vi: fix warnings, improve status display.

mbtowc(0, 0, 4) is weird, and ignoring the result is weird. Avoid all
this by just reusing the toybox lib utf8 functions.

Also fix the row/column display on the status line to count from 1 and
correctly distinguish bytes and characters in non-ASCII, and change the
mode output to only explicitly say when we're in insert mode, in the
same way that vim does. (Every time I saw the old blue-on-black text for
COMMAND I thought toybox vi had crashed!)

1 files changed, 22 insertions, 71 deletions

diff --git a/toys/pending/vi.c b/toys/pending/vi.c
index 1cf8bc7b..9906ca93 100644
--- a/toys/pending/vi.c
+++ b/toys/pending/vi.c
@@ -64,7 +64,6 @@ static void draw_page();
 //utf8 support
 static int utf8_lnw(int* width, char* str, int bytes);
 static int utf8_dec(char key, char *utf8_scratch, int *sta_p);
-static int utf8_len(char *str);
 static int utf8_width(char *str, int bytes);
 static char* utf8_last(char* str, int size);
 
@@ -1114,6 +1113,7 @@ static void draw_page()
   struct linelist *scr_buf = 0;
   unsigned y = 0;
   int x = 0;
+  wchar_t wc;
 
   char *line = 0, *end = 0;
   int utf_l = 0,  bytes = 0;
@@ -1246,33 +1246,21 @@ static void draw_page()
 
   tty_jump(0, TT.screen_height);
   tty_esc("2K");
-  switch (TT.vi_mode) {
-    case 0:
-    tty_esc("30;44m");
-    printf("COMMAND|");
-    break;
-    case 1:
-    tty_esc("30;42m");
-    printf("NORMAL|");
-    break;
-    case 2:
-    tty_esc("30;41m");
-    printf("INSERT|");
-    break;
+  if (TT.vi_mode == 2) printf("\x1b[1m-- INSERT --\x1b[m");
 
-  }
   //DEBUG
-  tty_esc("m");
-  utf_l = utf8_len(&c_r->line->data[TT.cur_col]);
-  if (utf_l) {
+  utf_l=utf8towc(&wc, &c_r->line->data[TT.cur_col], c_r->line->len-TT.cur_col);
+  if (utf_l > 1) {
     char t[5] = {0, 0, 0, 0, 0};
     strncpy(t, &c_r->line->data[TT.cur_col], utf_l);
-    printf("utf: %d %s", utf_l, t);
+    printf(" (utf: %d %s)", utf_l, t);
   }
-  printf("| %d, %d\n", cx_scr, cy_scr); //screen coord
+  //DEBUG
 
   tty_jump(TT.screen_width-12, TT.screen_height);
-  printf("| %d, %d\n", TT.cur_row, TT.cur_col);
+  printf("%d,%d", TT.cur_row+1, TT.cur_col+1);
+  if (TT.cur_col != cx_scr) printf("-%d", cx_scr+1);
+  putchar('\n');
 
   tty_esc("m");
   tty_jump(0, TT.screen_height+1);
@@ -1325,71 +1313,34 @@ static void adjust_screen_buffer()
 
 }
 
-//return 0 if not ASCII nor UTF-8
-//this is not fully tested
-//naive implementation with branches
-//there is better branchless lookup table versions out there
-//1 0xxxxxxx
-//2 110xxxxx  10xxxxxx
-//3 1110xxxx  10xxxxxx  10xxxxxx
-//4 11110xxx  10xxxxxx  10xxxxxx  10xxxxxx
-static int utf8_len(char *str)
-{
-  int len = 0;
-  int i = 0;
-  uint8_t *c = (uint8_t*)str;
-  if (!c || !(*c)) return 0;
-  if (*c < 0x7F) return 1;
-  if ((*c & 0xE0) == 0xc0) len = 2;
-  else if ((*c & 0xF0) == 0xE0 ) len = 3;
-  else if ((*c & 0xF8) == 0xF0 ) len = 4;
-  else return 0;
-  c++;
-  for (i = len-1; i > 0; i--) {
-    if ((*c++ & 0xc0) != 0x80) return 0;
-  }
-  return len;
-}
-
 //get utf8 length and width at same time
-static int utf8_lnw(int* width, char* str, int bytes)
+static int utf8_lnw(int* width, char* s, int bytes)
 {
   wchar_t wc;
-  int length = 1;
-  *width = 1;
-  if (*str == 0x09) {
+  int length;
+
+  *width = 0;
+  if (*s == '\t') {
     *width = TT.tabstop;
     return 1;
   }
-  length = mbtowc(&wc, str, bytes);
-  switch (length) {
-  case -1:
-    mbtowc(0,0,4);
-  case 0:
-    *width = 0;
-    length = 0;
-    break;
-  default:
+  length = utf8towc(&wc, s, bytes);
+  if (length < 1) return 0;
   *width = wcwidth(wc);
-  }
   return length;
 }
 
 //try to estimate width of next "glyph" in terminal buffer
 //combining chars 0x300-0x36F shall be zero width
-static int utf8_width(char *str, int bytes)
+static int utf8_width(char *s, int bytes)
 {
   wchar_t wc;
-  if (*str == 0x09) return TT.tabstop;
-  switch (mbtowc(&wc, str, bytes)) {
-  case -1:
-    mbtowc(0,0,4);
-  case 0:
-    return -1;
-  default:
+  int length;
+
+  if (*s == '\t') return TT.tabstop;
+  length = utf8towc(&wc, s, bytes);
+  if (length < 1) return -1;
   return wcwidth(wc);
-  }
-  return 0;
 }
 
 static int utf8_dec(char key, char *utf8_scratch, int *sta_p)