2 files changed, 20 insertions, 0 deletions
diff --git a/src/include/toxic/string.h b/src/include/toxic/string.h
index 69d8bd2..3cb4a30 100644
--- a/src/include/toxic/string.h
+++ b/src/include/toxic/string.h
@@ -3,7 +3,11 @@
 
 #include <stddef.h>
 
+#define NULL	((void *)0)
+
+bool isdigit(char c);
 size_t strlen(const char *s);
+size_t strnlen(const char *s, size_t maxlen);
 char *strcpy(char *restrict dst, const char *restrict src);
 
 void *memset(void *s, int c, size_t n);
diff --git a/src/lib/string.c b/src/lib/string.c
index e5b6972..365381b 100644
--- a/src/lib/string.c
+++ b/src/lib/string.c
@@ -1,4 +1,10 @@
 #include <stddef.h>
+#include <stdbool.h>
+
+bool isdigit(char c)
+{
+	return c >= 48 && c <= 57;
+}
 
 size_t strlen(const char *s)
 {
@@ -10,6 +16,16 @@ size_t strlen(const char *s)
 	return c;
 }
 
+size_t strnlen(const char *s, size_t maxlen)
+{
+	size_t c = 0;
+
+	while (c <= maxlen && s[c])
+		c++;
+
+	return c;
+}
+
 char *strcpy(char *restrict dst, const char *restrict src)
 {
 	size_t pos = 0;