/[pcre]/code/trunk/pcre_scanner.h
ViewVC logotype

Contents of /code/trunk/pcre_scanner.h

Parent Directory Parent Directory | Revision Log Revision Log


Revision 199 - (show annotations) (download)
Tue Jul 31 14:39:09 2007 UTC (6 years, 11 months ago) by ph10
File MIME type: text/plain
File size: 6588 byte(s)
Daniel's patch for config.h and Windows DLL declarations (not fully working).

1 // Copyright (c) 2005, Google Inc.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
8 // * Redistributions of source code must retain the above copyright
9 // notice, this list of conditions and the following disclaimer.
10 // * Redistributions in binary form must reproduce the above
11 // copyright notice, this list of conditions and the following disclaimer
12 // in the documentation and/or other materials provided with the
13 // distribution.
14 // * Neither the name of Google Inc. nor the names of its
15 // contributors may be used to endorse or promote products derived from
16 // this software without specific prior written permission.
17 //
18 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
21 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
22 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
23 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
24 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
28 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 //
30 // Author: Sanjay Ghemawat
31 //
32 // Regular-expression based scanner for parsing an input stream.
33 //
34 // Example 1: parse a sequence of "var = number" entries from input:
35 //
36 // Scanner scanner(input);
37 // string var;
38 // int number;
39 // scanner.SetSkipExpression("\\s+"); // Skip any white space we encounter
40 // while (scanner.Consume("(\\w+) = (\\d+)", &var, &number)) {
41 // ...;
42 // }
43
44 #ifndef _PCRE_SCANNER_H
45 #define _PCRE_SCANNER_H
46
47 #include <assert.h>
48 #include <string>
49 #include <vector>
50
51 #include <pcrecpp.h>
52 #include <pcre_stringpiece.h>
53
54 namespace pcrecpp {
55
56 class PCRECPP_EXP_DEFN Scanner {
57 public:
58 Scanner();
59 explicit Scanner(const std::string& input);
60 ~Scanner();
61
62 // Return current line number. The returned line-number is
63 // one-based. I.e. it returns 1 + the number of consumed newlines.
64 //
65 // Note: this method may be slow. It may take time proportional to
66 // the size of the input.
67 int LineNumber() const;
68
69 // Return the byte-offset that the scanner is looking in the
70 // input data;
71 int Offset() const;
72
73 // Return true iff the start of the remaining input matches "re"
74 bool LookingAt(const RE& re) const;
75
76 // Return true iff all of the following are true
77 // a. the start of the remaining input matches "re",
78 // b. if any arguments are supplied, matched sub-patterns can be
79 // parsed and stored into the arguments.
80 // If it returns true, it skips over the matched input and any
81 // following input that matches the "skip" regular expression.
82 bool Consume(const RE& re,
83 const Arg& arg0 = no_arg,
84 const Arg& arg1 = no_arg,
85 const Arg& arg2 = no_arg
86 // TODO: Allow more arguments?
87 );
88
89 // Set the "skip" regular expression. If after consuming some data,
90 // a prefix of the input matches this RE, it is automatically
91 // skipped. For example, a programming language scanner would use
92 // a skip RE that matches white space and comments.
93 //
94 // scanner.SetSkipExpression("\\s+|//.*|/[*](.|\n)*?[*]/");
95 //
96 // Skipping repeats as long as it succeeds. We used to let people do
97 // this by writing "(...)*" in the regular expression, but that added
98 // up to lots of recursive calls within the pcre library, so now we
99 // control repetition explicitly via the function call API.
100 //
101 // You can pass NULL for "re" if you do not want any data to be skipped.
102 void Skip(const char* re); // DEPRECATED; does *not* repeat
103 void SetSkipExpression(const char* re);
104
105 // Temporarily pause "skip"ing. This
106 // Skip("Foo"); code ; DisableSkip(); code; EnableSkip()
107 // is similar to
108 // Skip("Foo"); code ; Skip(NULL); code ; Skip("Foo");
109 // but avoids creating/deleting new RE objects.
110 void DisableSkip();
111
112 // Reenable previously paused skipping. Any prefix of the input
113 // that matches the skip pattern is immediately dropped.
114 void EnableSkip();
115
116 /***** Special wrappers around SetSkip() for some common idioms *****/
117
118 // Arranges to skip whitespace, C comments, C++ comments.
119 // The overall RE is a disjunction of the following REs:
120 // \\s whitespace
121 // //.*\n C++ comment
122 // /[*](.|\n)*?[*]/ C comment (x*? means minimal repetitions of x)
123 // We get repetition via the semantics of SetSkipExpression, not by using *
124 void SkipCXXComments() {
125 SetSkipExpression("\\s|//.*\n|/[*](?:\n|.)*?[*]/");
126 }
127
128 void set_save_comments(bool comments) {
129 save_comments_ = comments;
130 }
131
132 bool save_comments() {
133 return save_comments_;
134 }
135
136 // Append to vector ranges the comments found in the
137 // byte range [start,end] (inclusive) of the input data.
138 // Only comments that were extracted entirely within that
139 // range are returned: no range splitting of atomically-extracted
140 // comments is performed.
141 void GetComments(int start, int end, std::vector<StringPiece> *ranges);
142
143 // Append to vector ranges the comments added
144 // since the last time this was called. This
145 // functionality is provided for efficiency when
146 // interleaving scanning with parsing.
147 void GetNextComments(std::vector<StringPiece> *ranges);
148
149 private:
150 std::string data_; // All the input data
151 StringPiece input_; // Unprocessed input
152 RE* skip_; // If non-NULL, RE for skipping input
153 bool should_skip_; // If true, use skip_
154 bool skip_repeat_; // If true, repeat skip_ as long as it works
155 bool save_comments_; // If true, aggregate the skip expression
156
157 // the skipped comments
158 // TODO: later consider requiring that the StringPieces be added
159 // in order by their start position
160 std::vector<StringPiece> *comments_;
161
162 // the offset into comments_ that has been returned by GetNextComments
163 int comments_offset_;
164
165 // helper function to consume *skip_ and honour
166 // save_comments_
167 void ConsumeSkip();
168 };
169
170 } // namespace pcrecpp
171
172 #endif /* _PCRE_SCANNER_H */

Properties

Name Value
svn:eol-style native
svn:keywords "Author Date Id Revision Url"

webmaster@exim.org
ViewVC Help
Powered by ViewVC 1.1.12