ape: add strnlen

4 files changed, 13 insertions, 1 deletions

diff --git a/sys/include/ape/string.h b/sys/include/ape/string.h
index 52813b15d..50dfad93c 100644
--- a/sys/include/ape/string.h
+++ b/sys/include/ape/string.h
@@ -32,6 +32,7 @@ extern char *strtok(char *, const char *);
 extern void *memset(void *, int, size_t);
 extern char *strerror(int);
 extern size_t strlen(const char *);
+extern size_t strnlen(const char *, size_t);
 
 #ifdef _REENTRANT_SOURCE
 extern char *strerror_r(int, const char *, int);
diff --git a/sys/src/ape/lib/ap/gen/mkfile b/sys/src/ape/lib/ap/gen/mkfile
index 6594587f4..54ff7a617 100644
--- a/sys/src/ape/lib/ap/gen/mkfile
+++ b/sys/src/ape/lib/ap/gen/mkfile
@@ -43,6 +43,7 @@ ALLOFILES=\
 	strncat.$O\
 	strncmp.$O\
 	strncpy.$O\
+	strnlen.$O\
 	strpbrk.$O\
 	strrchr.$O\
 	strspn.$O\
diff --git a/sys/src/ape/lib/ap/gen/strlen.c b/sys/src/ape/lib/ap/gen/strlen.c
index e339cb16b..02632a6a3 100644
--- a/sys/src/ape/lib/ap/gen/strlen.c
+++ b/sys/src/ape/lib/ap/gen/strlen.c
@@ -3,6 +3,5 @@
 size_t
 strlen(const char *s)
 {
-
 	return strchr(s, 0) - s;
 }
diff --git a/sys/src/ape/lib/ap/gen/strnlen.c b/sys/src/ape/lib/ap/gen/strnlen.c
new file mode 100644
index 000000000..880d2eb59
--- /dev/null
+++ b/sys/src/ape/lib/ap/gen/strnlen.c
@@ -0,0 +1,11 @@
+#include <string.h>
+
+size_t
+strnlen(const char *s, size_t maxlen)
+{
+	size_t i;
+
+	for (i = 0; i < maxlen && s[i] != '\0'; i++)
+		;
+	return i;
+}