New methods for finding the next or previous position taking multi byte

characters into account.

5 files changed, 41 insertions, 24 deletions

diff --git a/doc/ScintillaDoc.html b/doc/ScintillaDoc.html
index a7970d614..66944ec97 100644
--- a/doc/ScintillaDoc.html
+++ b/doc/ScintillaDoc.html
@@ -885,6 +885,8 @@ struct TextToFind {
     onlyWordCharacters)</a><br />
      <a class="message" href="#SCI_WORDSTARTPOSITION">SCI_WORDSTARTPOSITION(int position, bool
     onlyWordCharacters)</a><br />
+     <a class="message" href="#SCI_POSITIONBEFORE">SCI_POSITIONBEFORE(int position)</a><br />
+     <a class="message" href="#SCI_POSITIONAFTER">SCI_POSITIONAFTER(int position)</a><br />
      <a class="message" href="#SCI_TEXTWIDTH">SCI_TEXTWIDTH(int styleNumber, char *text)</a><br />
      <a class="message" href="#SCI_TEXTHEIGHT">SCI_TEXTHEIGHT(int line)</a><br />
      <a class="message" href="#SCI_CHOOSECARETX">SCI_CHOOSECARETX</a><br />
@@ -1149,6 +1151,14 @@ struct TextToFind {
       </tbody>
     </table>
 
+    <p><b id="SCI_POSITIONBEFORE">SCI_POSITIONBEFORE(int position)</b><br />
+     <b id="SCI_POSITIONAFTER">SCI_POSITIONAFTER(int position)</b><br />
+     These messages return the position before and after another position
+     in the document taking into account the current code page. The minimum
+     position returned is 0 and the maximum is the last position in the document.
+     If called with a position within a multi byte character will return the position
+     of the start/end of that character.</p>
+
     <p><b id="SCI_TEXTWIDTH">SCI_TEXTWIDTH(int styleNumber, char *text)</b><br />
      This returns the pixel width of a string drawn in the given <code>styleNumber</code> which can
     be used, for example, to decide how wide to make the line number margin in order to display a
diff --git a/include/Scintilla.h b/include/Scintilla.h
index c377d07cc..470425e76 100644
--- a/include/Scintilla.h
+++ b/include/Scintilla.h
@@ -535,6 +535,8 @@ typedef sptr_t (*SciFnDirect)(sptr_t ptr, unsigned int iMessage, uptr_t wParam,
 #define SCI_PARADOWNEXTEND 2414
 #define SCI_PARAUP 2415
 #define SCI_PARAUPEXTEND 2416
+#define SCI_POSITIONBEFORE 2417
+#define SCI_POSITIONAFTER 2418
 #define SCI_STARTRECORD 3001
 #define SCI_STOPRECORD 3002
 #define SCI_SETLEXER 4001
diff --git a/include/Scintilla.iface b/include/Scintilla.iface
index 8ad828cd0..3b71a37a3 100644
--- a/include/Scintilla.iface
+++ b/include/Scintilla.iface
@@ -1441,6 +1441,14 @@ fun void ParaDownExtend=2414(,)
 fun void ParaUp=2415(,)
 fun void ParaUpExtend=2416(,)
 
+# Given a valid document position, return the previous position taking code
+# page into account. Returns 0 if passed 0.
+fun position PositionBefore=2417(position pos,)
+
+# Given a valid document position, return the next position taking code
+# page into account. Maximum value returned is the last position in the document.
+fun position PositionAfter=2418(position pos,)
+
 # Start notifying the container of all key presses and commands.
 fun void StartRecord=3001(,)
 
diff --git a/src/Document.cxx b/src/Document.cxx
index 255c9ee11..98fc6b330 100644
--- a/src/Document.cxx
+++ b/src/Document.cxx
@@ -265,7 +265,7 @@ int Document::LenChar(int pos) {
 		return 1;
 	}
 }
-
+#include <assert.h>
 // Normalise a position so that it is not halfway through a two byte character.
 // This can occur in two situations -
 // When lines are terminated with \r\n pairs which should be treated as one character.
@@ -273,17 +273,11 @@ int Document::LenChar(int pos) {
 // If moving, move the position in the indicated direction.
 int Document::MovePositionOutsideChar(int pos, int moveDir, bool checkLineEnd) {
 	//Platform::DebugPrintf("NoCRLF %d %d\n", pos, moveDir);
-	// If out of range, just return value - should be fixed up after
-	if (pos < 0)
-		return pos;
-	if (pos > Length())
-		return pos;
-
-	// Position 0 and Length() can not be between any two characters
-	if (pos == 0)
-		return pos;
-	if (pos == Length())
-		return pos;
+	// If out of range, just return minimum/maximum value.
+	if (pos <= 0)
+		return 0;
+	if (pos >= Length())
+		return Length();
 
 	// assert pos > 0 && pos < Length()
 	if (checkLineEnd && IsCrLf(pos - 1)) {
@@ -309,29 +303,26 @@ int Document::MovePositionOutsideChar(int pos, int moveDir, bool checkLineEnd) {
 		} else {
 			// Anchor DBCS calculations at start of line because start of line can
 			// not be a DBCS trail byte.
-			int startLine = pos;
-
-			while (startLine > 0 && cb.CharAt(startLine) != '\r' && cb.CharAt(startLine) != '\n')
-				startLine--;
-			while (startLine < pos) {
+			int posCheck = LineStart(LineFromPosition(pos));
+			while (posCheck < pos) {
 				char mbstr[maxBytesInDBCSCharacter+1];
 				int i;
 				for(i=0;i<Platform::DBCSCharMaxLength();i++) {
-					mbstr[i] = cb.CharAt(startLine+i);
+					mbstr[i] = cb.CharAt(posCheck+i);
 				}
 				mbstr[i] = '\0';
 
 				int mbsize = Platform::DBCSCharLength(dbcsCodePage, mbstr);
-				if (startLine + mbsize == pos) {
+				if (posCheck + mbsize == pos) {
 					return pos;
-				} else if (startLine + mbsize > pos) {
+				} else if (posCheck + mbsize > pos) {
 					if (moveDir > 0) {
-						return startLine + mbsize;
+						return posCheck + mbsize;
 					} else {
-						return startLine;
+						return posCheck;
 					}
 				}
-				startLine += mbsize;
+				posCheck += mbsize;
 			}
 		}
 	}
@@ -938,7 +929,7 @@ long Document::FindText(int minPos, int maxPos, const char *s,
 					endOfLine = startPos;
 				}
 			}
-			
+
 			DocumentIndexer di(this, endOfLine);
 			int success = pre->Execute(di, startOfLine, endOfLine);
 			if (success) {
diff --git a/src/Editor.cxx b/src/Editor.cxx
index 44399a5fb..2eba8a471 100644
--- a/src/Editor.cxx
+++ b/src/Editor.cxx
@@ -5199,6 +5199,12 @@ sptr_t Editor::WndProc(unsigned int iMessage, uptr_t wParam, sptr_t lParam) {
 	case SCI_GETSEARCHFLAGS:
 		return searchFlags;
 
+	case SCI_POSITIONBEFORE:
+		return pdoc->MovePositionOutsideChar(wParam-1, -1, true);
+
+	case SCI_POSITIONAFTER:
+		return pdoc->MovePositionOutsideChar(wParam+1, 1, true);
+
 	case SCI_LINESCROLL:
 		ScrollTo(topLine + lParam);
 		HorizontalScrollTo(xOffset + wParam * vs.spaceWidth);