1 files changed, 79 insertions, 0 deletions
diff --git a/str.c b/str.c
new file mode 100644
index 0000000..84436af
--- /dev/null
+++ b/str.c
@@ -0,0 +1,79 @@
+#include <stdlib.h>
+#include <string.h>
+#include "str.h"
+
+int str_cmp(str s1, str s2)
+{
+	if (s1.len != s2.len)
+		return (int) s1.len - (int) s2.len;
+
+	return memcmp(s1.data, s2.data, s1.len);
+}
+
+static bool match_char(char c, str tokens)
+{
+	for (size_t t = 0; t < tokens.len; t++)
+		if (c == tokens.data[t])
+			return true;
+
+	return false;
+}
+
+size_t str_find(str s, str tokens)
+{
+	for (size_t i = 0; i < s.len; i++)
+		if (match_char(s.data[i], tokens))
+			return i;
+
+	return s.len;
+}
+
+str str_walk(str *s, str sep)
+{
+	if (s->len == 0)
+		return NILS;
+
+	size_t x = str_find(*s, sep);
+	size_t o = x + (x < s->len);
+
+	*s = str_advance(*s, o);
+
+	if (x == 0)
+		return str_walk(s, sep);
+	else
+		return (str) { x, s->data - o };
+}
+
+str str_eat(str s, str tokens)
+{
+	while (s.len > 0 && match_char(s.data[0], tokens))
+		s = str_advance(s, 1);
+	return s;
+}
+
+str str_advance(str s, size_t x)
+{
+	s.len -= x;
+	s.data += x;
+	return s;
+}
+
+bool str_start(str s, str start)
+{
+	if (s.len < start.len)
+		return false;
+	s.len = start.len;
+	return str_cmp(s, start) == 0;
+}
+
+str str_intro(char *c)
+{
+	return (str) { strlen(c), c };
+}
+
+str str_clone(str s)
+{
+	str c = { s.len, malloc(s.len) };
+	memcpy(c.data, s.data, s.len);
+	return c;
+}