0x00000010, /// treat pattern as if it starts with a ^ [ctor, match]
        RE_DOLLAR_ENDONLY = 0x00000020, /// dollar matches end-of-string only, not last newline in string [ctor]
        RE_EXTRA = 0x00000040, /// enable optional PCRE functionality [ctor]
        RE_NOTBOL = 0x00000080, /// circumflex does not match beginning of string [match]
        RE_NOTEOL = 0x00000100, /// $ does not match end of string [match]
        RE_UNGREEDY = 0x00000200, /// make quantifiers ungreedy [ctor]
        RE_NOTEMPTY = 0x00000400, /// empty string never matches [match]
        RE_UTF8 = 0x00000800, /// assume pattern and subject is UTF-8 encoded [ctor]
        RE_NO_AUTO_CAPTURE = 0x00001000, /// disable numbered capturing parentheses [ctor, match]
        RE_NO_UTF8_CHECK = 0x00002000, /// do not check validity of UTF-8 code sequences [match]
        RE_FIRSTLINE = 0x00040000, /// an  unanchored  pattern  is  required  to  match
        /// before  or  at  the  first  newline  in  the subject string,
        /// though the matched text may continue over the newline [ctor]
        RE_DUPNAMES = 0x00080000, /// names used to identify capturing  subpatterns  need not be unique [ctor]
        RE_NEWLINE_CR = 0x00100000, /// assume newline is CR ('\r'), the default [ctor]
        RE_NEWLINE_LF = 0x00200000, /// assume newline is LF ('\n') [ctor]
        RE_NEWLINE_CRLF = 0x00300000, /// assume newline is CRLF ("\r\n") [ctor]
        RE_NEWLINE_ANY = 0x00400000, /// assume newline is any valid Unicode newline character [ctor]
        RE_NEWLINE_ANYCRLF = 0x00500000, /// assume newline is any of CR, LF, CRLF [ctor]
        RE_GLOBAL = 0x10000000, /// replace all occurrences (/g) [subst]
        RE_NO_VARS = 0x20000000 /// treat dollar in replacement string as ordinary character [subst]
    };

    struct Match
    {
        std::string::size_type offset; /// zero based offset (std::string::npos if subexpr does not match)
        std::string::size_type length; /// length of substring
    };
    typedef std::vector<Match> MatchVec;

    RegularExpression(const std::string & pattern, int options = 0, bool study = true);
    /// Creates a regular expression and parses the given pattern.
    /// If study is true, the pattern is analyzed and optimized. This
    /// is mainly useful if the pattern is used more than once.
    /// For a description of the options, please see the PCRE documentation.
    /// Throws a RegularExpressionException if the pattern cannot be compiled.

    ~RegularExpression();
    /// Destroys the regular expression.

    int match(const std::string & subject, Match & mtch, int options = 0) const;
    /// Matches the given subject string against the pattern. Returns the position
    /// of the first captured substring in mtch.
    /// If no part of the subject matches the pattern, mtch.offset is std::string::npos and
    /// mtch.length is 0.
    /// Throws a RegularExpressionException in case of an error.
    /// Returns the number of matches.

    int match(const std::string & subject, std::string::size_type offset, Match & mtch, int options = 0) const;
    /// Matches the given subject string, starting at offset, against the pattern.
    /// Returns the position of the captured substring in mtch.
    /// If no part of the subject matches the pattern, mtch.offset is std::string::npos and
    /// mtch.length is 0.
    /// Throws a RegularExpressionException in case of an error.
    /// Returns the number of matches.

    int match(const std::string & subject, std::string::size_type offset, MatchVec & matches, int options = 0) const;
    /// Matches the given subject string against the pattern.
    /// The first entry in matches contains the position of the captured substring.
    /// The following entries identify matching subpatterns. See the PCRE documentation
    /// for a more detailed explanation.
    /// If no part of the subject matches the pattern, matches is empty.
    /// Throws a RegularExpressionException in case of an error.
    /// Returns the number of matches.

    bool match(const std::string & subject, std::string::size_type offset = 0) const;
    /// Returns true if and only if the subject matches the regular expression.
    ///
    /// Internally, this method sets the RE_ANCHORED and RE_NOTEMPTY options for
    /// matching, which means that the empty string will never match and
    /// the pattern is treated as if it starts with a ^.

    bool match(const std::string & subject, std::string::size_type offset, int options) const;
    /// Returns true if and only if the subject matches the regular expression.

    bool operator==(const std::string & subject) const;
    /// Returns true if and only if the subject matches the regular expression.
    ///
    /// Internally, this method sets the RE_ANCHORED and RE_NOTEMPTY options for
    /// matching, which means that the empty string will never match and
    /// the pattern is treated as if it starts with a ^.

    bool operator!=(const std::string & subject) const;
    /// Returns true if and only if the subject does not match the regular expression.
    ///
    /// Internally, this method sets the RE_ANCHORED and RE_NOTEMPTY options for
    /// matching, which means that the empty string will never match and
    /// the pattern is treated as if it starts with a ^.

    int extract(const std::string & subject, std::string & str, int options = 0) const;
    /// Matches the given subject string against the pattern.
    /// Returns the captured string.
    /// Throws a RegularExpressionException in case of an error.
    /// Returns the number of matches.

    int extract(const std::string & subject, std::string::size_type offset, std::string & str, int options = 0) const;
    /// Matches the given subject string, starting at offset, against the pattern.
    /// Returns the captured string.
    /// Throws a RegularExpressionException in case of an error.
    /// Returns the number of matches.

    int split(const std::string & subject, std::vector<std::string> & strings, int options = 0) const;
    /// Matches the given subject string against the pattern.
    /// The first entry in captured is the captured substring.
    /// The following entries contain substrings matching subpatterns. See the PCRE documentation
    /// for a more detailed explanation.
    /// If no part of the subject matches the pattern, captured is empty.
    /// Throws a RegularExpressionException in case of an error.
    /// Returns the number of matches.

    int split(const std::string & subject, std::string::size_type offset, std::vector<std::string> & strings, int options = 0) const;
    /// Matches the given subject string against the pattern.
    /// The first entry in captured is the captured substring.
    /// The following entries contain substrings matching subpatterns. See the PCRE documentation
    /// for a more detailed explanation.
    /// If no part of the subject matches the pattern, captured is empty.
    /// Throws a RegularExpressionException in case of an error.
    /// Returns the number of matches.

    int subst(std::string & subject, const std::string & replacement, int options = 0) const;
    /// Substitute in subject all matches of the pattern with replacement.
    /// If RE_GLOBAL is specified as option, all matches are replaced. Otherwise,
    /// only the first match is replaced.
    /// Occurrences of $<n> (for example, $1, $2, ...) in replacement are replaced
    /// with the corresponding captured string. $0 is the original subject string.
    /// Returns the number of replaced occurrences.

    int subst(std::string & subject, std::string::size_type offset, const std::string & replacement, int options = 0) const;
    /// Substitute in subject all matches of the pattern with replacement,
    /// starting at offset.
    /// If RE_GLOBAL is specified as option, all matches are replaced. Otherwise,
    /// only the first match is replaced.
    /// Unless RE_NO_VARS is specified, occurrences of $<n> (for example, $0, $1, $2, ... $9)
    /// in replacement are replaced with the corresponding captured string.
    /// $0 is the captured substring. $1 ... $n are the substrings matching the subpatterns.
    /// Returns the number of replaced occurrences.

    static bool match(const std::string & subject, const std::string & pattern, int options = 0);
    /// Matches the given subject string against the regular expression given in pattern,
    /// using the given options.

protected:
    std::string::size_type
    substOne(std::string & subject, std::string::size_type offset, const std::string & replacement, int options) const;

private:
    // Note: to avoid a dependency on the pcre.h header the following are
    // declared as void* and casted to the correct type in the implementation file.
    void * _pcre; // Actual type is pcre*
    void * _extra; // Actual type is struct pcre_extra*

    static const int OVEC_SIZE;

    RegularExpression();
    RegularExpression(const RegularExpression &);
    RegularExpression & operator=(const RegularExpression &);
};


//
// inlines
//
inline int RegularExpression::match(const std::string & subject, Match & mtch, int options) const
{
    return match(subject, 0, mtch, options);
}


inline int RegularExpression::split(const std::string & subject, std::vector<std::string> & strings, int options) const
{
    return split(subject, 0, strings, options);
}


inline int RegularExpression::subst(std::string & subject, const std::string & replacement, int options) const
{
    return subst(subject, 0, replacement, options);
}


inline bool RegularExpression::operator==(const std::string & subject) const
{
    return match(subject);
}


inline bool RegularExpression::operator!=(const std::string & subject) const
{
    return !match(subject);
}


} // namespace Poco


#endif // Foundation_RegularExpression_INCLUDED