Add features to work with no_std, and with alloc in no_std

Cargo.toml

@@ -13,13 +13,15 @@ readme = "README.md"
 rust-version = "1.66"
 
 [features]
-default = ["unicode-width", "ansi-parsing"]
+default = ["unicode-width", "ansi-parsing", "std"]
+std = ["dep:libc", "dep:once_cell", "alloc"]
+alloc = []
 windows-console-colors = ["ansi-parsing"]
 ansi-parsing = []
 
 [dependencies]
-libc = "0.2.99"
-once_cell = "1.8"
+libc = { version = "0.2.99", optional = true }
+once_cell = { version = "1.8", optional = true }
 unicode-width = { version = "0.2", optional = true }
 
 [target.'cfg(windows)'.dependencies]
@@ -43,6 +45,26 @@ proptest = { version = "1.0.0", default-features = false, features = [
 ] }
 regex = "1.4.2"
 
+[[example]]
+name = "colors"
+required-features = ["std"]
+
+[[example]]
+name = "colors256"
+required-features = ["std"]
+
+[[example]]
+name = "cursor_at"
+required-features = ["std"]
+
+[[example]]
+name = "keyboard"
+required-features = ["std"]
+
+[[example]]
+name = "term"
+required-features = ["std"]
+
 ## These are currently disabled.  If you want to play around with the benchmarks
 ## uncommit this.
 #criterion = "0.3.5"

Makefile

@@ -13,9 +13,11 @@ test:
 	@echo "CARGO TESTS"
 	@cargo test
 	@cargo test --all-features
-	@cargo test --no-default-features
-	@cargo test --no-default-features --features ansi-parsing
-	@cargo test --no-default-features --features unicode-width
+	@cargo test --lib --no-default-features
+	@cargo test --lib --no-default-features --features alloc
+	@cargo test --no-default-features --features std
+	@cargo test --no-default-features --features std,ansi-parsing
+	@cargo test --no-default-features --features std,unicode-width
 
 check-minver:
 	@echo "MINVER CHECK"

src/ansi.rs

@@ -1,5 +1,6 @@
-use std::{
-    borrow::Cow,
+#[cfg(feature = "alloc")]
+use alloc::{borrow::Cow, string::String};
+use core::{
     iter::{FusedIterator, Peekable},
     str::CharIndices,
 };
@@ -186,6 +187,7 @@ fn find_ansi_code_exclusive(it: &mut Peekable<CharIndices>) -> Option<(usize, us
 }
 
 /// Helper function to strip ansi codes.
+#[cfg(feature = "alloc")]
 pub fn strip_ansi_codes(s: &str) -> Cow<str> {
     let mut char_it = s.char_indices().peekable();
     match find_ansi_code_exclusive(&mut char_it) {

src/kb.rs

@@ -1,3 +1,5 @@
+use alloc::vec::Vec;
+
 /// Key mapping
 ///
 /// This is an incomplete mapping of keys that are supported for reading

src/lib.rs

@@ -76,30 +76,46 @@
 //!   for stripping and taking ansi escape codes into account for length
 //!   calculations).
 
-#![warn(unreachable_pub)]
+#![warn(
+    unreachable_pub,
+    clippy::std_instead_of_core,
+    clippy::std_instead_of_alloc
+)]
+#![cfg_attr(not(feature = "std"), no_std)]
+#[cfg(feature = "alloc")]
+extern crate alloc;
 
+#[cfg(feature = "alloc")]
 pub use crate::kb::Key;
+#[cfg(feature = "std")]
 pub use crate::term::{
     user_attended, user_attended_stderr, Term, TermFamily, TermFeatures, TermTarget,
 };
+#[cfg(feature = "std")]
 pub use crate::utils::{
     colors_enabled, colors_enabled_stderr, measure_text_width, pad_str, pad_str_with,
     set_colors_enabled, set_colors_enabled_stderr, style, truncate_str, Alignment, Attribute,
     Color, Emoji, Style, StyledObject,
 };
 
+#[cfg(all(feature = "ansi-parsing", feature = "alloc"))]
+pub use crate::ansi::strip_ansi_codes;
 #[cfg(feature = "ansi-parsing")]
-pub use crate::ansi::{strip_ansi_codes, AnsiCodeIterator};
+pub use crate::ansi::AnsiCodeIterator;
 
+#[cfg(feature = "std")]
 mod common_term;
+#[cfg(feature = "alloc")]
 mod kb;
+#[cfg(feature = "std")]
 mod term;
-#[cfg(all(unix, not(target_arch = "wasm32")))]
+#[cfg(all(unix, not(target_arch = "wasm32"), feature = "std"))]
 mod unix_term;
+#[cfg(feature = "std")]
 mod utils;
-#[cfg(target_arch = "wasm32")]
+#[cfg(all(feature = "std", target_arch = "wasm32"))]
 mod wasm_term;
-#[cfg(windows)]
+#[cfg(all(feature = "std", windows))]
 mod windows_term;
 
 #[cfg(feature = "ansi-parsing")]

src/term.rs

@@ -1,11 +1,11 @@
-use std::fmt::{Debug, Display};
+use alloc::sync::Arc;
+use core::fmt::{Debug, Display};
 use std::io::{self, Read, Write};
-use std::sync::{Arc, Mutex, RwLock};
-
 #[cfg(any(unix, all(target_os = "wasi", target_env = "p1")))]
 use std::os::fd::{AsRawFd, RawFd};
 #[cfg(windows)]
 use std::os::windows::io::{AsRawHandle, RawHandle};
+use std::sync::{Mutex, RwLock};
 
 use crate::{kb::Key, utils::Style};
 

src/unix_term.rs

@@ -1,10 +1,8 @@
+use core::{fmt::Display, mem, str};
 use std::env;
-use std::fmt::Display;
 use std::fs;
 use std::io::{self, BufRead, BufReader};
-use std::mem;
 use std::os::fd::{AsRawFd, RawFd};
-use std::str;
 
 #[cfg(not(target_os = "macos"))]
 use once_cell::sync::Lazy;

src/utils.rs

@@ -1,8 +1,9 @@
-use std::borrow::Cow;
+use alloc::borrow::Cow;
+use core::{
+    fmt::{self, Debug, Formatter},
+    sync::atomic::{AtomicBool, Ordering},
+};
 use std::env;
-use std::fmt;
-use std::fmt::{Debug, Formatter};
-use std::sync::atomic::{AtomicBool, Ordering};
 
 use once_cell::sync::Lazy;
 
@@ -820,7 +821,7 @@ pub fn truncate_str<'a>(s: &'a str, width: usize, tail: &str) -> Cow<'a, str> {
 
     #[cfg(feature = "ansi-parsing")]
     {
-        use std::cmp::Ordering;
+        use core::cmp::Ordering;
         let mut iter = AnsiCodeIterator::new(s);
         let mut length = 0;
         let mut rv = None;