1 files changed, 37 insertions, 0 deletions
diff --git a/src/libstddjb/fd_move2.c b/src/libstddjb/fd_move2.c
new file mode 100644
index 0000000..7894e2f
--- /dev/null
+++ b/src/libstddjb/fd_move2.c
@@ -0,0 +1,37 @@
+/* ISC license. */
+
+#include <unistd.h>
+#include <errno.h>
+#include <skalibs/djbunix.h>
+
+int fd_move2 (int to1, int from1, int to2, int from2)
+{
+  register int tmp = from2 ;
+  if (to1 == from1) return fd_move(to2, from2) ;
+  if (to2 == from2) return fd_move(to1, from1) ;
+  if (from1 == from2) return (to1 == to2) ? fd_move(to1, from1) : (errno = EINVAL, -1) ;
+  if (to1 == to2) return (errno = EINVAL, -1) ;
+  if (from2 == to1)
+  {
+    tmp = dup(from2) ;
+    if (tmp == -1) return -1 ;
+  }
+  if (fd_copy(to1, from1) == -1)
+  {
+    register int e = errno ;
+    if (from2 != tmp) fd_close(tmp) ;
+    errno = e ;
+    return -1 ;
+  }
+  if (fd_copy(to2, tmp) == -1)
+  {
+    register int e = errno ;
+    fd_close(to1) ;
+    if (from2 != tmp) fd_move(from2, tmp) ;
+    errno = e ;
+    return -1 ;
+  }
+  if (from1 != to2) fd_close(from1) ;
+  fd_close(tmp) ;
+  return 0 ;
+}