add fstat() implementation for read_all_file_size()

1 files changed, 9 insertions, 0 deletions

diff --git a/strio.h b/strio.h
index a99f8c3..a7df9ca 100644
--- a/strio.h
+++ b/strio.h
@@ -28,12 +28,21 @@ const char *cstr_fmt(Arena *arena, const char *fmt, ...);
 #include <stdint.h>
 #include <stdarg.h>
 
+#if defined(__linux__) || defined(_POSIX_C_SOURCE)
+#include <sys/stat.h>
+static inline long read_all_file_size(FILE *f) {
+	struct stat b;
+	if (fstat(fileno(f), &b)) return -1;
+	return b.st_size;
+}
+#else
 static inline long read_all_file_size(FILE *f) {
 	fseek(f, 0, SEEK_END);
 	long t = ftell(f);
 	fseek(f, 0, SEEK_SET);
 	return t > 0 ? t : -1;
 }
+#endif
 
 int read_all(FILE *f, Str *buf, Arena *a) {
 	if (!f) return -1;