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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-04 12:47:55 +0000
commit2aadc03ef15cb5ca5cc2af8a7c08e070742f0ac4 (patch)
tree033cc839730fda84ff08db877037977be94e5e3a /vendor/vte_generate_state_changes/src
parentInitial commit. (diff)
downloadcargo-upstream.tar.xz
cargo-upstream.zip
Adding upstream version 0.70.1+ds1.upstream/0.70.1+ds1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'vendor/vte_generate_state_changes/src')
-rw-r--r--vendor/vte_generate_state_changes/src/lib.rs174
1 files changed, 174 insertions, 0 deletions
diff --git a/vendor/vte_generate_state_changes/src/lib.rs b/vendor/vte_generate_state_changes/src/lib.rs
new file mode 100644
index 0000000..5cfb3ac
--- /dev/null
+++ b/vendor/vte_generate_state_changes/src/lib.rs
@@ -0,0 +1,174 @@
+extern crate proc_macro;
+
+use std::iter::Peekable;
+
+use proc_macro2::TokenTree::{Group, Literal, Punct};
+use proc_macro2::{token_stream, TokenStream, TokenTree};
+use quote::quote;
+
+/// Create a `const fn` which will return an array with all state changes.
+#[proc_macro]
+pub fn generate_state_changes(item: proc_macro::TokenStream) -> proc_macro::TokenStream {
+ // Convert from proc_macro -> proc_macro2
+ let item: TokenStream = item.into();
+ let mut iter = item.into_iter().peekable();
+
+ // Determine output function name
+ let fn_name = iter.next().unwrap();
+
+ // Separator between name and body with state changes
+ expect_punct(&mut iter, ',');
+
+ // Create token stream to assign each state change to the array
+ let assignments_stream = states_stream(&mut iter);
+
+ quote!(
+ const fn #fn_name() -> [[u8; 256]; 16] {
+ let mut state_changes = [[0; 256]; 16];
+
+ #assignments_stream
+
+ state_changes
+ }
+ )
+ .into()
+}
+
+/// Generate the array assignment statements for all origin states.
+fn states_stream(iter: &mut impl Iterator<Item = TokenTree>) -> TokenStream {
+ let mut states_stream = next_group(iter).into_iter().peekable();
+
+ // Loop over all origin state entries
+ let mut tokens = quote!();
+ while states_stream.peek().is_some() {
+ // Add all mappings for this state
+ tokens.extend(state_entry_stream(&mut states_stream));
+
+ // Allow trailing comma
+ optional_punct(&mut states_stream, ',');
+ }
+ tokens
+}
+
+/// Generate the array assignment statements for one origin state.
+fn state_entry_stream(iter: &mut Peekable<token_stream::IntoIter>) -> TokenStream {
+ // Origin state name
+ let state = iter.next().unwrap().into();
+
+ // Token stream with all the byte->target mappings
+ let mut changes_stream = next_group(iter).into_iter().peekable();
+
+ let mut tokens = quote!();
+ while changes_stream.peek().is_some() {
+ // Add next mapping for this state
+ tokens.extend(change_stream(&mut changes_stream, &state));
+
+ // Allow trailing comma
+ optional_punct(&mut changes_stream, ',');
+ }
+ tokens
+}
+
+/// Generate the array assignment statement for a single byte->target mapping for one state.
+fn change_stream(iter: &mut Peekable<token_stream::IntoIter>, state: &TokenTree) -> TokenStream {
+ // Start of input byte range
+ let start = next_usize(iter);
+
+ // End of input byte range
+ let end = if optional_punct(iter, '.') {
+ // Read inclusive end of range
+ expect_punct(iter, '.');
+ expect_punct(iter, '=');
+ next_usize(iter)
+ } else {
+ // Without range, end is equal to start
+ start
+ };
+
+ // Separator between byte input range and output state
+ expect_punct(iter, '=');
+ expect_punct(iter, '>');
+
+ // Token stream with target state and action
+ let mut target_change_stream = next_group(iter).into_iter().peekable();
+
+ let mut tokens = quote!();
+ while target_change_stream.peek().is_some() {
+ // Target state/action for all bytes in the range
+ let (target_state, target_action) = target_change(&mut target_change_stream);
+
+ // Create a new entry for every byte in the range
+ for byte in start..=end {
+ // TODO: Force adding `State::` and `Action::`?
+ // TODO: Should we really use `pack` here without import?
+ tokens.extend(quote!(
+ state_changes[State::#state as usize][#byte] =
+ pack(State::#target_state, Action::#target_action);
+ ));
+ }
+ }
+ tokens
+}
+
+/// Get next target state and action.
+fn target_change(iter: &mut Peekable<token_stream::IntoIter>) -> (TokenTree, TokenTree) {
+ let target_state = iter.next().unwrap();
+
+ // Separator between state and action
+ expect_punct(iter, ',');
+
+ let target_action = iter.next().unwrap();
+
+ (target_state, target_action)
+}
+
+/// Check if next token matches specific punctuation.
+fn optional_punct(iter: &mut Peekable<token_stream::IntoIter>, c: char) -> bool {
+ match iter.peek() {
+ Some(Punct(punct)) if punct.as_char() == c => iter.next().is_some(),
+ _ => false,
+ }
+}
+
+/// Ensure next token matches specific punctuation.
+///
+/// # Panics
+///
+/// Panics if the punctuation does not match.
+fn expect_punct(iter: &mut impl Iterator<Item = TokenTree>, c: char) {
+ match iter.next() {
+ Some(Punct(ref punct)) if punct.as_char() == c => (),
+ token => panic!("Expected punctuation '{}', but got {:?}", c, token),
+ }
+}
+
+/// Get next token as [`usize`].
+///
+/// # Panics
+///
+/// Panics if the next token is not a [`usize`] in hex or decimal literal format.
+fn next_usize(iter: &mut impl Iterator<Item = TokenTree>) -> usize {
+ match iter.next() {
+ Some(Literal(literal)) => {
+ let literal = literal.to_string();
+ if literal.starts_with("0x") {
+ usize::from_str_radix(&literal[2..], 16).unwrap()
+ } else {
+ usize::from_str_radix(&literal, 10).unwrap()
+ }
+ },
+ token => panic!("Expected literal, but got {:?}", token),
+ }
+}
+
+/// Get next token as [`Group`].
+///
+/// # Panics
+///
+/// Panics if the next token is not a [`Group`].
+fn next_group(iter: &mut impl Iterator<Item = TokenTree>) -> TokenStream {
+ match iter.next() {
+ Some(Group(group)) => group.stream(),
+ token => panic!("Expected group, but got {:?}", token),
+ }
+}