1 files changed, 48 insertions, 0 deletions
diff --git a/src/u8c/str.h.d/strsubstr.c b/src/u8c/str.h.d/strsubstr.c
new file mode 100644
index 0000000..b9daac5
--- /dev/null
+++ b/src/u8c/str.h.d/strsubstr.c
@@ -0,0 +1,48 @@
+/*
+	Copyright 2021 Gabriel Jensen
+
+	This file is part of u8c.
+
+	u8c is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
+
+	u8c is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+	See the	GNU Affero General Public License for more details.
+
+	You should have received a copy of the GNU Affero General Public License along with u8c.
+
+	If not, see <https://www.gnu.org/licenses/>.
+*/
+# include <stdbool.h>
+# include <stdlib.h>
+# include <u8c/SIZE_C.h>
+# include <u8c/str.h>
+# include <uchar.h>
+struct u8c_strsubstr_tuple u8c_strsubstr(size_t const _start,size_t const _len,char32_t const * const restrict _in) {
+	struct u8c_strsubstr_tuple ret = {
+		.stat = false,
+	};
+	size_t insz = u8c_strsz(_in).sz;
+	size_t len = _len;
+	if(_len == SIZE_C(0x0)) {
+		len = insz - _start;
+	}
+	if(insz < _start + len) {
+		return ret;
+	}
+	size_t const outsz = len + SIZE_C(0x2);
+	char32_t *   out   = NULL;
+	{
+		struct u8c_stralloc_tuple const tuple = u8c_stralloc(outsz);
+		if(tuple.stat) {
+			ret.stat = true;
+			return ret;
+		}
+		out = tuple.str;
+	}
+	for(register size_t n = SIZE_C(0x0);n <= len;n += SIZE_C(0x1)) {
+		out[n] = _in[n + _start];
+	}
+	ret.str = out;
+	return ret;
+}