remove strnlen dependency and add jrk_strnlen.HEADmaster

As I target C99 it was annoying to be forced to define
_POSIX_C_SOURCE=200809L just for strnlen. Especially because it was called
only once throughout the whole library. I just copy pasted the strnlen
implementation used by musl as I would still like to take advantage of
libc's memchr optimizations. Same code but no POSIX extension required,
a true win.

1 files changed, 11 insertions, 6 deletions

diff --git a/jrk.h b/jrk.h
index a319bae..392a5b5 100644
--- a/jrk.h
+++ b/jrk.h
@@ -1,9 +1,4 @@
 /*
- * requires POSIX.1-2008
- * #define _POSIX_C_SOURCE 200809L
- */
-
-/*
  * TODO:
  *  - add a log interface to give user control of logging.
  *    disable completely, log to file, log format, etc.
@@ -16,6 +11,7 @@
  */
 
 #include <stdbool.h>
+#include <stddef.h>
 #include <stdint.h>
 
 typedef int8_t i8;
@@ -85,6 +81,7 @@ void *jrk_arena_resize(jrk_Arena*, void*, u64, u64);
 
 i32 jrk_rand_num(i32);
 i32 jrk_rand_num_range(i32, i32);
+size_t jrk_strnlen(const char *, size_t);
 
 jrk_fd jrk_fd_open_read(const char*);
 jrk_fd jrk_fd_open_write(const char*);
@@ -876,7 +873,7 @@ jrk_string_from_cstr(const char *data)
 {
 	jrk_String result = {0};
 	result.data = data;
-	result.len = strnlen(data, _JRK_MAX_STRNLEN);
+	result.len = jrk_strnlen(data, _JRK_MAX_STRNLEN);
 	return result;
 }
 
@@ -990,4 +987,12 @@ jrk_rand_num_range(i32 min, i32 max)
 	return rand() % (max - min + 1) + min;
 }
 
+/* musl implementation */
+size_t
+jrk_strnlen(const char *s, size_t n)
+{
+	const char *p = memchr(s, 0, n);
+	return p ? (size_t) (p-s) : n;
+}
+
 #endif /* JRK_IMPLEMENTATION */