Auto merge of servo#249 - servo:position-byte-index, r=jdm

Expose byte index in tokenizer's position.

I need it to finish my implementation of Properties and Values syntax.

It works on bytes rather than CSS tokens, but it calls the consume a name
algorithm, for which I'm using cssparser.

However I need to know how much of the input was actually consumed
after consuming a name to continue the parse.

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Author: bors-servo

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cssparser"
-version = "0.25.5"
+version = "0.25.6"
 authors = [ "Simon Sapin <simon.sapin@exyr.org>" ]
 
 description = "Rust implementation of CSS Syntax Level 3"

src/tokenizer.rs

@@ -520,6 +520,14 @@ impl<'a> Tokenizer<'a> {
 #[derive(PartialEq, Eq, PartialOrd, Ord, Debug, Clone, Copy)]
 pub struct SourcePosition(pub(crate) usize);
 
+impl SourcePosition {
+    /// Returns the current byte index in the original input.
+    #[inline]
+    pub fn byte_index(&self) -> usize {
+        self.0
+    }
+}
+
 /// The line and column number for a given position within the input.
 #[derive(PartialEq, Eq, Debug, Clone, Copy)]
 pub struct SourceLocation {