Switch parser to multi-byte processing

This patch overhauls the `Parser::advance` API to operate on byte slices
instead of individual bytes, which allows for additional performance
optimizations.

VTE does not support C1 escapes and C0 escapes always start with an
escape character. This makes it possible to simplify processing if a
byte stream is determined to not contain any escapes. The `memchr` crate
provides a battle-tested implementation for SIMD-accelerated byte
searches, which is why this implementation makes use of it.

VTE also only supports UTF8 characters in the ground state, which means
that the new non-escape parsing path is able to rely completely on STD's
`str::from_utf8` since `memchr` gives us the full length of the plain
text character buffer. This allows us to completely remove `utf8parse`
and all related code.

We also make use of `memchr` in the synchronized escape handling in
`ansi.rs`, since it realies heavily on scanning large amounts of text
for the extension/termination escape sequences.

Cargo.toml

@@ -13,21 +13,20 @@ name = "vte"
 edition = "2021"
 rust-version = "1.62.1"
 
-[dependencies]
-arrayvec = { version = "0.7.2", default-features = false, optional = true }
-bitflags = { version = "2.3.3", default-features = false, optional = true }
-cursor-icon = { version = "1.0.0", default-features = false, optional = true }
-log = { version = "0.4.17", optional = true }
-serde = { version = "1.0.160", features = ["derive"], optional = true }
-utf8parse = { version = "0.2.0", path = "utf8parse" }
-vte_generate_state_changes = { version = "0.1.0", path = "vte_generate_state_changes" }
+[workspace]
+members = ["vte_generate_state_changes"]
 
 [features]
 ansi = ["log", "cursor-icon", "bitflags"]
 default = ["no_std"]
-nightly = ["utf8parse/nightly"]
 no_std = ["arrayvec"]
 serde = ["dep:serde"]
 
-[workspace]
-members = ["utf8parse", "vte_generate_state_changes"]
+[dependencies]
+arrayvec = { version = "0.7.2", default-features = false, optional = true }
+bitflags = { version = "2.3.3", default-features = false, optional = true }
+cursor-icon = { version = "1.0.0", default-features = false, optional = true }
+log = { version = "0.4.17", optional = true }
+memchr = "2.7.4"
+serde = { version = "1.0.160", features = ["derive"], optional = true }
+vte_generate_state_changes = { version = "0.1.0", path = "vte_generate_state_changes" }

examples/parselog.rs

@@ -61,11 +61,7 @@ fn main() {
     loop {
         match handle.read(&mut buf) {
             Ok(0) => break,
-            Ok(n) => {
-                for byte in &buf[..n] {
-                    statemachine.advance(&mut performer, *byte);
-                }
-            },
+            Ok(n) => statemachine.advance(&mut performer, &buf[..n]),
             Err(err) => {
                 println!("err: {}", err);
                 break;

rustfmt.toml

@@ -1,13 +1,17 @@
 format_code_in_doc_comments = true
+group_imports = "StdExternalCrate"
 match_block_trailing_comma = true
 condense_wildcard_suffixes = true
 use_field_init_shorthand = true
+normalize_doc_attributes = true
 overflow_delimited_expr = true
+imports_granularity = "Module"
+format_macro_matchers = true
 use_small_heuristics = "Max"
+hex_literal_case = "Upper"
 normalize_comments = true
 reorder_impl_items = true
 use_try_shorthand = true
 newline_style = "Unix"
 format_strings = true
 wrap_comments = true
-comment_width = 100