Remove table generation

This completely removes the `codegen` project, which relied on outdated
libraries to parse DSLs to build the utf8 and vte state tables, to make
the library easier to maintain.

The utf8 table could be completely removed in favor of a `match`
statement, which also lead to a performance improvement with the utf8
parser.

The vte table did not benefit from `match` statements at all and instead
had significantly worse performance with it. To replace the old
codegeneration for vte, the `generate_state_changes` crate has been
created instead, which uses the language's proc_macro feature to create
a `const fn` which will generate the table at compile time.

4 files changed, 115 insertions, 282 deletions

diff --git a/utf8parse/src/lib.rs b/utf8parse/src/lib.rs
index 8c866f5..c092647 100644
--- a/utf8parse/src/lib.rs
+++ b/utf8parse/src/lib.rs
@@ -3,15 +3,14 @@
 //! This module implements a table-driven UTF-8 parser which should
 //! theoretically contain the minimal number of branches (1). The only branch is
 //! on the `Action` returned from unpacking a transition.
+#![cfg_attr(all(feature = "nightly", test), feature(test))]
 #![no_std]
 
 use core::char;
 
-mod table;
 mod types;
 
-use table::TRANSITIONS;
-use types::{unpack, Action, State};
+use types::{Action, State};
 
 /// Handles codepoint and invalid sequence events from the parser.
 pub trait Receiver {
@@ -48,10 +47,7 @@ impl Parser {
     where
         R: Receiver,
     {
-        let cur = self.state as usize;
-        let change = TRANSITIONS[cur][byte as usize];
-        let (state, action) = unsafe { unpack(change) };
-
+        let (state, action) = self.state.advance(byte);
         self.perform_action(receiver, byte, action);
         self.state = state;
     }
@@ -93,3 +89,43 @@ impl Parser {
         }
     }
 }
+
+#[cfg(all(feature = "nightly", test))]
+mod benches {
+    extern crate std;
+    extern crate test;
+
+    use super::{Parser, Receiver};
+
+    use self::test::{black_box, Bencher};
+
+    static UTF8_DEMO: &[u8] = include_bytes!("../tests/UTF-8-demo.txt");
+
+    impl Receiver for () {
+        fn codepoint(&mut self, c: char) {
+            black_box(c);
+        }
+
+        fn invalid_sequence(&mut self) {}
+    }
+
+    #[bench]
+    fn parse_bench_utf8_demo(b: &mut Bencher) {
+        let mut parser = Parser::new();
+
+        b.iter(|| {
+            for byte in UTF8_DEMO {
+                parser.advance(&mut (), *byte);
+            }
+        })
+    }
+
+    #[bench]
+    fn std_string_parse_utf8(b: &mut Bencher) {
+        b.iter(|| {
+            for c in std::str::from_utf8(UTF8_DEMO).unwrap().chars() {
+                black_box(c);
+            }
+        });
+    }
+}
diff --git a/utf8parse/src/table.rs b/utf8parse/src/table.rs
deleted file mode 100644
index 04c4d34..0000000
--- a/utf8parse/src/table.rs
+++ /dev/null
@@ -1,166 +0,0 @@
-//! UTF-8 Parse Transition Table
-
-/// Transition table for parsing UTF-8. This is built from the grammar described
-/// at https://tools.ietf.org/html/rfc3629#section-4 which I have copied and
-/// formatted below.
-///
-/// # UTF-8 Grammar
-///
-/// ```notrust
-///     UTF8-octets = *( UTF8-char )
-///     UTF8-char   = UTF8-1 / UTF8-2 / UTF8-3 / UTF8-4
-///     UTF8-1      = %x00-7F
-///     UTF8-2      = %xC2-DF UTF8-tail
-///     UTF8-3      = %xE0    %xA0-BF UTF8-tail /
-///                   %xE1-EC 2( UTF8-tail )    /
-///                   %xED    %x80-9F UTF8-tail /
-///                   %xEE-EF 2( UTF8-tail )
-///     UTF8-4      = %xF0    %x90-BF 2( UTF8-tail ) /
-///                   %xF1-F3 3( UTF8-tail )         /
-///                   %xF4    %x80-8F 2( UTF8-tail )
-///     UTF8-tail   = %x80-BF
-/// ```
-///
-/// Not specifying an action in this table is equivalent to specifying
-/// Action::InvalidSequence. Not specifying a state is equivalent to specifying
-/// state::ground.
-pub static TRANSITIONS: [[u8; 256]; 8] = [
-    [
-        16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8,
-        16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8,
-        16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8,
-        16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8,
-        16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8,
-        16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8,
-        16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8,
-        16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8,
-        16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 16u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8,
-        67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8, 67u8,
-        67u8, 67u8, 67u8, 100u8, 98u8, 98u8, 98u8, 98u8, 98u8, 98u8, 98u8, 98u8, 98u8, 98u8, 98u8,
-        98u8, 101u8, 98u8, 98u8, 118u8, 113u8, 113u8, 113u8, 119u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8,
-    ],
-    [
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8,
-        82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8,
-        82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8,
-        82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8,
-        82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-    ],
-    [
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8,
-        51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8,
-        51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8,
-        51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8,
-        51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-    ],
-    [
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8,
-        32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8,
-        32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8,
-        32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 32u8,
-        32u8, 32u8, 32u8, 32u8, 32u8, 32u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-    ],
-    [
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 51u8, 51u8,
-        51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8,
-        51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-    ],
-    [
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8,
-        51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8, 51u8,
-        51u8, 51u8, 51u8, 51u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-    ],
-    [
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8,
-        82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8,
-        82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8,
-        82u8, 82u8, 82u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-    ],
-    [
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8, 82u8,
-        82u8, 82u8, 82u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-        0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8,
-    ],
-];
diff --git a/utf8parse/src/table.rs.in b/utf8parse/src/table.rs.in
deleted file mode 100644
index 2acafe7..0000000
--- a/utf8parse/src/table.rs.in
+++ /dev/null
@@ -1,60 +0,0 @@
-//! UTF-8 Parse Transition Table
-
-/// Transition table for parsing UTF-8. This is built from the grammar described
-/// at https://tools.ietf.org/html/rfc3629#section-4 which I have copied and
-/// formatted below.
-///
-/// # UTF-8 Grammar
-///
-/// ```ignore
-///     UTF8-octets = *( UTF8-char )
-///     UTF8-char   = UTF8-1 / UTF8-2 / UTF8-3 / UTF8-4
-///     UTF8-1      = %x00-7F
-///     UTF8-2      = %xC2-DF UTF8-tail
-///     UTF8-3      = %xE0    %xA0-BF UTF8-tail /
-///                   %xE1-EC 2( UTF8-tail )    /
-///                   %xED    %x80-9F UTF8-tail /
-///                   %xEE-EF 2( UTF8-tail )
-///     UTF8-4      = %xF0    %x90-BF 2( UTF8-tail ) /
-///                   %xF1-F3 3( UTF8-tail )         /
-///                   %xF4    %x80-8F 2( UTF8-tail )
-///     UTF8-tail   = %x80-BF
-/// ```
-///
-/// Not specifying an action in this table is equivalent to specifying
-/// Action::InvalidSequence. Not specifying a state is equivalent to specifying
-/// state::ground.
-pub static TRANSITIONS: [[u8; 256]; 8] = utf8_state_table! {
-    State::Ground => {
-        0x00...0x7f => (State::Ground,      Action::EmitByte),
-        0xc2...0xdf => (State::Tail1,       Action::SetByte2Top),
-        0xe0        => (State::U3_2_e0,     Action::SetByte3Top),
-        0xe1...0xec => (State::Tail2,       Action::SetByte3Top),
-        0xed        => (State::U3_2_ed,     Action::SetByte3Top),
-        0xee...0xef => (State::Tail2,       Action::SetByte3Top),
-        0xf0        => (State::Utf8_4_3_f0, Action::SetByte4),
-        0xf1...0xf3 => (State::Tail3,       Action::SetByte4),
-        0xf4        => (State::Utf8_4_3_f4, Action::SetByte4),
-    },
-    State::U3_2_e0 => {
-        0xa0...0xbf => (State::Tail1, Action::SetByte2),
-    },
-    State::U3_2_ed => {
-        0x80...0x9f => (State::Tail1, Action::SetByte2),
-    },
-    State::Utf8_4_3_f0 => {
-        0x90...0xbf => (State::Tail2, Action::SetByte3),
-    },
-    State::Utf8_4_3_f4 => {
-        0x80...0x8f => (State::Tail2, Action::SetByte3),
-    },
-    State::Tail3 => {
-        0x80...0xbf => (State::Tail2, Action::SetByte3),
-    },
-    State::Tail2 => {
-        0x80...0xbf => (State::Tail1, Action::SetByte2),
-    },
-    State::Tail1 => {
-        0x80...0xbf => (State::Ground, Action::SetByte1),
-    },
-};
diff --git a/utf8parse/src/types.rs b/utf8parse/src/types.rs
index 93607fb..5a70b3c 100644
--- a/utf8parse/src/types.rs
+++ b/utf8parse/src/types.rs
@@ -1,12 +1,31 @@
 //! Types supporting the UTF-8 parser
-#![allow(non_camel_case_types)]
-use core::mem;
+
+/// Action to take when receiving a byte
+#[derive(Debug, Copy, Clone)]
+pub enum Action {
+    /// Unexpected byte; sequence is invalid
+    InvalidSequence = 0,
+    /// Received valid 7-bit ASCII byte which can be directly emitted.
+    EmitByte = 1,
+    /// Set the bottom continuation byte
+    SetByte1 = 2,
+    /// Set the 2nd-from-last continuation byte
+    SetByte2 = 3,
+    /// Set the 2nd-from-last byte which is part of a two byte sequence
+    SetByte2Top = 4,
+    /// Set the 3rd-from-last continuation byte
+    SetByte3 = 5,
+    /// Set the 3rd-from-last byte which is part of a three byte sequence
+    SetByte3Top = 6,
+    /// Set the top byte of a four byte sequence.
+    SetByte4 = 7,
+}
 
 /// States the parser can be in.
 ///
 /// There is a state for each initial input of the 3 and 4 byte sequences since
 /// the following bytes are subject to different conditions than a tail byte.
-#[allow(dead_code)]
+#[allow(non_camel_case_types)]
 #[derive(Debug, Copy, Clone)]
 pub enum State {
     /// Ground state; expect anything
@@ -33,50 +52,54 @@ impl Default for State {
     }
 }
 
-/// Action to take when receiving a byte
-#[allow(dead_code)]
-#[derive(Debug, Copy, Clone)]
-pub enum Action {
-    /// Unexpected byte; sequence is invalid
-    InvalidSequence = 0,
-    /// Received valid 7-bit ASCII byte which can be directly emitted.
-    EmitByte = 1,
-    /// Set the bottom continuation byte
-    SetByte1 = 2,
-    /// Set the 2nd-from-last continuation byte
-    SetByte2 = 3,
-    /// Set the 2nd-from-last byte which is part of a two byte sequence
-    SetByte2Top = 4,
-    /// Set the 3rd-from-last continuation byte
-    SetByte3 = 5,
-    /// Set the 3rd-from-last byte which is part of a three byte sequence
-    SetByte3Top = 6,
-    /// Set the top byte of a four byte sequence.
-    SetByte4 = 7,
-}
-
-/// Convert a state and action to a u8
-///
-/// State will be the bottom 4 bits and action the top 4
-#[inline]
-#[allow(dead_code)]
-pub fn pack(state: State, action: Action) -> u8 {
-    ((action as u8) << 4) | (state as u8)
-}
-
-/// Convert a u8 to a state and action
-///
-/// # Unsafety
-///
-/// If this function is called with a byte that wasn't encoded with the `pack`
-/// function in this module, there is no guarantee that a valid state and action
-/// can be produced.
-#[inline]
-pub unsafe fn unpack(val: u8) -> (State, Action) {
-    (
-        // State is stored in bottom 4 bits
-        mem::transmute(val & 0x0f),
-        // Action is stored in top 4 bits
-        mem::transmute(val >> 4),
-    )
+impl State {
+    /// Advance the parser state.
+    ///
+    /// This takes the current state and input byte into consideration, to determine the next state
+    /// and any action that should be taken.
+    #[inline]
+    pub fn advance(&self, byte: u8) -> (State, Action) {
+        match self {
+            State::Ground => match byte {
+                0x00..=0x7f => (State::Ground, Action::EmitByte),
+                0xc2..=0xdf => (State::Tail1, Action::SetByte2Top),
+                0xe0 => (State::U3_2_e0, Action::SetByte3Top),
+                0xe1..=0xec => (State::Tail2, Action::SetByte3Top),
+                0xed => (State::U3_2_ed, Action::SetByte3Top),
+                0xee..=0xef => (State::Tail2, Action::SetByte3Top),
+                0xf0 => (State::Utf8_4_3_f0, Action::SetByte4),
+                0xf1..=0xf3 => (State::Tail3, Action::SetByte4),
+                0xf4 => (State::Utf8_4_3_f4, Action::SetByte4),
+                _ => (State::Ground, Action::InvalidSequence),
+            },
+            State::U3_2_e0 => match byte {
+                0xa0..=0xbf => (State::Tail1, Action::SetByte2),
+                _ => (State::Ground, Action::InvalidSequence),
+            },
+            State::U3_2_ed => match byte {
+                0x80..=0x9f => (State::Tail1, Action::SetByte2),
+                _ => (State::Ground, Action::InvalidSequence),
+            },
+            State::Utf8_4_3_f0 => match byte {
+                0x90..=0xbf => (State::Tail2, Action::SetByte3),
+                _ => (State::Ground, Action::InvalidSequence),
+            },
+            State::Utf8_4_3_f4 => match byte {
+                0x80..=0x8f => (State::Tail2, Action::SetByte3),
+                _ => (State::Ground, Action::InvalidSequence),
+            },
+            State::Tail3 => match byte {
+                0x80..=0xbf => (State::Tail2, Action::SetByte3),
+                _ => (State::Ground, Action::InvalidSequence),
+            },
+            State::Tail2 => match byte {
+                0x80..=0xbf => (State::Tail1, Action::SetByte2),
+                _ => (State::Ground, Action::InvalidSequence),
+            },
+            State::Tail1 => match byte {
+                0x80..=0xbf => (State::Ground, Action::SetByte1),
+                _ => (State::Ground, Action::InvalidSequence),
+            },
+        }
+    }
 }