From 1455834a50b8b6a15567e971db664fe7a6cdfaf6 Mon Sep 17 00:00:00 2001
From: Nicholas Noll <nbnoll@eml.cc>
Date: Fri, 29 Oct 2021 17:46:41 -0700
Subject: fix(unicode): emoji widths and readline now moves in a more unicode
 aware manner

---
 sys/cmd/rc/input.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

(limited to 'sys/cmd')

diff --git a/sys/cmd/rc/input.c b/sys/cmd/rc/input.c
index 08363f0..5d30ccd 100644
--- a/sys/cmd/rc/input.c
+++ b/sys/cmd/rc/input.c
@@ -341,14 +341,16 @@ refreshsingleline(struct TerminalState *term)
         w = utf8·runewidth(r);
 
         buf+=n, len-=n;
-        pos-=w,  col-=w;
+        pos-=w, col-=w;
     }
 
     assert(buf <= term->edit.buf + len);
 
     while(off+col > term->cursor.cap){
         n = utf8·decodeprev(buf+len-1, &r);
-        len-=n, col--;
+        w = utf8·runewidth(r);
+
+        len-=n, col-=w;
     }
     assert(len >= 0);
 
@@ -510,8 +512,8 @@ insertrune(struct TerminalState *term, int n, char *c)
             memmove(term->edit.buf+term->edit.len+n, term->edit.buf+term->edit.len, term->edit.len-term->edit.pos);
             memcpy(term->edit.buf+term->edit.pos, c, n);
 
-            term->edit.pos+=n,   term->edit.len+=n;
-            term->cursor.pos++, term->cursor.len++;
+            term->edit.pos   += n,   term->edit.len   += n;
+            term->cursor.pos += w,   term->cursor.len += w;
 
             term->edit.buf[term->edit.len] = '\0';
             refreshline(term);
@@ -664,15 +666,21 @@ static
 Position
 left(struct TerminalState *term, int n)
 {
+    int  w, d;
     rune r;
     Position pos = CURRENT(term);
     char *buf = term->edit.buf + term->edit.pos;
 
-    pos.cursor = MAX(pos.cursor-n, 0);
-
-    while(n-- > 0 && buf > term->edit.buf)
+    d = 0;
+    while(n > 0 && buf > term->edit.buf){
         buf -= utf8·decodeprev(buf-1, &r);
 
+        w  = utf8·runewidth(r);
+        n -= w;
+        d += w;
+    }
+
+    pos.cursor = MAX(pos.cursor-d, 0);
     pos.buffer = MAX(buf-term->edit.buf, 0);
     return pos;
 }
@@ -682,16 +690,22 @@ static
 Position
 right(struct TerminalState *term, int n)
 {
+    int  w, d;
     rune r;
     Position pos = CURRENT(term);
     char *end = term->edit.buf + term->edit.len;
     char *buf = term->edit.buf + term->edit.pos;
 
-    pos.cursor = MIN(pos.cursor+n, term->cursor.len);
-
-    while(n-- > 0 && buf < end)
+    d = 0;
+    while(n > 0 && buf < end){
         buf += utf8·decode(buf, &r);
 
+        w  = utf8·runewidth(r);
+        n -= w;
+        d += w;
+    }
+
+    pos.cursor = MIN(pos.cursor+d, term->cursor.len);
     pos.buffer = MIN(buf-term->edit.buf, term->edit.len);
     return pos;
 }
-- 
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