![Michael Jerris](/assets/img/avatar_default.png)
git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@13706 d0543943-73ff-0310-b7d9-9358b9ac24b2
173 lines
6.4 KiB
C++
173 lines
6.4 KiB
C++
// Copyright (c) 2005, Google Inc.
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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//
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// Author: Sanjay Ghemawat
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//
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// Regular-expression based scanner for parsing an input stream.
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//
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// Example 1: parse a sequence of "var = number" entries from input:
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//
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// Scanner scanner(input);
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// string var;
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// int number;
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// scanner.SetSkipExpression("\\s+"); // Skip any white space we encounter
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// while (scanner.Consume("(\\w+) = (\\d+)", &var, &number)) {
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// ...;
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// }
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#ifndef _PCRE_SCANNER_H
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#define _PCRE_SCANNER_H
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#include <assert.h>
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#include <string>
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#include <vector>
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#include <pcrecpp.h>
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#include <pcre_stringpiece.h>
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namespace pcrecpp {
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class PCRECPP_EXP_DEFN Scanner {
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public:
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Scanner();
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explicit Scanner(const std::string& input);
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~Scanner();
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// Return current line number. The returned line-number is
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// one-based. I.e. it returns 1 + the number of consumed newlines.
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//
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// Note: this method may be slow. It may take time proportional to
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// the size of the input.
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int LineNumber() const;
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// Return the byte-offset that the scanner is looking in the
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// input data;
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int Offset() const;
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// Return true iff the start of the remaining input matches "re"
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bool LookingAt(const RE& re) const;
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// Return true iff all of the following are true
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// a. the start of the remaining input matches "re",
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// b. if any arguments are supplied, matched sub-patterns can be
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// parsed and stored into the arguments.
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// If it returns true, it skips over the matched input and any
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// following input that matches the "skip" regular expression.
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bool Consume(const RE& re,
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const Arg& arg0 = RE::no_arg,
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const Arg& arg1 = RE::no_arg,
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const Arg& arg2 = RE::no_arg
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// TODO: Allow more arguments?
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);
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// Set the "skip" regular expression. If after consuming some data,
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// a prefix of the input matches this RE, it is automatically
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// skipped. For example, a programming language scanner would use
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// a skip RE that matches white space and comments.
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//
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// scanner.SetSkipExpression("\\s+|//.*|/[*](.|\n)*?[*]/");
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//
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// Skipping repeats as long as it succeeds. We used to let people do
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// this by writing "(...)*" in the regular expression, but that added
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// up to lots of recursive calls within the pcre library, so now we
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// control repetition explicitly via the function call API.
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//
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// You can pass NULL for "re" if you do not want any data to be skipped.
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void Skip(const char* re); // DEPRECATED; does *not* repeat
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void SetSkipExpression(const char* re);
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// Temporarily pause "skip"ing. This
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// Skip("Foo"); code ; DisableSkip(); code; EnableSkip()
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// is similar to
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// Skip("Foo"); code ; Skip(NULL); code ; Skip("Foo");
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// but avoids creating/deleting new RE objects.
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void DisableSkip();
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// Reenable previously paused skipping. Any prefix of the input
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// that matches the skip pattern is immediately dropped.
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void EnableSkip();
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/***** Special wrappers around SetSkip() for some common idioms *****/
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// Arranges to skip whitespace, C comments, C++ comments.
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// The overall RE is a disjunction of the following REs:
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// \\s whitespace
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// //.*\n C++ comment
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// /[*](.|\n)*?[*]/ C comment (x*? means minimal repetitions of x)
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// We get repetition via the semantics of SetSkipExpression, not by using *
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void SkipCXXComments() {
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SetSkipExpression("\\s|//.*\n|/[*](?:\n|.)*?[*]/");
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}
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void set_save_comments(bool comments) {
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save_comments_ = comments;
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}
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bool save_comments() {
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return save_comments_;
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}
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// Append to vector ranges the comments found in the
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// byte range [start,end] (inclusive) of the input data.
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// Only comments that were extracted entirely within that
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// range are returned: no range splitting of atomically-extracted
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// comments is performed.
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void GetComments(int start, int end, std::vector<StringPiece> *ranges);
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// Append to vector ranges the comments added
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// since the last time this was called. This
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// functionality is provided for efficiency when
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// interleaving scanning with parsing.
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void GetNextComments(std::vector<StringPiece> *ranges);
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private:
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std::string data_; // All the input data
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StringPiece input_; // Unprocessed input
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RE* skip_; // If non-NULL, RE for skipping input
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bool should_skip_; // If true, use skip_
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bool skip_repeat_; // If true, repeat skip_ as long as it works
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bool save_comments_; // If true, aggregate the skip expression
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// the skipped comments
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// TODO: later consider requiring that the StringPieces be added
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// in order by their start position
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std::vector<StringPiece> *comments_;
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// the offset into comments_ that has been returned by GetNextComments
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int comments_offset_;
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// helper function to consume *skip_ and honour
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// save_comments_
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void ConsumeSkip();
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};
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} // namespace pcrecpp
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#endif /* _PCRE_SCANNER_H */
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