Backport from xs.

1 files changed, 46 insertions, 0 deletions

diff --git a/xs_unicode.h b/xs_unicode.h
new file mode 100644
index 0000000..6f78d58
--- /dev/null
+++ b/xs_unicode.h
@@ -0,0 +1,46 @@
+/* copyright (c) 2022 - 2023 grunfink / MIT license */
+
+#ifndef _XS_UNICODE_H
+
+#define _XS_UNICODE_H
+
+ xs_str *xs_utf8_enc(xs_str *str, unsigned int cpoint);
+
+
+#ifdef XS_IMPLEMENTATION
+
+/** utf-8 **/
+
+xs_str *xs_utf8_enc(xs_str *str, unsigned int cpoint)
+/* encodes an Unicode codepoint to utf8 */
+{
+    unsigned char tmp[4];
+    int n = 0;
+
+    if (cpoint < 0x80)
+        tmp[n++] = cpoint & 0xff;
+    else
+    if (cpoint < 0x800) {
+        tmp[n++] = 0xc0 | (cpoint >> 6);
+        tmp[n++] = 0x80 | (cpoint & 0x3f);
+    }
+    else
+    if (cpoint < 0x10000) {
+        tmp[n++] = 0xe0 | (cpoint >> 12);
+        tmp[n++] = 0x80 | ((cpoint >> 6) & 0x3f);
+        tmp[n++] = 0x80 | (cpoint & 0x3f);
+    }
+    else
+    if (cpoint < 0x200000) {
+        tmp[n++] = 0xf0 | (cpoint >> 18);
+        tmp[n++] = 0x80 | ((cpoint >> 12) & 0x3f);
+        tmp[n++] = 0x80 | ((cpoint >> 6) & 0x3f);
+        tmp[n++] = 0x80 | (cpoint & 0x3f);
+    }
+
+    return xs_append_m(str, (char *)tmp, n);
+}
+
+#endif /* XS_IMPLEMENTATION */
+
+#endif /* _XS_UNICODE_H */