[dev] [dmenu] patch: utf-8 strings editing

[Ramil Farkhshatov]

Hello.

I made a patch against dmenu-4.1 that fixes editing (cursor movement,
character deletion) of utf-8 strings containing multibyte characters.

-- 
Ramil Farkhshatov


--- a/dmenu.c
+++ b/dmenu.c
@@ -19,6 +19,7 @@
 #define INRECT(X,Y,RX,RY,RW,RH) ((X) >= (RX) && (X) < (RX) + (RW) && (Y) >= 
(RY) && (Y) < (RY) + (RH))
 #define MIN(a, b)               ((a) < (b) ? (a) : (b))
 #define MAX(a, b)               ((a) > (b) ? (a) : (b))
+#define IS_UTF8_1ST_CHAR(c)     ((((c) & 0xc0) == 0xc0) || !((c) & 0x80))
 
 /* enums */
 enum { ColFG, ColBG, ColLast };
@@ -360,7 +361,7 @@ initfont(const char *fontstr) {
 void
 kpress(XKeyEvent * e) {
        char buf[sizeof text];
-       int i, num;
+       int i, num, off;
        unsigned int len;
        KeySym ksym;
 
@@ -475,13 +476,19 @@ kpress(XKeyEvent * e) {
                break;
        case XK_BackSpace:
                if(cursor > 0) {
-                       memmove(text + cursor - 1, text + cursor, sizeof text - 
cursor + 1);
-                       cursor--;
+                       off = 1;
+                       while(cursor > off && !IS_UTF8_1ST_CHAR(text[cursor - 
off]))
+                               off++;
+                       memmove(text + cursor - off, text + cursor, sizeof text 
- cursor + off);
+                       cursor -= off;
                        match(text);
                }
                break;
        case XK_Delete:
-               memmove(text + cursor, text + cursor + 1, sizeof text - cursor);
+               off = 1;
+               while(cursor + off < sizeof text - 1 && 
!IS_UTF8_1ST_CHAR(text[cursor + off]))
+                       off++;
+               memmove(text + cursor, text + cursor + off, sizeof text - 
cursor);
                match(text);
                break;
        case XK_End:
@@ -517,9 +524,11 @@ kpress(XKeyEvent * e) {
                                calcoffsets();
                        }
                }
-               else if(cursor > 0)
-                       cursor--;
-               else
+               else if(cursor > 0) {
+                       do {
+                               cursor--;
+                       } while(cursor > 0 && !IS_UTF8_1ST_CHAR(text[cursor]));
+               } else
                        return;
                break;
        case XK_Next:
@@ -544,9 +553,11 @@ kpress(XKeyEvent * e) {
                break;
        case XK_Right:
        case XK_Down:
-               if(cursor < len)
-                       cursor++;
-               else if(sel && sel->right) {
+               if(cursor < len) {
+                       do {
+                               cursor++;
+                       } while(cursor < len && 
!IS_UTF8_1ST_CHAR(text[cursor]));
+               } else if(sel && sel->right) {
                        sel=sel->right;
                        if(sel == next) {
                                curr = next;