From 2c213107bc2db24bdd2785d25fec903b614d912e Mon Sep 17 00:00:00 2001
From: WormHeamer
Date: Fri, 30 Jan 2026 02:59:06 -0500
Subject: more utf8 stuff

---
 main.c | 46 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/main.c b/main.c
index 363db16..ca1132e 100644
--- a/main.c
+++ b/main.c
@@ -50,17 +50,35 @@ txt_delete_byte(DynStr *s, int i, int n)
 	return i - n;
 }
 
+static inline int
+utf8contp(unsigned char c)
+{
+	return (c & 0xc0) == 0x80;
+}
+
 int
 txt_delete(DynStr *s, int i, int n)
 {
 	while (n--) {
-		i = txt_delete_byte(s, i, 1);
-		while (i > 0 && (s->v[i-1] & 0x80))
+		while (i > 0 && utf8contp(s->v[i-1]))
 			i = txt_delete_byte(s, i, 1);
+		i = txt_delete_byte(s, i, 1);
 	}
 	return i;
 }
 
+int
+read_all(FILE *f, DynStr *out, Arena *a)
+{
+	char buf[256];
+	while (!feof(f)) {
+		size_t n = fread(buf, 1, sizeof buf, f);
+		if (ferror(f)) return -1;
+		DA_APUSH_MULT(out, a, buf, n);
+	}
+	return 0;
+}
+
 int
 delete_word(DynStr *s, int i)
 {
@@ -92,15 +110,19 @@ next_word(DynStr *s, int i)
 }
 
 int
-read_all(FILE *f, DynStr *out, Arena *a)
+prev_char(DynStr *s, int i)
 {
-	char buf[256];
-	while (!feof(f)) {
-		size_t n = fread(buf, 1, sizeof buf, f);
-		if (ferror(f)) return -1;
-		DA_APUSH_MULT(out, a, buf, n);
-	}
-	return 0;
+	while (i > 0 && utf8contp(s->v[i-1])) i--;
+	if (i > 0) i--;
+	return i;
+}
+
+int
+next_char(DynStr *s, int i)
+{
+	if (i < s->n) i++;
+	while (i < s->n && utf8contp(s->v[i])) i++;
+	return i;
 }
 
 int
@@ -166,13 +188,13 @@ main(int argc, char **argv)
 				if (ev.key.mod & UIM_CTRL)
 					inpi = prev_word(&input, inpi);
 				else if (inpi > 0)
-					inpi--;
+					inpi = prev_char(&input, inpi);
 				goto draw;
 			case UIK_RIGHT:
 				if (ev.key.mod & UIM_CTRL)
 					inpi = next_word(&input, inpi);
 				else if (inpi < input.n)
-					inpi++;
+					inpi = next_char(&input, inpi);
 				goto draw;
 			case UIK_HOME:
 				if (ev.key.mod & UIM_CTRL)
-- 
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