Add FD_* functions/macros for redox; implementations copied from linux_like

Author: coolreader18

src/unix/redox/mod.rs

@@ -839,6 +839,32 @@ f! {
     pub fn WCOREDUMP(status: ::c_int) -> bool {
         (status & 0x80) != 0
     }
+
+    pub fn FD_CLR(fd: ::c_int, set: *mut fd_set) -> () {
+        let fd = fd as usize;
+        let size = ::mem::size_of_val(&(*set).fds_bits[0]) * 8;
+        (*set).fds_bits[fd / size] &= !(1 << (fd % size));
+        return
+    }
+
+    pub fn FD_ISSET(fd: ::c_int, set: *mut fd_set) -> bool {
+        let fd = fd as usize;
+        let size = ::mem::size_of_val(&(*set).fds_bits[0]) * 8;
+        return ((*set).fds_bits[fd / size] & (1 << (fd % size))) != 0
+    }
+
+    pub fn FD_SET(fd: ::c_int, set: *mut fd_set) -> () {
+        let fd = fd as usize;
+        let size = ::mem::size_of_val(&(*set).fds_bits[0]) * 8;
+        (*set).fds_bits[fd / size] |= 1 << (fd % size);
+        return
+    }
+
+    pub fn FD_ZERO(set: *mut fd_set) -> () {
+        for slot in (*set).fds_bits.iter_mut() {
+            *slot = 0;
+        }
+    }
 }
 
 extern "C" {