// moves an endpoint backward a certain number of units. // the endpoint is just an index into the text so it could represent either // the endpoint. private int MoveEndpointBackward(int index, TextUnit unit, int count, out int moved) { switch (unit) { case TextUnit.Character: { int limit = _provider.GetTextLength(); ValidateEndpoints(); int oneBasedIndex = index + 1; moved = Math.Max(count, -oneBasedIndex); index = index + moved; index = index < 0 ? 0 : index; } break; case TextUnit.Word: { string text = _provider.GetText(); ValidateEndpoints(); #if WCP_NLS_ENABLED // use the same word breaker as Avalon Text. WordBreaker breaker = new WordBreaker(); TextContainer container = new TextContainer(text); TextNavigator navigator = new TextNavigator(index, container); // move backward one word break for each count for (moved = 0; moved > count && index > 0; moved--) { if (!breaker.MoveToPreviousWordBreak(navigator)) { break; } } index = navigator.Position; #else for (moved = 0; moved > count && index > 0; moved--) { for (index--; !AtWordBoundary(text, index); index--) { ; } } #endif } break; case TextUnit.Line: { // Note count < 0. // Get 1-based line. int line = _provider.LineFromChar(index) + 1; int lineMax = _provider.GetLineCount(); // Truncate the count to the number of available lines. int actualCount = Math.Max(count, -line); moved = actualCount; if (actualCount == -line) { // We are moving by the maximum number of possible lines, // so we know the resulting index will be 0. index = 0; // If a line other than the first consists of only "\r\n", // you can move backwards past this line and the position changes, // hence this is counted. The first line is special, though: // if it is empty, and you move say from the second line back up // to the first, you cannot move further; however if the first line // is nonempty, you can move from the end of the first line to its // beginning! This latter move is counted, but if the first line // is empty, it is not counted. // Recalculate the value of "moved". // The first line is empty if it consists only of // a line separator sequence. bool firstLineEmpty = ((lineMax > 1 && _provider.LineIndex(1) == _lineSeparator.Length) || lineMax == 0); if (moved < 0 && firstLineEmpty) { ++moved; } } else // actualCount > -line { // Move the endpoint to the beginning of the following line, // then back by the line separator length to get to the end // of the previous line, since the Edit control has // no method to get the character index of the end // of a line directly. index = _provider.LineIndex(line + actualCount) - _lineSeparator.Length; } } break; case TextUnit.Paragraph: { // just like moving words but we look for paragraph boundaries instead of // word boundaries. string text = _provider.GetText(); ValidateEndpoints(); for (moved = 0; moved > count && index > 0; moved--) { for (index--; !AtParagraphBoundary(text, index); index--) { ; } } } break; case TextUnit.Format: case TextUnit.Page: case TextUnit.Document: { // since edit controls are plain text moving one uniform format unit will // take us all the way to the beginning of the document, just like // "pages" and document. // we'll move 1 format unit if we aren't already at the beginning of the // document. Otherwise, we won't move at all. moved = index > 0 ? -1 : 0; index = 0; } break; default: throw new System.ComponentModel.InvalidEnumArgumentException("unit", (int)unit, typeof(TextUnit)); } return(index); }
void ITextRangeProvider.ExpandToEnclosingUnit(TextUnit unit) { Misc.SetFocus(_provider._hwnd); switch (unit) { case TextUnit.Character: // if it is a degenerate range then expand it to be one character. // otherwise, leave it as it is. if (Start == End) { int moved; End = MoveEndpointForward(End, TextUnit.Character, 1, out moved); } break; case TextUnit.Word: { // this works same as paragraph except we look for word boundaries instead of paragraph boundaries. // get the text so we can figure out where the boundaries are string text = _provider.GetText(); ValidateEndpoints(); #if WCP_NLS_ENABLED // use the same word breaker that Avalon Text uses. WordBreaker breaker = new WordBreaker(); TextContainer container = new TextContainer(text); // if the starting point of the range is not already at a word break // then move it backwards to the nearest word break. TextNavigator startNavigator = new TextNavigator(Start, container); if (!breaker.IsAtWordBreak(startNavigator)) { breaker.MoveToPreviousWordBreak(startNavigator); Start = startNavigator.Position; } // if the range is degenerate or the ending point of the range is not already at a word break // then move it forwards to the nearest word break. TextNavigator endNavigator = new TextNavigator(End, container); if (Start == End || !breaker.IsAtWordBreak(endNavigator)) { breaker.MoveToNextWordBreak(endNavigator); End = endNavigator.Position; } #else // move start left until we reach a word boundary. for (; !AtWordBoundary(text, Start); Start--) { ; } // move end right until we reach word boundary (different from Start). End = Math.Min(Math.Max(End, Start + 1), text.Length); for (; !AtWordBoundary(text, End); End++) { ; } #endif } break; case TextUnit.Line: { if (_provider.GetLineCount() != 1) { int startLine = _provider.LineFromChar(Start); int endLine = _provider.LineFromChar(End); MoveTo(_provider.LineIndex(startLine), _provider.LineIndex(endLine + 1)); } else { MoveTo(0, _provider.GetTextLength()); } } break; case TextUnit.Paragraph: { // this works same as paragraph except we look for word boundaries instead of paragraph boundaries. // get the text so we can figure out where the boundaries are string text = _provider.GetText(); ValidateEndpoints(); // move start left until we reach a paragraph boundary. for (; !AtParagraphBoundary(text, Start); Start--) { ; } // move end right until we reach a paragraph boundary (different from Start). End = Math.Min(Math.Max(End, Start + 1), text.Length); for (; !AtParagraphBoundary(text, End); End++) { ; } } break; case TextUnit.Format: case TextUnit.Page: case TextUnit.Document: MoveTo(0, _provider.GetTextLength()); break; //break; default: throw new System.ComponentModel.InvalidEnumArgumentException("unit", (int)unit, typeof(TextUnit)); } }