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    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 #ifdef HAVE_CONFIG_H
   33 #include "config.h"
   34 #endif
   35 
   36 #include <vector>
   37 #include <assert.h>
   38 
   39 #include "pcrecpp_internal.h"
   40 #include "pcre_scanner.h"
   41 
   42 using std::vector;
   43 
   44 namespace pcrecpp {
   45 
   46 Scanner::Scanner()
   47   : data_(),
   48     input_(data_),
   49     skip_(NULL),
   50     should_skip_(false),
   51     skip_repeat_(false),
   52     save_comments_(false),
   53     comments_(NULL),
   54     comments_offset_(0) {
   55 }
   56 
   57 Scanner::Scanner(const string& in)
   58   : data_(in),
   59     input_(data_),
   60     skip_(NULL),
   61     should_skip_(false),
   62     skip_repeat_(false),
   63     save_comments_(false),
   64     comments_(NULL),
   65     comments_offset_(0) {
   66 }
   67 
   68 Scanner::~Scanner() {
   69   delete skip_;
   70   delete comments_;
   71 }
   72 
   73 void Scanner::SetSkipExpression(const char* re) {
   74   delete skip_;
   75   if (re != NULL) {
   76     skip_ = new RE(re);
   77     should_skip_ = true;
   78     skip_repeat_ = true;
   79     ConsumeSkip();
   80   } else {
   81     skip_ = NULL;
   82     should_skip_ = false;
   83     skip_repeat_ = false;
   84   }
   85 }
   86 
   87 void Scanner::Skip(const char* re) {
   88   delete skip_;
   89   if (re != NULL) {
   90     skip_ = new RE(re);
   91     should_skip_ = true;
   92     skip_repeat_ = false;
   93     ConsumeSkip();
   94   } else {
   95     skip_ = NULL;
   96     should_skip_ = false;
   97     skip_repeat_ = false;
   98   }
   99 }
  100 
  101 void Scanner::DisableSkip() {
  102   assert(skip_ != NULL);
  103   should_skip_ = false;
  104 }
  105 
  106 void Scanner::EnableSkip() {
  107   assert(skip_ != NULL);
  108   should_skip_ = true;
  109   ConsumeSkip();
  110 }
  111 
  112 int Scanner::LineNumber() const {
  113   // TODO: Make it more efficient by keeping track of the last point
  114   // where we computed line numbers and counting newlines since then.
  115   // We could use std:count, but not all systems have it. :-(
  116   int count = 1;
  117   for (const char* p = data_.data(); p < input_.data(); ++p)
  118     if (*p == '\n')
  119       ++count;
  120   return count;
  121 }
  122 
  123 int Scanner::Offset() const {
  124   return (int)(input_.data() - data_.c_str());
  125 }
  126 
  127 bool Scanner::LookingAt(const RE& re) const {
  128   int consumed;
  129   return re.DoMatch(input_, RE::ANCHOR_START, &consumed, 0, 0);
  130 }
  131 
  132 
  133 bool Scanner::Consume(const RE& re,
  134                       const Arg& arg0,
  135                       const Arg& arg1,
  136                       const Arg& arg2) {
  137   const bool result = re.Consume(&input_, arg0, arg1, arg2);
  138   if (result && should_skip_) ConsumeSkip();
  139   return result;
  140 }
  141 
  142 // helper function to consume *skip_ and honour save_comments_
  143 void Scanner::ConsumeSkip() {
  144   const char* start_data = input_.data();
  145   while (skip_->Consume(&input_)) {
  146     if (!skip_repeat_) {
  147       // Only one skip allowed.
  148       break;
  149     }
  150   }
  151   if (save_comments_) {
  152     if (comments_ == NULL) {
  153       comments_ = new vector<StringPiece>;
  154     }
  155     // already pointing one past end, so no need to +1
  156     int length = (int)(input_.data() - start_data);
  157     if (length > 0) {
  158       comments_->push_back(StringPiece(start_data, length));
  159     }
  160   }
  161 }
  162 
  163 
  164 void Scanner::GetComments(int start, int end, vector<StringPiece> *ranges) {
  165   // short circuit out if we've not yet initialized comments_
  166   // (e.g., when save_comments is false)
  167   if (!comments_) {
  168     return;
  169   }
  170   // TODO: if we guarantee that comments_ will contain StringPieces
  171   // that are ordered by their start, then we can do a binary search
  172   // for the first StringPiece at or past start and then scan for the
  173   // ones contained in the range, quit early (use equal_range or
  174   // lower_bound)
  175   for (vector<StringPiece>::const_iterator it = comments_->begin();
  176        it != comments_->end(); ++it) {
  177     if ((it->data() >= data_.c_str() + start &&
  178          it->data() + it->size() <= data_.c_str() + end)) {
  179       ranges->push_back(*it);
  180     }
  181   }
  182 }
  183 
  184 
  185 void Scanner::GetNextComments(vector<StringPiece> *ranges) {
  186   // short circuit out if we've not yet initialized comments_
  187   // (e.g., when save_comments is false)
  188   if (!comments_) {
  189     return;
  190   }
  191   for (vector<StringPiece>::const_iterator it =
  192          comments_->begin() + comments_offset_;
  193        it != comments_->end(); ++it) {
  194     ranges->push_back(*it);
  195     ++comments_offset_;
  196   }
  197 }
  198 
  199 }   // namespace pcrecpp