update

1 files changed, 49 insertions, 0 deletions

diff --git a/src/util.c b/src/util.c
new file mode 100644
index 0000000..10485db
--- /dev/null
+++ b/src/util.c
@@ -0,0 +1,49 @@
+#include "util.h"
+
+#define UTF8_MULTIBYTE_BIT BIT(7)
+
+unsigned int gcd(unsigned int a, unsigned int b) {
+    while (b > 0) {
+        const unsigned int temp = a % b;
+        a = b;
+        b = temp;
+    }
+
+    return a;
+}
+
+size_t truncate_utf8_string(char* const buffer, const size_t size,
+                            const size_t char_limit) {
+    size_t char_count = 0;
+    size_t i = 0;
+    while (char_count < char_limit) {
+        char ch = buffer[i];
+        if (ch == '\0') {
+            break;
+        }
+
+        unsigned short skip = 1;
+
+        // Multibyte unicode character.
+        if ((ch & UTF8_MULTIBYTE_BIT) != 0) {
+            // Skip continuation bytes.
+            ch <<= 1;
+            while ((ch & UTF8_MULTIBYTE_BIT) != 0) {
+                ch <<= 1;
+                ++skip;
+            }
+        }
+
+        // Avoid buffer overflow.
+        if (i + skip >= size) {
+            break;
+        }
+
+        ++char_count;
+        i += skip;
+    }
+
+    buffer[i] = '\0';
+
+    return i + 1;
+}