summaryrefslogtreecommitdiff
path: root/src/string/strlcpy.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/string/strlcpy.c')
-rw-r--r--src/string/strlcpy.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/src/string/strlcpy.c b/src/string/strlcpy.c
new file mode 100644
index 00000000..bbebf1db
--- /dev/null
+++ b/src/string/strlcpy.c
@@ -0,0 +1,32 @@
+#include <string.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <limits.h>
+#include "libc.h"
+
+#define ALIGN (sizeof(size_t)-1)
+#define ONES ((size_t)-1/UCHAR_MAX)
+#define HIGHS (ONES * (UCHAR_MAX/2+1))
+#define HASZERO(x) ((x)-ONES & ~(x) & HIGHS)
+
+size_t strlcpy(char *d, const char *s, size_t n)
+{
+ char *d0 = d;
+ size_t *wd;
+ const size_t *ws;
+
+ if (!n--) goto finish;
+ if (((uintptr_t)s & ALIGN) != ((uintptr_t)d & ALIGN)) {
+ for (; ((uintptr_t)s & ALIGN) && n && (*d=*s); n--, s++, d++);
+ if (n && *s) {
+ wd=(void *)d; ws=(const void *)s;
+ for (; n>=sizeof(size_t) && !HASZERO(*ws);
+ n-=sizeof(size_t), ws++, *wd++) *wd = *ws;
+ d=(void *)wd; s=(const void *)ws;
+ }
+ }
+ for (; n && (*d=*s); n--, s++, d++);
+ *d = 0;
+finish:
+ return d-d0 + strlen(s);
+}