options/posix: Implement basename()
-#include <libgen.h>
#include <bits/ensure.h>
+#include <libgen.h>
+#include <string.h>
-char *basename(char *) {
- __ensure(!"Not implemented");
- __builtin_unreachable();
+// Adopted from musl's code.
+char *basename(char *s) {
+ // This empty string behavior is specified by POSIX.
+ if (!s || !*s)
+ return const_cast<char *>(".");
+
+ // Delete trailing slashes.
+ // Note that we do not delete the slash at index zero.
+ auto i = strlen(s) - 1;
+ for(; i && s[i] == '/'; i--)
+ s[i] = 0;
+
+ // Find the last non-trailing slash.
+ for(; i && s[i - 1] != '/'; i--)
+ ;
+ return s + i;
}
char *dirname(char *) {
