From 8e376f59f9f7b4c54527550fc0a7afa171467c63 Mon Sep 17 00:00:00 2001
From: Mitya Selivanov <automainint@guattari.tech>
Date: Sun, 11 Aug 2024 13:44:08 +0200
Subject: UTF-8

---
 examples/ui.c | 94 ++++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 64 insertions(+), 30 deletions(-)

(limited to 'examples')

diff --git a/examples/ui.c b/examples/ui.c
index d853c4b..cd355c5 100755
--- a/examples/ui.c
+++ b/examples/ui.c
@@ -159,6 +159,10 @@ typedef struct {
 
 typedef i64 (*Thread_Proc)(void *user_data);
 
+//  UTF-8
+c32 read_utf8(i64 len, c8 *s);
+i32 write_utf8(c32 c, c8 *buffer);
+
 //  Window
 void p_init(void);
 void p_cleanup(void);
@@ -257,7 +261,7 @@ b8 char_column_empty(c32 c, i64 column_index) {
 i64 char_width(c32 c) {
   if (c < 32)
     return 0;
-  if (c == ' ')
+  if (c == ' ' || c > 127)
     return 4;
 
   i64 width = 0;
@@ -702,6 +706,64 @@ i32 main(i32 argc, c8 **argv) {
 #include <assert.h>
 #include <string.h>
 
+c32 read_utf8(i64 len, c8 *s) {
+  if (len <= 1 &&
+      (s[0] & 0x80) == 0)
+    return s[0];
+  if (len <= 2 &&
+      (s[0] & 0xe0) == 0xc0 &&
+      (s[1] & 0xc0) == 0x80)
+    return (s[1] & 0x3f)
+        | ((s[0] & 0x1f) << 6);
+  if (len <= 3 &&
+      (s[0] & 0xf0) == 0xe0 &&
+      (s[1] & 0xc0) == 0x80 &&
+      (s[2] & 0xc0) == 0x80)
+    return (s[2] & 0x3f)
+        | ((s[1] & 0x3f) <<  6)
+        | ((s[0] & 0x0f) << 12);
+  if (len <= 4 &&
+      (s[0] & 0xf8) == 0xf0 &&
+      (s[1] & 0xc0) == 0x80 &&
+      (s[2] & 0xc0) == 0x80 &&
+      (s[3] & 0xc0) == 0x80)
+    return (s[3] & 0x3f)
+        | ((s[2] & 0x3f) <<  6)
+        | ((s[1] & 0x3f) << 12)
+        | ((s[0] & 0x07) << 18);
+  return 0;
+}
+
+i32 write_utf8(c32 c, c8 *buffer) {
+  if ((c & 0x7f) == c) {
+    buffer[0] = (c8) c;
+    return 1;
+  }
+
+  if ((c & 0x7ff) == c) {
+    buffer[0] = 0xc0 | ((c >> 6) & 0x1f);
+    buffer[1] = 0x80 | ( c       & 0x3f);
+    return 2;
+  }
+
+  if ((c & 0xffff) == c) {
+    buffer[0] = 0xc0 | ((c >> 12) & 0x0f);
+    buffer[1] = 0x80 | ((c >>  6) & 0x3f);
+    buffer[2] = 0x80 | ( c        & 0x3f);
+    return 3;
+  }
+
+  if ((c & 0x1fffff) == c) {
+    buffer[0] = 0xc0 | ((c >> 18) & 0x07);
+    buffer[1] = 0x80 | ((c >> 12) & 0x3f);
+    buffer[2] = 0x80 | ((c >>  6) & 0x3f);
+    buffer[3] = 0x80 | ( c        & 0x3f);
+    return 4;
+  }
+
+  return 0;
+}
+
 //  ================================================================
 //
 //  UDP sockets
@@ -917,34 +979,6 @@ void p_cleanup(void) {
   XCloseDisplay (_display);
 }
 
-c32 c32_from_utf8(i64 len, c8 *s) {
-  if (len <= 1 &&
-      (s[0] & 0x80) == 0)
-    return s[0];
-  if (len <= 2 &&
-      (s[0] & 0xe0) == 0xc0 &&
-      (s[1] & 0xc0) == 0x80)
-    return (s[1] & 0x3f)
-        | ((s[0] & 0x1f) << 6);
-  if (len <= 3 &&
-      (s[0] & 0xf0) == 0xe0 &&
-      (s[1] & 0xc0) == 0x80 &&
-      (s[2] & 0xc0) == 0x80)
-    return (s[2] & 0x3f)
-        | ((s[1] & 0x3f) <<  6)
-        | ((s[0] & 0x0f) << 12);
-  if (len <= 4 &&
-      (s[0] & 0xf8) == 0xf0 &&
-      (s[1] & 0xc0) == 0x80 &&
-      (s[2] & 0xc0) == 0x80 &&
-      (s[3] & 0xc0) == 0x80)
-    return (s[3] & 0x3f)
-        | ((s[2] & 0x3f) <<  6)
-        | ((s[1] & 0x3f) << 12)
-        | ((s[0] & 0x07) << 18);
-  return 0;
-}
-
 i32 p_handle_events(void) {
   i32 num_events = 0;
 
@@ -1027,7 +1061,7 @@ i32 p_handle_events(void) {
             c8  buf[16];
             i32 len = Xutf8LookupString(_ic, &ev.xkey, buf, sizeof buf - 1, NULL, NULL);
             if (len > 0)
-              platform.input[platform.input_size++] = (Input_Key) { .key = k, .c = c32_from_utf8(len, buf), };
+              platform.input[platform.input_size++] = (Input_Key) { .key = k, .c = read_utf8(len, buf), };
           }
         }
       } break;
-- 
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