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  #include "qregexp.h"
  
  #include "qalgorithms.h"
  #include "qbitarray.h"
  #include "qcache.h"
  #include "qdatastream.h"
  #include "qdebug.h"
  #include "qhashfunctions.h"
  #include "qlist.h"
  #include "qmap.h"
  #include "qmutex.h"
  #include "qstring.h"
  #include "qstringlist.h"
  #include "qstringmatcher.h"
  #include "qvector.h"
  
  #include <limits.h>
  #include <algorithm>
  
  QT_BEGIN_NAMESPACE
  
  int qFindString(const QChar *haystack, int haystackLen, int from,
      const QChar *needle, int needleLen, Qt::CaseSensitivity cs);
  
  // error strings for the regexp parser
  #define RXERR_OK         QT_TRANSLATE_NOOP("QRegExp", "no error occurred")
  #define RXERR_DISABLED   QT_TRANSLATE_NOOP("QRegExp", "disabled feature used")
  #define RXERR_CHARCLASS  QT_TRANSLATE_NOOP("QRegExp", "bad char class syntax")
  #define RXERR_LOOKAHEAD  QT_TRANSLATE_NOOP("QRegExp", "bad lookahead syntax")
  #define RXERR_LOOKBEHIND QT_TRANSLATE_NOOP("QRegExp", "lookbehinds not supported, see QTBUG-2371")
  #define RXERR_REPETITION QT_TRANSLATE_NOOP("QRegExp", "bad repetition syntax")
  #define RXERR_OCTAL      QT_TRANSLATE_NOOP("QRegExp", "invalid octal value")
  #define RXERR_LEFTDELIM  QT_TRANSLATE_NOOP("QRegExp", "missing left delim")
  #define RXERR_END        QT_TRANSLATE_NOOP("QRegExp", "unexpected end")
  #define RXERR_LIMIT      QT_TRANSLATE_NOOP("QRegExp", "met internal limit")
  #define RXERR_INTERVAL   QT_TRANSLATE_NOOP("QRegExp", "invalid interval")
  #define RXERR_CATEGORY   QT_TRANSLATE_NOOP("QRegExp", "invalid category")
  
  /*!
      \class QRegExp
      \inmodule QtCore
      \reentrant
      \brief The QRegExp class provides pattern matching using regular expressions.
  
      \ingroup tools
      \ingroup shared
  
      \keyword regular expression
  
      A regular expression, or "regexp", is a pattern for matching
      substrings in a text. This is useful in many contexts, e.g.,
  
      \table
      \row \li Validation
           \li A regexp can test whether a substring meets some criteria,
           e.g. is an integer or contains no whitespace.
      \row \li Searching
           \li A regexp provides more powerful pattern matching than
           simple substring matching, e.g., match one of the words
           \e{mail}, \e{letter} or \e{correspondence}, but none of the
           words \e{email}, \e{mailman}, \e{mailer}, \e{letterbox}, etc.
       \row \li Search and Replace
           \li A regexp can replace all occurrences of a substring with a
           different substring, e.g., replace all occurrences of \e{&}
           with \e{\&amp;} except where the \e{&} is already followed by
           an \e{amp;}.
      \row \li String Splitting
           \li A regexp can be used to identify where a string should be
           split apart, e.g. splitting tab-delimited strings.
      \endtable
  
      A brief introduction to regexps is presented, a description of
      Qt's regexp language, some examples, and the function
      documentation itself. QRegExp is modeled on Perl's regexp
      language. It fully supports Unicode. QRegExp can also be used in a
      simpler, \e{wildcard mode} that is similar to the functionality
      found in command shells. The syntax rules used by QRegExp can be
      changed with setPatternSyntax(). In particular, the pattern syntax
      can be set to QRegExp::FixedString, which means the pattern to be
      matched is interpreted as a plain string, i.e., special characters
      (e.g., backslash) are not escaped.
  
      A good text on regexps is \e {Mastering Regular Expressions}
      (Third Edition) by Jeffrey E. F.  Friedl, ISBN 0-596-52812-4.
  
      \note In Qt 5, the new QRegularExpression class provides a Perl
      compatible implementation of regular expressions and is recommended
      in place of QRegExp.
  
      \tableofcontents
  
      \section1 Introduction
  
      Regexps are built up from expressions, quantifiers, and
      assertions. The simplest expression is a character, e.g. \b{x}
      or \b{5}. An expression can also be a set of characters
      enclosed in square brackets. \b{[ABCD]} will match an \b{A}
      or a \b{B} or a \b{C} or a \b{D}. We can write this same
      expression as \b{[A-D]}, and an expression to match any
      capital letter in the English alphabet is written as
      \b{[A-Z]}.
  
      A quantifier specifies the number of occurrences of an expression
      that must be matched. \b{x{1,1}} means match one and only one
      \b{x}. \b{x{1,5}} means match a sequence of \b{x}
      characters that contains at least one \b{x} but no more than
      five.
  
      Note that in general regexps cannot be used to check for balanced
      brackets or tags. For example, a regexp can be written to match an
      opening html \c{<b>} and its closing \c{</b>}, if the \c{<b>} tags
      are not nested, but if the \c{<b>} tags are nested, that same
      regexp will match an opening \c{<b>} tag with the wrong closing
      \c{</b>}.  For the fragment \c{<b>bold <b>bolder</b></b>}, the
      first \c{<b>} would be matched with the first \c{</b>}, which is
      not correct. However, it is possible to write a regexp that will
      match nested brackets or tags correctly, but only if the number of
      nesting levels is fixed and known. If the number of nesting levels
      is not fixed and known, it is impossible to write a regexp that
      will not fail.
  
      Suppose we want a regexp to match integers in the range 0 to 99.
      At least one digit is required, so we start with the expression
      \b{[0-9]{1,1}}, which matches a single digit exactly once. This
      regexp matches integers in the range 0 to 9. To match integers up
      to 99, increase the maximum number of occurrences to 2, so the
      regexp becomes \b{[0-9]{1,2}}. This regexp satisfies the
      original requirement to match integers from 0 to 99, but it will
      also match integers that occur in the middle of strings. If we
      want the matched integer to be the whole string, we must use the
      anchor assertions, \b{^} (caret) and \b{$} (dollar). When
      \b{^} is the first character in a regexp, it means the regexp
      must match from the beginning of the string. When \b{$} is the
      last character of the regexp, it means the regexp must match to
      the end of the string. The regexp becomes \b{^[0-9]{1,2}$}.
      Note that assertions, e.g. \b{^} and \b{$}, do not match
      characters but locations in the string.
  
      If you have seen regexps described elsewhere, they may have looked
      different from the ones shown here. This is because some sets of
      characters and some quantifiers are so common that they have been
      given special symbols to represent them. \b{[0-9]} can be
      replaced with the symbol \b{\\d}. The quantifier to match
      exactly one occurrence, \b{{1,1}}, can be replaced with the
      expression itself, i.e. \b{x{1,1}} is the same as \b{x}. So
      our 0 to 99 matcher could be written as \b{^\\d{1,2}$}. It can
      also be written \b{^\\d\\d{0,1}$}, i.e. \e{From the start of
      the string, match a digit, followed immediately by 0 or 1 digits}.
      In practice, it would be written as \b{^\\d\\d?$}. The \b{?}
      is shorthand for the quantifier \b{{0,1}}, i.e. 0 or 1
      occurrences. \b{?} makes an expression optional. The regexp
      \b{^\\d\\d?$} means \e{From the beginning of the string, match
      one digit, followed immediately by 0 or 1 more digit, followed
      immediately by end of string}.
  
      To write a regexp that matches one of the words 'mail' \e or
      'letter' \e or 'correspondence' but does not match words that
      contain these words, e.g., 'email', 'mailman', 'mailer', and
      'letterbox', start with a regexp that matches 'mail'. Expressed
      fully, the regexp is \b{m{1,1}a{1,1}i{1,1}l{1,1}}, but because
      a character expression is automatically quantified by
      \b{{1,1}}, we can simplify the regexp to \b{mail}, i.e., an
      'm' followed by an 'a' followed by an 'i' followed by an 'l'. Now
      we can use the vertical bar \b{|}, which means \b{or}, to
      include the other two words, so our regexp for matching any of the
      three words becomes \b{mail|letter|correspondence}. Match
      'mail' \b{or} 'letter' \b{or} 'correspondence'. While this
      regexp will match one of the three words we want to match, it will
      also match words we don't want to match, e.g., 'email'.  To
      prevent the regexp from matching unwanted words, we must tell it
      to begin and end the match at word boundaries. First we enclose
      our regexp in parentheses, \b{(mail|letter|correspondence)}.
      Parentheses group expressions together, and they identify a part
      of the regexp that we wish to \l{capturing text}{capture}.
      Enclosing the expression in parentheses allows us to use it as a
      component in more complex regexps. It also allows us to examine
      which of the three words was actually matched. To force the match
      to begin and end on word boundaries, we enclose the regexp in
      \b{\\b} \e{word boundary} assertions:
      \b{\\b(mail|letter|correspondence)\\b}.  Now the regexp means:
      \e{Match a word boundary, followed by the regexp in parentheses,
      followed by a word boundary}. The \b{\\b} assertion matches a
      \e position in the regexp, not a \e character. A word boundary is
      any non-word character, e.g., a space, newline, or the beginning
      or ending of a string.
  
      If we want to replace ampersand characters with the HTML entity
      \b{\&amp;}, the regexp to match is simply \b{\&}. But this
      regexp will also match ampersands that have already been converted
      to HTML entities. We want to replace only ampersands that are not
      already followed by \b{amp;}. For this, we need the negative
      lookahead assertion, \b{(?!}__\b{)}. The regexp can then be
      written as \b{\&(?!amp;)}, i.e. \e{Match an ampersand that is}
      \b{not} \e{followed by} \b{amp;}.
  
      If we want to count all the occurrences of 'Eric' and 'Eirik' in a
      string, two valid solutions are \b{\\b(Eric|Eirik)\\b} and
      \b{\\bEi?ri[ck]\\b}. The word boundary assertion '\\b' is
      required to avoid matching words that contain either name,
      e.g. 'Ericsson'. Note that the second regexp matches more
      spellings than we want: 'Eric', 'Erik', 'Eiric' and 'Eirik'.
  
      Some of the examples discussed above are implemented in the
      \l{#code-examples}{code examples} section.
  
      \target characters-and-abbreviations-for-sets-of-characters
      \section1 Characters and Abbreviations for Sets of Characters
  
      \table
      \header \li Element \li Meaning
      \row \li \b{c}
           \li A character represents itself unless it has a special
           regexp meaning. e.g. \b{c} matches the character \e c.
      \row \li \b{\\c}
           \li A character that follows a backslash matches the character
           itself, except as specified below. e.g., To match a literal
           caret at the beginning of a string, write \b{\\^}.
      \row \li \b{\\a}
           \li Matches the ASCII bell (BEL, 0x07).
      \row \li \b{\\f}
           \li Matches the ASCII form feed (FF, 0x0C).
      \row \li \b{\\n}
           \li Matches the ASCII line feed (LF, 0x0A, Unix newline).
      \row \li \b{\\r}
           \li Matches the ASCII carriage return (CR, 0x0D).
      \row \li \b{\\t}
           \li Matches the ASCII horizontal tab (HT, 0x09).
      \row \li \b{\\v}
           \li Matches the ASCII vertical tab (VT, 0x0B).
      \row \li \b{\\x\e{hhhh}}
           \li Matches the Unicode character corresponding to the
           hexadecimal number \e{hhhh} (between 0x0000 and 0xFFFF).
      \row \li \b{\\0\e{ooo}} (i.e., \\zero \e{ooo})
           \li matches the ASCII/Latin1 character for the octal number
           \e{ooo} (between 0 and 0377).
      \row \li \b{. (dot)}
           \li Matches any character (including newline).
      \row \li \b{\\d}
           \li Matches a digit (QChar::isDigit()).
      \row \li \b{\\D}
           \li Matches a non-digit.
      \row \li \b{\\s}
           \li Matches a whitespace character (QChar::isSpace()).
      \row \li \b{\\S}
           \li Matches a non-whitespace character.
      \row \li \b{\\w}
           \li Matches a word character (QChar::isLetterOrNumber(), QChar::isMark(), or '_').
      \row \li \b{\\W}
           \li Matches a non-word character.
      \row \li \b{\\\e{n}}
           \li The \e{n}-th backreference, e.g. \\1, \\2, etc.
      \endtable
  
      \b{Note:} The C++ compiler transforms backslashes in strings.
      To include a \b{\\} in a regexp, enter it twice, i.e. \c{\\}.
      To match the backslash character itself, enter it four times, i.e.
      \c{\\\\}.
  
      \target sets-of-characters
      \section1 Sets of Characters
  
      Square brackets mean match any character contained in the square
      brackets. The character set abbreviations described above can
      appear in a character set in square brackets. Except for the
      character set abbreviations and the following two exceptions,
      characters do not have special meanings in square brackets.
  
      \table
      \row \li \b{^}
  
           \li The caret negates the character set if it occurs as the
           first character (i.e. immediately after the opening square
           bracket). \b{[abc]} matches 'a' or 'b' or 'c', but
           \b{[^abc]} matches anything \e but 'a' or 'b' or 'c'.
  
      \row \li \b{-}
  
           \li The dash indicates a range of characters. \b{[W-Z]}
           matches 'W' or 'X' or 'Y' or 'Z'.
  
      \endtable
  
      Using the predefined character set abbreviations is more portable
      than using character ranges across platforms and languages. For
      example, \b{[0-9]} matches a digit in Western alphabets but
      \b{\\d} matches a digit in \e any alphabet.
  
      Note: In other regexp documentation, sets of characters are often
      called "character classes".
  
      \target quantifiers
      \section1 Quantifiers
  
      By default, an expression is automatically quantified by
      \b{{1,1}}, i.e. it should occur exactly once. In the following
      list, \b{\e {E}} stands for expression. An expression is a
      character, or an abbreviation for a set of characters, or a set of
      characters in square brackets, or an expression in parentheses.
  
      \table
      \row \li \b{\e {E}?}
  
           \li Matches zero or one occurrences of \e E. This quantifier
           means \e{The previous expression is optional}, because it
           will match whether or not the expression is found. \b{\e
           {E}?} is the same as \b{\e {E}{0,1}}. e.g., \b{dents?}
           matches 'dent' or 'dents'.
  
      \row \li \b{\e {E}+}
  
           \li Matches one or more occurrences of \e E. \b{\e {E}+} is
           the same as \b{\e {E}{1,}}. e.g., \b{0+} matches '0',
           '00', '000', etc.
  
      \row \li \b{\e {E}*}
  
           \li Matches zero or more occurrences of \e E. It is the same
           as \b{\e {E}{0,}}. The \b{*} quantifier is often used
           in error where \b{+} should be used. For example, if
           \b{\\s*$} is used in an expression to match strings that
           end in whitespace, it will match every string because
           \b{\\s*$} means \e{Match zero or more whitespaces followed
           by end of string}. The correct regexp to match strings that
           have at least one trailing whitespace character is
           \b{\\s+$}.
  
      \row \li \b{\e {E}{n}}
  
           \li Matches exactly \e n occurrences of \e E. \b{\e {E}{n}}
           is the same as repeating \e E \e n times. For example,
           \b{x{5}} is the same as \b{xxxxx}. It is also the same
           as \b{\e {E}{n,n}}, e.g. \b{x{5,5}}.
  
      \row \li \b{\e {E}{n,}}
           \li Matches at least \e n occurrences of \e E.
  
      \row \li \b{\e {E}{,m}}
           \li Matches at most \e m occurrences of \e E. \b{\e {E}{,m}}
           is the same as \b{\e {E}{0,m}}.
  
      \row \li \b{\e {E}{n,m}}
           \li Matches at least \e n and at most \e m occurrences of \e E.
      \endtable
  
      To apply a quantifier to more than just the preceding character,
      use parentheses to group characters together in an expression. For
      example, \b{tag+} matches a 't' followed by an 'a' followed by
      at least one 'g', whereas \b{(tag)+} matches at least one
      occurrence of 'tag'.
  
      Note: Quantifiers are normally "greedy". They always match as much
      text as they can. For example, \b{0+} matches the first zero it
      finds and all the consecutive zeros after the first zero. Applied
      to '20005', it matches '2\underline{000}5'. Quantifiers can be made
      non-greedy, see setMinimal().
  
      \target capturing parentheses
      \target backreferences
      \section1 Capturing Text
  
      Parentheses allow us to group elements together so that we can
      quantify and capture them. For example if we have the expression
      \b{mail|letter|correspondence} that matches a string we know
      that \e one of the words matched but not which one. Using
      parentheses allows us to "capture" whatever is matched within
      their bounds, so if we used \b{(mail|letter|correspondence)}
      and matched this regexp against the string "I sent you some email"
      we can use the cap() or capturedTexts() functions to extract the
      matched characters, in this case 'mail'.
  
      We can use captured text within the regexp itself. To refer to the
      captured text we use \e backreferences which are indexed from 1,
      the same as for cap(). For example we could search for duplicate
      words in a string using \b{\\b(\\w+)\\W+\\1\\b} which means match a
      word boundary followed by one or more word characters followed by
      one or more non-word characters followed by the same text as the
      first parenthesized expression followed by a word boundary.
  
      If we want to use parentheses purely for grouping and not for
      capturing we can use the non-capturing syntax, e.g.
      \b{(?:green|blue)}. Non-capturing parentheses begin '(?:' and
      end ')'. In this example we match either 'green' or 'blue' but we
      do not capture the match so we only know whether or not we matched
      but not which color we actually found. Using non-capturing
      parentheses is more efficient than using capturing parentheses
      since the regexp engine has to do less book-keeping.
  
      Both capturing and non-capturing parentheses may be nested.
  
      \target greedy quantifiers
  
      For historical reasons, quantifiers (e.g. \b{*}) that apply to
      capturing parentheses are more "greedy" than other quantifiers.
      For example, \b{a*(a*)} will match "aaa" with cap(1) == "aaa".
      This behavior is different from what other regexp engines do
      (notably, Perl). To obtain a more intuitive capturing behavior,
      specify QRegExp::RegExp2 to the QRegExp constructor or call
      setPatternSyntax(QRegExp::RegExp2).
  
      \target cap_in_a_loop
  
      When the number of matches cannot be determined in advance, a
      common idiom is to use cap() in a loop. For example:
  
      \snippet code/src_corelib_tools_qregexp.cpp 0
  
      \target assertions
      \section1 Assertions
  
      Assertions make some statement about the text at the point where
      they occur in the regexp but they do not match any characters. In
      the following list \b{\e {E}} stands for any expression.
  
      \table
      \row \li \b{^}
           \li The caret signifies the beginning of the string. If you
           wish to match a literal \c{^} you must escape it by
           writing \c{\\^}. For example, \b{^#include} will only
           match strings which \e begin with the characters '#include'.
           (When the caret is the first character of a character set it
           has a special meaning, see \l{#sets-of-characters}{Sets of Characters}.)
  
      \row \li \b{$}
           \li The dollar signifies the end of the string. For example
           \b{\\d\\s*$} will match strings which end with a digit
           optionally followed by whitespace. If you wish to match a
           literal \c{$} you must escape it by writing
           \c{\\$}.
  
      \row \li \b{\\b}
           \li A word boundary. For example the regexp
           \b{\\bOK\\b} means match immediately after a word
           boundary (e.g. start of string or whitespace) the letter 'O'
           then the letter 'K' immediately before another word boundary
           (e.g. end of string or whitespace). But note that the
           assertion does not actually match any whitespace so if we
           write \b{(\\bOK\\b)} and we have a match it will only
           contain 'OK' even if the string is "It's \underline{OK} now".
  
      \row \li \b{\\B}
           \li A non-word boundary. This assertion is true wherever
           \b{\\b} is false. For example if we searched for
           \b{\\Bon\\B} in "Left on" the match would fail (space
           and end of string aren't non-word boundaries), but it would
           match in "t\underline{on}ne".
  
      \row \li \b{(?=\e E)}
           \li Positive lookahead. This assertion is true if the
           expression matches at this point in the regexp. For example,
           \b{const(?=\\s+char)} matches 'const' whenever it is
           followed by 'char', as in 'static \underline{const} char *'.
           (Compare with \b{const\\s+char}, which matches 'static
           \underline{const char} *'.)
  
      \row \li \b{(?!\e E)}
           \li Negative lookahead. This assertion is true if the
           expression does not match at this point in the regexp. For
           example, \b{const(?!\\s+char)} matches 'const' \e except
           when it is followed by 'char'.
      \endtable
  
      \target QRegExp wildcard matching
      \section1 Wildcard Matching
  
      Most command shells such as \e bash or \e cmd.exe support "file
      globbing", the ability to identify a group of files by using
      wildcards. The setPatternSyntax() function is used to switch
      between regexp and wildcard mode. Wildcard matching is much
      simpler than full regexps and has only four features:
  
      \table
      \row \li \b{c}
           \li Any character represents itself apart from those mentioned
           below. Thus \b{c} matches the character \e c.
      \row \li \b{?}
           \li Matches any single character. It is the same as
           \b{.} in full regexps.
      \row \li \b{*}
           \li Matches zero or more of any characters. It is the
           same as \b{.*} in full regexps.
      \row \li \b{[...]}
           \li Sets of characters can be represented in square brackets,
           similar to full regexps. Within the character class, like
           outside, backslash has no special meaning.
      \endtable
  
      In the mode Wildcard, the wildcard characters cannot be
      escaped. In the mode WildcardUnix, the character '\\' escapes the
      wildcard.
  
      For example if we are in wildcard mode and have strings which
      contain filenames we could identify HTML files with \b{*.html}.
      This will match zero or more characters followed by a dot followed
      by 'h', 't', 'm' and 'l'.
  
      To test a string against a wildcard expression, use exactMatch().
      For example:
  
      \snippet code/src_corelib_tools_qregexp.cpp 1
  
      \target perl-users
      \section1 Notes for Perl Users
  
      Most of the character class abbreviations supported by Perl are
      supported by QRegExp, see \l{#characters-and-abbreviations-for-sets-of-characters}
      {characters and abbreviations for sets of characters}.
  
      In QRegExp, apart from within character classes, \c{^} always
      signifies the start of the string, so carets must always be
      escaped unless used for that purpose. In Perl the meaning of caret
      varies automagically depending on where it occurs so escaping it
      is rarely necessary. The same applies to \c{$} which in
      QRegExp always signifies the end of the string.
  
      QRegExp's quantifiers are the same as Perl's greedy quantifiers
      (but see the \l{greedy quantifiers}{note above}). Non-greedy
      matching cannot be applied to individual quantifiers, but can be
      applied to all the quantifiers in the pattern. For example, to
      match the Perl regexp \b{ro+?m} requires:
  
      \snippet code/src_corelib_tools_qregexp.cpp 2
  
      The equivalent of Perl's \c{/i} option is
      setCaseSensitivity(Qt::CaseInsensitive).
  
      Perl's \c{/g} option can be emulated using a \l{#cap_in_a_loop}{loop}.
  
      In QRegExp \b{.} matches any character, therefore all QRegExp
      regexps have the equivalent of Perl's \c{/s} option. QRegExp
      does not have an equivalent to Perl's \c{/m} option, but this
      can be emulated in various ways for example by splitting the input
      into lines or by looping with a regexp that searches for newlines.
  
      Because QRegExp is string oriented, there are no \\A, \\Z, or \\z
      assertions. The \\G assertion is not supported but can be emulated
      in a loop.
  
      Perl's $& is cap(0) or capturedTexts()[0]. There are no QRegExp
      equivalents for $`, $' or $+. Perl's capturing variables, $1, $2,
      ... correspond to cap(1) or capturedTexts()[1], cap(2) or
      capturedTexts()[2], etc.
  
      To substitute a pattern use QString::replace().
  
      Perl's extended \c{/x} syntax is not supported, nor are
      directives, e.g. (?i), or regexp comments, e.g. (?#comment). On
      the other hand, C++'s rules for literal strings can be used to
      achieve the same:
  
      \snippet code/src_corelib_tools_qregexp.cpp 3
  
      Both zero-width positive and zero-width negative lookahead
      assertions (?=pattern) and (?!pattern) are supported with the same
      syntax as Perl. Perl's lookbehind assertions, "independent"
      subexpressions and conditional expressions are not supported.
  
      Non-capturing parentheses are also supported, with the same
      (?:pattern) syntax.
  
      See QString::split() and QStringList::join() for equivalents
      to Perl's split and join functions.
  
      Note: because C++ transforms \\'s they must be written \e twice in
      code, e.g. \b{\\b} must be written \b{\\\\b}.
  
      \target code-examples
      \section1 Code Examples
  
      \snippet code/src_corelib_tools_qregexp.cpp 4
  
      The third string matches '\underline{6}'. This is a simple validation
      regexp for integers in the range 0 to 99.
  
      \snippet code/src_corelib_tools_qregexp.cpp 5
  
      The second string matches '\underline{This_is-OK}'. We've used the
      character set abbreviation '\\S' (non-whitespace) and the anchors
      to match strings which contain no whitespace.
  
      In the following example we match strings containing 'mail' or
      'letter' or 'correspondence' but only match whole words i.e. not
      'email'
  
      \snippet code/src_corelib_tools_qregexp.cpp 6
  
      The second string matches "Please write the \underline{letter}". The
      word 'letter' is also captured (because of the parentheses). We
      can see what text we've captured like this:
  
      \snippet code/src_corelib_tools_qregexp.cpp 7
  
      This will capture the text from the first set of capturing
      parentheses (counting capturing left parentheses from left to
      right). The parentheses are counted from 1 since cap(0) is the
      whole matched regexp (equivalent to '&' in most regexp engines).
  
      \snippet code/src_corelib_tools_qregexp.cpp 8
  
      Here we've passed the QRegExp to QString's replace() function to
      replace the matched text with new text.
  
      \snippet code/src_corelib_tools_qregexp.cpp 9
  
      We've used the indexIn() function to repeatedly match the regexp in
      the string. Note that instead of moving forward by one character
      at a time \c pos++ we could have written \c {pos +=
      rx.matchedLength()} to skip over the already matched string. The
      count will equal 3, matching 'One \underline{Eric} another
      \underline{Eirik}, and an Ericsson. How many Eiriks, \underline{Eric}?'; it
      doesn't match 'Ericsson' or 'Eiriks' because they are not bounded
      by non-word boundaries.
  
      One common use of regexps is to split lines of delimited data into
      their component fields.
  
      \snippet code/src_corelib_tools_qregexp.cpp 10
  
      In this example our input lines have the format company name, web
      address and country. Unfortunately the regexp is rather long and
      not very versatile -- the code will break if we add any more
      fields. A simpler and better solution is to look for the
      separator, '\\t' in this case, and take the surrounding text. The
      QString::split() function can take a separator string or regexp
      as an argument and split a string accordingly.
  
      \snippet code/src_corelib_tools_qregexp.cpp 11
  
      Here field[0] is the company, field[1] the web address and so on.
  
      To imitate the matching of a shell we can use wildcard mode.
  
      \snippet code/src_corelib_tools_qregexp.cpp 12
  
      Wildcard matching can be convenient because of its simplicity, but
      any wildcard regexp can be defined using full regexps, e.g.
      \b{.*\\.html$}. Notice that we can't match both \c .html and \c
      .htm files with a wildcard unless we use \b{*.htm*} which will
      also match 'test.html.bak'. A full regexp gives us the precision
      we need, \b{.*\\.html?$}.
  
      QRegExp can match case insensitively using setCaseSensitivity(),
      and can use non-greedy matching, see setMinimal(). By
      default QRegExp uses full regexps but this can be changed with
      setPatternSyntax(). Searching can be done forward with indexIn() or backward
      with lastIndexIn(). Captured text can be accessed using
      capturedTexts() which returns a string list of all captured
      strings, or using cap() which returns the captured string for the
      given index. The pos() function takes a match index and returns
      the position in the string where the match was made (or -1 if
      there was no match).
  
      \sa QString, QStringList, QRegExpValidator, QSortFilterProxyModel,
          {tools/regexp}{Regular Expression Example}
  */
  
  #if defined(Q_OS_VXWORKS) && defined(EOS)
  #  undef EOS
  #endif
  
  const int NumBadChars = 64;
  #define BadChar(ch) ((ch).unicode() % NumBadChars)
  
  const int NoOccurrence = INT_MAX;
  const int EmptyCapture = INT_MAX;
  const int InftyLen = INT_MAX;
  const int InftyRep = 1025;
  const int EOS = -1;
  
  static bool isWord(QChar ch)
  {
      return ch.isLetterOrNumber() || ch.isMark() || ch == QLatin1Char('_');
  }
  
  /*
    Merges two vectors of ints and puts the result into the first
    one.
  */
  static void mergeInto(QVector<int> *a, const QVector<int> &b)
  {
      int asize = a->size();
      int bsize = b.size();
      if (asize == 0) {
          *a = b;
  #ifndef QT_NO_REGEXP_OPTIM
      } else if (bsize == 1 && a->at(asize - 1) < b.at(0)) {
          a->resize(asize + 1);
          (*a)[asize] = b.at(0);
  #endif
      } else if (bsize >= 1) {
          int csize = asize + bsize;
          QVector<int> c(csize);
          int i = 0, j = 0, k = 0;
          while (i < asize) {
              if (j < bsize) {
                  if (a->at(i) == b.at(j)) {
                      ++i;
                      --csize;
                  } else if (a->at(i) < b.at(j)) {
                      c[k++] = a->at(i++);
                  } else {
                      c[k++] = b.at(j++);
                  }
              } else {
                  memcpy(c.data() + k, a->constData() + i, (asize - i) * sizeof(int));
                  break;
              }
          }
          c.resize(csize);
          if (j < bsize)
              memcpy(c.data() + k, b.constData() + j, (bsize - j) * sizeof(int));
          *a = c;
      }
  }
  
  #ifndef QT_NO_REGEXP_WILDCARD
  /*
    Translates a wildcard pattern to an equivalent regular expression
    pattern (e.g., *.cpp to .*\.cpp).
  
    If enableEscaping is true, it is possible to escape the wildcard
    characters with \
  */
  static QString wc2rx(const QString &wc_str, const bool enableEscaping)
  {
      const int wclen = wc_str.length();
      QString rx;
      int i = 0;
      bool isEscaping = false; // the previous character is '\'
      const QChar *wc = wc_str.unicode();
  
      while (i < wclen) {
          const QChar c = wc[i++];
          switch (c.unicode()) {
          case '\\':
              if (enableEscaping) {
                  if (isEscaping) {
                      rx += QLatin1String("\\\\");
                  } // we insert the \\ later if necessary
                  if (i == wclen) { // the end
                      rx += QLatin1String("\\\\");
                  }
              } else {
                  rx += QLatin1String("\\\\");
              }
              isEscaping = true;
              break;
          case '*':
              if (isEscaping) {
                  rx += QLatin1String("\\*");
                  isEscaping = false;
              } else {
                  rx += QLatin1String(".*");
              }
              break;
          case '?':
              if (isEscaping) {
                  rx += QLatin1String("\\?");
                  isEscaping = false;
              } else {
                  rx += QLatin1Char('.');
              }
  
              break;
          case '$':
          case '(':
          case ')':
          case '+':
          case '.':
          case '^':
          case '{':
          case '|':
          case '}':
              if (isEscaping) {
                  isEscaping = false;
                  rx += QLatin1String("\\\\");
              }
              rx += QLatin1Char('\\');
              rx += c;
              break;
           case '[':
              if (isEscaping) {
                  isEscaping = false;
                  rx += QLatin1String("\\[");
              } else {
                  rx += c;
                  if (wc[i] == QLatin1Char('^'))
                      rx += wc[i++];
                  if (i < wclen) {
                      if (rx[i] == QLatin1Char(']'))
                          rx += wc[i++];
                      while (i < wclen && wc[i] != QLatin1Char(']')) {
                          if (wc[i] == QLatin1Char('\\'))
                              rx += QLatin1Char('\\');
                          rx += wc[i++];
                      }
                  }
              }
               break;
  
          case ']':
              if(isEscaping){
                  isEscaping = false;
                  rx += QLatin1String("\\");
              }
              rx += c;
              break;
  
          default:
              if(isEscaping){
                  isEscaping = false;
                  rx += QLatin1String("\\\\");
              }
              rx += c;
          }
      }
      return rx;
  }
  #endif
  
  static int caretIndex(int offset, QRegExp::CaretMode caretMode)
  {
      if (caretMode == QRegExp::CaretAtZero) {
          return 0;
      } else if (caretMode == QRegExp::CaretAtOffset) {
          return offset;
      } else { // QRegExp::CaretWontMatch
          return -1;
      }
  }
  
  /*
      The QRegExpEngineKey struct uniquely identifies an engine.
  */
  struct QRegExpEngineKey
  {
      QString pattern;
      QRegExp::PatternSyntax patternSyntax;
      Qt::CaseSensitivity cs;
  
      inline QRegExpEngineKey(const QString &pattern, QRegExp::PatternSyntax patternSyntax,
                              Qt::CaseSensitivity cs)
          : pattern(pattern), patternSyntax(patternSyntax), cs(cs) {}
  
      inline void clear() {
          pattern.clear();
          patternSyntax = QRegExp::RegExp;
          cs = Qt::CaseSensitive;
      }
  };
  
  static bool operator==(const QRegExpEngineKey &key1, const QRegExpEngineKey &key2)
  {
      return key1.pattern == key2.pattern && key1.patternSyntax == key2.patternSyntax
             && key1.cs == key2.cs;
  }
  
  static uint qHash(const QRegExpEngineKey &key, uint seed = 0) Q_DECL_NOTHROW
  {
      QtPrivate::QHashCombine hash;
      seed = hash(seed, key.pattern);
      seed = hash(seed, key.patternSyntax);
      seed = hash(seed, key.cs);
      return seed;
  }
  
  class QRegExpEngine;
  
  //Q_DECLARE_TYPEINFO(QVector<int>, Q_MOVABLE_TYPE);
  
  /*
    This is the engine state during matching.
  */
  struct QRegExpMatchState
  {
      const QChar *in; // a pointer to the input string data
      int pos; // the current position in the string
      int caretPos;
      int len; // the length of the input string
      bool minimal; // minimal matching?
      int *bigArray; // big array holding the data for the next pointers
      int *inNextStack; // is state is nextStack?
      int *curStack; // stack of current states
      int *nextStack; // stack of next states
      int *curCapBegin; // start of current states' captures
      int *nextCapBegin; // start of next states' captures
      int *curCapEnd; // end of current states' captures
      int *nextCapEnd; // end of next states' captures
      int *tempCapBegin; // start of temporary captures
      int *tempCapEnd; // end of temporary captures
      int *capBegin; // start of captures for a next state
      int *capEnd; // end of captures for a next state
      int *slideTab; // bump-along slide table for bad-character heuristic
      int *captured; // what match() returned last
      int slideTabSize; // size of slide table
      int capturedSize;
  #ifndef QT_NO_REGEXP_BACKREF
      QList<QVector<int> > sleeping; // list of back-reference sleepers
  #endif
      int matchLen; // length of match
      int oneTestMatchedLen; // length of partial match
  
      const QRegExpEngine *eng;
  
      inline QRegExpMatchState() : bigArray(0), captured(0) {}
      inline ~QRegExpMatchState() { free(bigArray); }
  
      void drain() { free(bigArray); bigArray = 0; captured = 0; } // to save memory
      void prepareForMatch(QRegExpEngine *eng);
      void match(const QChar *str, int len, int pos, bool minimal,
          bool oneTest, int caretIndex);
      bool matchHere();
      bool testAnchor(int i, int a, const int *capBegin);
  };
  
  /*
    The struct QRegExpAutomatonState represents one state in a modified NFA. The
    input characters matched are stored in the state instead of on
    the transitions, something possible for an automaton
    constructed from a regular expression.
  */
  struct QRegExpAutomatonState
  {
  #ifndef QT_NO_REGEXP_CAPTURE
      int atom; // which atom does this state belong to?
  #endif
      int match; // what does it match? (see CharClassBit and BackRefBit)
      QVector<int> outs; // out-transitions
      QMap<int, int> reenter; // atoms reentered when transiting out
      QMap<int, int> anchors; // anchors met when transiting out
  
      inline QRegExpAutomatonState() { }
  #ifndef QT_NO_REGEXP_CAPTURE
      inline QRegExpAutomatonState(int a, int m)
          : atom(a), match(m) { }
  #else
      inline QRegExpAutomatonState(int m)
          : match(m) { }
  #endif
  };
  
  Q_DECLARE_TYPEINFO(QRegExpAutomatonState, Q_MOVABLE_TYPE);
  
  /*
    The struct QRegExpCharClassRange represents a range of characters (e.g.,
    [0-9] denotes range 48 to 57).
  */
  struct QRegExpCharClassRange
  {
      ushort from; // 48
      ushort len; // 10
  };
  
  Q_DECLARE_TYPEINFO(QRegExpCharClassRange, Q_PRIMITIVE_TYPE);
  
  #ifndef QT_NO_REGEXP_CAPTURE
  /*
    The struct QRegExpAtom represents one node in the hierarchy of regular
    expression atoms.
  */
  struct QRegExpAtom
  {
      enum { NoCapture = -1, OfficialCapture = -2, UnofficialCapture = -3 };
  
      int parent; // index of parent in array of atoms
      int capture; // index of capture, from 1 to ncap - 1
  };
  
  Q_DECLARE_TYPEINFO(QRegExpAtom, Q_PRIMITIVE_TYPE);
  #endif
  
  struct QRegExpLookahead;
  
  #ifndef QT_NO_REGEXP_ANCHOR_ALT
  /*
    The struct QRegExpAnchorAlternation represents a pair of anchors with
    OR semantics.
  */
  struct QRegExpAnchorAlternation
  {
      int a; // this anchor...
      int b; // ...or this one
  };
  
  Q_DECLARE_TYPEINFO(QRegExpAnchorAlternation, Q_PRIMITIVE_TYPE);
  #endif
  
  #ifndef QT_NO_REGEXP_CCLASS
  
  #define FLAG(x) (1 << (x))
  /*
    The class QRegExpCharClass represents a set of characters, such as can
    be found in regular expressions (e.g., [a-z] denotes the set
    {a, b, ..., z}).
  */
  class QRegExpCharClass
  {
  public:
      QRegExpCharClass();
  
      void clear();
      bool negative() const { return n; }
      void setNegative(bool negative);
      void addCategories(uint cats);
      void addRange(ushort from, ushort to);
      void addSingleton(ushort ch) { addRange(ch, ch); }
  
      bool in(QChar ch) const;
  #ifndef QT_NO_REGEXP_OPTIM
      const QVector<int> &firstOccurrence() const { return occ1; }
  #endif
  
  #if defined(QT_DEBUG)
      void dump() const;
  #endif
  
  private:
      QVector<QRegExpCharClassRange> r; // character ranges
  #ifndef QT_NO_REGEXP_OPTIM
      QVector<int> occ1; // first-occurrence array
  #endif
      uint c; // character classes
      bool n; // negative?
  };
  #else
  struct QRegExpCharClass
  {
      int dummy;
  
  #ifndef QT_NO_REGEXP_OPTIM
      QRegExpCharClass() { occ1.fill(0, NumBadChars); }
  
      const QVector<int> &firstOccurrence() const { return occ1; }
      QVector<int> occ1;
  #endif
  };
  #endif
  
  Q_DECLARE_TYPEINFO(QRegExpCharClass, Q_MOVABLE_TYPE);
  
  /*
    The QRegExpEngine class encapsulates a modified nondeterministic
    finite automaton (NFA).
  */
  class QRegExpEngine
  {
  public:
      QRegExpEngine(Qt::CaseSensitivity cs, bool greedyQuantifiers)
          : cs(cs), greedyQuantifiers(greedyQuantifiers) { setup(); }
  
      QRegExpEngine(const QRegExpEngineKey &key);
      ~QRegExpEngine();
  
      bool isValid() const { return valid; }
      const QString &errorString() const { return yyError; }
      int captureCount() const { return officialncap; }
  
      int createState(QChar ch);
      int createState(const QRegExpCharClass &cc);
  #ifndef QT_NO_REGEXP_BACKREF
      int createState(int bref);
  #endif
  
      void addCatTransitions(const QVector<int> &from, const QVector<int> &to);
  #ifndef QT_NO_REGEXP_CAPTURE
      void addPlusTransitions(const QVector<int> &from, const QVector<int> &to, int atom);
  #endif
  
  #ifndef QT_NO_REGEXP_ANCHOR_ALT
      int anchorAlternation(int a, int b);
      int anchorConcatenation(int a, int b);
  #else
      int anchorAlternation(int a, int b) { return a & b; }
      int anchorConcatenation(int a, int b) { return a | b; }
  #endif
      void addAnchors(int from, int to, int a);
  
  #ifndef QT_NO_REGEXP_OPTIM
      void heuristicallyChooseHeuristic();
  #endif
  
  #if defined(QT_DEBUG)
      void dump() const;
  #endif
  
      QAtomicInt ref;
  
  private:
      enum { CharClassBit = 0x10000, BackRefBit = 0x20000 };
      enum { InitialState = 0, FinalState = 1 };
  
      void setup();
      int setupState(int match);
  
      /*
        Let's hope that 13 lookaheads and 14 back-references are
        enough.
       */
      enum { MaxLookaheads = 13, MaxBackRefs = 14 };
      enum { Anchor_Dollar = 0x00000001, Anchor_Caret = 0x00000002, Anchor_Word = 0x00000004,
             Anchor_NonWord = 0x00000008, Anchor_FirstLookahead = 0x00000010,
             Anchor_BackRef1Empty = Anchor_FirstLookahead << MaxLookaheads,
             Anchor_BackRef0Empty = Anchor_BackRef1Empty >> 1,
             Anchor_Alternation = unsigned(Anchor_BackRef1Empty) << MaxBackRefs,
  
             Anchor_LookaheadMask = (Anchor_FirstLookahead - 1) ^
                     ((Anchor_FirstLookahead << MaxLookaheads) - 1) };
  #ifndef QT_NO_REGEXP_CAPTURE
      int startAtom(bool officialCapture);
      void finishAtom(int atom, bool needCapture);
  #endif
  
  #ifndef QT_NO_REGEXP_LOOKAHEAD
      int addLookahead(QRegExpEngine *eng, bool negative);
  #endif
  
  #ifndef QT_NO_REGEXP_OPTIM
      bool goodStringMatch(QRegExpMatchState &matchState) const;
      bool badCharMatch(QRegExpMatchState &matchState) const;
  #else
      bool bruteMatch(QRegExpMatchState &matchState) const;
  #endif
  
      QVector<QRegExpAutomatonState> s; // array of states
  #ifndef QT_NO_REGEXP_CAPTURE
      QVector<QRegExpAtom> f; // atom hierarchy
      int nf; // number of atoms
      int cf; // current atom
      QVector<int> captureForOfficialCapture;
  #endif
      int officialncap; // number of captures, seen from the outside
      int ncap; // number of captures, seen from the inside
  #ifndef QT_NO_REGEXP_CCLASS
      QVector<QRegExpCharClass> cl; // array of character classes
  #endif
  #ifndef QT_NO_REGEXP_LOOKAHEAD
      QVector<QRegExpLookahead *> ahead; // array of lookaheads
  #endif
  #ifndef QT_NO_REGEXP_ANCHOR_ALT
      QVector<QRegExpAnchorAlternation> aa; // array of (a, b) pairs of anchors
  #endif
  #ifndef QT_NO_REGEXP_OPTIM
      bool caretAnchored; // does the regexp start with ^?
      bool trivial; // is the good-string all that needs to match?
  #endif
      bool valid; // is the regular expression valid?
      Qt::CaseSensitivity cs; // case sensitive?
      bool greedyQuantifiers; // RegExp2?
      bool xmlSchemaExtensions;
  #ifndef QT_NO_REGEXP_BACKREF
      int nbrefs; // number of back-references
  #endif
  
  #ifndef QT_NO_REGEXP_OPTIM
      bool useGoodStringHeuristic; // use goodStringMatch? otherwise badCharMatch
  
      int goodEarlyStart; // the index where goodStr can first occur in a match
      int goodLateStart; // the index where goodStr can last occur in a match
      QString goodStr; // the string that any match has to contain
  
      int minl; // the minimum length of a match
      QVector<int> occ1; // first-occurrence array
  #endif
  
      /*
        The class Box is an abstraction for a regular expression
        fragment. It can also be seen as one node in the syntax tree of
        a regular expression with synthetized attributes.
  
        Its interface is ugly for performance reasons.
      */
      class Box
      {
      public:
          Box(QRegExpEngine *engine);
          Box(const Box &b) { operator=(b); }
  
          Box &operator=(const Box &b);
  
          void clear() { operator=(Box(eng)); }
          void set(QChar ch);
          void set(const QRegExpCharClass &cc);
  #ifndef QT_NO_REGEXP_BACKREF
          void set(int bref);
  #endif
  
          void cat(const Box &b);
          void orx(const Box &b);
          void plus(int atom);
          void opt();
          void catAnchor(int a);
  #ifndef QT_NO_REGEXP_OPTIM
          void setupHeuristics();
  #endif
  
  #if defined(QT_DEBUG)
          void dump() const;
  #endif
  
      private:
          void addAnchorsToEngine(const Box &to) const;
  
          QRegExpEngine *eng; // the automaton under construction
          QVector<int> ls; // the left states (firstpos)
          QVector<int> rs; // the right states (lastpos)
          QMap<int, int> lanchors; // the left anchors
          QMap<int, int> ranchors; // the right anchors
          int skipanchors; // the anchors to match if the box is skipped
  
  #ifndef QT_NO_REGEXP_OPTIM
          int earlyStart; // the index where str can first occur
          int lateStart; // the index where str can last occur
          QString str; // a string that has to occur in any match
          QString leftStr; // a string occurring at the left of this box
          QString rightStr; // a string occurring at the right of this box
          int maxl; // the maximum length of this box (possibly InftyLen)
  #endif
  
          int minl; // the minimum length of this box
  #ifndef QT_NO_REGEXP_OPTIM
          QVector<int> occ1; // first-occurrence array
  #endif
      };
  
      friend class Box;
  
      /*
        This is the lexical analyzer for regular expressions.
      */
      enum { Tok_Eos, Tok_Dollar, Tok_LeftParen, Tok_MagicLeftParen, Tok_PosLookahead,
             Tok_NegLookahead, Tok_RightParen, Tok_CharClass, Tok_Caret, Tok_Quantifier, Tok_Bar,
             Tok_Word, Tok_NonWord, Tok_Char = 0x10000, Tok_BackRef = 0x20000 };
      int getChar();
      int getEscape();
  #ifndef QT_NO_REGEXP_INTERVAL
      int getRep(int def);
  #endif
  #ifndef QT_NO_REGEXP_LOOKAHEAD
      void skipChars(int n);
  #endif
      void error(const char *msg);
      void startTokenizer(const QChar *rx, int len);
      int getToken();
  
      const QChar *yyIn; // a pointer to the input regular expression pattern
      int yyPos0; // the position of yyTok in the input pattern
      int yyPos; // the position of the next character to read
      int yyLen; // the length of yyIn
      int yyCh; // the last character read
      QScopedPointer<QRegExpCharClass> yyCharClass; // attribute for Tok_CharClass tokens
      int yyMinRep; // attribute for Tok_Quantifier
      int yyMaxRep; // ditto
      QString yyError; // syntax error or overflow during parsing?
  
      /*
        This is the syntactic analyzer for regular expressions.
      */
      int parse(const QChar *rx, int len);
      void parseAtom(Box *box);
      void parseFactor(Box *box);
      void parseTerm(Box *box);
      void parseExpression(Box *box);
  
      int yyTok; // the last token read
      bool yyMayCapture; // set this to false to disable capturing
  
      friend struct QRegExpMatchState;
  };
  
  #ifndef QT_NO_REGEXP_LOOKAHEAD
  /*
    The struct QRegExpLookahead represents a lookahead a la Perl (e.g.,
    (?=foo) and (?!bar)).
  */
  struct QRegExpLookahead
  {
      QRegExpEngine *eng; // NFA representing the embedded regular expression
      bool neg; // negative lookahead?
  
      inline QRegExpLookahead(QRegExpEngine *eng0, bool neg0)
          : eng(eng0), neg(neg0) { }
      inline ~QRegExpLookahead() { delete eng; }
  };
  #endif
  
  /*!
      \internal
      convert the pattern string to the RegExp syntax.
  
      This is also used by QScriptEngine::newRegExp to convert to a pattern that JavaScriptCore can understan
   */
  Q_CORE_EXPORT QString qt_regexp_toCanonical(const QString &pattern, QRegExp::PatternSyntax patternSyntax)
  {
      switch (patternSyntax) {
  #ifndef QT_NO_REGEXP_WILDCARD
      case QRegExp::Wildcard:
          return wc2rx(pattern, false);
      case QRegExp::WildcardUnix:
          return wc2rx(pattern, true);
  #endif
      case QRegExp::FixedString:
          return QRegExp::escape(pattern);
      case QRegExp::W3CXmlSchema11:
      default:
          return pattern;
      }
  }
  
  QRegExpEngine::QRegExpEngine(const QRegExpEngineKey &key)
      : cs(key.cs), greedyQuantifiers(key.patternSyntax == QRegExp::RegExp2),
        xmlSchemaExtensions(key.patternSyntax == QRegExp::W3CXmlSchema11)
  {
      setup();
  
      QString rx = qt_regexp_toCanonical(key.pattern, key.patternSyntax);
  
      valid = (parse(rx.unicode(), rx.length()) == rx.length());
      if (!valid) {
  #ifndef QT_NO_REGEXP_OPTIM
          trivial = false;
  #endif
          error(RXERR_LEFTDELIM);
      }
  }
  
  QRegExpEngine::~QRegExpEngine()
  {
  #ifndef QT_NO_REGEXP_LOOKAHEAD
      qDeleteAll(ahead);
  #endif
  }
  
  void QRegExpMatchState::prepareForMatch(QRegExpEngine *eng)
  {
      /*
        We use one QVector<int> for all the big data used a lot in
        matchHere() and friends.
      */
      int ns = eng->s.size(); // number of states
      int ncap = eng->ncap;
  #ifndef QT_NO_REGEXP_OPTIM
      int newSlideTabSize = qMax(eng->minl + 1, 16);
  #else
      int newSlideTabSize = 0;
  #endif
      int numCaptures = eng->captureCount();
      int newCapturedSize = 2 + 2 * numCaptures;
      bigArray = q_check_ptr((int *)realloc(bigArray, ((3 + 4 * ncap) * ns + 4 * ncap + newSlideTabSize + newCapturedSize)*sizeof(int)));
  
      // set all internal variables only _after_ bigArray is realloc'ed
      // to prevent a broken regexp in oom case
  
      slideTabSize = newSlideTabSize;
      capturedSize = newCapturedSize;
      inNextStack = bigArray;
      memset(inNextStack, -1, ns * sizeof(int));
      curStack = inNextStack + ns;
      nextStack = inNextStack + 2 * ns;
  
      curCapBegin = inNextStack + 3 * ns;
      nextCapBegin = curCapBegin + ncap * ns;
      curCapEnd = curCapBegin + 2 * ncap * ns;
      nextCapEnd = curCapBegin + 3 * ncap * ns;
  
      tempCapBegin = curCapBegin + 4 * ncap * ns;
      tempCapEnd = tempCapBegin + ncap;
      capBegin = tempCapBegin + 2 * ncap;
      capEnd = tempCapBegin + 3 * ncap;
  
      slideTab = tempCapBegin + 4 * ncap;
      captured = slideTab + slideTabSize;
      memset(captured, -1, capturedSize*sizeof(int));
      this->eng = eng;
  }
  
  /*
    Tries to match in str and returns an array of (begin, length) pairs
    for captured text. If there is no match, all pairs are (-1, -1).
  */
  void QRegExpMatchState::match(const QChar *str0, int len0, int pos0,
      bool minimal0, bool oneTest, int caretIndex)
  {
      bool matched = false;
      QChar char_null;
  
  #ifndef QT_NO_REGEXP_OPTIM
      if (eng->trivial && !oneTest) {
          pos = qFindString(str0, len0, pos0, eng->goodStr.unicode(), eng->goodStr.length(), eng->cs);
          matchLen = eng->goodStr.length();
          matched = (pos != -1);
      } else
  #endif
      {
          in = str0;
          if (in == 0)
              in = &char_null;
          pos = pos0;
          caretPos = caretIndex;
          len = len0;
          minimal = minimal0;
          matchLen = 0;
          oneTestMatchedLen = 0;
  
          if (eng->valid && pos >= 0 && pos <= len) {
  #ifndef QT_NO_REGEXP_OPTIM
              if (oneTest) {
                  matched = matchHere();
              } else {
                  if (pos <= len - eng->minl) {
                      if (eng->caretAnchored) {
                          matched = matchHere();
                      } else if (eng->useGoodStringHeuristic) {
                          matched = eng->goodStringMatch(*this);
                      } else {
                          matched = eng->badCharMatch(*this);
                      }
                  }
              }
  #else
              matched = oneTest ? matchHere() : eng->bruteMatch(*this);
  #endif
          }
      }
  
      if (matched) {
          int *c = captured;
          *c++ = pos;
          *c++ = matchLen;
  
          int numCaptures = (capturedSize - 2) >> 1;
  #ifndef QT_NO_REGEXP_CAPTURE
          for (int i = 0; i < numCaptures; ++i) {
              int j = eng->captureForOfficialCapture.at(i);
              if (capBegin[j] != EmptyCapture) {
                  int len = capEnd[j] - capBegin[j];
                  *c++ = (len > 0) ? pos + capBegin[j] : 0;
                  *c++ = len;
              } else {
                  *c++ = -1;
                  *c++ = -1;
              }
          }
  #endif
      } else {
          // we rely on 2's complement here
          memset(captured, -1, capturedSize * sizeof(int));
      }
  }
  
  /*
    The three following functions add one state to the automaton and
    return the number of the state.
  */
  
  int QRegExpEngine::createState(QChar ch)
  {
      return setupState(ch.unicode());
  }
  
  int QRegExpEngine::createState(const QRegExpCharClass &cc)
  {
  #ifndef QT_NO_REGEXP_CCLASS
      int n = cl.size();
      cl += QRegExpCharClass(cc);
      return setupState(CharClassBit | n);
  #else
      Q_UNUSED(cc);
      return setupState(CharClassBit);
  #endif
  }
  
  #ifndef QT_NO_REGEXP_BACKREF
  int QRegExpEngine::createState(int bref)
  {
      if (bref > nbrefs) {
          nbrefs = bref;
          if (nbrefs > MaxBackRefs) {
              error(RXERR_LIMIT);
              return 0;
          }
      }
      return setupState(BackRefBit | bref);
  }
  #endif
  
  /*
    The two following functions add a transition between all pairs of
    states (i, j) where i is found in from, and j is found in to.
  
    Cat-transitions are distinguished from plus-transitions for
    capturing.
  */
  
  void QRegExpEngine::addCatTransitions(const QVector<int> &from, const QVector<int> &to)
  {
      for (int i = 0; i < from.size(); i++)
          mergeInto(&s[from.at(i)].outs, to);
  }
  
  #ifndef QT_NO_REGEXP_CAPTURE
  void QRegExpEngine::addPlusTransitions(const QVector<int> &from, const QVector<int> &to, int atom)
  {
      for (int i = 0; i < from.size(); i++) {
          QRegExpAutomatonState &st = s[from.at(i)];
          const QVector<int> oldOuts = st.outs;
          mergeInto(&st.outs, to);
          if (f.at(atom).capture != QRegExpAtom::NoCapture) {
              for (int j = 0; j < to.size(); j++) {
                  // ### st.reenter.contains(to.at(j)) check looks suspicious
                  if (!st.reenter.contains(to.at(j)) &&
                       !std::binary_search(oldOuts.constBegin(), oldOuts.constEnd(), to.at(j)))
                      st.reenter.insert(to.at(j), atom);
              }
          }
      }
  }
  #endif
  
  #ifndef QT_NO_REGEXP_ANCHOR_ALT
  /*
    Returns an anchor that means a OR b.
  */
  int QRegExpEngine::anchorAlternation(int a, int b)
  {
      if (((a & b) == a || (a & b) == b) && ((a | b) & Anchor_Alternation) == 0)
          return a & b;
  
      int n = aa.size();
  #ifndef QT_NO_REGEXP_OPTIM
      if (n > 0 && aa.at(n - 1).a == a && aa.at(n - 1).b == b)
          return Anchor_Alternation | (n - 1);
  #endif
  
      QRegExpAnchorAlternation element = {a, b};
      aa.append(element);
      return Anchor_Alternation | n;
  }
  
  /*
    Returns an anchor that means a AND b.
  */
  int QRegExpEngine::anchorConcatenation(int a, int b)
  {
      if (((a | b) & Anchor_Alternation) == 0)
          return a | b;
      if ((b & Anchor_Alternation) != 0)
          qSwap(a, b);
  
      int aprime = anchorConcatenation(aa.at(a ^ Anchor_Alternation).a, b);
      int bprime = anchorConcatenation(aa.at(a ^ Anchor_Alternation).b, b);
      return anchorAlternation(aprime, bprime);
  }
  #endif
  
  /*
    Adds anchor a on a transition caracterised by its from state and
    its to state.
  */
  void QRegExpEngine::addAnchors(int from, int to, int a)
  {
      QRegExpAutomatonState &st = s[from];
      if (st.anchors.contains(to))
          a = anchorAlternation(st.anchors.value(to), a);
      st.anchors.insert(to, a);
  }
  
  #ifndef QT_NO_REGEXP_OPTIM
  /*
    This function chooses between the good-string and the bad-character
    heuristics. It computes two scores and chooses the heuristic with
    the highest score.
  
    Here are some common-sense constraints on the scores that should be
    respected if the formulas are ever modified: (1) If goodStr is
    empty, the good-string heuristic scores 0. (2) If the regular
    expression is trivial, the good-string heuristic should be used.
    (3) If the search is case insensitive, the good-string heuristic
    should be used, unless it scores 0. (Case insensitivity turns all
    entries of occ1 to 0.) (4) If (goodLateStart - goodEarlyStart) is
    big, the good-string heuristic should score less.
  */
  void QRegExpEngine::heuristicallyChooseHeuristic()
  {
      if (minl == 0) {
          useGoodStringHeuristic = false;
      } else if (trivial) {
          useGoodStringHeuristic = true;
      } else {
          /*
            Magic formula: The good string has to constitute a good
            proportion of the minimum-length string, and appear at a
            more-or-less known index.
          */
          int goodStringScore = (64 * goodStr.length() / minl) -
                                (goodLateStart - goodEarlyStart);
          /*
            Less magic formula: We pick some characters at random, and
            check whether they are good or bad.
          */
          int badCharScore = 0;
          int step = qMax(1, NumBadChars / 32);
          for (int i = 1; i < NumBadChars; i += step) {
              if (occ1.at(i) == NoOccurrence)
                  badCharScore += minl;
              else
                  badCharScore += occ1.at(i);
          }
          badCharScore /= minl;
          useGoodStringHeuristic = (goodStringScore > badCharScore);
      }
  }
  #endif
  
  #if defined(QT_DEBUG)
  void QRegExpEngine::dump() const
  {
      int i, j;
      qDebug("Case %ssensitive engine", cs ? "" : "in");
      qDebug("  States");
      for (i = 0; i < s.size(); i++) {
          qDebug("  %d%s", i, i == InitialState ? " (initial)" : i == FinalState ? " (final)" : "");
  #ifndef QT_NO_REGEXP_CAPTURE
          if (nf > 0)
              qDebug("    in atom %d", s[i].atom);
  #endif
          int m = s[i].match;
          if ((m & CharClassBit) != 0) {
              qDebug("    match character class %d", m ^ CharClassBit);
  #ifndef QT_NO_REGEXP_CCLASS
              cl[m ^ CharClassBit].dump();
  #else
              qDebug("    negative character class");
  #endif
          } else if ((m & BackRefBit) != 0) {
              qDebug("    match back-reference %d", m ^ BackRefBit);
          } else if (m >= 0x20 && m <= 0x7e) {
              qDebug("    match 0x%.4x (%c)", m, m);
          } else {
              qDebug("    match 0x%.4x", m);
          }
          for (j = 0; j < s[i].outs.size(); j++) {
              int next = s[i].outs[j];
              qDebug("    -> %d", next);
              if (s[i].reenter.contains(next))
                  qDebug("       [reenter %d]", s[i].reenter[next]);
              if (s[i].anchors.value(next) != 0)
                  qDebug("       [anchors 0x%.8x]", s[i].anchors[next]);
          }
      }
  #ifndef QT_NO_REGEXP_CAPTURE
      if (nf > 0) {
          qDebug("  Atom    Parent  Capture");
          for (i = 0; i < nf; i++) {
              if (f[i].capture == QRegExpAtom::NoCapture) {
                  qDebug("  %6d  %6d     nil", i, f[i].parent);
              } else {
                  int cap = f[i].capture;
                  bool official = captureForOfficialCapture.contains(cap);
                  qDebug("  %6d  %6d  %6d  %s", i, f[i].parent, f[i].capture,
                         official ? "official" : "");
              }
          }
      }
  #endif
  #ifndef QT_NO_REGEXP_ANCHOR_ALT
      for (i = 0; i < aa.size(); i++)
          qDebug("  Anchor alternation 0x%.8x: 0x%.8x 0x%.9x", i, aa[i].a, aa[i].b);
  #endif
  }
  #endif
  
  void QRegExpEngine::setup()
  {
      ref.store(1);
  #ifndef QT_NO_REGEXP_CAPTURE
      f.resize(32);
      nf = 0;
      cf = -1;
  #endif
      officialncap = 0;
      ncap = 0;
  #ifndef QT_NO_REGEXP_OPTIM
      caretAnchored = true;
      trivial = true;
  #endif
      valid = false;
  #ifndef QT_NO_REGEXP_BACKREF
      nbrefs = 0;
  #endif
  #ifndef QT_NO_REGEXP_OPTIM
      useGoodStringHeuristic = true;
      minl = 0;
      occ1.fill(0, NumBadChars);
  #endif
  }
  
  int QRegExpEngine::setupState(int match)
  {
  #ifndef QT_NO_REGEXP_CAPTURE
      s += QRegExpAutomatonState(cf, match);
  #else
      s += QRegExpAutomatonState(match);
  #endif
      return s.size() - 1;
  }
  
  #ifndef QT_NO_REGEXP_CAPTURE
  /*
    Functions startAtom() and finishAtom() should be called to delimit
    atoms. When a state is created, it is assigned to the current atom.
    The information is later used for capturing.
  */
  int QRegExpEngine::startAtom(bool officialCapture)
  {
      if ((nf & (nf + 1)) == 0 && nf + 1 >= f.size())
          f.resize((nf + 1) << 1);
      f[nf].parent = cf;
      cf = nf++;
      f[cf].capture = officialCapture ? QRegExpAtom::OfficialCapture : QRegExpAtom::NoCapture;
      return cf;
  }
  
  void QRegExpEngine::finishAtom(int atom, bool needCapture)
  {
      if (greedyQuantifiers && needCapture && f[atom].capture == QRegExpAtom::NoCapture)
          f[atom].capture = QRegExpAtom::UnofficialCapture;
      cf = f.at(atom).parent;
  }
  #endif
  
  #ifndef QT_NO_REGEXP_LOOKAHEAD
  /*
    Creates a lookahead anchor.
  */
  int QRegExpEngine::addLookahead(QRegExpEngine *eng, bool negative)
  {
      int n = ahead.size();
      if (n == MaxLookaheads) {
          error(RXERR_LIMIT);
          return 0;
      }
      ahead += new QRegExpLookahead(eng, negative);
      return Anchor_FirstLookahead << n;
  }
  #endif
  
  #ifndef QT_NO_REGEXP_CAPTURE
  /*
    We want the longest leftmost captures.
  */
  static bool isBetterCapture(int ncap, const int *begin1, const int *end1, const int *begin2,
                              const int *end2)
  {
      for (int i = 0; i < ncap; i++) {
          int delta = begin2[i] - begin1[i]; // it has to start early...
          if (delta == 0)
              delta = end1[i] - end2[i]; // ...and end late
  
          if (delta != 0)
              return delta > 0;
      }
      return false;
  }
  #endif
  
  /*
    Returns \c true if anchor a matches at position pos + i in the input
    string, otherwise false.
  */
  bool QRegExpMatchState::testAnchor(int i, int a, const int *capBegin)
  {
      int j;
  
  #ifndef QT_NO_REGEXP_ANCHOR_ALT
      if ((a & QRegExpEngine::Anchor_Alternation) != 0)
          return testAnchor(i, eng->aa.at(a ^ QRegExpEngine::Anchor_Alternation).a, capBegin)
                 || testAnchor(i, eng->aa.at(a ^ QRegExpEngine::Anchor_Alternation).b, capBegin);
  #endif
  
      if ((a & QRegExpEngine::Anchor_Caret) != 0) {
          if (pos + i != caretPos)
              return false;
      }
      if ((a & QRegExpEngine::Anchor_Dollar) != 0) {
          if (pos + i != len)
              return false;
      }
  #ifndef QT_NO_REGEXP_ESCAPE
      if ((a & (QRegExpEngine::Anchor_Word | QRegExpEngine::Anchor_NonWord)) != 0) {
          bool before = false;
          bool after = false;
          if (pos + i != 0)
              before = isWord(in[pos + i - 1]);
          if (pos + i != len)
              after = isWord(in[pos + i]);
          if ((a & QRegExpEngine::Anchor_Word) != 0 && (before == after))
              return false;
          if ((a & QRegExpEngine::Anchor_NonWord) != 0 && (before != after))
              return false;
      }
  #endif
  #ifndef QT_NO_REGEXP_LOOKAHEAD
      if ((a & QRegExpEngine::Anchor_LookaheadMask) != 0) {
          const QVector<QRegExpLookahead *> &ahead = eng->ahead;
          for (j = 0; j < ahead.size(); j++) {
              if ((a & (QRegExpEngine::Anchor_FirstLookahead << j)) != 0) {
                  QRegExpMatchState matchState;
                  matchState.prepareForMatch(ahead[j]->eng);
                  matchState.match(in + pos + i, len - pos - i, 0,
                      true, true, caretPos - pos - i);
                  if ((matchState.captured[0] == 0) == ahead[j]->neg)
                      return false;
              }
          }
      }
  #endif
  #ifndef QT_NO_REGEXP_CAPTURE
  #ifndef QT_NO_REGEXP_BACKREF
      for (j = 0; j < eng->nbrefs; j++) {
          if ((a & (QRegExpEngine::Anchor_BackRef1Empty << j)) != 0) {
              int i = eng->captureForOfficialCapture.at(j);
              if (capBegin[i] != EmptyCapture)
                  return false;
          }
      }
  #endif
  #endif
      return true;
  }
  
  #ifndef QT_NO_REGEXP_OPTIM
  /*
    The three following functions are what Jeffrey Friedl would call
    transmissions (or bump-alongs). Using one or the other should make
    no difference except in performance.
  */
  
  bool QRegExpEngine::goodStringMatch(QRegExpMatchState &matchState) const
  {
      int k = matchState.pos + goodEarlyStart;
      QStringMatcher matcher(goodStr.unicode(), goodStr.length(), cs);
      while ((k = matcher.indexIn(matchState.in, matchState.len, k)) != -1) {
          int from = k - goodLateStart;
          int to = k - goodEarlyStart;
          if (from > matchState.pos)
              matchState.pos = from;
  
          while (matchState.pos <= to) {
              if (matchState.matchHere())
                  return true;
              ++matchState.pos;
          }
          ++k;
      }
      return false;
  }
  
  bool QRegExpEngine::badCharMatch(QRegExpMatchState &matchState) const
  {
      int slideHead = 0;
      int slideNext = 0;
      int i;
      int lastPos = matchState.len - minl;
      memset(matchState.slideTab, 0, matchState.slideTabSize * sizeof(int));
  
      /*
        Set up the slide table, used for the bad-character heuristic,
        using the table of first occurrence of each character.
      */
      for (i = 0; i < minl; i++) {
          int sk = occ1[BadChar(matchState.in[matchState.pos + i])];
          if (sk == NoOccurrence)
              sk = i + 1;
          if (sk > 0) {
              int k = i + 1 - sk;
              if (k < 0) {
                  sk = i + 1;
                  k = 0;
              }
              if (sk > matchState.slideTab[k])
                  matchState.slideTab[k] = sk;
          }
      }
  
      if (matchState.pos > lastPos)
          return false;
  
      for (;;) {
          if (++slideNext >= matchState.slideTabSize)
              slideNext = 0;
          if (matchState.slideTab[slideHead] > 0) {
              if (matchState.slideTab[slideHead] - 1 > matchState.slideTab[slideNext])
                  matchState.slideTab[slideNext] = matchState.slideTab[slideHead] - 1;
              matchState.slideTab[slideHead] = 0;
          } else {
              if (matchState.matchHere())
                  return true;
          }
  
          if (matchState.pos == lastPos)
              break;
  
          /*
            Update the slide table. This code has much in common with
            the initialization code.
          */
          int sk = occ1[BadChar(matchState.in[matchState.pos + minl])];
          if (sk == NoOccurrence) {
              matchState.slideTab[slideNext] = minl;
          } else if (sk > 0) {
              int k = slideNext + minl - sk;
              if (k >= matchState.slideTabSize)
                  k -= matchState.slideTabSize;
              if (sk > matchState.slideTab[k])
                  matchState.slideTab[k] = sk;
          }
          slideHead = slideNext;
          ++matchState.pos;
      }
      return false;
  }
  #else
  bool QRegExpEngine::bruteMatch(QRegExpMatchState &matchState) const
  {
      while (matchState.pos <= matchState.len) {
          if (matchState.matchHere())
              return true;
          ++matchState.pos;
      }
      return false;
  }
  #endif
  
  /*
    Here's the core of the engine. It tries to do a match here and now.
  */
  bool QRegExpMatchState::matchHere()
  {
      int ncur = 1, nnext = 0;
      int i = 0, j, k, m;
      bool stop = false;
  
      matchLen = -1;
      oneTestMatchedLen = -1;
      curStack[0] = QRegExpEngine::InitialState;
  
      int ncap = eng->ncap;
  #ifndef QT_NO_REGEXP_CAPTURE
      if (ncap > 0) {
          for (j = 0; j < ncap; j++) {
              curCapBegin[j] = EmptyCapture;
              curCapEnd[j] = EmptyCapture;
          }
      }
  #endif
  
  #ifndef QT_NO_REGEXP_BACKREF
      while ((ncur > 0 || !sleeping.isEmpty()) && i <= len - pos && !stop)
  #else
      while (ncur > 0 && i <= len - pos && !stop)
  #endif
      {
          int ch = (i < len - pos) ? in[pos + i].unicode() : 0;
          for (j = 0; j < ncur; j++) {
              int cur = curStack[j];
              const QRegExpAutomatonState &scur = eng->s.at(cur);
              const QVector<int> &outs = scur.outs;
              for (k = 0; k < outs.size(); k++) {
                  int next = outs.at(k);
                  const QRegExpAutomatonState &snext = eng->s.at(next);
                  bool inside = true;
  #if !defined(QT_NO_REGEXP_BACKREF) && !defined(QT_NO_REGEXP_CAPTURE)
                  int needSomeSleep = 0;
  #endif
  
                  /*
                    First, check if the anchors are anchored properly.
                  */
                  int a = scur.anchors.value(next);
                  if (a != 0 && !testAnchor(i, a, curCapBegin + j * ncap))
                      inside = false;
  
                  /*
                    If indeed they are, check if the input character is
                    correct for this transition.
                  */
                  if (inside) {
                      m = snext.match;
                      if ((m & (QRegExpEngine::CharClassBit | QRegExpEngine::BackRefBit)) == 0) {
                          if (eng->cs)
                              inside = (m == ch);
                          else
                              inside = (QChar(m).toLower() == QChar(ch).toLower());
                      } else if (next == QRegExpEngine::FinalState) {
                          matchLen = i;
                          stop = minimal;
                          inside = true;
                      } else if ((m & QRegExpEngine::CharClassBit) != 0) {
  #ifndef QT_NO_REGEXP_CCLASS
                          const QRegExpCharClass &cc = eng->cl.at(m ^ QRegExpEngine::CharClassBit);
                          if (eng->cs)
                              inside = cc.in(ch);
                          else if (cc.negative())
                              inside = cc.in(QChar(ch).toLower()) &&
                                       cc.in(QChar(ch).toUpper());
                          else
                              inside = cc.in(QChar(ch).toLower()) ||
                                       cc.in(QChar(ch).toUpper());
  #endif
  #if !defined(QT_NO_REGEXP_BACKREF) && !defined(QT_NO_REGEXP_CAPTURE)
                      } else { /* ((m & QRegExpEngine::BackRefBit) != 0) */
                          int bref = m ^ QRegExpEngine::BackRefBit;
                          int ell = j * ncap + eng->captureForOfficialCapture.at(bref - 1);
  
                          inside = bref <= ncap && curCapBegin[ell] != EmptyCapture;
                          if (inside) {
                              if (eng->cs)
                                  inside = (in[pos + curCapBegin[ell]] == QChar(ch));
                              else
                                  inside = (in[pos + curCapBegin[ell]].toLower()
                                         == QChar(ch).toLower());
                          }
  
                          if (inside) {
                              int delta;
                              if (curCapEnd[ell] == EmptyCapture)
                                  delta = i - curCapBegin[ell];
                              else
                                  delta = curCapEnd[ell] - curCapBegin[ell];
  
                              inside = (delta <= len - (pos + i));
                              if (inside && delta > 1) {
                                  int n = 1;
                                  if (eng->cs) {
                                      while (n < delta) {
                                          if (in[pos + curCapBegin[ell] + n]
                                              != in[pos + i + n])
                                              break;
                                          ++n;
                                      }
                                  } else {
                                      while (n < delta) {
                                          QChar a = in[pos + curCapBegin[ell] + n];
                                          QChar b = in[pos + i + n];
                                          if (a.toLower() != b.toLower())
                                              break;
                                          ++n;
                                      }
                                  }
                                  inside = (n == delta);
                                  if (inside)
                                      needSomeSleep = delta - 1;
                              }
                          }
  #endif
                      }
                  }
  
                  /*
                    We must now update our data structures.
                  */
                  if (inside) {
  #ifndef QT_NO_REGEXP_CAPTURE
                      int *capBegin, *capEnd;
  #endif
                      /*
                        If the next state was not encountered yet, all
                        is fine.
                      */
                      if ((m = inNextStack[next]) == -1) {
                          m = nnext++;
                          nextStack[m] = next;
                          inNextStack[next] = m;
  #ifndef QT_NO_REGEXP_CAPTURE
                          capBegin = nextCapBegin + m * ncap;
                          capEnd = nextCapEnd + m * ncap;
  
                      /*
                        Otherwise, we'll first maintain captures in
                        temporary arrays, and decide at the end whether
                        it's best to keep the previous capture zones or
                        the new ones.
                      */
                      } else {
                          capBegin = tempCapBegin;
                          capEnd = tempCapEnd;
  #endif
                      }
  
  #ifndef QT_NO_REGEXP_CAPTURE
                      /*
                        Updating the capture zones is much of a task.
                      */
                      if (ncap > 0) {
                          memcpy(capBegin, curCapBegin + j * ncap, ncap * sizeof(int));
                          memcpy(capEnd, curCapEnd + j * ncap, ncap * sizeof(int));
                          int c = scur.atom, n = snext.atom;
                          int p = -1, q = -1;
                          int cap;
  
                          /*
                            Lemma 1. For any x in the range [0..nf), we
                            have f[x].parent < x.
  
                            Proof. By looking at startAtom(), it is
                            clear that cf < nf holds all the time, and
                            thus that f[nf].parent < nf.
                          */
  
                          /*
                            If we are reentering an atom, we empty all
                            capture zones inside it.
                          */
                          if ((q = scur.reenter.value(next)) != 0) {
                              QBitArray b(eng->nf, false);
                              b.setBit(q, true);
                              for (int ell = q + 1; ell < eng->nf; ell++) {
                                  if (b.testBit(eng->f.at(ell).parent)) {
                                      b.setBit(ell, true);
                                      cap = eng->f.at(ell).capture;
                                      if (cap >= 0) {
                                          capBegin[cap] = EmptyCapture;
                                          capEnd[cap] = EmptyCapture;
                                      }
                                  }
                              }
                              p = eng->f.at(q).parent;
  
                          /*
                            Otherwise, close the capture zones we are
                            leaving. We are leaving f[c].capture,
                            f[f[c].parent].capture,
                            f[f[f[c].parent].parent].capture, ...,
                            until f[x].capture, with x such that
                            f[x].parent is the youngest common ancestor
                            for c and n.
  
                            We go up along c's and n's ancestry until
                            we find x.
                          */
                          } else {
                              p = c;
                              q = n;
                              while (p != q) {
                                  if (p > q) {
                                      cap = eng->f.at(p).capture;
                                      if (cap >= 0) {
                                          if (capBegin[cap] == i) {
                                              capBegin[cap] = EmptyCapture;
                                              capEnd[cap] = EmptyCapture;
                                          } else {
                                              capEnd[cap] = i;
                                          }
                                      }
                                      p = eng->f.at(p).parent;
                                  } else {
                                      q = eng->f.at(q).parent;
                                  }
                              }
                          }
  
                          /*
                            In any case, we now open the capture zones
                            we are entering. We work upwards from n
                            until we reach p (the parent of the atom we
                            reenter or the youngest common ancestor).
                          */
                          while (n > p) {
                              cap = eng->f.at(n).capture;
                              if (cap >= 0) {
                                  capBegin[cap] = i;
                                  capEnd[cap] = EmptyCapture;
                              }
                              n = eng->f.at(n).parent;
                          }
                          /*
                            If the next state was already in
                            nextStack, we must choose carefully which
                            capture zones we want to keep.
                          */
                          if (capBegin == tempCapBegin &&
                                  isBetterCapture(ncap, capBegin, capEnd, nextCapBegin + m * ncap,
                                                  nextCapEnd + m * ncap)) {
                              memcpy(nextCapBegin + m * ncap, capBegin, ncap * sizeof(int));
                              memcpy(nextCapEnd + m * ncap, capEnd, ncap * sizeof(int));
                          }
                      }
  #ifndef QT_NO_REGEXP_BACKREF
                      /*
                        We are done with updating the capture zones.
                        It's now time to put the next state to sleep,
                        if it needs to, and to remove it from
                        nextStack.
                      */
                      if (needSomeSleep > 0) {
                          QVector<int> zzZ(2 + 2 * ncap);
                          zzZ[0] = i + needSomeSleep;
                          zzZ[1] = next;
                          if (ncap > 0) {
                              memcpy(zzZ.data() + 2, capBegin, ncap * sizeof(int));
                              memcpy(zzZ.data() + 2 + ncap, capEnd, ncap * sizeof(int));
                          }
                          inNextStack[nextStack[--nnext]] = -1;
                          sleeping.append(zzZ);
                      }
  #endif
  #endif
                  }
              }
          }
  #ifndef QT_NO_REGEXP_CAPTURE
          /*
            If we reached the final state, hurray! Copy the captured
            zone.
          */
          if (ncap > 0 && (m = inNextStack[QRegExpEngine::FinalState]) != -1) {
              memcpy(capBegin, nextCapBegin + m * ncap, ncap * sizeof(int));
              memcpy(capEnd, nextCapEnd + m * ncap, ncap * sizeof(int));
          }
  #ifndef QT_NO_REGEXP_BACKREF
          /*
            It's time to wake up the sleepers.
          */
          j = 0;
          while (j < sleeping.count()) {
              if (sleeping.at(j)[0] == i) {
                  const QVector<int> &zzZ = sleeping.at(j);
                  int next = zzZ[1];
                  const int *capBegin = zzZ.data() + 2;
                  const int *capEnd = zzZ.data() + 2 + ncap;
                  bool copyOver = true;
  
                  if ((m = inNextStack[next]) == -1) {
                      m = nnext++;
                      nextStack[m] = next;
                      inNextStack[next] = m;
                  } else {
                      copyOver = isBetterCapture(ncap, nextCapBegin + m * ncap, nextCapEnd + m * ncap,
                                                 capBegin, capEnd);
                  }
                  if (copyOver) {
                      memcpy(nextCapBegin + m * ncap, capBegin, ncap * sizeof(int));
                      memcpy(nextCapEnd + m * ncap, capEnd, ncap * sizeof(int));
                  }
  
                  sleeping.removeAt(j);
              } else {
                  ++j;
              }
          }
  #endif
  #endif
          for (j = 0; j < nnext; j++)
              inNextStack[nextStack[j]] = -1;
  
          // avoid needless iteration that confuses oneTestMatchedLen
          if (nnext == 1 && nextStack[0] == QRegExpEngine::FinalState
  #ifndef QT_NO_REGEXP_BACKREF
               && sleeping.isEmpty()
  #endif
             )
              stop = true;
  
          qSwap(curStack, nextStack);
  #ifndef QT_NO_REGEXP_CAPTURE
          qSwap(curCapBegin, nextCapBegin);
          qSwap(curCapEnd, nextCapEnd);
  #endif
          ncur = nnext;
          nnext = 0;
          ++i;
      }
  
  #ifndef QT_NO_REGEXP_BACKREF
      /*
        If minimal matching is enabled, we might have some sleepers
        left.
      */
      if (!sleeping.isEmpty())
          sleeping.clear();
  #endif
  
      oneTestMatchedLen = i - 1;
      return (matchLen >= 0);
  }
  
  #ifndef QT_NO_REGEXP_CCLASS
  
  QRegExpCharClass::QRegExpCharClass()
      : c(0), n(false)
  {
  #ifndef QT_NO_REGEXP_OPTIM
      occ1.fill(NoOccurrence, NumBadChars);
  #endif
  }
  
  void QRegExpCharClass::clear()
  {
      c = 0;
      r.resize(0);
      n = false;
  }
  
  void QRegExpCharClass::setNegative(bool negative)
  {
      n = negative;
  #ifndef QT_NO_REGEXP_OPTIM
      occ1.fill(0, NumBadChars);
  #endif
  }
  
  void QRegExpCharClass::addCategories(uint cats)
  {
      static const int all_cats = FLAG(QChar::Mark_NonSpacing) |
                                  FLAG(QChar::Mark_SpacingCombining) |
                                  FLAG(QChar::Mark_Enclosing) |
                                  FLAG(QChar::Number_DecimalDigit) |
                                  FLAG(QChar::Number_Letter) |
                                  FLAG(QChar::Number_Other) |
                                  FLAG(QChar::Separator_Space) |
                                  FLAG(QChar::Separator_Line) |
                                  FLAG(QChar::Separator_Paragraph) |
                                  FLAG(QChar::Other_Control) |
                                  FLAG(QChar::Other_Format) |
                                  FLAG(QChar::Other_Surrogate) |
                                  FLAG(QChar::Other_PrivateUse) |
                                  FLAG(QChar::Other_NotAssigned) |
                                  FLAG(QChar::Letter_Uppercase) |
                                  FLAG(QChar::Letter_Lowercase) |
                                  FLAG(QChar::Letter_Titlecase) |
                                  FLAG(QChar::Letter_Modifier) |
                                  FLAG(QChar::Letter_Other) |
                                  FLAG(QChar::Punctuation_Connector) |
                                  FLAG(QChar::Punctuation_Dash) |
                                  FLAG(QChar::Punctuation_Open) |
                                  FLAG(QChar::Punctuation_Close) |
                                  FLAG(QChar::Punctuation_InitialQuote) |
                                  FLAG(QChar::Punctuation_FinalQuote) |
                                  FLAG(QChar::Punctuation_Other) |
                                  FLAG(QChar::Symbol_Math) |
                                  FLAG(QChar::Symbol_Currency) |
                                  FLAG(QChar::Symbol_Modifier) |
                                  FLAG(QChar::Symbol_Other);
      c |= (all_cats & cats);
  #ifndef QT_NO_REGEXP_OPTIM
      occ1.fill(0, NumBadChars);
  #endif
  }
  
  void QRegExpCharClass::addRange(ushort from, ushort to)
  {
      if (from > to)
          qSwap(from, to);
      int m = r.size();
      r.resize(m + 1);
      r[m].from = from;
      r[m].len = to - from + 1;
  
  #ifndef QT_NO_REGEXP_OPTIM
      int i;
  
      if (to - from < NumBadChars) {
          if (from % NumBadChars <= to % NumBadChars) {
              for (i = from % NumBadChars; i <= to % NumBadChars; i++)
                  occ1[i] = 0;
          } else {
              for (i = 0; i <= to % NumBadChars; i++)
                  occ1[i] = 0;
              for (i = from % NumBadChars; i < NumBadChars; i++)
                  occ1[i] = 0;
          }
      } else {
          occ1.fill(0, NumBadChars);
      }
  #endif
  }
  
  bool QRegExpCharClass::in(QChar ch) const
  {
  #ifndef QT_NO_REGEXP_OPTIM
      if (occ1.at(BadChar(ch)) == NoOccurrence)
          return n;
  #endif
  
      if (c != 0 && (c & FLAG(ch.category())) != 0)
          return !n;
  
      const int uc = ch.unicode();
      int size = r.size();
  
      for (int i = 0; i < size; ++i) {
          const QRegExpCharClassRange &range = r.at(i);
          if (uint(uc - range.from) < uint(r.at(i).len))
              return !n;
      }
      return n;
  }
  
  #if defined(QT_DEBUG)
  void QRegExpCharClass::dump() const
  {
      int i;
      qDebug("    %stive character class", n ? "nega" : "posi");
  #ifndef QT_NO_REGEXP_CCLASS
      if (c != 0)
          qDebug("      categories 0x%.8x", c);
  #endif
      for (i = 0; i < r.size(); i++)
          qDebug("      0x%.4x through 0x%.4x", r[i].from, r[i].from + r[i].len - 1);
  }
  #endif
  #endif
  
  QRegExpEngine::Box::Box(QRegExpEngine *engine)
      : eng(engine), skipanchors(0)
  #ifndef QT_NO_REGEXP_OPTIM
        , earlyStart(0), lateStart(0), maxl(0)
  #endif
  {
  #ifndef QT_NO_REGEXP_OPTIM
      occ1.fill(NoOccurrence, NumBadChars);
  #endif
      minl = 0;
  }
  
  QRegExpEngine::Box &QRegExpEngine::Box::operator=(const Box &b)
  {
      eng = b.eng;
      ls = b.ls;
      rs = b.rs;
      lanchors = b.lanchors;
      ranchors = b.ranchors;
      skipanchors = b.skipanchors;
  #ifndef QT_NO_REGEXP_OPTIM
      earlyStart = b.earlyStart;
      lateStart = b.lateStart;
      str = b.str;
      leftStr = b.leftStr;
      rightStr = b.rightStr;
      maxl = b.maxl;
      occ1 = b.occ1;
  #endif
      minl = b.minl;
      return *this;
  }
  
  void QRegExpEngine::Box::set(QChar ch)
  {
      ls.resize(1);
      ls[0] = eng->createState(ch);
      rs = ls;
  #ifndef QT_NO_REGEXP_OPTIM
      str = ch;
      leftStr = ch;
      rightStr = ch;
      maxl = 1;
      occ1[BadChar(ch)] = 0;
  #endif
      minl = 1;
  }
  
  void QRegExpEngine::Box::set(const QRegExpCharClass &cc)
  {
      ls.resize(1);
      ls[0] = eng->createState(cc);
      rs = ls;
  #ifndef QT_NO_REGEXP_OPTIM
      maxl = 1;
      occ1 = cc.firstOccurrence();
  #endif
      minl = 1;
  }
  
  #ifndef QT_NO_REGEXP_BACKREF
  void QRegExpEngine::Box::set(int bref)
  {
      ls.resize(1);
      ls[0] = eng->createState(bref);
      rs = ls;
      if (bref >= 1 && bref <= MaxBackRefs)
          skipanchors = Anchor_BackRef0Empty << bref;
  #ifndef QT_NO_REGEXP_OPTIM
      maxl = InftyLen;
  #endif
      minl = 0;
  }
  #endif
  
  void QRegExpEngine::Box::cat(const Box &b)
  {
      eng->addCatTransitions(rs, b.ls);
      addAnchorsToEngine(b);
      if (minl == 0) {
          lanchors.unite(b.lanchors);
          if (skipanchors != 0) {
              for (int i = 0; i < b.ls.size(); i++) {
                  int a = eng->anchorConcatenation(lanchors.value(b.ls.at(i), 0), skipanchors);
                  lanchors.insert(b.ls.at(i), a);
              }
          }
          mergeInto(&ls, b.ls);
      }
      if (b.minl == 0) {
          ranchors.unite(b.ranchors);
          if (b.skipanchors != 0) {
              for (int i = 0; i < rs.size(); i++) {
                  int a = eng->anchorConcatenation(ranchors.value(rs.at(i), 0), b.skipanchors);
                  ranchors.insert(rs.at(i), a);
              }
          }
          mergeInto(&rs, b.rs);
      } else {
          ranchors = b.ranchors;
          rs = b.rs;
      }
  
  #ifndef QT_NO_REGEXP_OPTIM
      if (maxl != InftyLen) {
          if (rightStr.length() + b.leftStr.length() >
               qMax(str.length(), b.str.length())) {
              earlyStart = minl - rightStr.length();
              lateStart = maxl - rightStr.length();
              str = rightStr + b.leftStr;
          } else if (b.str.length() > str.length()) {
              earlyStart = minl + b.earlyStart;
              lateStart = maxl + b.lateStart;
              str = b.str;
          }
      }
  
      if (leftStr.length() == maxl)
          leftStr += b.leftStr;
  
      if (b.rightStr.length() == b.maxl) {
          rightStr += b.rightStr;
      } else {
          rightStr = b.rightStr;
      }
  
      if (maxl == InftyLen || b.maxl == InftyLen) {
          maxl = InftyLen;
      } else {
          maxl += b.maxl;
      }
  
      for (int i = 0; i < NumBadChars; i++) {
          if (b.occ1.at(i) != NoOccurrence && minl + b.occ1.at(i) < occ1.at(i))
              occ1[i] = minl + b.occ1.at(i);
      }
  #endif
  
      minl += b.minl;
      if (minl == 0)
          skipanchors = eng->anchorConcatenation(skipanchors, b.skipanchors);
      else
          skipanchors = 0;
  }
  
  void QRegExpEngine::Box::orx(const Box &b)
  {
      mergeInto(&ls, b.ls);
      lanchors.unite(b.lanchors);
      mergeInto(&rs, b.rs);
      ranchors.unite(b.ranchors);
  
      if (b.minl == 0) {
          if (minl == 0)
              skipanchors = eng->anchorAlternation(skipanchors, b.skipanchors);
          else
              skipanchors = b.skipanchors;
      }
  
  #ifndef QT_NO_REGEXP_OPTIM
      for (int i = 0; i < NumBadChars; i++) {
          if (occ1.at(i) > b.occ1.at(i))
              occ1[i] = b.occ1.at(i);
      }
      earlyStart = 0;
      lateStart = 0;
      str = QString();
      leftStr = QString();
      rightStr = QString();
      if (b.maxl > maxl)
          maxl = b.maxl;
  #endif
      if (b.minl < minl)
          minl = b.minl;
  }
  
  void QRegExpEngine::Box::plus(int atom)
  {
  #ifndef QT_NO_REGEXP_CAPTURE
      eng->addPlusTransitions(rs, ls, atom);
  #else
      Q_UNUSED(atom);
      eng->addCatTransitions(rs, ls);
  #endif
      addAnchorsToEngine(*this);
  #ifndef QT_NO_REGEXP_OPTIM
      maxl = InftyLen;
  #endif
  }
  
  void QRegExpEngine::Box::opt()
  {
  #ifndef QT_NO_REGEXP_OPTIM
      earlyStart = 0;
      lateStart = 0;
      str = QString();
      leftStr = QString();
      rightStr = QString();
  #endif
      skipanchors = 0;
      minl = 0;
  }
  
  void QRegExpEngine::Box::catAnchor(int a)
  {
      if (a != 0) {
          for (int i = 0; i < rs.size(); i++) {
              a = eng->anchorConcatenation(ranchors.value(rs.at(i), 0), a);
              ranchors.insert(rs.at(i), a);
          }
          if (minl == 0)
              skipanchors = eng->anchorConcatenation(skipanchors, a);
      }
  }
  
  #ifndef QT_NO_REGEXP_OPTIM
  void QRegExpEngine::Box::setupHeuristics()
  {
      eng->goodEarlyStart = earlyStart;
      eng->goodLateStart = lateStart;
      eng->goodStr = eng->cs ? str : str.toLower();
  
      eng->minl = minl;
      if (eng->cs) {
          /*
            A regular expression such as 112|1 has occ1['2'] = 2 and minl =
            1 at this point. An entry of occ1 has to be at most minl or
            infinity for the rest of the algorithm to go well.
  
            We waited until here before normalizing these cases (instead of
            doing it in Box::orx()) because sometimes things improve by
            themselves. Consider for example (112|1)34.
          */
          for (int i = 0; i < NumBadChars; i++) {
              if (occ1.at(i) != NoOccurrence && occ1.at(i) >= minl)
                  occ1[i] = minl;
          }
          eng->occ1 = occ1;
      } else {
          eng->occ1.fill(0, NumBadChars);
      }
  
      eng->heuristicallyChooseHeuristic();
  }
  #endif
  
  #if defined(QT_DEBUG)
  void QRegExpEngine::Box::dump() const
  {
      int i;
      qDebug("Box of at least %d character%s", minl, minl == 1 ? "" : "s");
      qDebug("  Left states:");
      for (i = 0; i < ls.size(); i++) {
          if (lanchors.value(ls[i], 0) == 0)
              qDebug("    %d", ls[i]);
          else
              qDebug("    %d [anchors 0x%.8x]", ls[i], lanchors[ls[i]]);
      }
      qDebug("  Right states:");
      for (i = 0; i < rs.size(); i++) {
          if (ranchors.value(rs[i], 0) == 0)
              qDebug("    %d", rs[i]);
          else
              qDebug("    %d [anchors 0x%.8x]", rs[i], ranchors[rs[i]]);
      }
      qDebug("  Skip anchors: 0x%.8x", skipanchors);
  }
  #endif
  
  void QRegExpEngine::Box::addAnchorsToEngine(const Box &to) const
  {
      for (int i = 0; i < to.ls.size(); i++) {
          for (int j = 0; j < rs.size(); j++) {
              int a = eng->anchorConcatenation(ranchors.value(rs.at(j), 0),
                                               to.lanchors.value(to.ls.at(i), 0));
              eng->addAnchors(rs[j], to.ls[i], a);
          }
      }
  }
  
  #ifndef QT_NO_REGEXP_CCLASS
  // fast lookup hash for xml schema extensions
  // sorted by name for b-search
  static const struct CategoriesRangeMapEntry {
      const char name[40];
      uint first, second;
  } categoriesRangeMap[] = {
      { "AegeanNumbers",                        0x10100, 0x1013F },
      { "AlphabeticPresentationForms",          0xFB00, 0xFB4F },
      { "AncientGreekMusicalNotation",          0x1D200, 0x1D24F },
      { "AncientGreekNumbers",                  0x10140, 0x1018F },
      { "Arabic",                               0x0600, 0x06FF },
      { "ArabicPresentationForms-A",            0xFB50, 0xFDFF },
      { "ArabicPresentationForms-B",            0xFE70, 0xFEFF },
      { "ArabicSupplement",                     0x0750, 0x077F },
      { "Armenian",                             0x0530, 0x058F },
      { "Arrows",                               0x2190, 0x21FF },
      { "BasicLatin",                           0x0000, 0x007F },
      { "Bengali",                              0x0980, 0x09FF },
      { "BlockElements",                        0x2580, 0x259F },
      { "Bopomofo",                             0x3100, 0x312F },
      { "BopomofoExtended",                     0x31A0, 0x31BF },
      { "BoxDrawing",                           0x2500, 0x257F },
      { "BraillePatterns",                      0x2800, 0x28FF },
      { "Buginese",                             0x1A00, 0x1A1F },
      { "Buhid",                                0x1740, 0x175F },
      { "ByzantineMusicalSymbols",              0x1D000, 0x1D0FF },
      { "CJKCompatibility",                     0x3300, 0x33FF },
      { "CJKCompatibilityForms",                0xFE30, 0xFE4F },
      { "CJKCompatibilityIdeographs",           0xF900, 0xFAFF },
      { "CJKCompatibilityIdeographsSupplement", 0x2F800, 0x2FA1F },
      { "CJKRadicalsSupplement",                0x2E80, 0x2EFF },
      { "CJKStrokes",                           0x31C0, 0x31EF },
      { "CJKSymbolsandPunctuation",             0x3000, 0x303F },
      { "CJKUnifiedIdeographs",                 0x4E00, 0x9FFF },
      { "CJKUnifiedIdeographsExtensionA",       0x3400, 0x4DB5 },
      { "CJKUnifiedIdeographsExtensionB",       0x20000, 0x2A6DF },
      { "Cherokee",                             0x13A0, 0x13FF },
      { "CombiningDiacriticalMarks",            0x0300, 0x036F },
      { "CombiningDiacriticalMarksSupplement",  0x1DC0, 0x1DFF },
      { "CombiningHalfMarks",                   0xFE20, 0xFE2F },
      { "CombiningMarksforSymbols",             0x20D0, 0x20FF },
      { "ControlPictures",                      0x2400, 0x243F },
      { "Coptic",                               0x2C80, 0x2CFF },
      { "CurrencySymbols",                      0x20A0, 0x20CF },
      { "CypriotSyllabary",                     0x10800, 0x1083F },
      { "Cyrillic",                             0x0400, 0x04FF },
      { "CyrillicSupplement",                   0x0500, 0x052F },
      { "Deseret",                              0x10400, 0x1044F },
      { "Devanagari",                           0x0900, 0x097F },
      { "Dingbats",                             0x2700, 0x27BF },
      { "EnclosedAlphanumerics",                0x2460, 0x24FF },
      { "EnclosedCJKLettersandMonths",          0x3200, 0x32FF },
      { "Ethiopic",                             0x1200, 0x137F },
      { "EthiopicExtended",                     0x2D80, 0x2DDF },
      { "EthiopicSupplement",                   0x1380, 0x139F },
      { "GeneralPunctuation",                   0x2000, 0x206F },
      { "GeometricShapes",                      0x25A0, 0x25FF },
      { "Georgian",                             0x10A0, 0x10FF },
      { "GeorgianSupplement",                   0x2D00, 0x2D2F },
      { "Glagolitic",                           0x2C00, 0x2C5F },
      { "Gothic",                               0x10330, 0x1034F },
      { "Greek",                                0x0370, 0x03FF },
      { "GreekExtended",                        0x1F00, 0x1FFF },
      { "Gujarati",                             0x0A80, 0x0AFF },
      { "Gurmukhi",                             0x0A00, 0x0A7F },
      { "HalfwidthandFullwidthForms",           0xFF00, 0xFFEF },
      { "HangulCompatibilityJamo",              0x3130, 0x318F },
      { "HangulJamo",                           0x1100, 0x11FF },
      { "HangulSyllables",                      0xAC00, 0xD7A3 },
      { "Hanunoo",                              0x1720, 0x173F },
      { "Hebrew",                               0x0590, 0x05FF },
      { "Hiragana",                             0x3040, 0x309F },
      { "IPAExtensions",                        0x0250, 0x02AF },
      { "IdeographicDescriptionCharacters",     0x2FF0, 0x2FFF },
      { "Kanbun",                               0x3190, 0x319F },
      { "KangxiRadicals",                       0x2F00, 0x2FDF },
      { "Kannada",                              0x0C80, 0x0CFF },
      { "Katakana",                             0x30A0, 0x30FF },
      { "KatakanaPhoneticExtensions",           0x31F0, 0x31FF },
      { "Kharoshthi",                           0x10A00, 0x10A5F },
      { "Khmer",                                0x1780, 0x17FF },
      { "KhmerSymbols",                         0x19E0, 0x19FF },
      { "Lao",                                  0x0E80, 0x0EFF },
      { "Latin-1Supplement",                    0x0080, 0x00FF },
      { "LatinExtended-A",                      0x0100, 0x017F },
      { "LatinExtended-B",                      0x0180, 0x024F },
      { "LatinExtendedAdditional",              0x1E00, 0x1EFF },
      { "LetterlikeSymbols",                    0x2100, 0x214F },
      { "Limbu",                                0x1900, 0x194F },
      { "LinearBIdeograms",                     0x10080, 0x100FF },
      { "LinearBSyllabary",                     0x10000, 0x1007F },
      { "Malayalam",                            0x0D00, 0x0D7F },
      { "MathematicalAlphanumericSymbols",      0x1D400, 0x1D7FF },
      { "MathematicalOperators",                0x2200, 0x22FF },
      { "MiscellaneousMathematicalSymbols-A",   0x27C0, 0x27EF },
      { "MiscellaneousMathematicalSymbols-B",   0x2980, 0x29FF },
      { "MiscellaneousSymbols",                 0x2600, 0x26FF },
      { "MiscellaneousSymbolsandArrows",        0x2B00, 0x2BFF },
      { "MiscellaneousTechnical",               0x2300, 0x23FF },
      { "ModifierToneLetters",                  0xA700, 0xA71F },
      { "Mongolian",                            0x1800, 0x18AF },
      { "MusicalSymbols",                       0x1D100, 0x1D1FF },
      { "Myanmar",                              0x1000, 0x109F },
      { "NewTaiLue",                            0x1980, 0x19DF },
      { "NumberForms",                          0x2150, 0x218F },
      { "Ogham",                                0x1680, 0x169F },
      { "OldItalic",                            0x10300, 0x1032F },
      { "OldPersian",                           0x103A0, 0x103DF },
      { "OpticalCharacterRecognition",          0x2440, 0x245F },
      { "Oriya",                                0x0B00, 0x0B7F },
      { "Osmanya",                              0x10480, 0x104AF },
      { "PhoneticExtensions",                   0x1D00, 0x1D7F },
      { "PhoneticExtensionsSupplement",         0x1D80, 0x1DBF },
      { "PrivateUse",                           0xE000, 0xF8FF },
      { "Runic",                                0x16A0, 0x16FF },
      { "Shavian",                              0x10450, 0x1047F },
      { "Sinhala",                              0x0D80, 0x0DFF },
      { "SmallFormVariants",                    0xFE50, 0xFE6F },
      { "SpacingModifierLetters",               0x02B0, 0x02FF },
      { "Specials",                             0xFFF0, 0xFFFF },
      { "SuperscriptsandSubscripts",            0x2070, 0x209F },
      { "SupplementalArrows-A",                 0x27F0, 0x27FF },
      { "SupplementalArrows-B",                 0x2900, 0x297F },
      { "SupplementalMathematicalOperators",    0x2A00, 0x2AFF },
      { "SupplementalPunctuation",              0x2E00, 0x2E7F },
      { "SupplementaryPrivateUseArea-A",        0xF0000, 0xFFFFF },
      { "SupplementaryPrivateUseArea-B",        0x100000, 0x10FFFF },
      { "SylotiNagri",                          0xA800, 0xA82F },
      { "Syriac",                               0x0700, 0x074F },
      { "Tagalog",                              0x1700, 0x171F },
      { "Tagbanwa",                             0x1760, 0x177F },
      { "Tags",                                 0xE0000, 0xE007F },
      { "TaiLe",                                0x1950, 0x197F },
      { "TaiXuanJingSymbols",                   0x1D300, 0x1D35F },
      { "Tamil",                                0x0B80, 0x0BFF },
      { "Telugu",                               0x0C00, 0x0C7F },
      { "Thaana",                               0x0780, 0x07BF },
      { "Thai",                                 0x0E00, 0x0E7F },
      { "Tibetan",                              0x0F00, 0x0FFF },
      { "Tifinagh",                             0x2D30, 0x2D7F },
      { "Ugaritic",                             0x10380, 0x1039F },
      { "UnifiedCanadianAboriginalSyllabics",   0x1400, 0x167F },
      { "VariationSelectors",                   0xFE00, 0xFE0F },
      { "VariationSelectorsSupplement",         0xE0100, 0xE01EF },
      { "VerticalForms",                        0xFE10, 0xFE1F },
      { "YiRadicals",                           0xA490, 0xA4CF },
      { "YiSyllables",                          0xA000, 0xA48F },
      { "YijingHexagramSymbols",                0x4DC0, 0x4DFF }
  };
  
  inline bool operator<(const CategoriesRangeMapEntry &entry1, const CategoriesRangeMapEntry &entry2)
  { return qstrcmp(entry1.name, entry2.name) < 0; }
  inline bool operator<(const char *name, const CategoriesRangeMapEntry &entry)
  { return qstrcmp(name, entry.name) < 0; }
  inline bool operator<(const CategoriesRangeMapEntry &entry, const char *name)
  { return qstrcmp(entry.name, name) < 0; }
  #endif // QT_NO_REGEXP_CCLASS
  
  int QRegExpEngine::getChar()
  {
      return (yyPos == yyLen) ? EOS : yyIn[yyPos++].unicode();
  }
  
  int QRegExpEngine::getEscape()
  {
  #ifndef QT_NO_REGEXP_ESCAPE
      const char tab[] = "afnrtv"; // no b, as \b means word boundary
      const char backTab[] = "\a\f\n\r\t\v";
      ushort low;
      int i;
  #endif
      ushort val;
      int prevCh = yyCh;
  
      if (prevCh == EOS) {
          error(RXERR_END);
          return Tok_Char | '\\';
      }
      yyCh = getChar();
  #ifndef QT_NO_REGEXP_ESCAPE
      if ((prevCh & ~0xff) == 0) {
          const char *p = strchr(tab, prevCh);
          if (p != 0)
              return Tok_Char | backTab[p - tab];
      }
  #endif
  
      switch (prevCh) {
  #ifndef QT_NO_REGEXP_ESCAPE
      case '0':
          val = 0;
          for (i = 0; i < 3; i++) {
              if (yyCh >= '0' && yyCh <= '7')
                  val = (val << 3) | (yyCh - '0');
              else
                  break;
              yyCh = getChar();
          }
          if ((val & ~0377) != 0)
              error(RXERR_OCTAL);
          return Tok_Char | val;
  #endif
  #ifndef QT_NO_REGEXP_ESCAPE
      case 'B':
          return Tok_NonWord;
  #endif
  #ifndef QT_NO_REGEXP_CCLASS
      case 'D':
          // see QChar::isDigit()
          yyCharClass->addCategories(uint(-1) ^ FLAG(QChar::Number_DecimalDigit));
          return Tok_CharClass;
      case 'S':
          // see QChar::isSpace()
          yyCharClass->addCategories(uint(-1) ^ (FLAG(QChar::Separator_Space) |
                                                 FLAG(QChar::Separator_Line) |
                                                 FLAG(QChar::Separator_Paragraph) |
                                                 FLAG(QChar::Other_Control)));
          yyCharClass->addRange(0x0000, 0x0008);
          yyCharClass->addRange(0x000e, 0x001f);
          yyCharClass->addRange(0x007f, 0x0084);
          yyCharClass->addRange(0x0086, 0x009f);
          return Tok_CharClass;
      case 'W':
          // see QChar::isLetterOrNumber() and QChar::isMark()
          yyCharClass->addCategories(uint(-1) ^ (FLAG(QChar::Mark_NonSpacing) |
                                                 FLAG(QChar::Mark_SpacingCombining) |
                                                 FLAG(QChar::Mark_Enclosing) |
                                                 FLAG(QChar::Number_DecimalDigit) |
                                                 FLAG(QChar::Number_Letter) |
                                                 FLAG(QChar::Number_Other) |
                                                 FLAG(QChar::Letter_Uppercase) |
                                                 FLAG(QChar::Letter_Lowercase) |
                                                 FLAG(QChar::Letter_Titlecase) |
                                                 FLAG(QChar::Letter_Modifier) |
                                                 FLAG(QChar::Letter_Other) |
                                                 FLAG(QChar::Punctuation_Connector)));
          yyCharClass->addRange(0x203f, 0x2040);
          yyCharClass->addSingleton(0x2040);
          yyCharClass->addSingleton(0x2054);
          yyCharClass->addSingleton(0x30fb);
          yyCharClass->addRange(0xfe33, 0xfe34);
          yyCharClass->addRange(0xfe4d, 0xfe4f);
          yyCharClass->addSingleton(0xff3f);
          yyCharClass->addSingleton(0xff65);
          return Tok_CharClass;
  #endif
  #ifndef QT_NO_REGEXP_ESCAPE
      case 'b':
          return Tok_Word;
  #endif
  #ifndef QT_NO_REGEXP_CCLASS
      case 'd':
          // see QChar::isDigit()
          yyCharClass->addCategories(FLAG(QChar::Number_DecimalDigit));
          return Tok_CharClass;
      case 's':
          // see QChar::isSpace()
          yyCharClass->addCategories(FLAG(QChar::Separator_Space) |
                                     FLAG(QChar::Separator_Line) |
                                     FLAG(QChar::Separator_Paragraph));
          yyCharClass->addRange(0x0009, 0x000d);
          yyCharClass->addSingleton(0x0085);
          return Tok_CharClass;
      case 'w':
          // see QChar::isLetterOrNumber() and QChar::isMark()
          yyCharClass->addCategories(FLAG(QChar::Mark_NonSpacing) |
                                     FLAG(QChar::Mark_SpacingCombining) |
                                     FLAG(QChar::Mark_Enclosing) |
                                     FLAG(QChar::Number_DecimalDigit) |
                                     FLAG(QChar::Number_Letter) |
                                     FLAG(QChar::Number_Other) |
                                     FLAG(QChar::Letter_Uppercase) |
                                     FLAG(QChar::Letter_Lowercase) |
                                     FLAG(QChar::Letter_Titlecase) |
                                     FLAG(QChar::Letter_Modifier) |
                                     FLAG(QChar::Letter_Other));
          yyCharClass->addSingleton(0x005f); // '_'
          return Tok_CharClass;
      case 'I':
          if (xmlSchemaExtensions) {
              yyCharClass->setNegative(!yyCharClass->negative());
              // fall through
          } else {
              break;
          }
      case 'i':
          if (xmlSchemaExtensions) {
              yyCharClass->addCategories(FLAG(QChar::Mark_NonSpacing) |
                                         FLAG(QChar::Mark_SpacingCombining) |
                                         FLAG(QChar::Mark_Enclosing) |
                                         FLAG(QChar::Number_DecimalDigit) |
                                         FLAG(QChar::Number_Letter) |
                                         FLAG(QChar::Number_Other) |
                                         FLAG(QChar::Letter_Uppercase) |
                                         FLAG(QChar::Letter_Lowercase) |
                                         FLAG(QChar::Letter_Titlecase) |
                                         FLAG(QChar::Letter_Modifier) |
                                         FLAG(QChar::Letter_Other));
              yyCharClass->addSingleton(0x003a); // ':'
              yyCharClass->addSingleton(0x005f); // '_'
              yyCharClass->addRange(0x0041, 0x005a); // [A-Z]
              yyCharClass->addRange(0x0061, 0x007a); // [a-z]
              yyCharClass->addRange(0xc0, 0xd6);
              yyCharClass->addRange(0xd8, 0xf6);
              yyCharClass->addRange(0xf8, 0x2ff);
              yyCharClass->addRange(0x370, 0x37d);
              yyCharClass->addRange(0x37f, 0x1fff);
              yyCharClass->addRange(0x200c, 0x200d);
              yyCharClass->addRange(0x2070, 0x218f);
              yyCharClass->addRange(0x2c00, 0x2fef);
              yyCharClass->addRange(0x3001, 0xd7ff);
              yyCharClass->addRange(0xf900, 0xfdcf);
              yyCharClass->addRange(0xfdf0, 0xfffd);
              yyCharClass->addRange((ushort)0x10000, (ushort)0xeffff);
              return Tok_CharClass;
          } else {
              break;
          }
      case 'C':
          if (xmlSchemaExtensions) {
              yyCharClass->setNegative(!yyCharClass->negative());
              // fall through
          } else {
              break;
          }
      case 'c':
          if (xmlSchemaExtensions) {
              yyCharClass->addCategories(FLAG(QChar::Mark_NonSpacing) |
                                         FLAG(QChar::Mark_SpacingCombining) |
                                         FLAG(QChar::Mark_Enclosing) |
                                         FLAG(QChar::Number_DecimalDigit) |
                                         FLAG(QChar::Number_Letter) |
                                         FLAG(QChar::Number_Other) |
                                         FLAG(QChar::Letter_Uppercase) |
                                         FLAG(QChar::Letter_Lowercase) |
                                         FLAG(QChar::Letter_Titlecase) |
                                         FLAG(QChar::Letter_Modifier) |
                                         FLAG(QChar::Letter_Other));
              yyCharClass->addSingleton(0x002d); // '-'
              yyCharClass->addSingleton(0x002e); // '.'
              yyCharClass->addSingleton(0x003a); // ':'
              yyCharClass->addSingleton(0x005f); // '_'
              yyCharClass->addSingleton(0xb7);
              yyCharClass->addRange(0x0030, 0x0039); // [0-9]
              yyCharClass->addRange(0x0041, 0x005a); // [A-Z]
              yyCharClass->addRange(0x0061, 0x007a); // [a-z]
              yyCharClass->addRange(0xc0, 0xd6);
              yyCharClass->addRange(0xd8, 0xf6);
              yyCharClass->addRange(0xf8, 0x2ff);
              yyCharClass->addRange(0x370, 0x37d);
              yyCharClass->addRange(0x37f, 0x1fff);
              yyCharClass->addRange(0x200c, 0x200d);
              yyCharClass->addRange(0x2070, 0x218f);
              yyCharClass->addRange(0x2c00, 0x2fef);
              yyCharClass->addRange(0x3001, 0xd7ff);
              yyCharClass->addRange(0xf900, 0xfdcf);
              yyCharClass->addRange(0xfdf0, 0xfffd);
              yyCharClass->addRange((ushort)0x10000, (ushort)0xeffff);
              yyCharClass->addRange(0x0300, 0x036f);
              yyCharClass->addRange(0x203f, 0x2040);
              return Tok_CharClass;
          } else {
              break;
          }
      case 'P':
          if (xmlSchemaExtensions) {
              yyCharClass->setNegative(!yyCharClass->negative());
              // fall through
          } else {
              break;
          }
      case 'p':
          if (xmlSchemaExtensions) {
              if (yyCh != '{') {
                  error(RXERR_CHARCLASS);
                  return Tok_CharClass;
              }
  
              QByteArray category;
              yyCh = getChar();
              while (yyCh != '}') {
                  if (yyCh == EOS) {
                      error(RXERR_END);
                      return Tok_CharClass;
                  }
                  category.append(yyCh);
                  yyCh = getChar();
              }
              yyCh = getChar(); // skip closing '}'
  
              int catlen = category.length();
              if (catlen == 1 || catlen == 2) {
                  switch (category.at(0)) {
                  case 'M':
                      if (catlen == 1) {
                          yyCharClass->addCategories(FLAG(QChar::Mark_NonSpacing) |
                                                     FLAG(QChar::Mark_SpacingCombining) |
                                                     FLAG(QChar::Mark_Enclosing));
                      } else {
                          switch (category.at(1)) {
                          case 'n': yyCharClass->addCategories(FLAG(QChar::Mark_NonSpacing)); break; // Mn
                          case 'c': yyCharClass->addCategories(FLAG(QChar::Mark_SpacingCombining)); break; // Mc
                          case 'e': yyCharClass->addCategories(FLAG(QChar::Mark_Enclosing)); break; // Me
                          default: error(RXERR_CATEGORY); break;
                          }
                      }
                      break;
                  case 'N':
                      if (catlen == 1) {
                          yyCharClass->addCategories(FLAG(QChar::Number_DecimalDigit) |
                                                     FLAG(QChar::Number_Letter) |
                                                     FLAG(QChar::Number_Other));
                      } else {
                          switch (category.at(1)) {
                          case 'd': yyCharClass->addCategories(FLAG(QChar::Number_DecimalDigit)); break; // Nd
                          case 'l': yyCharClass->addCategories(FLAG(QChar::Number_Letter)); break; // Hl
                          case 'o': yyCharClass->addCategories(FLAG(QChar::Number_Other)); break; // No
                          default: error(RXERR_CATEGORY); break;
                          }
                      }
                      break;
                  case 'Z':
                      if (catlen == 1) {
                          yyCharClass->addCategories(FLAG(QChar::Separator_Space) |
                                                     FLAG(QChar::Separator_Line) |
                                                     FLAG(QChar::Separator_Paragraph));
                      } else {
                          switch (category.at(1)) {
                          case 's': yyCharClass->addCategories(FLAG(QChar::Separator_Space)); break; // Zs
                          case 'l': yyCharClass->addCategories(FLAG(QChar::Separator_Line)); break; // Zl
                          case 'p': yyCharClass->addCategories(FLAG(QChar::Separator_Paragraph)); break; // Zp
                          default: error(RXERR_CATEGORY); break;
                          }
                      }
                      break;
                  case 'C':
                      if (catlen == 1) {
                          yyCharClass->addCategories(FLAG(QChar::Other_Control) |
                                                     FLAG(QChar::Other_Format) |
                                                     FLAG(QChar::Other_Surrogate) |
                                                     FLAG(QChar::Other_PrivateUse) |
                                                     FLAG(QChar::Other_NotAssigned));
                      } else {
                          switch (category.at(1)) {
                          case 'c': yyCharClass->addCategories(FLAG(QChar::Other_Control)); break; // Cc
                          case 'f': yyCharClass->addCategories(FLAG(QChar::Other_Format)); break; // Cf
                          case 's': yyCharClass->addCategories(FLAG(QChar::Other_Surrogate)); break; // Cs
                          case 'o': yyCharClass->addCategories(FLAG(QChar::Other_PrivateUse)); break; // Co
                          case 'n': yyCharClass->addCategories(FLAG(QChar::Other_NotAssigned)); break; // Cn
                          default: error(RXERR_CATEGORY); break;
                          }
                      }
                      break;
                  case 'L':
                      if (catlen == 1) {
                          yyCharClass->addCategories(FLAG(QChar::Letter_Uppercase) |
                                                     FLAG(QChar::Letter_Lowercase) |
                                                     FLAG(QChar::Letter_Titlecase) |
                                                     FLAG(QChar::Letter_Modifier) |
                                                     FLAG(QChar::Letter_Other));
                      } else {
                          switch (category.at(1)) {
                          case 'u': yyCharClass->addCategories(FLAG(QChar::Letter_Uppercase)); break; // Lu
                          case 'l': yyCharClass->addCategories(FLAG(QChar::Letter_Lowercase)); break; // Ll
                          case 't': yyCharClass->addCategories(FLAG(QChar::Letter_Titlecase)); break; // Lt
                          case 'm': yyCharClass->addCategories(FLAG(QChar::Letter_Modifier)); break; // Lm
                          case 'o': yyCharClass->addCategories(FLAG(QChar::Letter_Other)); break; // Lo
                          default: error(RXERR_CATEGORY); break;
                          }
                      }
                      break;
                  case 'P':
                      if (catlen == 1) {
                          yyCharClass->addCategories(FLAG(QChar::Punctuation_Connector) |
                                                     FLAG(QChar::Punctuation_Dash) |
                                                     FLAG(QChar::Punctuation_Open) |
                                                     FLAG(QChar::Punctuation_Close) |
                                                     FLAG(QChar::Punctuation_InitialQuote) |
                                                     FLAG(QChar::Punctuation_FinalQuote) |
                                                     FLAG(QChar::Punctuation_Other));
                      } else {
                          switch (category.at(1)) {
                          case 'c': yyCharClass->addCategories(FLAG(QChar::Punctuation_Connector)); break; // Pc
                          case 'd': yyCharClass->addCategories(FLAG(QChar::Punctuation_Dash)); break; // Pd
                          case 's': yyCharClass->addCategories(FLAG(QChar::Punctuation_Open)); break; // Ps
                          case 'e': yyCharClass->addCategories(FLAG(QChar::Punctuation_Close)); break; // Pe
                          case 'i': yyCharClass->addCategories(FLAG(QChar::Punctuation_InitialQuote)); break; // Pi
                          case 'f': yyCharClass->addCategories(FLAG(QChar::Punctuation_FinalQuote)); break; // Pf
                          case 'o': yyCharClass->addCategories(FLAG(QChar::Punctuation_Other)); break; // Po
                          default: error(RXERR_CATEGORY); break;
                          }
                      }
                      break;
                  case 'S':
                      if (catlen == 1) {
                          yyCharClass->addCategories(FLAG(QChar::Symbol_Math) |
                                                     FLAG(QChar::Symbol_Currency) |
                                                     FLAG(QChar::Symbol_Modifier) |
                                                     FLAG(QChar::Symbol_Other));
                      } else {
                          switch (category.at(1)) {
                          case 'm': yyCharClass->addCategories(FLAG(QChar::Symbol_Math)); break; // Sm
                          case 'c': yyCharClass->addCategories(FLAG(QChar::Symbol_Currency)); break; // Sc
                          case 'k': yyCharClass->addCategories(FLAG(QChar::Symbol_Modifier)); break; // Sk
                          case 'o': yyCharClass->addCategories(FLAG(QChar::Symbol_Other)); break; // So
                          default: error(RXERR_CATEGORY); break;
                          }
                      }
                      break;
                  default:
                      error(RXERR_CATEGORY);
                      break;
                  }
              } else if (catlen > 2 && category.at(0) == 'I' && category.at(1) == 's') {
                  static const int N = sizeof(categoriesRangeMap) / sizeof(categoriesRangeMap[0]);
                  const char * const categoryFamily = category.constData() + 2;
                  const CategoriesRangeMapEntry *r = std::lower_bound(categoriesRangeMap, categoriesRangeMap + N, categoryFamily);
                  if (r != categoriesRangeMap + N && qstrcmp(r->name, categoryFamily) == 0)
                      yyCharClass->addRange(r->first, r->second);
                  else
                      error(RXERR_CATEGORY);
              } else {
                  error(RXERR_CATEGORY);
              }
              return Tok_CharClass;
          } else {
              break;
          }
  #endif
  #ifndef QT_NO_REGEXP_ESCAPE
      case 'x':
          val = 0;
          for (i = 0; i < 4; i++) {
              low = QChar(yyCh).toLower().unicode();
              if (low >= '0' && low <= '9')
                  val = (val << 4) | (low - '0');
              else if (low >= 'a' && low <= 'f')
                  val = (val << 4) | (low - 'a' + 10);
              else
                  break;
              yyCh = getChar();
          }
          return Tok_Char | val;
  #endif
      default:
          break;
      }
      if (prevCh >= '1' && prevCh <= '9') {
  #ifndef QT_NO_REGEXP_BACKREF
          val = prevCh - '0';
          while (yyCh >= '0' && yyCh <= '9') {
              val = (val * 10) + (yyCh - '0');
              yyCh = getChar();
          }
          return Tok_BackRef | val;
  #else
          error(RXERR_DISABLED);
  #endif
      }
      return Tok_Char | prevCh;
  }
  
  #ifndef QT_NO_REGEXP_INTERVAL
  int QRegExpEngine::getRep(int def)
  {
      if (yyCh >= '0' && yyCh <= '9') {
          int rep = 0;
          do {
              rep = 10 * rep + yyCh - '0';
              if (rep >= InftyRep) {
                  error(RXERR_REPETITION);
                  rep = def;
              }
              yyCh = getChar();
          } while (yyCh >= '0' && yyCh <= '9');
          return rep;
      } else {
          return def;
      }
  }
  #endif
  
  #ifndef QT_NO_REGEXP_LOOKAHEAD
  void QRegExpEngine::skipChars(int n)
  {
      if (n > 0) {
          yyPos += n - 1;
          yyCh = getChar();
      }
  }
  #endif
  
  void QRegExpEngine::error(const char *msg)
  {
      if (yyError.isEmpty())
          yyError = QLatin1String(msg);
  }
  
  void QRegExpEngine::startTokenizer(const QChar *rx, int len)
  {
      yyIn = rx;
      yyPos0 = 0;
      yyPos = 0;
      yyLen = len;
      yyCh = getChar();
      yyCharClass.reset(new QRegExpCharClass);
      yyMinRep = 0;
      yyMaxRep = 0;
      yyError = QString();
  }
  
  int QRegExpEngine::getToken()
  {
  #ifndef QT_NO_REGEXP_CCLASS
      ushort pendingCh = 0;
      bool charPending;
      bool rangePending;
      int tok;
  #endif
      int prevCh = yyCh;
  
      yyPos0 = yyPos - 1;
  #ifndef QT_NO_REGEXP_CCLASS
      yyCharClass->clear();
  #endif
      yyMinRep = 0;
      yyMaxRep = 0;
      yyCh = getChar();
  
      switch (prevCh) {
      case EOS:
          yyPos0 = yyPos;
          return Tok_Eos;
      case '$':
          return Tok_Dollar;
      case '(':
          if (yyCh == '?') {
              prevCh = getChar();
              yyCh = getChar();
              switch (prevCh) {
  #ifndef QT_NO_REGEXP_LOOKAHEAD
              case '!':
                  return Tok_NegLookahead;
              case '=':
                  return Tok_PosLookahead;
  #endif
              case ':':
                  return Tok_MagicLeftParen;
              case '<':
                  error(RXERR_LOOKBEHIND);
                  return Tok_MagicLeftParen;
              default:
                  error(RXERR_LOOKAHEAD);
                  return Tok_MagicLeftParen;
              }
          } else {
              return Tok_LeftParen;
          }
      case ')':
          return Tok_RightParen;
      case '*':
          yyMinRep = 0;
          yyMaxRep = InftyRep;
          return Tok_Quantifier;
      case '+':
          yyMinRep = 1;
          yyMaxRep = InftyRep;
          return Tok_Quantifier;
      case '.':
  #ifndef QT_NO_REGEXP_CCLASS
          yyCharClass->setNegative(true);
  #endif
          return Tok_CharClass;
      case '?':
          yyMinRep = 0;
          yyMaxRep = 1;
          return Tok_Quantifier;
      case '[':
  #ifndef QT_NO_REGEXP_CCLASS
          if (yyCh == '^') {
              yyCharClass->setNegative(true);
              yyCh = getChar();
          }
          charPending = false;
          rangePending = false;
          do {
              if (yyCh == '-' && charPending && !rangePending) {
                  rangePending = true;
                  yyCh = getChar();
              } else {
                  if (charPending && !rangePending) {
                      yyCharClass->addSingleton(pendingCh);
                      charPending = false;
                  }
                  if (yyCh == '\\') {
                      yyCh = getChar();
                      tok = getEscape();
                      if (tok == Tok_Word)
                          tok = '\b';
                  } else {
                      tok = Tok_Char | yyCh;
                      yyCh = getChar();
                  }
                  if (tok == Tok_CharClass) {
                      if (rangePending) {
                          yyCharClass->addSingleton('-');
                          yyCharClass->addSingleton(pendingCh);
                          charPending = false;
                          rangePending = false;
                      }
                  } else if ((tok & Tok_Char) != 0) {
                      if (rangePending) {
                          yyCharClass->addRange(pendingCh, tok ^ Tok_Char);
                          charPending = false;
                          rangePending = false;
                      } else {
                          pendingCh = tok ^ Tok_Char;
                          charPending = true;
                      }
                  } else {
                      error(RXERR_CHARCLASS);
                  }
              }
          }  while (yyCh != ']' && yyCh != EOS);
          if (rangePending)
              yyCharClass->addSingleton('-');
          if (charPending)
              yyCharClass->addSingleton(pendingCh);
          if (yyCh == EOS)
              error(RXERR_END);
          else
              yyCh = getChar();
          return Tok_CharClass;
  #else
          error(RXERR_END);
          return Tok_Char | '[';
  #endif
      case '\\':
          return getEscape();
      case ']':
          error(RXERR_LEFTDELIM);
          return Tok_Char | ']';
      case '^':
          return Tok_Caret;
      case '{':
  #ifndef QT_NO_REGEXP_INTERVAL
          yyMinRep = getRep(0);
          yyMaxRep = yyMinRep;
          if (yyCh == ',') {
              yyCh = getChar();
              yyMaxRep = getRep(InftyRep);
          }
          if (yyMaxRep < yyMinRep)
              error(RXERR_INTERVAL);
          if (yyCh != '}')
              error(RXERR_REPETITION);
          yyCh = getChar();
          return Tok_Quantifier;
  #else
          error(RXERR_DISABLED);
          return Tok_Char | '{';
  #endif
      case '|':
          return Tok_Bar;
      case '}':
          error(RXERR_LEFTDELIM);
          return Tok_Char | '}';
      default:
          return Tok_Char | prevCh;
      }
  }
  
  int QRegExpEngine::parse(const QChar *pattern, int len)
  {
      valid = true;
      startTokenizer(pattern, len);
      yyTok = getToken();
  #ifndef QT_NO_REGEXP_CAPTURE
      yyMayCapture = true;
  #else
      yyMayCapture = false;
  #endif
  
  #ifndef QT_NO_REGEXP_CAPTURE
      int atom = startAtom(false);
  #endif
      QRegExpCharClass anything;
      Box box(this); // create InitialState
      box.set(anything);
      Box rightBox(this); // create FinalState
      rightBox.set(anything);
  
      Box middleBox(this);
      parseExpression(&middleBox);
  #ifndef QT_NO_REGEXP_CAPTURE
      finishAtom(atom, false);
  #endif
  #ifndef QT_NO_REGEXP_OPTIM
      middleBox.setupHeuristics();
  #endif
      box.cat(middleBox);
      box.cat(rightBox);
      yyCharClass.reset(0);
  
  #ifndef QT_NO_REGEXP_CAPTURE
      for (int i = 0; i < nf; ++i) {
          switch (f[i].capture) {
          case QRegExpAtom::NoCapture:
              break;
          case QRegExpAtom::OfficialCapture:
              f[i].capture = ncap;
              captureForOfficialCapture.append(ncap);
              ++ncap;
              ++officialncap;
              break;
          case QRegExpAtom::UnofficialCapture:
              f[i].capture = greedyQuantifiers ? ncap++ : QRegExpAtom::NoCapture;
          }
      }
  
  #ifndef QT_NO_REGEXP_BACKREF
  #ifndef QT_NO_REGEXP_OPTIM
      if (officialncap == 0 && nbrefs == 0) {
          ncap = nf = 0;
          f.clear();
      }
  #endif
      // handle the case where there's a \5 with no corresponding capture
      // (captureForOfficialCapture.size() != officialncap)
      for (int i = 0; i < nbrefs - officialncap; ++i) {
          captureForOfficialCapture.append(ncap);
          ++ncap;
      }
  #endif
  #endif
  
      if (!yyError.isEmpty())
          return -1;
  
  #ifndef QT_NO_REGEXP_OPTIM
      const QRegExpAutomatonState &sinit = s.at(InitialState);
      caretAnchored = !sinit.anchors.isEmpty();
      if (caretAnchored) {
          const QMap<int, int> &anchors = sinit.anchors;
          QMap<int, int>::const_iterator a;
          for (a = anchors.constBegin(); a != anchors.constEnd(); ++a) {
              if (
  #ifndef QT_NO_REGEXP_ANCHOR_ALT
                  (*a & Anchor_Alternation) != 0 ||
  #endif
                  (*a & Anchor_Caret) == 0)
              {
                  caretAnchored = false;
                  break;
              }
          }
      }
  #endif
  
      // cleanup anchors
      int numStates = s.count();
      for (int i = 0; i < numStates; ++i) {
          QRegExpAutomatonState &state = s[i];
          if (!state.anchors.isEmpty()) {
              QMap<int, int>::iterator a = state.anchors.begin();
              while (a != state.anchors.end()) {
                  if (a.value() == 0)
                      a = state.anchors.erase(a);
                  else
                      ++a;
              }
          }
      }
  
      return yyPos0;
  }
  
  void QRegExpEngine::parseAtom(Box *box)
  {
  #ifndef QT_NO_REGEXP_LOOKAHEAD
      QRegExpEngine *eng = 0;
      bool neg;
      int len;
  #endif
  
      if ((yyTok & Tok_Char) != 0) {
          box->set(QChar(yyTok ^ Tok_Char));
      } else {
  #ifndef QT_NO_REGEXP_OPTIM
          trivial = false;
  #endif
          switch (yyTok) {
          case Tok_Dollar:
              box->catAnchor(Anchor_Dollar);
              break;
          case Tok_Caret:
              box->catAnchor(Anchor_Caret);
              break;
  #ifndef QT_NO_REGEXP_LOOKAHEAD
          case Tok_PosLookahead:
          case Tok_NegLookahead:
              neg = (yyTok == Tok_NegLookahead);
              eng = new QRegExpEngine(cs, greedyQuantifiers);
              len = eng->parse(yyIn + yyPos - 1, yyLen - yyPos + 1);
              if (len >= 0)
                  skipChars(len);
              else
                  error(RXERR_LOOKAHEAD);
              box->catAnchor(addLookahead(eng, neg));
              yyTok = getToken();
              if (yyTok != Tok_RightParen)
                  error(RXERR_LOOKAHEAD);
              break;
  #endif
  #ifndef QT_NO_REGEXP_ESCAPE
          case Tok_Word:
              box->catAnchor(Anchor_Word);
              break;
          case Tok_NonWord:
              box->catAnchor(Anchor_NonWord);
              break;
  #endif
          case Tok_LeftParen:
          case Tok_MagicLeftParen:
              yyTok = getToken();
              parseExpression(box);
              if (yyTok != Tok_RightParen)
                  error(RXERR_END);
              break;
          case Tok_CharClass:
              box->set(*yyCharClass);
              break;
          case Tok_Quantifier:
              error(RXERR_REPETITION);
              break;
          default:
  #ifndef QT_NO_REGEXP_BACKREF
              if ((yyTok & Tok_BackRef) != 0)
                  box->set(yyTok ^ Tok_BackRef);
              else
  #endif
                  error(RXERR_DISABLED);
          }
      }
      yyTok = getToken();
  }
  
  void QRegExpEngine::parseFactor(Box *box)
  {
  #ifndef QT_NO_REGEXP_CAPTURE
      int outerAtom = greedyQuantifiers ? startAtom(false) : -1;
      int innerAtom = startAtom(yyMayCapture && yyTok == Tok_LeftParen);
      bool magicLeftParen = (yyTok == Tok_MagicLeftParen);
  #else
      const int innerAtom = -1;
  #endif
  
  #ifndef QT_NO_REGEXP_INTERVAL
  #define YYREDO() \
          yyIn = in, yyPos0 = pos0, yyPos = pos, yyLen = len, yyCh = ch, \
          *yyCharClass = charClass, yyMinRep = 0, yyMaxRep = 0, yyTok = tok
  
      const QChar *in = yyIn;
      int pos0 = yyPos0;
      int pos = yyPos;
      int len = yyLen;
      int ch = yyCh;
      QRegExpCharClass charClass;
      if (yyTok == Tok_CharClass)
          charClass = *yyCharClass;
      int tok = yyTok;
      bool mayCapture = yyMayCapture;
  #endif
  
      parseAtom(box);
  #ifndef QT_NO_REGEXP_CAPTURE
      finishAtom(innerAtom, magicLeftParen);
  #endif
  
      bool hasQuantifier = (yyTok == Tok_Quantifier);
      if (hasQuantifier) {
  #ifndef QT_NO_REGEXP_OPTIM
          trivial = false;
  #endif
          if (yyMaxRep == InftyRep) {
              box->plus(innerAtom);
  #ifndef QT_NO_REGEXP_INTERVAL
          } else if (yyMaxRep == 0) {
              box->clear();
  #endif
          }
          if (yyMinRep == 0)
              box->opt();
  
  #ifndef QT_NO_REGEXP_INTERVAL
          yyMayCapture = false;
          int alpha = (yyMinRep == 0) ? 0 : yyMinRep - 1;
          int beta = (yyMaxRep == InftyRep) ? 0 : yyMaxRep - (alpha + 1);
  
          Box rightBox(this);
          int i;
  
          for (i = 0; i < beta; i++) {
              YYREDO();
              Box leftBox(this);
              parseAtom(&leftBox);
              leftBox.cat(rightBox);
              leftBox.opt();
              rightBox = leftBox;
          }
          for (i = 0; i < alpha; i++) {
              YYREDO();
              Box leftBox(this);
              parseAtom(&leftBox);
              leftBox.cat(rightBox);
              rightBox = leftBox;
          }
          rightBox.cat(*box);
          *box = rightBox;
  #endif
          yyTok = getToken();
  #ifndef QT_NO_REGEXP_INTERVAL
          yyMayCapture = mayCapture;
  #endif
      }
  #undef YYREDO
  #ifndef QT_NO_REGEXP_CAPTURE
      if (greedyQuantifiers)
          finishAtom(outerAtom, hasQuantifier);
  #endif
  }
  
  void QRegExpEngine::parseTerm(Box *box)
  {
  #ifndef QT_NO_REGEXP_OPTIM
      if (yyTok != Tok_Eos && yyTok != Tok_RightParen && yyTok != Tok_Bar)
          parseFactor(box);
  #endif
      while (yyTok != Tok_Eos && yyTok != Tok_RightParen && yyTok != Tok_Bar) {
          Box rightBox(this);
          parseFactor(&rightBox);
          box->cat(rightBox);
      }
  }
  
  void QRegExpEngine::parseExpression(Box *box)
  {
      parseTerm(box);
      while (yyTok == Tok_Bar) {
  #ifndef QT_NO_REGEXP_OPTIM
          trivial = false;
  #endif
          Box rightBox(this);
          yyTok = getToken();
          parseTerm(&rightBox);
          box->orx(rightBox);
      }
  }
  
  /*
    The struct QRegExpPrivate contains the private data of a regular
    expression other than the automaton. It makes it possible for many
    QRegExp objects to use the same QRegExpEngine object with different
    QRegExpPrivate objects.
  */
  struct QRegExpPrivate
  {
      QRegExpEngine *eng;
      QRegExpEngineKey engineKey;
      bool minimal;
  #ifndef QT_NO_REGEXP_CAPTURE
      QString t; // last string passed to QRegExp::indexIn() or lastIndexIn()
      QStringList capturedCache; // what QRegExp::capturedTexts() returned last
  #endif
      QRegExpMatchState matchState;
  
      inline QRegExpPrivate()
          : eng(0), engineKey(QString(), QRegExp::RegExp, Qt::CaseSensitive), minimal(false) { }
      inline QRegExpPrivate(const QRegExpEngineKey &key)
          : eng(0), engineKey(key), minimal(false) {}
  };
  
  #if !defined(QT_NO_REGEXP_OPTIM)
  typedef QCache<QRegExpEngineKey, QRegExpEngine> EngineCache;
  Q_GLOBAL_STATIC(EngineCache, globalEngineCache)
  static QBasicMutex globalEngineCacheMutex;
  #endif // QT_NO_REGEXP_OPTIM
  
  static void derefEngine(QRegExpEngine *eng, const QRegExpEngineKey &key)
  {
      if (!eng->ref.deref()) {
  #if !defined(QT_NO_REGEXP_OPTIM)
          if (globalEngineCache()) {
              QMutexLocker locker(&globalEngineCacheMutex);
              QT_TRY {
                  globalEngineCache()->insert(key, eng, 4 + key.pattern.length() / 4);
              } QT_CATCH(const std::bad_alloc &) {
                  // in case of an exception (e.g. oom), just delete the engine
                  delete eng;
              }
          } else {
              delete eng;
          }
  #else
          Q_UNUSED(key);
          delete eng;
  #endif
      }
  }
  
  static void prepareEngine_helper(QRegExpPrivate *priv)
  {
      bool initMatchState = !priv->eng;
  #if !defined(QT_NO_REGEXP_OPTIM)
      if (!priv->eng && globalEngineCache()) {
          QMutexLocker locker(&globalEngineCacheMutex);
          priv->eng = globalEngineCache()->take(priv->engineKey);
          if (priv->eng != 0)
              priv->eng->ref.ref();
      }
  #endif // QT_NO_REGEXP_OPTIM
  
      if (!priv->eng)
          priv->eng = new QRegExpEngine(priv->engineKey);
  
      if (initMatchState)
          priv->matchState.prepareForMatch(priv->eng);
  }
  
  inline static void prepareEngine(QRegExpPrivate *priv)
  {
      if (priv->eng)
          return;
      prepareEngine_helper(priv);
  }
  
  static void prepareEngineForMatch(QRegExpPrivate *priv, const QString &str)
  {
      prepareEngine(priv);
      priv->matchState.prepareForMatch(priv->eng);
  #ifndef QT_NO_REGEXP_CAPTURE
      priv->t = str;
      priv->capturedCache.clear();
  #else
      Q_UNUSED(str);
  #endif
  }
  
  static void invalidateEngine(QRegExpPrivate *priv)
  {
      if (priv->eng != 0) {
          derefEngine(priv->eng, priv->engineKey);
          priv->eng = 0;
          priv->matchState.drain();
      }
  }
  
  /*!
      \enum QRegExp::CaretMode
  
      The CaretMode enum defines the different meanings of the caret
      (\b{^}) in a regular expression. The possible values are:
  
      \value CaretAtZero
             The caret corresponds to index 0 in the searched string.
  
      \value CaretAtOffset
             The caret corresponds to the start offset of the search.
  
      \value CaretWontMatch
             The caret never matches.
  */
  
  /*!
      \enum QRegExp::PatternSyntax
  
      The syntax used to interpret the meaning of the pattern.
  
      \value RegExp A rich Perl-like pattern matching syntax. This is
      the default.
  
      \value RegExp2 Like RegExp, but with \l{greedy quantifiers}.
      (Introduced in Qt 4.2.)
  
      \value Wildcard This provides a simple pattern matching syntax
      similar to that used by shells (command interpreters) for "file
      globbing". See \l{QRegExp wildcard matching}.
  
      \value WildcardUnix This is similar to Wildcard but with the
      behavior of a Unix shell. The wildcard characters can be escaped
      with the character "\\".
  
      \value FixedString The pattern is a fixed string. This is
      equivalent to using the RegExp pattern on a string in
      which all metacharacters are escaped using escape().
  
      \value W3CXmlSchema11 The pattern is a regular expression as
      defined by the W3C XML Schema 1.1 specification.
  
      \sa setPatternSyntax()
  */
  
  /*!
      Constructs an empty regexp.
  
      \sa isValid(), errorString()
  */
  QRegExp::QRegExp()
  {
      priv = new QRegExpPrivate;
      prepareEngine(priv);
  }
  
  /*!
      Constructs a regular expression object for the given \a pattern
      string. The pattern must be given using wildcard notation if \a
      syntax is \l Wildcard; the default is \l RegExp. The pattern is
      case sensitive, unless \a cs is Qt::CaseInsensitive. Matching is
      greedy (maximal), but can be changed by calling
      setMinimal().
  
      \sa setPattern(), setCaseSensitivity(), setPatternSyntax()
  */
  QRegExp::QRegExp(const QString &pattern, Qt::CaseSensitivity cs, PatternSyntax syntax)
  {
      priv = new QRegExpPrivate(QRegExpEngineKey(pattern, syntax, cs));
      prepareEngine(priv);
  }
  
  /*!
      Constructs a regular expression as a copy of \a rx.
  
      \sa operator=()
  */
  QRegExp::QRegExp(const QRegExp &rx)
  {
      priv = new QRegExpPrivate;
      operator=(rx);
  }
  
  /*!
      Destroys the regular expression and cleans up its internal data.
  */
  QRegExp::~QRegExp()
  {
      invalidateEngine(priv);
      delete priv;
  }
  
  /*!
      Copies the regular expression \a rx and returns a reference to the
      copy. The case sensitivity, wildcard, and minimal matching options
      are also copied.
  */
  QRegExp &QRegExp::operator=(const QRegExp &rx)
  {
      prepareEngine(rx.priv); // to allow sharing
      QRegExpEngine *otherEng = rx.priv->eng;
      if (otherEng)
          otherEng->ref.ref();
      invalidateEngine(priv);
      priv->eng = otherEng;
      priv->engineKey = rx.priv->engineKey;
      priv->minimal = rx.priv->minimal;
  #ifndef QT_NO_REGEXP_CAPTURE
      priv->t = rx.priv->t;
      priv->capturedCache = rx.priv->capturedCache;
  #endif
      if (priv->eng)
          priv->matchState.prepareForMatch(priv->eng);
      priv->matchState.captured = rx.priv->matchState.captured;
      return *this;
  }
  
  /*!
      \fn QRegExp &QRegExp::operator=(QRegExp &&other)
  
      Move-assigns \a other to this QRegExp instance.
  
      \since 5.2
  */
  
  /*!
      \fn void QRegExp::swap(QRegExp &other)
      \since 4.8
  
      Swaps regular expression \a other with this regular
      expression. This operation is very fast and never fails.
  */
  
  /*!
      Returns \c true if this regular expression is equal to \a rx;
      otherwise returns \c false.
  
      Two QRegExp objects are equal if they have the same pattern
      strings and the same settings for case sensitivity, wildcard and
      minimal matching.
  */
  bool QRegExp::operator==(const QRegExp &rx) const
  {
      return priv->engineKey == rx.priv->engineKey && priv->minimal == rx.priv->minimal;
  }
  
  /*!
      \since 5.6
      \relates QRegExp
  
      Returns the hash value for \a key, using
      \a seed to seed the calculation.
  */
  uint qHash(const QRegExp &key, uint seed) Q_DECL_NOTHROW
  {
      QtPrivate::QHashCombine hash;
      seed = hash(seed, key.priv->engineKey);
      seed = hash(seed, key.priv->minimal);
      return seed;
  }
  
  /*!
      \fn bool QRegExp::operator!=(const QRegExp &rx) const
  
      Returns \c true if this regular expression is not equal to \a rx;
      otherwise returns \c false.
  
      \sa operator==()
  */
  
  /*!
      Returns \c true if the pattern string is empty; otherwise returns
      false.
  
      If you call exactMatch() with an empty pattern on an empty string
      it will return true; otherwise it returns \c false since it operates
      over the whole string. If you call indexIn() with an empty pattern
      on \e any string it will return the start offset (0 by default)
      because the empty pattern matches the 'emptiness' at the start of
      the string. In this case the length of the match returned by
      matchedLength() will be 0.
  
      See QString::isEmpty().
  */
  
  bool QRegExp::isEmpty() const
  {
      return priv->engineKey.pattern.isEmpty();
  }
  
  /*!
      Returns \c true if the regular expression is valid; otherwise returns
      false. An invalid regular expression never matches.
  
      The pattern \b{[a-z} is an example of an invalid pattern, since
      it lacks a closing square bracket.
  
      Note that the validity of a regexp may also depend on the setting
      of the wildcard flag, for example \b{*.html} is a valid
      wildcard regexp but an invalid full regexp.
  
      \sa errorString()
  */
  bool QRegExp::isValid() const
  {
      if (priv->engineKey.pattern.isEmpty()) {
          return true;
      } else {
          prepareEngine(priv);
          return priv->eng->isValid();
      }
  }
  
  /*!
      Returns the pattern string of the regular expression. The pattern
      has either regular expression syntax or wildcard syntax, depending
      on patternSyntax().
  
      \sa patternSyntax(), caseSensitivity()
  */
  QString QRegExp::pattern() const
  {
      return priv->engineKey.pattern;
  }
  
  /*!
      Sets the pattern string to \a pattern. The case sensitivity,
      wildcard, and minimal matching options are not changed.
  
      \sa setPatternSyntax(), setCaseSensitivity()
  */
  void QRegExp::setPattern(const QString &pattern)
  {
      if (priv->engineKey.pattern != pattern) {
          invalidateEngine(priv);
          priv->engineKey.pattern = pattern;
      }
  }
  
  /*!
      Returns Qt::CaseSensitive if the regexp is matched case
      sensitively; otherwise returns Qt::CaseInsensitive.
  
      \sa patternSyntax(), pattern(), isMinimal()
  */
  Qt::CaseSensitivity QRegExp::caseSensitivity() const
  {
      return priv->engineKey.cs;
  }
  
  /*!
      Sets case sensitive matching to \a cs.
  
      If \a cs is Qt::CaseSensitive, \b{\\.txt$} matches
      \c{readme.txt} but not \c{README.TXT}.
  
      \sa setPatternSyntax(), setPattern(), setMinimal()
  */
  void QRegExp::setCaseSensitivity(Qt::CaseSensitivity cs)
  {
      if ((bool)cs != (bool)priv->engineKey.cs) {
          invalidateEngine(priv);
          priv->engineKey.cs = cs;
      }
  }
  
  /*!
      Returns the syntax used by the regular expression. The default is
      QRegExp::RegExp.
  
      \sa pattern(), caseSensitivity()
  */
  QRegExp::PatternSyntax QRegExp::patternSyntax() const
  {
      return priv->engineKey.patternSyntax;
  }
  
  /*!
      Sets the syntax mode for the regular expression. The default is
      QRegExp::RegExp.
  
      Setting \a syntax to QRegExp::Wildcard enables simple shell-like
      \l{QRegExp wildcard matching}. For example, \b{r*.txt} matches the
      string \c{readme.txt} in wildcard mode, but does not match
      \c{readme}.
  
      Setting \a syntax to QRegExp::FixedString means that the pattern
      is interpreted as a plain string. Special characters (e.g.,
      backslash) don't need to be escaped then.
  
      \sa setPattern(), setCaseSensitivity(), escape()
  */
  void QRegExp::setPatternSyntax(PatternSyntax syntax)
  {
      if (syntax != priv->engineKey.patternSyntax) {
          invalidateEngine(priv);
          priv->engineKey.patternSyntax = syntax;
      }
  }
  
  /*!
      Returns \c true if minimal (non-greedy) matching is enabled;
      otherwise returns \c false.
  
      \sa caseSensitivity(), setMinimal()
  */
  bool QRegExp::isMinimal() const
  {
      return priv->minimal;
  }
  
  /*!
      Enables or disables minimal matching. If \a minimal is false,
      matching is greedy (maximal) which is the default.
  
      For example, suppose we have the input string "We must be
      <b>bold</b>, very <b>bold</b>!" and the pattern
      \b{<b>.*</b>}. With the default greedy (maximal) matching,
      the match is "We must be \underline{<b>bold</b>, very
      <b>bold</b>}!". But with minimal (non-greedy) matching, the
      first match is: "We must be \underline{<b>bold</b>}, very
      <b>bold</b>!" and the second match is "We must be <b>bold</b>,
      very \underline{<b>bold</b>}!". In practice we might use the pattern
      \b{<b>[^<]*\</b>} instead, although this will still fail for
      nested tags.
  
      \sa setCaseSensitivity()
  */
  void QRegExp::setMinimal(bool minimal)
  {
      priv->minimal = minimal;
  }
  
  // ### Qt 5: make non-const
  /*!
      Returns \c true if \a str is matched exactly by this regular
      expression; otherwise returns \c false. You can determine how much of
      the string was matched by calling matchedLength().
  
      For a given regexp string R, exactMatch("R") is the equivalent of
      indexIn("^R$") since exactMatch() effectively encloses the regexp
      in the start of string and end of string anchors, except that it
      sets matchedLength() differently.
  
      For example, if the regular expression is \b{blue}, then
      exactMatch() returns \c true only for input \c blue. For inputs \c
      bluebell, \c blutak and \c lightblue, exactMatch() returns \c false
      and matchedLength() will return 4, 3 and 0 respectively.
  
      Although const, this function sets matchedLength(),
      capturedTexts(), and pos().
  
      \sa indexIn(), lastIndexIn()
  */
  bool QRegExp::exactMatch(const QString &str) const
  {
      prepareEngineForMatch(priv, str);
      priv->matchState.match(str.unicode(), str.length(), 0, priv->minimal, true, 0);
      if (priv->matchState.captured[1] == str.length()) {
          return true;
      } else {
          priv->matchState.captured[0] = 0;
          priv->matchState.captured[1] = priv->matchState.oneTestMatchedLen;
          return false;
      }
  }
  
  // ### Qt 5: make non-const
  /*!
      Attempts to find a match in \a str from position \a offset (0 by
      default). If \a offset is -1, the search starts at the last
      character; if -2, at the next to last character; etc.
  
      Returns the position of the first match, or -1 if there was no
      match.
  
      The \a caretMode parameter can be used to instruct whether \b{^}
      should match at index 0 or at \a offset.
  
      You might prefer to use QString::indexOf(), QString::contains(),
      or even QStringList::filter(). To replace matches use
      QString::replace().
  
      Example:
      \snippet code/src_corelib_tools_qregexp.cpp 13
  
      Although const, this function sets matchedLength(),
      capturedTexts() and pos().
  
      If the QRegExp is a wildcard expression (see setPatternSyntax())
      and want to test a string against the whole wildcard expression,
      use exactMatch() instead of this function.
  
      \sa lastIndexIn(), exactMatch()
  */
  
  int QRegExp::indexIn(const QString &str, int offset, CaretMode caretMode) const
  {
      prepareEngineForMatch(priv, str);
      if (offset < 0)
          offset += str.length();
      priv->matchState.match(str.unicode(), str.length(), offset,
          priv->minimal, false, caretIndex(offset, caretMode));
      return priv->matchState.captured[0];
  }
  
  // ### Qt 5: make non-const
  /*!
      Attempts to find a match backwards in \a str from position \a
      offset. If \a offset is -1 (the default), the search starts at the
      last character; if -2, at the next to last character; etc.
  
      Returns the position of the first match, or -1 if there was no
      match.
  
      The \a caretMode parameter can be used to instruct whether \b{^}
      should match at index 0 or at \a offset.
  
      Although const, this function sets matchedLength(),
      capturedTexts() and pos().
  
      \warning Searching backwards is much slower than searching
      forwards.
  
      \sa indexIn(), exactMatch()
  */
  
  int QRegExp::lastIndexIn(const QString &str, int offset, CaretMode caretMode) const
  {
      prepareEngineForMatch(priv, str);
      if (offset < 0)
          offset += str.length();
      if (offset < 0 || offset > str.length()) {
          memset(priv->matchState.captured, -1, priv->matchState.capturedSize*sizeof(int));
          return -1;
      }
  
      while (offset >= 0) {
          priv->matchState.match(str.unicode(), str.length(), offset,
              priv->minimal, true, caretIndex(offset, caretMode));
          if (priv->matchState.captured[0] == offset)
              return offset;
          --offset;
      }
      return -1;
  }
  
  /*!
      Returns the length of the last matched string, or -1 if there was
      no match.
  
      \sa exactMatch(), indexIn(), lastIndexIn()
  */
  int QRegExp::matchedLength() const
  {
      return priv->matchState.captured[1];
  }
  
  #ifndef QT_NO_REGEXP_CAPTURE
  
  /*!
    \since 4.6
    Returns the number of captures contained in the regular expression.
   */
  int QRegExp::captureCount() const
  {
      prepareEngine(priv);
      return priv->eng->captureCount();
  }
  
  /*!
      Returns a list of the captured text strings.
  
      The first string in the list is the entire matched string. Each
      subsequent list element contains a string that matched a
      (capturing) subexpression of the regexp.
  
      For example:
      \snippet code/src_corelib_tools_qregexp.cpp 14
  
      The above example also captures elements that may be present but
      which we have no interest in. This problem can be solved by using
      non-capturing parentheses:
  
      \snippet code/src_corelib_tools_qregexp.cpp 15
  
      Note that if you want to iterate over the list, you should iterate
      over a copy, e.g.
      \snippet code/src_corelib_tools_qregexp.cpp 16
  
      Some regexps can match an indeterminate number of times. For
      example if the input string is "Offsets: 12 14 99 231 7" and the
      regexp, \c{rx}, is \b{(\\d+)+}, we would hope to get a list of
      all the numbers matched. However, after calling
      \c{rx.indexIn(str)}, capturedTexts() will return the list ("12",
      "12"), i.e. the entire match was "12" and the first subexpression
      matched was "12". The correct approach is to use cap() in a
      \l{QRegExp#cap_in_a_loop}{loop}.
  
      The order of elements in the string list is as follows. The first
      element is the entire matching string. Each subsequent element
      corresponds to the next capturing open left parentheses. Thus
      capturedTexts()[1] is the text of the first capturing parentheses,
      capturedTexts()[2] is the text of the second and so on
      (corresponding to $1, $2, etc., in some other regexp languages).
  
      \sa cap(), pos()
  */
  QStringList QRegExp::capturedTexts() const
  {
      if (priv->capturedCache.isEmpty()) {
          prepareEngine(priv);
          const int *captured = priv->matchState.captured;
          int n = priv->matchState.capturedSize;
  
          for (int i = 0; i < n; i += 2) {
              QString m;
              if (captured[i + 1] == 0)
                  m = QLatin1String(""); // ### Qt 5: don't distinguish between null and empty
              else if (captured[i] >= 0)
                  m = priv->t.mid(captured[i], captured[i + 1]);
              priv->capturedCache.append(m);
          }
          priv->t.clear();
      }
      return priv->capturedCache;
  }
  
  /*!
      \internal
  */
  QStringList QRegExp::capturedTexts()
  {
      return const_cast<const QRegExp *>(this)->capturedTexts();
  }
  
  /*!
      Returns the text captured by the \a nth subexpression. The entire
      match has index 0 and the parenthesized subexpressions have
      indexes starting from 1 (excluding non-capturing parentheses).
  
      \snippet code/src_corelib_tools_qregexp.cpp 17
  
      The order of elements matched by cap() is as follows. The first
      element, cap(0), is the entire matching string. Each subsequent
      element corresponds to the next capturing open left parentheses.
      Thus cap(1) is the text of the first capturing parentheses, cap(2)
      is the text of the second, and so on.
  
      \sa capturedTexts(), pos()
  */
  QString QRegExp::cap(int nth) const
  {
      return capturedTexts().value(nth);
  }
  
  /*!
      \internal
  */
  QString QRegExp::cap(int nth)
  {
      return const_cast<const QRegExp *>(this)->cap(nth);
  }
  
  /*!
      Returns the position of the \a nth captured text in the searched
      string. If \a nth is 0 (the default), pos() returns the position
      of the whole match.
  
      Example:
      \snippet code/src_corelib_tools_qregexp.cpp 18
  
      For zero-length matches, pos() always returns -1. (For example, if
      cap(4) would return an empty string, pos(4) returns -1.) This is
      a feature of the implementation.
  
      \sa cap(), capturedTexts()
  */
  int QRegExp::pos(int nth) const
  {
      if (nth < 0 || nth >= priv->matchState.capturedSize / 2)
          return -1;
      else
          return priv->matchState.captured[2 * nth];
  }
  
  /*!
      \internal
  */
  int QRegExp::pos(int nth)
  {
      return const_cast<const QRegExp *>(this)->pos(nth);
  }
  
  /*!
    Returns a text string that explains why a regexp pattern is
    invalid the case being; otherwise returns "no error occurred".
  
    \sa isValid()
  */
  QString QRegExp::errorString() const
  {
      if (isValid()) {
          return QString::fromLatin1(RXERR_OK);
      } else {
          return priv->eng->errorString();
      }
  }
  
  /*!
      \internal
  */
  QString QRegExp::errorString()
  {
      return const_cast<const QRegExp *>(this)->errorString();
  }
  #endif
  
  /*!
      Returns the string \a str with every regexp special character
      escaped with a backslash. The special characters are $, (,), *, +,
      ., ?, [, \,], ^, {, | and }.
  
      Example:
  
      \snippet code/src_corelib_tools_qregexp.cpp 19
  
      This function is useful to construct regexp patterns dynamically:
  
      \snippet code/src_corelib_tools_qregexp.cpp 20
  
      \sa setPatternSyntax()
  */
  QString QRegExp::escape(const QString &str)
  {
      QString quoted;
      const int count = str.count();
      quoted.reserve(count * 2);
      const QLatin1Char backslash('\\');
      for (int i = 0; i < count; i++) {
          switch (str.at(i).toLatin1()) {
          case '$':
          case '(':
          case ')':
          case '*':
          case '+':
          case '.':
          case '?':
          case '[':
          case '\\':
          case ']':
          case '^':
          case '{':
          case '|':
          case '}':
              quoted.append(backslash);
          }
          quoted.append(str.at(i));
      }
      return quoted;
  }
  
  
  #ifndef QT_NO_DATASTREAM
  /*!
      \relates QRegExp
  
      Writes the regular expression \a regExp to stream \a out.
  
      \sa {Serializing Qt Data Types}
  */
  QDataStream &operator<<(QDataStream &out, const QRegExp &regExp)
  {
      return out << regExp.pattern() << (quint8)regExp.caseSensitivity()
                 << (quint8)regExp.patternSyntax()
                 << (quint8)!!regExp.isMinimal();
  }
  
  /*!
      \relates QRegExp
  
      Reads a regular expression from stream \a in into \a regExp.
  
      \sa {Serializing Qt Data Types}
  */
  QDataStream &operator>>(QDataStream &in, QRegExp &regExp)
  {
      QString pattern;
      quint8 cs;
      quint8 patternSyntax;
      quint8 isMinimal;
  
      in >> pattern >> cs >> patternSyntax >> isMinimal;
  
      QRegExp newRegExp(pattern, Qt::CaseSensitivity(cs),
                        QRegExp::PatternSyntax(patternSyntax));
  
      newRegExp.setMinimal(isMinimal);
      regExp = newRegExp;
      return in;
  }
  #endif // QT_NO_DATASTREAM
  
  #ifndef QT_NO_DEBUG_STREAM
  QDebug operator<<(QDebug dbg, const QRegExp &r)
  {
      QDebugStateSaver saver(dbg);
      dbg.nospace() << "QRegExp(patternSyntax=" << r.patternSyntax()
                    << ", pattern='"<< r.pattern() << "')";
      return dbg;
  }
  #endif
  
  QT_END_NAMESPACE
  