From c18f87ad13da518af5ff245dbce2a9e608097ea1 Mon Sep 17 00:00:00 2001
From: dec05eba <dec05eba@protonmail.com>
Date: Wed, 17 Nov 2021 03:15:16 +0100
Subject: Attempt to fix font glyph texture overlap by aligning texture size to
 next character size

Add function to get the start of a utf8 codepoint (backwards), test utf8
functions
---
 src/system/utf8.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

(limited to 'src/system')

diff --git a/src/system/utf8.c b/src/system/utf8.c
index 201fedf..5d5ec79 100644
--- a/src/system/utf8.c
+++ b/src/system/utf8.c
@@ -73,3 +73,20 @@ bool mgl_utf8_decode(const unsigned char *str, size_t size, uint32_t *decoded_co
     *decoded_codepoint = codepoint;
     return true;
 }
+
+/* TODO: Optimize (remove branching, etc) */
+size_t mgl_utf8_get_start_of_codepoint(const unsigned char *str, size_t size, size_t offset) {
+    if(size == 0)
+        return 0;
+
+    if(offset > size - 1)
+        offset = size - 1;
+
+    /* i <= offset is an overflow (underflow?) check */
+    for(size_t i = offset; i <= offset; --i) {
+        if((str[i] & 0xC0) != 0x80)
+            return i;
+    }
+
+    return 0;
+}
-- 
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