1 // Copyright (c) 2011 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 "ui/accessibility/ax_text_utils.h" 6 7 #include "base/logging.h" 8 #include "base/strings/string_util.h" 9 10 namespace ui { 11 FindAccessibleTextBoundary(const base::string16 & text,const std::vector<int> & line_breaks,TextBoundaryType boundary,size_t start_offset,TextBoundaryDirection direction)12size_t FindAccessibleTextBoundary(const base::string16& text, 13 const std::vector<int>& line_breaks, 14 TextBoundaryType boundary, 15 size_t start_offset, 16 TextBoundaryDirection direction) { 17 size_t text_size = text.size(); 18 DCHECK(start_offset <= text_size); 19 20 if (boundary == CHAR_BOUNDARY) { 21 if (direction == FORWARDS_DIRECTION && start_offset < text_size) 22 return start_offset + 1; 23 else 24 return start_offset; 25 } else if (boundary == LINE_BOUNDARY) { 26 if (direction == FORWARDS_DIRECTION) { 27 for (size_t j = 0; j < line_breaks.size(); ++j) { 28 size_t line_break = line_breaks[j] >= 0 ? line_breaks[j] : 0; 29 if (line_break > start_offset) 30 return line_break; 31 } 32 return text_size; 33 } else { 34 for (size_t j = line_breaks.size(); j != 0; --j) { 35 size_t line_break = line_breaks[j - 1] >= 0 ? line_breaks[j - 1] : 0; 36 if (line_break <= start_offset) 37 return line_break; 38 } 39 return 0; 40 } 41 } 42 43 size_t result = start_offset; 44 for (;;) { 45 size_t pos; 46 if (direction == FORWARDS_DIRECTION) { 47 if (result >= text_size) 48 return text_size; 49 pos = result; 50 } else { 51 if (result == 0) 52 return 0; 53 pos = result - 1; 54 } 55 56 switch (boundary) { 57 case CHAR_BOUNDARY: 58 case LINE_BOUNDARY: 59 NOTREACHED(); // These are handled above. 60 break; 61 case WORD_BOUNDARY: 62 if (IsWhitespace(text[pos])) 63 return result; 64 break; 65 case PARAGRAPH_BOUNDARY: 66 if (text[pos] == '\n') 67 return result; 68 break; 69 case SENTENCE_BOUNDARY: 70 if ((text[pos] == '.' || text[pos] == '!' || text[pos] == '?') && 71 (pos == text_size - 1 || IsWhitespace(text[pos + 1]))) { 72 return result; 73 } 74 break; 75 case ALL_BOUNDARY: 76 default: 77 break; 78 } 79 80 if (direction == FORWARDS_DIRECTION) { 81 result++; 82 } else { 83 result--; 84 } 85 } 86 } 87 88 } // Namespace ui 89