1 files changed, 23 insertions, 0 deletions
diff --git a/src/file.c b/src/file.c
new file mode 100644
index 0000000..c6823b9
--- /dev/null
+++ b/src/file.c
@@ -0,0 +1,23 @@
+#include <errno.h>
+#include <string.h>
+
+#include "file.h"
+#include "print.h"
+
+long
+file_size(FILE *const file)
+{
+    fpos_t p;
+
+    if ((fgetpos(file, &p) != 0) || (fseek(file, 0L, SEEK_END) != 0)) {
+        return -1;
+    }
+
+    const long size = ftell(file);
+
+    if (fsetpos(file, &p) != 0) {
+        return -1;
+    }
+
+    return size;
+}