// 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

//

// Regular-expression based scanner for parsing an input stream.

//

// Example 1: parse a sequence of "var = number" entries from input:

//

//      Scanner scanner(input);

//      string var;

//      int number;

//      scanner.SetSkipExpression("\\s+"); // Skip any white space we encounter

//      while (scanner.Consume("(\\w+) = (\\d+)", &var, &number)) {

//        ...;

//      }

#ifndef _PCRE_SCANNER_H

#define _PCRE_SCANNER_H

#include <assert.h>

#include <string>

#include <vector>

#include <pcrecpp.h>

#include <pcre_stringpiece.h>

namespace pcrecpp {

class PCRECPP_EXP_DEFN Scanner {

 public:

  Scanner();

  explicit Scanner(const std::string& input);

  ~Scanner();

  // Return current line number.  The returned line-number is

  // one-based.  I.e. it returns 1 + the number of consumed newlines.

  //

  // Note: this method may be slow.  It may take time proportional to

  // the size of the input.

  int LineNumber() const;

  // Return the byte-offset that the scanner is looking in the

  // input data;

  int Offset() const;

  // Return true iff the start of the remaining input matches "re"

  bool LookingAt(const RE& re) const;

  // Return true iff all of the following are true

  //    a. the start of the remaining input matches "re",

  //    b. if any arguments are supplied, matched sub-patterns can be

  //       parsed and stored into the arguments.

  // If it returns true, it skips over the matched input and any

  // following input that matches the "skip" regular expression.

  bool Consume(const RE& re,

               const Arg& arg0 = RE::no_arg,

               const Arg& arg1 = RE::no_arg,

               const Arg& arg2 = RE::no_arg

               // TODO: Allow more arguments?

               );

  // Set the "skip" regular expression.  If after consuming some data,

  // a prefix of the input matches this RE, it is automatically

  // skipped.  For example, a programming language scanner would use

  // a skip RE that matches white space and comments.

  //

  //    scanner.SetSkipExpression("\\s+|//.*|/[*](.|\n)*?[*]/");

  //

  // Skipping repeats as long as it succeeds.  We used to let people do

  // this by writing "(...)*" in the regular expression, but that added

  // up to lots of recursive calls within the pcre library, so now we

  // control repetition explicitly via the function call API.

  //

  // You can pass NULL for "re" if you do not want any data to be skipped.

  void Skip(const char* re);   // DEPRECATED; does *not* repeat

  void SetSkipExpression(const char* re);

  // Temporarily pause "skip"ing. This

  //   Skip("Foo"); code ; DisableSkip(); code; EnableSkip()

  // is similar to

  //   Skip("Foo"); code ; Skip(NULL); code ; Skip("Foo");

  // but avoids creating/deleting new RE objects.

  void DisableSkip();

  // Reenable previously paused skipping.  Any prefix of the input

  // that matches the skip pattern is immediately dropped.

  void EnableSkip();

  /***** Special wrappers around SetSkip() for some common idioms *****/

  // Arranges to skip whitespace, C comments, C++ comments.

  // The overall RE is a disjunction of the following REs:

  //    \\s                     whitespace

  //    //.*\n                  C++ comment

  //    /[*](.|\n)*?[*]/        C comment (x*? means minimal repetitions of x)

  // We get repetition via the semantics of SetSkipExpression, not by using *

  void SkipCXXComments() {

    SetSkipExpression("\\s|//.*\n|/[*](?:\n|.)*?[*]/");

  }

  void set_save_comments(bool comments) {

    save_comments_ = comments;

  }

  bool save_comments() {

    return save_comments_;

  }

  // Append to vector ranges the comments found in the

  // byte range [start,end] (inclusive) of the input data.

  // Only comments that were extracted entirely within that

  // range are returned: no range splitting of atomically-extracted

  // comments is performed.

  void GetComments(int start, int end, std::vector<StringPiece> *ranges);

  // Append to vector ranges the comments added

  // since the last time this was called. This

  // functionality is provided for efficiency when

  // interleaving scanning with parsing.

  void GetNextComments(std::vector<StringPiece> *ranges);

 private:

  std::string   data_;          // All the input data

  StringPiece   input_;         // Unprocessed input

  RE*           skip_;          // If non-NULL, RE for skipping input

  bool          should_skip_;   // If true, use skip_

  bool          skip_repeat_;   // If true, repeat skip_ as long as it works

  bool          save_comments_; // If true, aggregate the skip expression

  // the skipped comments

  // TODO: later consider requiring that the StringPieces be added

  // in order by their start position

  std::vector<StringPiece> *comments_;

  // the offset into comments_ that has been returned by GetNextComments

  int           comments_offset_;

  // helper function to consume *skip_ and honour

  // save_comments_

  void ConsumeSkip();

};

}   // namespace pcrecpp

#endif /* _PCRE_SCANNER_H */