pcre_scanner.cc

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  10 //     * Redistributions in binary form must reproduce the above
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  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