Implement casefolding

1 files changed, 24 insertions, 0 deletions

diff --git a/lib/unicode/string/u8casefold.c b/lib/unicode/string/u8casefold.c
new file mode 100644
index 0000000..6c0b61d
--- /dev/null
+++ b/lib/unicode/string/u8casefold.c
@@ -0,0 +1,24 @@
+#include "mbstring.h"
+#include "unicode/prop.h"
+#include "unicode/string.h"
+
+size_t
+u8casefold(char8_t *restrict dst, size_t dstn, const char8_t *src, size_t srcn,
+           enum caseflags flags)
+{
+	rune ch;
+	size_t n = 0;
+
+	while (u8next(&ch, &src, &srcn)) {
+		struct rview rv = uprop_get_cf(ch, flags & CF_LANG_AZ);
+		for (size_t i = 0; i < rv.len; i++) {
+			if (n >= dstn) {
+				char8_t buf[U8_LEN_MAX];
+				n += rtou8(buf, sizeof(buf), rv.p[i]);
+			} else
+				n += rtou8(dst + n, dstn - n, rv.p[i]);
+		}
+	}
+
+	return n;
+}