Create no_std examples

jaarg-nostd/src/simplepathbuf.rs

@@ -0,0 +1,81 @@
+/* jaarg-nostd - Minimal harness to run examples in no_std on desktop
+ * SPDX-FileCopyrightText: (C) 2025 Gay Pizza Specifications
+ * SPDX-License-Identifier: MIT
+ */
+
+use alloc::format;
+use alloc::string::String;
+use core::fmt::{Display, Formatter};
+
+/// Dirty and simple path buffer that's good enough for the `no_std` examples, not for production use.
+#[derive(Default, Debug, Eq, PartialEq, Ord, PartialOrd)]
+pub struct SimplePathBuf(String);
+
+impl<S: AsRef<str>> From<S> for SimplePathBuf where String: From<S> {
+  fn from(value: S) -> Self {
+    Self(value.into())
+  }
+}
+
+impl Display for SimplePathBuf {
+  fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+    write!(f, "{}", self.0)
+  }
+}
+
+impl SimplePathBuf {
+  #[inline(always)]
+  fn path_predicate(c: char) -> bool {
+    #[cfg(target_family = "windows")]
+    if c == '\\' { return true; }
+    c == '/'
+  }
+
+  pub fn with_extension(&self, ext: &str) -> Self {
+    let dir_sep = self.0.rfind(Self::path_predicate)
+      .map_or(0, |n| n + 1);
+    let without_ext: &str = self.0[dir_sep..].rfind('.')
+      .map_or(&self.0, |ext_sep_rel| {
+        if ext_sep_rel == 0 { return &self.0; }
+        let ext_sep = dir_sep + ext_sep_rel;
+        &self.0[..ext_sep]
+      });
+    Self(format!("{without_ext}.{ext}"))
+  }
+
+  pub fn basename(&self) -> &str {
+    self.0.trim_end_matches(|c| Self::path_predicate(c) || c == '.')
+      .rsplit_once(Self::path_predicate)
+      .map_or(&self.0, |(_, base)| base)
+  }
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  #[test]
+  fn test_with_extension() {
+    assert_eq!(
+      SimplePathBuf::from("name.ext").with_extension("new"),
+      SimplePathBuf::from("name.new"));
+    assert_eq!(
+      SimplePathBuf::from("/path/name.ext").with_extension("new"),
+      SimplePathBuf::from("/path/name.new"));
+    assert_eq!(
+      SimplePathBuf::from("/path.ext/name").with_extension("new"),
+      SimplePathBuf::from("/path.ext/name.new"));
+    assert_eq!(
+      SimplePathBuf::from("/path.ext/.name").with_extension("new"),
+      SimplePathBuf::from("/path.ext/.name.new"));
+  }
+
+  #[test]
+  fn test_basename() {
+    assert_eq!(SimplePathBuf::from("name.ext").basename(), "name.ext");
+    assert_eq!(SimplePathBuf::from("/path/name.ext").basename(), "name.ext");
+    assert_eq!(SimplePathBuf::from("/path/name/").basename(), "name");
+    assert_eq!(SimplePathBuf::from("/path/name/.").basename(), "name");
+    assert_eq!(SimplePathBuf::from("/path/name/.//").basename(), "name");
+  }
+}