// Copyright (c) 2005, Google Inc.

// All rights reserved.

//

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are

// met:

//

//     * Redistributions of source code must retain the above copyright

// notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above

// copyright notice, this list of conditions and the following disclaimer

// in the documentation and/or other materials provided with the

// distribution.

//     * Neither the name of Google Inc. nor the names of its

// contributors may be used to endorse or promote products derived from

// this software without specific prior written permission.

//

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

//

// Author: Sanjay Ghemawat

// Support for PCRE_XXX modifiers added by Giuseppe Maxia, July 2005

#ifndef _PCRECPP_H

#define _PCRECPP_H

// C++ interface to the pcre regular-expression library.  RE supports

// Perl-style regular expressions (with extensions like \d, \w, \s,

// ...).

//

// -----------------------------------------------------------------------

// REGEXP SYNTAX:

//

// This module is part of the pcre library and hence supports its syntax

// for regular expressions.

//

// The syntax is pretty similar to Perl's.  For those not familiar

// with Perl's regular expressions, here are some examples of the most

// commonly used extensions:

//

//   "hello (\\w+) world"  -- \w matches a "word" character

//   "version (\\d+)"      -- \d matches a digit

//   "hello\\s+world"      -- \s matches any whitespace character

//   "\\b(\\w+)\\b"        -- \b matches empty string at a word boundary

//   "(?i)hello"           -- (?i) turns on case-insensitive matching

//   "/\\*(.*?)\\*/"       -- .*? matches . minimum no. of times possible

//

// -----------------------------------------------------------------------

// MATCHING INTERFACE:

//

// The "FullMatch" operation checks that supplied text matches a

// supplied pattern exactly.

//

// Example: successful match

//    pcrecpp::RE re("h.*o");

//    re.FullMatch("hello");

//

// Example: unsuccessful match (requires full match):

//    pcrecpp::RE re("e");

//    !re.FullMatch("hello");

//

// Example: creating a temporary RE object:

//    pcrecpp::RE("h.*o").FullMatch("hello");

//

// You can pass in a "const char*" or a "string" for "text".  The

// examples below tend to use a const char*.

//

// You can, as in the different examples above, store the RE object

// explicitly in a variable or use a temporary RE object.  The

// examples below use one mode or the other arbitrarily.  Either

// could correctly be used for any of these examples.

//

// -----------------------------------------------------------------------

// MATCHING WITH SUB-STRING EXTRACTION:

//

// You can supply extra pointer arguments to extract matched subpieces.

//

// Example: extracts "ruby" into "s" and 1234 into "i"

//    int i;

//    string s;

//    pcrecpp::RE re("(\\w+):(\\d+)");

//    re.FullMatch("ruby:1234", &s, &i);

//

// Example: does not try to extract any extra sub-patterns

//    re.FullMatch("ruby:1234", &s);

//

// Example: does not try to extract into NULL

//    re.FullMatch("ruby:1234", NULL, &i);

//

// Example: integer overflow causes failure

//    !re.FullMatch("ruby:1234567891234", NULL, &i);

//

// Example: fails because there aren't enough sub-patterns:

//    !pcrecpp::RE("\\w+:\\d+").FullMatch("ruby:1234", &s);

//

// Example: fails because string cannot be stored in integer

//    !pcrecpp::RE("(.*)").FullMatch("ruby", &i);

//

// The provided pointer arguments can be pointers to any scalar numeric

// type, or one of

//    string        (matched piece is copied to string)

//    StringPiece   (StringPiece is mutated to point to matched piece)

//    T             (where "bool T::ParseFrom(const char*, int)" exists)

//    NULL          (the corresponding matched sub-pattern is not copied)

//

// CAVEAT: An optional sub-pattern that does not exist in the matched

// string is assigned the empty string.  Therefore, the following will

// return false (because the empty string is not a valid number):

//    int number;

//    pcrecpp::RE::FullMatch("abc", "[a-z]+(\\d+)?", &number);

//

// -----------------------------------------------------------------------

// DO_MATCH

//

// The matching interface supports at most 16 arguments per call.

// If you need more, consider using the more general interface

// pcrecpp::RE::DoMatch().  See pcrecpp.h for the signature for DoMatch.

//

// -----------------------------------------------------------------------

// PARTIAL MATCHES

//

// You can use the "PartialMatch" operation when you want the pattern

// to match any substring of the text.

//

// Example: simple search for a string:

//    pcrecpp::RE("ell").PartialMatch("hello");

//

// Example: find first number in a string:

//    int number;

//    pcrecpp::RE re("(\\d+)");

//    re.PartialMatch("x*100 + 20", &number);

//    assert(number == 100);

//

// -----------------------------------------------------------------------

// UTF-8 AND THE MATCHING INTERFACE:

//

// By default, pattern and text are plain text, one byte per character.

// The UTF8 flag, passed to the constructor, causes both pattern

// and string to be treated as UTF-8 text, still a byte stream but

// potentially multiple bytes per character. In practice, the text

// is likelier to be UTF-8 than the pattern, but the match returned

// may depend on the UTF8 flag, so always use it when matching

// UTF8 text.  E.g., "." will match one byte normally but with UTF8

// set may match up to three bytes of a multi-byte character.

//

// Example:

//    pcrecpp::RE_Options options;

//    options.set_utf8();

//    pcrecpp::RE re(utf8_pattern, options);

//    re.FullMatch(utf8_string);

//

// Example: using the convenience function UTF8():

//    pcrecpp::RE re(utf8_pattern, pcrecpp::UTF8());

//    re.FullMatch(utf8_string);

//

// NOTE: The UTF8 option is ignored if pcre was not configured with the

//       --enable-utf8 flag.

//

// -----------------------------------------------------------------------

// PASSING MODIFIERS TO THE REGULAR EXPRESSION ENGINE

//

// PCRE defines some modifiers to change the behavior of the regular

// expression engine.

// The C++ wrapper defines an auxiliary class, RE_Options, as a vehicle

// to pass such modifiers to a RE class.

//

// Currently, the following modifiers are supported

//

//    modifier              description               Perl corresponding

//

//    PCRE_CASELESS         case insensitive match    /i

//    PCRE_MULTILINE        multiple lines match      /m

//    PCRE_DOTALL           dot matches newlines      /s

//    PCRE_DOLLAR_ENDONLY   $ matches only at end     N/A

//    PCRE_EXTRA            strict escape parsing     N/A

//    PCRE_EXTENDED         ignore whitespaces        /x

//    PCRE_UTF8             handles UTF8 chars        built-in

//    PCRE_UNGREEDY         reverses * and *?         N/A

//    PCRE_NO_AUTO_CAPTURE  disables matching parens  N/A (*)

//

// (For a full account on how each modifier works, please check the

// PCRE API reference manual).

//

// (*) Both Perl and PCRE allow non matching parentheses by means of the

// "?:" modifier within the pattern itself. e.g. (?:ab|cd) does not

// capture, while (ab|cd) does.

//

// For each modifier, there are two member functions whose name is made

// out of the modifier in lowercase, without the "PCRE_" prefix. For

// instance, PCRE_CASELESS is handled by

//    bool caseless(),

// which returns true if the modifier is set, and

//    RE_Options & set_caseless(bool),

// which sets or unsets the modifier.

//

// Moreover, PCRE_EXTRA_MATCH_LIMIT can be accessed through the

// set_match_limit() and match_limit() member functions.

// Setting match_limit to a non-zero value will limit the executation of

// pcre to keep it from doing bad things like blowing the stack or taking

// an eternity to return a result.  A value of 5000 is good enough to stop

// stack blowup in a 2MB thread stack.  Setting match_limit to zero will

// disable match limiting.  Alternately, you can set match_limit_recursion()

// which uses PCRE_EXTRA_MATCH_LIMIT_RECURSION to limit how much pcre

// recurses.  match_limit() caps the number of matches pcre does;

// match_limit_recrusion() caps the depth of recursion.

//

// Normally, to pass one or more modifiers to a RE class, you declare

// a RE_Options object, set the appropriate options, and pass this

// object to a RE constructor. Example:

//

//    RE_options opt;

//    opt.set_caseless(true);

//

//    if (RE("HELLO", opt).PartialMatch("hello world")) ...

//

// RE_options has two constructors. The default constructor takes no

// arguments and creates a set of flags that are off by default.

//

// The optional parameter 'option_flags' is to facilitate transfer

// of legacy code from C programs.  This lets you do

//    RE(pattern, RE_Options(PCRE_CASELESS|PCRE_MULTILINE)).PartialMatch(str);

//

// But new code is better off doing

//    RE(pattern,

//      RE_Options().set_caseless(true).set_multiline(true)).PartialMatch(str);

// (See below)

//

// If you are going to pass one of the most used modifiers, there are some

// convenience functions that return a RE_Options class with the

// appropriate modifier already set:

// CASELESS(), UTF8(), MULTILINE(), DOTALL(), EXTENDED()

//

// If you need to set several options at once, and you don't want to go

// through the pains of declaring a RE_Options object and setting several

// options, there is a parallel method that give you such ability on the

// fly. You can concatenate several set_xxxxx member functions, since each

// of them returns a reference to its class object.  e.g.: to pass

// PCRE_CASELESS, PCRE_EXTENDED, and PCRE_MULTILINE to a RE with one

// statement, you may write

//

//    RE(" ^ xyz \\s+ .* blah$", RE_Options()

//                            .set_caseless(true)

//                            .set_extended(true)

//                            .set_multiline(true)).PartialMatch(sometext);

//

// -----------------------------------------------------------------------

// SCANNING TEXT INCREMENTALLY

//

// The "Consume" operation may be useful if you want to repeatedly

// match regular expressions at the front of a string and skip over

// them as they match.  This requires use of the "StringPiece" type,

// which represents a sub-range of a real string.  Like RE, StringPiece

// is defined in the pcrecpp namespace.

//

// Example: read lines of the form "var = value" from a string.

//    string contents = ...;                 // Fill string somehow

//    pcrecpp::StringPiece input(contents);  // Wrap in a StringPiece

//

//    string var;

//    int value;

//    pcrecpp::RE re("(\\w+) = (\\d+)\n");

//    while (re.Consume(&input, &var, &value)) {

//      ...;

//    }

//

// Each successful call to "Consume" will set "var/value", and also

// advance "input" so it points past the matched text.

//

// The "FindAndConsume" operation is similar to "Consume" but does not

// anchor your match at the beginning of the string.  For example, you

// could extract all words from a string by repeatedly calling

//     pcrecpp::RE("(\\w+)").FindAndConsume(&input, &word)

//

// -----------------------------------------------------------------------

// PARSING HEX/OCTAL/C-RADIX NUMBERS

//

// By default, if you pass a pointer to a numeric value, the

// corresponding text is interpreted as a base-10 number.  You can

// instead wrap the pointer with a call to one of the operators Hex(),

// Octal(), or CRadix() to interpret the text in another base.  The

// CRadix operator interprets C-style "0" (base-8) and "0x" (base-16)

// prefixes, but defaults to base-10.

//

// Example:

//   int a, b, c, d;

//   pcrecpp::RE re("(.*) (.*) (.*) (.*)");

//   re.FullMatch("100 40 0100 0x40",

//                pcrecpp::Octal(&a), pcrecpp::Hex(&b),

//                pcrecpp::CRadix(&c), pcrecpp::CRadix(&d));

// will leave 64 in a, b, c, and d.

//

// -----------------------------------------------------------------------

// REPLACING PARTS OF STRINGS

//

// You can replace the first match of "pattern" in "str" with

// "rewrite".  Within "rewrite", backslash-escaped digits (\1 to \9)

// can be used to insert text matching corresponding parenthesized

// group from the pattern.  \0 in "rewrite" refers to the entire

// matching text.  E.g.,

//

//   string s = "yabba dabba doo";

//   pcrecpp::RE("b+").Replace("d", &s);

//

// will leave "s" containing "yada dabba doo".  The result is true if

// the pattern matches and a replacement occurs, or false otherwise.

//

// GlobalReplace() is like Replace(), except that it replaces all

// occurrences of the pattern in the string with the rewrite.

// Replacements are not subject to re-matching.  E.g.,

//

//   string s = "yabba dabba doo";

//   pcrecpp::RE("b+").GlobalReplace("d", &s);

//

// will leave "s" containing "yada dada doo".  It returns the number

// of replacements made.

//

// Extract() is like Replace(), except that if the pattern matches,

// "rewrite" is copied into "out" (an additional argument) with

// substitutions.  The non-matching portions of "text" are ignored.

// Returns true iff a match occurred and the extraction happened

// successfully.  If no match occurs, the string is left unaffected.

#include <string>

#include <pcre.h>

#include <pcrecpparg.h>   // defines the Arg class

// This isn't technically needed here, but we include it

// anyway so folks who include pcrecpp.h don't have to.

#include <pcre_stringpiece.h>

namespace pcrecpp {

#define PCRE_SET_OR_CLEAR(b, o) \

    if (b) all_options_ |= (o); else all_options_ &= ~(o); \

    return *this

#define PCRE_IS_SET(o)  \

        (all_options_ & o) == o

/***** Compiling regular expressions: the RE class *****/

// RE_Options allow you to set options to be passed along to pcre,

// along with other options we put on top of pcre.

// Only 9 modifiers, plus match_limit and match_limit_recursion,

// are supported now.

class PCRECPP_EXP_DEFN RE_Options {

 public:

  // constructor

  RE_Options() : match_limit_(0), match_limit_recursion_(0), all_options_(0) {}

  // alternative constructor.

  // To facilitate transfer of legacy code from C programs

  //

  // This lets you do

  //    RE(pattern, RE_Options(PCRE_CASELESS|PCRE_MULTILINE)).PartialMatch(str);

  // But new code is better off doing

  //    RE(pattern,

  //      RE_Options().set_caseless(true).set_multiline(true)).PartialMatch(str);

  RE_Options(int option_flags) : match_limit_(0), match_limit_recursion_(0),

                                 all_options_(option_flags) {}

  // we're fine with the default destructor, copy constructor, etc.

  // accessors and mutators

  int match_limit() const { return match_limit_; };

  RE_Options &set_match_limit(int limit) {

    match_limit_ = limit;

    return *this;

  }

  int match_limit_recursion() const { return match_limit_recursion_; };

  RE_Options &set_match_limit_recursion(int limit) {

    match_limit_recursion_ = limit;

    return *this;

  }

  bool caseless() const {

    return PCRE_IS_SET(PCRE_CASELESS);

  }

  RE_Options &set_caseless(bool x) {

    PCRE_SET_OR_CLEAR(x, PCRE_CASELESS);

  }

  bool multiline() const {

    return PCRE_IS_SET(PCRE_MULTILINE);

  }

  RE_Options &set_multiline(bool x) {

    PCRE_SET_OR_CLEAR(x, PCRE_MULTILINE);

  }

  bool dotall() const {

    return PCRE_IS_SET(PCRE_DOTALL);

  }

  RE_Options &set_dotall(bool x) {

    PCRE_SET_OR_CLEAR(x, PCRE_DOTALL);

  }

  bool extended() const {

    return PCRE_IS_SET(PCRE_EXTENDED);

  }

  RE_Options &set_extended(bool x) {

    PCRE_SET_OR_CLEAR(x, PCRE_EXTENDED);

  }

  bool dollar_endonly() const {

    return PCRE_IS_SET(PCRE_DOLLAR_ENDONLY);

  }

  RE_Options &set_dollar_endonly(bool x) {

    PCRE_SET_OR_CLEAR(x, PCRE_DOLLAR_ENDONLY);

  }

  bool extra() const {

    return PCRE_IS_SET(PCRE_EXTRA);

  }

  RE_Options &set_extra(bool x) {

    PCRE_SET_OR_CLEAR(x, PCRE_EXTRA);

  }

  bool ungreedy() const {

    return PCRE_IS_SET(PCRE_UNGREEDY);

  }

  RE_Options &set_ungreedy(bool x) {

    PCRE_SET_OR_CLEAR(x, PCRE_UNGREEDY);

  }

  bool utf8() const {

    return PCRE_IS_SET(PCRE_UTF8);

  }

  RE_Options &set_utf8(bool x) {

    PCRE_SET_OR_CLEAR(x, PCRE_UTF8);

  }

  bool no_auto_capture() const {

    return PCRE_IS_SET(PCRE_NO_AUTO_CAPTURE);

  }

  RE_Options &set_no_auto_capture(bool x) {

    PCRE_SET_OR_CLEAR(x, PCRE_NO_AUTO_CAPTURE);

  }

  RE_Options &set_all_options(int opt) {

    all_options_ = opt;

    return *this;

  }

  int all_options() const {

    return all_options_ ;

  }

  // TODO: add other pcre flags

 private:

  int match_limit_;

  int match_limit_recursion_;

  int all_options_;

};

// These functions return some common RE_Options

static inline RE_Options UTF8() {

  return RE_Options().set_utf8(true);

}

static inline RE_Options CASELESS() {

  return RE_Options().set_caseless(true);

}

static inline RE_Options MULTILINE() {

  return RE_Options().set_multiline(true);

}

static inline RE_Options DOTALL() {

  return RE_Options().set_dotall(true);

}

static inline RE_Options EXTENDED() {

  return RE_Options().set_extended(true);

}

// Interface for regular expression matching.  Also corresponds to a

// pre-compiled regular expression.  An "RE" object is safe for

// concurrent use by multiple threads.

class PCRECPP_EXP_DEFN RE {

 public:

  // We provide implicit conversions from strings so that users can

  // pass in a string or a "const char*" wherever an "RE" is expected.

  RE(const string& pat) { Init(pat, NULL); }

  RE(const string& pat, const RE_Options& option) { Init(pat, &option); }

  RE(const char* pat) { Init(pat, NULL); }

  RE(const char* pat, const RE_Options& option) { Init(pat, &option); }

  RE(const unsigned char* pat) {

    Init(reinterpret_cast<const char*>(pat), NULL);

  }

  RE(const unsigned char* pat, const RE_Options& option) {

    Init(reinterpret_cast<const char*>(pat), &option);

  }

  // Copy constructor & assignment - note that these are expensive

  // because they recompile the expression.

  RE(const RE& re) { Init(re.pattern_, &re.options_); }

  const RE& operator=(const RE& re) {

    if (this != &re) {

      Cleanup();

      // This is the code that originally came from Google

      // Init(re.pattern_.c_str(), &re.options_);

      // This is the replacement from Ari Pollak

      Init(re.pattern_, &re.options_);

    }

    return *this;

  }

  ~RE();

  // The string specification for this RE.  E.g.

  //   RE re("ab*c?d+");

  //   re.pattern();    // "ab*c?d+"

  const string& pattern() const { return pattern_; }

  // If RE could not be created properly, returns an error string.

  // Else returns the empty string.

  const string& error() const { return *error_; }

  /***** The useful part: the matching interface *****/

  // This is provided so one can do pattern.ReplaceAll() just as

  // easily as ReplaceAll(pattern-text, ....)

  bool FullMatch(const StringPiece& text,

                 const Arg& ptr1 = no_arg,

                 const Arg& ptr2 = no_arg,

                 const Arg& ptr3 = no_arg,

                 const Arg& ptr4 = no_arg,

                 const Arg& ptr5 = no_arg,

                 const Arg& ptr6 = no_arg,

                 const Arg& ptr7 = no_arg,

                 const Arg& ptr8 = no_arg,

                 const Arg& ptr9 = no_arg,

                 const Arg& ptr10 = no_arg,

                 const Arg& ptr11 = no_arg,

                 const Arg& ptr12 = no_arg,

                 const Arg& ptr13 = no_arg,

                 const Arg& ptr14 = no_arg,

                 const Arg& ptr15 = no_arg,

                 const Arg& ptr16 = no_arg) const;

  bool PartialMatch(const StringPiece& text,

                    const Arg& ptr1 = no_arg,

                    const Arg& ptr2 = no_arg,

                    const Arg& ptr3 = no_arg,

                    const Arg& ptr4 = no_arg,

                    const Arg& ptr5 = no_arg,

                    const Arg& ptr6 = no_arg,

                    const Arg& ptr7 = no_arg,

                    const Arg& ptr8 = no_arg,

                    const Arg& ptr9 = no_arg,

                    const Arg& ptr10 = no_arg,

                    const Arg& ptr11 = no_arg,

                    const Arg& ptr12 = no_arg,

                    const Arg& ptr13 = no_arg,

                    const Arg& ptr14 = no_arg,

                    const Arg& ptr15 = no_arg,

                    const Arg& ptr16 = no_arg) const;

  bool Consume(StringPiece* input,

               const Arg& ptr1 = no_arg,

               const Arg& ptr2 = no_arg,

               const Arg& ptr3 = no_arg,

               const Arg& ptr4 = no_arg,

               const Arg& ptr5 = no_arg,

               const Arg& ptr6 = no_arg,

               const Arg& ptr7 = no_arg,

               const Arg& ptr8 = no_arg,

               const Arg& ptr9 = no_arg,

               const Arg& ptr10 = no_arg,

               const Arg& ptr11 = no_arg,

               const Arg& ptr12 = no_arg,

               const Arg& ptr13 = no_arg,

               const Arg& ptr14 = no_arg,

               const Arg& ptr15 = no_arg,

               const Arg& ptr16 = no_arg) const;

  bool FindAndConsume(StringPiece* input,

                      const Arg& ptr1 = no_arg,

                      const Arg& ptr2 = no_arg,

                      const Arg& ptr3 = no_arg,

                      const Arg& ptr4 = no_arg,

                      const Arg& ptr5 = no_arg,

                      const Arg& ptr6 = no_arg,

                      const Arg& ptr7 = no_arg,

                      const Arg& ptr8 = no_arg,

                      const Arg& ptr9 = no_arg,

                      const Arg& ptr10 = no_arg,

                      const Arg& ptr11 = no_arg,

                      const Arg& ptr12 = no_arg,

                      const Arg& ptr13 = no_arg,

                      const Arg& ptr14 = no_arg,

                      const Arg& ptr15 = no_arg,

                      const Arg& ptr16 = no_arg) const;

  bool Replace(const StringPiece& rewrite,

               string *str) const;

  int GlobalReplace(const StringPiece& rewrite,

                    string *str) const;

  bool Extract(const StringPiece &rewrite,

               const StringPiece &text,

               string *out) const;

  // Escapes all potentially meaningful regexp characters in

  // 'unquoted'.  The returned string, used as a regular expression,

  // will exactly match the original string.  For example,

  //           1.5-2.0?

  // may become:

  //           1\.5\-2\.0\?

  // Note QuoteMeta behaves the same as perl's QuoteMeta function,

  // *except* that it escapes the NUL character (\0) as backslash + 0,

  // rather than backslash + NUL.

  static string QuoteMeta(const StringPiece& unquoted);

  /***** Generic matching interface *****/

  // Type of match (TODO: Should be restructured as part of RE_Options)

  enum Anchor {

    UNANCHORED,         // No anchoring

    ANCHOR_START,       // Anchor at start only

    ANCHOR_BOTH         // Anchor at start and end

  };

  // General matching routine.  Stores the length of the match in

  // "*consumed" if successful.

  bool DoMatch(const StringPiece& text,

               Anchor anchor,

               int* consumed,

               const Arg* const* args, int n) const;

  // Return the number of capturing subpatterns, or -1 if the

  // regexp wasn't valid on construction.

  int NumberOfCapturingGroups() const;

  // The default value for an argument, to indicate the end of the argument

  // list. This must be used only in optional argument defaults. It should NOT

  // be passed explicitly. Some people have tried to use it like this:

  //

  //   FullMatch(x, y, &z, no_arg, &w);

  //

  // This is a mistake, and will not work.

  static Arg no_arg;

 private:

  void Init(const string& pattern, const RE_Options* options);

  void Cleanup();

  // Match against "text", filling in "vec" (up to "vecsize" * 2/3) with

  // pairs of integers for the beginning and end positions of matched

  // text.  The first pair corresponds to the entire matched text;

  // subsequent pairs correspond, in order, to parentheses-captured

  // matches.  Returns the number of pairs (one more than the number of

  // the last subpattern with a match) if matching was successful

  // and zero if the match failed.

  // I.e. for RE("(foo)|(bar)|(baz)") it will return 2, 3, and 4 when matching

  // against "foo", "bar", and "baz" respectively.

  // When matching RE("(foo)|hello") against "hello", it will return 1.

  // But the values for all subpattern are filled in into "vec".

  int TryMatch(const StringPiece& text,

               int startpos,

               Anchor anchor,

               int *vec,

               int vecsize) const;