software/scaling: add software scaling feature

src/software/scaling/support.rs

@@ -0,0 +1,20 @@
+use ffi::*;
+use ::util::format;
+
+pub fn input(format: format::Pixel) -> bool {
+	unsafe {
+		sws_isSupportedInput(format.into()) != 0
+	}
+}
+
+pub fn output(format: format::Pixel) -> bool {
+	unsafe {
+		sws_isSupportedOutput(format.into()) != 0
+	}
+}
+
+pub fn endianness_conversion(format: format::Pixel) -> bool {
+	unsafe {
+		sws_isSupportedEndiannessConversion(format.into()) != 0
+	}
+}