1 files changed, 47 insertions, 0 deletions
diff --git a/zap/source/any/str/utf8dec.c b/zap/source/any/str/utf8dec.c
new file mode 100644
index 0000000..add8697
--- /dev/null
+++ b/zap/source/any/str/utf8dec.c
@@ -0,0 +1,47 @@
+/*
+	Copyright 2022-2023 Gabriel Jensen.
+	This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
+	If a copy of the MPL was not distributed with this file, You can obtain one at <https://mozilla.org/MPL/2.0>.
+*/
+
+#include <zap/str.h>
+
+void zap_utf8dec(zap_i02 * dest,zap_i8 const * src) {
+	for (;;++dest) {
+		zap_i8 const oct = *src;
+		if (oct == 0x0u) break;
+		if (oct >= 0xF0u) { /* Four octets. */
+			zap_i02 chr =  ((zap_i02)oct ^ 0xF0u) << 0x12u;
+			++src;
+			chr           += ((zap_i02)*src ^ 0x80u) << 0xCu;
+			++src;
+			chr           += ((zap_i02)*src ^ 0x80u) << 0x6u;
+			++src;
+			chr           +=  (zap_i02)*src ^ 0x80u;
+			++src;
+			*dest = chr;
+			continue;
+		}
+		if (oct >= 0xE0u) { /* Three octets. */
+			zap_i02 chr =  ((zap_i02)oct ^ 0xE0u) << 0xCu;
+			++src;
+			chr           += ((zap_i02)*src ^ 0x80u) << 0x6u;
+			++src;
+			chr           +=  (zap_i02)*src ^ 0x80u;
+			++src;
+			*dest = chr;
+			continue;
+		}
+		if (oct >= 0xC0u) { /* Two octets. */
+			zap_i02 chr =  ((zap_i02)oct ^ 0xC0u) << 0x6u;
+			++src;
+			          chr +=  (zap_i02)*src ^ 0x80u;
+			++src;
+			*dest = chr;
+			continue;
+		}
+		/* One octet. */
+		*dest = oct;
+		++src;
+	}
+}