Changed way word-wrapping works to allow for Chinese characters

Author: nickgammon

Line.cpp

@@ -34,7 +34,6 @@ CLine::CLine (const long nLineNumber,
   {
   hard_return = false;
   len = 0;
-  last_space = -1;
   m_iPreambleOffset = 0;
   m_theTime = CTime::GetCurrentTime(); 
   QueryPerformanceCounter (&m_lineHighPerformanceTime);

OtherTypes.h

@@ -322,7 +322,6 @@ class CLine : public CObject
   bool hard_return;
   unsigned char flags;
   int len;
-  int last_space;
   char * text;          // allocated as necessary and then resized
   CStyleList styleList; // list of styles applying to text, see above
   CTime m_theTime;      // time this line arrived

Utilities.cpp

@@ -3441,3 +3441,17 @@ const char * p = sName;
 
   return true;
   }  // end of IsSubName
+
+// find the last occurrence of c in the string s, maximum length count
+const char *strnrchr(const char *s, const char c, size_t count)
+{
+  const char * ret = NULL;
+  size_t n = 0;
+  while (*s && n < count++)
+    {
+    if( *s == c )
+        ret = s;  // remember where character is, keep searching
+    s++;
+    }
+  return ret;
+} // end of strnrchr

dialogs/TextAttributesDlg.cpp

@@ -113,9 +113,15 @@ void CTextAttributesDlg::OnLineInfo()
         YES_OR_NO (m_pLine->flags & BOOKMARK)
         ));
 
+  // work out where the last space is
+  const char * space = strnrchr(m_pLine->text, ' ', m_pLine->len);
+  int last_space = -1;
+  if (space)
+    last_space = space - m_pLine->text;
+
   INFO (TFormat (" Length = %i, last space = %i", 
                   m_pLine->len,
-                  m_pLine->last_space));
+                  last_space));
 
   CString strText = CString (m_pLine->text, m_pLine->len);
 

doc.cpp

@@ -1627,57 +1627,56 @@ Unicode range              UTF-8 bytes
         (m_pCurrentLine->len >= m_pCurrentLine->iMemoryAllocated))  // emergency bail-out
       {
 
+      int last_space = -1;
+
       // do auto line wrapping here
 
-      // first see if we can split at a multibyte character if no space was found
+      // see if we can split at a multibyte character
 
-      if (m_pCurrentLine->last_space < 0 &&   // no space found
-          (m_pCurrentLine->len - m_pCurrentLine->last_space) >= m_nWrapColumn &&
+      if (m_pCurrentLine->len >= m_nWrapColumn &&
           m_pCurrentLine->len >= 10 &&
           !m_bUTF_8)    // not for UTF-8
         {
-        int multibyte_start = -1;
         for (int i = 0; i < m_pCurrentLine->len - 1; i++)
           {
           unsigned char c1 = m_pCurrentLine->text [i];
           unsigned char c2 = m_pCurrentLine->text [i + 1];
           if (c1 >= 0x81 && c1 <= 0xFE &&  // first Big5 character
-              ((c2 >= 0x40 && c2 <= 0x7E) || (c2 >= 0xA1 && c2 <= 0xFE))) // second Big5 character
-            multibyte_start = i++;  // remember position, jump the second byte
-          else if (c1 >= 0xA1 && c1 <= 0xF7 && c2 >= 0xA1 && c2 <= 0xFE)  // GB2132
-            multibyte_start = i++;  // remember position, jump the second byte
-          else if (c1 <= 0x7F)
-            multibyte_start = i;    // we can split after any ordinary character
+            ((c2 >= 0x40 && c2 <= 0x7E) || (c2 >= 0xA1 && c2 <= 0xFE))) // second Big5 character
+            last_space = i++;  // remember position, skip the second byte
+          else if (c1 >= 0xA1 && c1 <= 0xF7 &&
+                   c2 >= 0xA1 && c2 <= 0xFE)  // GB2132
+            last_space = i++;  // remember position, skip the second byte
+          else if (c1 == ' ' && m_wrap)
+            last_space = i;    // or split at a space
           }
 
-        m_pCurrentLine->last_space = multibyte_start;
         } // end of checking for a Big5 or GB2132 break point
 
       if (!m_wrap || 
-        m_pCurrentLine->last_space < 0 ||
-        (m_pCurrentLine->len - m_pCurrentLine->last_space) >= m_nWrapColumn)
+          last_space < 0 ||
+        (m_pCurrentLine->len - last_space) >= m_nWrapColumn)
           StartNewLine_KeepPreviousStyle (flags);
       else
         {
-        saved_count = m_pCurrentLine->len - 
-                      m_pCurrentLine->last_space; 
+        saved_count = m_pCurrentLine->len - last_space;
 
         // note - saved_count should not be zero because length is 1-relative
         // (eg. 1) and last_space is zero-relative (eg. 0)
         if (!m_indent_paras)
           {
           saved_count--;    // one less to copy
-          m_pCurrentLine->last_space++;  // one more on this line (the space)
-          m_pCurrentLine->len = m_pCurrentLine->last_space; // this line is longer
+          last_space++;  // one more on this line (the space)
+          m_pCurrentLine->len = last_space; // this line is longer
           }   // end of indenting not wanted
 
         // saved_count might be zero now, because of no indenting
         if (saved_count > 0)
           {
           // save portion of text destined for new line
-          CString strText = CString (&m_pCurrentLine->text [m_pCurrentLine->last_space],
+          CString strText = CString (&m_pCurrentLine->text [last_space],
                                      saved_count); 
-          m_pCurrentLine->len = m_pCurrentLine->last_space;
+          m_pCurrentLine->len = last_space;
 
           CLine * pPreviousLine = m_pCurrentLine; // remember this line
 
@@ -1744,9 +1743,6 @@ Unicode range              UTF-8 bytes
 
         } // end of line wrapping wanted and possible
       }   // end of line being full
-    else
-      if (c == ' ')
-        m_pCurrentLine->last_space = m_pCurrentLine->len;
 
     ASSERT (m_pCurrentLine->text);
 
@@ -2189,9 +2185,15 @@ CString strLine (lpszText, size);
                 }  // end of \n\n
               else
                 {
+                // work out where the last space is
+                const char * space = strnrchr(m_pCurrentLine->text, ' ', m_pCurrentLine->len);
+                int last_space = -1;
+                if (space)
+                  last_space = space - m_pCurrentLine->text;
+
                 // don't run words together - if a newline follows a word,
                 // insert a space
-                if (m_pCurrentLine->last_space != (m_pCurrentLine->len - 1))
+                if (last_space != (m_pCurrentLine->len - 1))
                   {
                   if (m_cLastChar == '.' && m_pCurrentLine->len < m_nWrapColumn)
                     AddToLine ("  ", flags);  // two spaces after period
@@ -2237,7 +2239,6 @@ CString strLine (lpszText, size);
 
               m_pCurrentLine->hard_return = false;
               m_pCurrentLine->len = 0;
-              m_pCurrentLine->last_space = -1;
 
               }   // end of letting a \r delete line contents
 
@@ -2254,8 +2255,14 @@ CString strLine (lpszText, size);
       case ' ':     // space
             if (m_bInParagraph && !(flags & NOTE_OR_COMMAND))  // for <P>
               {
+              // work out where the last space is
+              const char * space = strnrchr(m_pCurrentLine->text, ' ', m_pCurrentLine->len);
+              int last_space = -1;
+              if (space)
+                last_space = space - m_pCurrentLine->text;
+
               // multiple consecutive spaces - discard extras
-              if (m_pCurrentLine->last_space == (m_pCurrentLine->len - 1))
+              if (last_space == (m_pCurrentLine->len - 1))
                 {
                 if (m_cLastChar != '\n')
                     m_cLastChar = c;  // remember it

stdafx.h

@@ -869,6 +869,7 @@ convenient for user programs that want to test its value. */
 #define DEBUG_PLUGIN_ID "138a692642ab4f9e7a1af63b"  // special plugin ID for Debug "summary"
 bool IsPluginID (const char * sID);
 bool IsSubName (const char * sName);
+const char *strnrchr(const char *s, const char c, size_t count);
 
 typedef struct
   {