allow for no_std and embedded-io builds

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "vt100"
-version = "0.16.2"
+version = "0.16.3"
 authors = ["Jesse Luehrs <doy@tozt.net>"]
 edition = "2021"
 rust-version = "1.70"
@@ -15,9 +15,10 @@ license = "MIT"
 include = ["src/**/*", "LICENSE", "README.md", "CHANGELOG.md"]
 
 [dependencies]
+embedded-io = { version = "0.7.1", optional = true }
 itoa = "1.0.15"
 unicode-width = "0.2.1"
-vte = "0.15.0"
+vte = { version = "0.15.0", default-features = false }
 
 [dev-dependencies]
 nix = { version = "0.30.1", features = ["term"] }
@@ -26,3 +27,7 @@ rand = "0.9"
 serde = { version = "1.0.219", features = ["derive"] }
 serde_json = "1.0.140"
 terminal_size = "0.4.2"
+
+[features]
+default = ["std"]
+std = ["vte/std"]

src/attrs.rs

@@ -1,4 +1,5 @@
 use crate::term::BufWrite as _;
+use alloc::vec::Vec;
 
 /// Represents a foreground or background color for cells.
 #[derive(Eq, PartialEq, Debug, Copy, Clone, Default)]

src/cell.rs

@@ -14,7 +14,7 @@ pub struct Cell {
     len: u8,
     attrs: crate::attrs::Attrs,
 }
-const _: () = assert!(std::mem::size_of::<Cell>() == 32);
+const _: () = assert!(core::mem::size_of::<Cell>() == 32);
 
 impl PartialEq<Self> for Cell {
     fn eq(&self, other: &Self) -> bool {
@@ -87,7 +87,7 @@ impl Cell {
     #[allow(clippy::missing_panics_doc)]
     #[must_use]
     pub fn contents(&self) -> &str {
-        std::str::from_utf8(&self.contents[..self.len()]).unwrap()
+        core::str::from_utf8(&self.contents[..self.len()]).unwrap()
     }
 
     /// Returns whether the cell contains any text data.

src/grid.rs

@@ -1,4 +1,5 @@
 use crate::term::BufWrite as _;
+use alloc::{collections::VecDeque, string::String, vec::Vec};
 
 #[derive(Clone, Debug)]
 pub struct Grid {
@@ -10,7 +11,7 @@ pub struct Grid {
     scroll_bottom: u16,
     origin_mode: bool,
     saved_origin_mode: bool,
-    scrollback: std::collections::VecDeque<crate::row::Row>,
+    scrollback: VecDeque<crate::row::Row>,
     scrollback_len: usize,
     scrollback_offset: usize,
 }
@@ -26,7 +27,7 @@ impl Grid {
             scroll_bottom: size.rows - 1,
             origin_mode: false,
             saved_origin_mode: false,
-            scrollback: std::collections::VecDeque::new(),
+            scrollback: VecDeque::new(),
             scrollback_len,
             scrollback_offset: 0,
         }
@@ -35,7 +36,7 @@ impl Grid {
     pub fn allocate_rows(&mut self) {
         if self.rows.is_empty() {
             self.rows.extend(
-                std::iter::repeat_with(|| {
+                core::iter::repeat_with(|| {
                     crate::row::Row::new(self.size.cols)
                 })
                 .take(usize::from(self.size.rows)),

src/lib.rs

@@ -33,6 +33,7 @@
 //! );
 //! ```
 
+#![cfg_attr(not(feature = "std"), no_std)]
 #![warn(missing_docs)]
 #![warn(clippy::cargo)]
 #![warn(clippy::pedantic)]
@@ -47,6 +48,9 @@
 #![allow(clippy::too_many_lines)]
 #![allow(clippy::type_complexity)]
 
+#[macro_use]
+extern crate alloc;
+
 mod attrs;
 mod callbacks;
 mod cell;

src/parser.rs

@@ -84,6 +84,7 @@ impl Default for Parser {
     }
 }
 
+#[cfg(feature = "std")]
 impl std::io::Write for Parser {
     fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
         self.process(buf);
@@ -94,3 +95,30 @@ impl std::io::Write for Parser {
         Ok(())
     }
 }
+
+#[cfg(feature = "embedded-io")]
+impl embedded_io::ErrorType for Parser {
+    type Error = core::convert::Infallible;
+}
+
+#[cfg(feature = "embedded-io")]
+impl embedded_io::Write for Parser {
+    fn write(
+        &mut self,
+        buf: &[u8],
+    ) -> core::result::Result<usize, Self::Error> {
+        self.process(buf);
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> core::result::Result<(), Self::Error> {
+        Ok(())
+    }
+}
+
+#[cfg(feature = "embedded-io")]
+impl embedded_io::WriteReady for Parser {
+    fn write_ready(&mut self) -> core::result::Result<bool, Self::Error> {
+        Ok(true)
+    }
+}

src/perform.rs

@@ -1,3 +1,5 @@
+use alloc::vec::Vec;
+
 const BASE64: &[u8] =
     b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
 const CLIPBOARD_SELECTOR: &[u8] = b"cpqs01234567";

src/row.rs

@@ -1,4 +1,5 @@
 use crate::term::BufWrite as _;
+use alloc::{string::String, vec::Vec};
 
 #[derive(Clone, Debug)]
 pub struct Row {

src/screen.rs

@@ -1,4 +1,5 @@
 use crate::term::BufWrite as _;
+use alloc::{string::String, vec::Vec};
 use unicode_width::UnicodeWidthChar as _;
 
 const MODE_APPLICATION_KEYPAD: u8 = 0b0000_0001;
@@ -172,7 +173,7 @@ impl Screen {
         end_col: u16,
     ) -> String {
         match start_row.cmp(&end_row) {
-            std::cmp::Ordering::Less => {
+            core::cmp::Ordering::Less => {
                 let (_, cols) = self.size();
                 let mut contents = String::new();
                 for (i, row) in self
@@ -203,7 +204,7 @@ impl Screen {
                 }
                 contents
             }
-            std::cmp::Ordering::Equal => {
+            core::cmp::Ordering::Equal => {
                 if start_col < end_col {
                     self.rows(start_col, end_col - start_col)
                         .nth(usize::from(start_row))
@@ -212,7 +213,7 @@ impl Screen {
                     String::new()
                 }
             }
-            std::cmp::Ordering::Greater => String::new(),
+            core::cmp::Ordering::Greater => String::new(),
         }
     }
 

src/term.rs

@@ -1,5 +1,7 @@
 // TODO: read all of this from terminfo
 
+use alloc::vec::Vec;
+
 pub trait BufWrite {
     fn write_buf(&self, buf: &mut Vec<u8>);
 }

tests/write.rs

@@ -1,5 +1,13 @@
+#![cfg(any(feature = "std", feature = "embedded-io"))]
+
+#[cfg(feature = "std")]
 use std::io::Write as _;
 
+// Caveat: if both embedded-io and std features are specified, we only test
+// the std feature.
+#[cfg(all(feature = "embedded-io", not(feature = "std")))]
+use embedded_io::Write as _;
+
 #[test]
 fn write_text() {
     let mut parser = vt100::Parser::default();