binding/src/c_flags.rs

/// Creates a Flag type that is also very useful for working with C FFIs.
#[macro_export]
macro_rules! c_flags
{
   {
      $(#[$attribute: meta])* flags $name: ident : $fieldType: ty
      {
         $(
            $(#[$flagAttribute: meta])*
            const $flag: ident = $value: expr
         ),+
      }
   } =>
   {
      // Create the structure that will represent the bitflag.
      // Derive the basic needed functionality and
      // add any required extra attributes.
      $(#[$attribute])*
      #[derive(Clone, Copy, Eq, PartialEq, PartialOrd, Ord, Hash)]
      pub struct $name
      {
         bits: $fieldType
      }


      $($(#[$flagAttribute])* pub const $flag: $name = $name {bits: $value};)+


      impl $name
      {
         /// Create a new default version of the
         /// bitflag structure.
         pub fn new() -> $name
         {
            $name::empty()
         }

         /// Create a new bitflag structure from
         /// the given bits.
         pub fn from_bits(bits: $fieldType) -> Option<$name>
         {
            if bits & !$name::all().get_bits() != 0
            {
               None
            }
            else
            {
               Some($name {bits: bits})
            }
         }

         /// Returns an empty set of flags.
         #[inline]
         pub fn empty() -> $name
         {
            $name {bits: 0}
         }

         /// Returns the set containing all flags.
         pub fn all() -> $name
         {
            $name {bits: $($flag.bits)|+}
         }

         /// Returns `true` if no flags are currently stored;
         /// Otherwise, `false` is returned.
         pub fn is_empty(&self) -> bool
         {
            *self == $name::empty()
         }

         /// Returns `true` if all the flags are currently set;
         /// Otherwise, `false` is returned.
         pub fn is_all(&self) -> bool
         {
            *self == $name::all()
         }

         /// Returns the raw value of the flags currently stored.
         pub fn get_bits(&self) -> $fieldType
         {
            self.bits
         }

         /// Returns `true` if there are flags common to
         /// both `self` and `other`; Otherwise, `false` is returned.
         pub fn intersects(&self, other: $name) -> bool
         {
            !(*self & other).is_empty()
         }

         /// Returns `true` all of the flags in `other` are
         /// contained within `self`; Otherwise, `false` is returned.
         pub fn contains(&self, other: $name) -> bool
         {
            (*self & other) == other
         }

         /// Inserts the specified flags in-place.
         pub fn insert(&mut self, other: $name)
         {
            self.bits |= other.bits;
         }

         /// Removes the specified flags in-place.
         pub fn remove(&mut self, other: $name)
         {
            self.bits &= !other.bits;
         }

         /// Toggles the specified flags in-place.
         pub fn toggle(&mut self, other: $name)
         {
            self.bits ^= other.bits;
         }
      }

      impl ::std::ops::BitOr for $name
      {
         type Output = $name;

         /// Returns the union of the two sets of flags.
         fn bitor(self, other: $name) -> $name
         {
            $name {bits: self.bits | other.bits}
         }
      }

      impl ::std::ops::BitXor for $name
      {
         type Output = $name;

         /// Returns the left flags, but with all the right flags toggled.
         fn bitxor(self, other: $name) -> $name
         {
            $name {bits: self.bits ^ other.bits}
         }
      }

      impl ::std::ops::BitAnd for $name
      {
         type Output = $name;

         /// Returns the intersection between the two sets of flags.
         fn bitand(self, other: $name) -> $name
         {
            $name {bits: self.bits & other.bits}
         }
      }

      impl ::std::ops::Sub for $name
      {
         type Output = $name;

         /// Returns the set difference of the two sets of flags.
         fn sub(self, other: $name) -> $name
         {
            $name {bits: self.bits & !other.bits}
         }
      }

      impl ::std::ops::Not for $name
      {
         type Output = $name;

         /// Returns the complement of this set of flags.
         fn not(self) -> $name
         {
            $name {bits: !self.bits} & $name::all()
         }
      }

      impl ::std::fmt::Debug for $name
      {
         fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result
         {
            ::std::fmt::Display::fmt(self, f)
         }
      }

      impl ::std::fmt::Display for $name
      {
         #[warn(unused_assignments)]
         fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result
         {
            let mut first: bool;

            // Push the left bracket onto the string.
            try!(write!(f, "{}", '{'));

            // Handle checking each flag to see if it
            // is part of this flag.
            first = true;
            $(
               if self.intersects($flag) == true
               {
                  // If this is not the first flag,
                  // then add an OR symbol.
                  if first == false
                  {
                     try!(write!(f, " | "));
                  }

                  // Push the flags name onto the string.
                  try!(write!(f, "{}", stringify!($flag)));
                  first = false;
               }
            )+

            // No flags were set.
            if first == true
            {
               // Put a space in the string.
               try!(write!(f, " "));
            }

            // Push the right bracket onto the string
            // and return it.
            write!(f, "{}", '}')
         }
      }
   }
}