Auto merge of rust-lang#587 - sfackler:makedev, r=alexcrichton

Add major, minor, makedev functions

Only for Linux and Android currently, though they also exist on BSDs

Author: bors

src/unix/notbsd/android/mod.rs

@@ -753,6 +753,17 @@ f! {
     pub fn CPU_EQUAL(set1: &cpu_set_t, set2: &cpu_set_t) -> bool {
         set1.__bits == set2.__bits
     }
+    pub fn major(dev: ::dev_t) -> ::c_int {
+        ((dev >> 8) & 0xfff) as ::c_int
+    }
+    pub fn minor(dev: ::dev_t) -> ::c_int {
+        ((dev & 0xff) | ((dev >> 12) & 0xfff00)) as ::c_int
+    }
+    pub fn makedev(ma: ::c_int, mi: ::c_int) -> ::dev_t {
+        let ma = ma as ::dev_t;
+        let mi = mi as ::dev_t;
+        ((ma & 0xfff) << 8) | (mi & 0xff) | ((mi & 0xfff00) << 12)
+    }
 }
 
 extern {

src/unix/notbsd/linux/mod.rs

@@ -722,6 +722,31 @@ f! {
     pub fn CPU_EQUAL(set1: &cpu_set_t, set2: &cpu_set_t) -> bool {
         set1.bits == set2.bits
     }
+
+    pub fn major(dev: ::dev_t) -> ::c_uint {
+        let mut major = 0;
+        major |= (dev & 0x00000000000fff00) >> 8;
+        major |= (dev & 0xfffff00000000000) >> 32;
+        major as ::c_uint
+    }
+
+    pub fn minor(dev: ::dev_t) -> ::c_uint {
+        let mut minor = 0;
+        minor |= (dev & 0xfffff00000000000) >> 0;
+        minor |= (dev & 0x00000ffffff00000) >> 12;
+        minor as ::c_uint
+    }
+
+    pub fn makedev(major: ::c_uint, minor: ::c_uint) -> ::dev_t {
+        let major = major as ::dev_t;
+        let minor = minor as ::dev_t;
+        let mut dev = 0;
+        dev |= (major & 0x00000fff) << 8;
+        dev |= (major & 0xfffff000) << 32;
+        dev |= (minor & 0x000000ff) << 0;
+        dev |= (minor & 0xffffff00) << 12;
+        dev
+    }
 }
 
 extern {