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      1 // Copyright 2013 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "chrome/browser/ui/app_list/search/term_break_iterator.h"
      6 
      7 #include "base/i18n/char_iterator.h"
      8 #include "base/logging.h"
      9 #include "base/strings/string_util.h"
     10 #include "third_party/icu/source/common/unicode/uchar.h"
     11 
     12 namespace app_list {
     13 
     14 TermBreakIterator::TermBreakIterator(const string16& word)
     15     : word_(word),
     16       prev_(npos),
     17       pos_(0),
     18       iter_(new base::i18n::UTF16CharIterator(&word)),
     19       state_(STATE_START) {
     20 }
     21 
     22 TermBreakIterator::~TermBreakIterator() {}
     23 
     24 bool TermBreakIterator::Advance() {
     25   // 2D matrix that defines term boundaries. Each row represents current state.
     26   // Each col represents new state from input char. Cells with true value
     27   // represents a term boundary.
     28   const bool kBoundary[][STATE_LAST] = {
     29     // START  NUMBER UPPER  LOWER  CHAR
     30     {  false, false, false, false, false },  // START
     31     {  false, false, true,  true,  true },   // NUMBER
     32     {  false, true,  false, false, true },   // UPPER
     33     {  false, true,  true,  false, true },   // LOWER
     34     {  false, true,  true,  true,  false },  // CHAR
     35   };
     36 
     37   while (iter_->Advance()) {
     38     const State new_state = GetNewState(word_[iter_->array_pos()]);
     39     const bool is_boundary = kBoundary[state_][new_state];
     40     state_ = new_state;
     41     if (is_boundary)
     42       break;
     43   }
     44 
     45   prev_ = pos_;
     46   pos_ = iter_->array_pos();
     47 
     48   return prev_ != pos_ || !iter_->end();
     49 }
     50 
     51 const string16 TermBreakIterator::GetCurrentTerm() const {
     52   DCHECK(prev_ != npos && pos_ != npos);
     53   return word_.substr(prev_, pos_ - prev_);
     54 }
     55 
     56 TermBreakIterator::State TermBreakIterator::GetNewState(char16 ch) {
     57   if (IsAsciiDigit(ch) || ch == '.' || ch == ',')
     58     return STATE_NUMBER;
     59 
     60   const bool is_upper = !!u_isUUppercase(ch);
     61   const bool is_lower = !!u_isULowercase(ch);
     62 
     63   if (is_upper && is_lower) {
     64     NOTREACHED() << "Invalid state for ch=" << ch;
     65     return STATE_CHAR;
     66   }
     67 
     68   if (is_upper)
     69     return STATE_UPPER;
     70   if (is_lower)
     71     return STATE_LOWER;
     72 
     73   return STATE_CHAR;
     74 }
     75 
     76 }  // namespace app_list
     77