Support no_std

This increases the MSRV to 1.81 for `core::error`.

.github/workflows/ci.yml

@@ -8,10 +8,12 @@ env:
   # If the compilation fails, then the version specified here needs to be bumped up to reality.
   # Be sure to also update the rust-version property in the workspace Cargo.toml file,
   # plus all the README.md files of the affected packages.
-  RUST_MIN_VER: "1.65"
+  RUST_MIN_VER: "1.81"
   # List of packages that will be checked with the minimum supported Rust version.
   # This should be limited to packages that are intended for publishing.
   RUST_MIN_VER_PKGS: "-p svgtypes"
+  # List of features that depend on the standard library and will be excluded from no_std checks.
+  FEATURES_DEPENDING_ON_STD: "std,default"
 
 
 # Rationale
@@ -39,6 +41,10 @@ env:
 # The MSRV jobs run only cargo check because different clippy versions can disagree on goals and
 # running tests introduces dev dependencies which may require a higher MSRV than the bare package.
 #
+# For no_std checks we target x86_64-unknown-none, because this target doesn't support std
+# and as such will error out if our dependency tree accidentally tries to use std.
+# https://doc.rust-lang.org/stable/rustc/platform-support/x86_64-unknown-none.html
+#
 # We don't save caches in the merge-group cases, because those caches will never be re-used (apart
 # from the very rare cases where there are multiple PRs in the merge queue).
 # This is because GitHub doesn't share caches between merge queues and the main branch.
@@ -105,11 +111,14 @@ jobs:
         with:
           save-if: ${{ github.event_name != 'merge_group' }}
 
+      - name: cargo clippy (no_std)
+        run: cargo hack clippy --workspace --locked --optional-deps --each-feature --ignore-unknown-features --features libm --exclude-features ${{ env.FEATURES_DEPENDING_ON_STD }} --target x86_64-unknown-none -- -D warnings
+
       - name: cargo clippy
-        run: cargo hack clippy --workspace --locked --optional-deps --each-feature -- -D warnings
+        run: cargo hack clippy --workspace --locked --optional-deps --each-feature --ignore-unknown-features --features std -- -D warnings
 
       - name: cargo clippy (auxiliary)
-        run: cargo hack clippy --workspace --locked --optional-deps --each-feature --tests --examples -- -D warnings
+        run: cargo hack clippy --workspace --locked --optional-deps --each-feature --ignore-unknown-features --features std --tests --examples -- -D warnings
 
   clippy-stable-wasm:
     name: cargo clippy (wasm32)
@@ -135,10 +144,10 @@ jobs:
           save-if: ${{ github.event_name != 'merge_group' }}
 
       - name: cargo clippy
-        run: cargo hack clippy --workspace --locked --target wasm32-unknown-unknown --optional-deps --each-feature -- -D warnings
+        run: cargo hack clippy --workspace --locked --target wasm32-unknown-unknown --optional-deps --each-feature --ignore-unknown-features --features std -- -D warnings
 
       - name: cargo clippy (auxiliary)
-        run: cargo hack clippy --workspace --locked --target wasm32-unknown-unknown --optional-deps --each-feature --tests --examples -- -D warnings
+        run: cargo hack clippy --workspace --locked --target wasm32-unknown-unknown --optional-deps --each-feature --ignore-unknown-features --features std --tests --examples -- -D warnings
 
   test-stable:
     name: cargo test
@@ -216,8 +225,11 @@ jobs:
         with:
           save-if: ${{ github.event_name != 'merge_group' }}
 
+      - name: cargo check (no_std)
+        run: cargo hack check ${{ env.RUST_MIN_VER_PKGS }} --locked --optional-deps --each-feature --ignore-unknown-features --features libm --exclude-features ${{ env.FEATURES_DEPENDING_ON_STD }} --target x86_64-unknown-none
+
       - name: cargo check
-        run: cargo hack check ${{ env.RUST_MIN_VER_PKGS }} --locked --optional-deps --each-feature
+        run: cargo hack check ${{ env.RUST_MIN_VER_PKGS }} --locked --optional-deps --each-feature --ignore-unknown-features --features std
 
   check-msrv-wasm:
     name: cargo check (msrv) (wasm32)
@@ -242,7 +254,7 @@ jobs:
           save-if: ${{ github.event_name != 'merge_group' }}
 
       - name: cargo check
-        run: cargo hack check ${{ env.RUST_MIN_VER_PKGS }} --locked --target wasm32-unknown-unknown --optional-deps --each-feature
+        run: cargo hack check ${{ env.RUST_MIN_VER_PKGS }} --locked --target wasm32-unknown-unknown --optional-deps --each-feature --ignore-unknown-features --features std
 
   doc:
     name: cargo doc

Cargo.toml

@@ -15,6 +15,11 @@ exclude = ["benches/", "codegen/", "fuzz/"]
 [workspace]
 members = ["benches"]
 
+[features]
+default = ["std"]
+std = ["kurbo/std"]
+libm = ["kurbo/libm"]
+
 [dependencies]
 siphasher = "1.0" # perfect hash implementation for color names
-kurbo = "0.11" # ArcTo to CurveTo(s)
+kurbo = { version = "0.11", default-features = false } # ArcTo to CurveTo(s)

src/angle.rs

@@ -42,7 +42,7 @@ impl Angle {
     }
 }
 
-impl std::str::FromStr for Angle {
+impl core::str::FromStr for Angle {
     type Err = Error;
 
     #[inline]
@@ -99,7 +99,7 @@ impl Stream<'_> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     macro_rules! test_p {
         ($name:ident, $text:expr, $result:expr) => (

src/aspect_ratio.rs

@@ -41,7 +41,7 @@ pub struct AspectRatio {
     pub slice: bool,
 }
 
-impl std::str::FromStr for AspectRatio {
+impl core::str::FromStr for AspectRatio {
     type Err = Error;
 
     fn from_str(text: &str) -> Result<Self, Error> {
@@ -109,7 +109,7 @@ impl Default for AspectRatio {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     macro_rules! test {
         ($name:ident, $text:expr, $result:expr) => (

src/color.rs

@@ -3,6 +3,9 @@
 
 use crate::{colors, ByteExt, Error, Stream};
 
+#[cfg(not(feature = "std"))]
+use kurbo::common::FloatFuncs;
+
 /// Representation of the [`<color>`] type.
 ///
 /// [`<color>`]: https://www.w3.org/TR/css-color-3/
@@ -75,7 +78,7 @@ impl Color {
     }
 }
 
-impl std::str::FromStr for Color {
+impl core::str::FromStr for Color {
     type Err = Error;
 
     /// Parses [CSS3](https://www.w3.org/TR/css-color-3/) `Color` from a string.
@@ -300,7 +303,7 @@ fn hue_to_rgb(t1: f32, t2: f32, mut hue: f32) -> f32 {
 
 #[inline]
 fn bound<T: Ord>(min: T, val: T, max: T) -> T {
-    std::cmp::max(min, std::cmp::min(max, val))
+    core::cmp::max(min, core::cmp::min(max, val))
 }
 
 #[inline]
@@ -314,7 +317,7 @@ fn f64_bound(min: f64, val: f64, max: f64) -> f64 {
 #[rustfmt::skip]
 #[cfg(test)]
 mod tests {
-    use std::str::FromStr;
+    use core::str::FromStr;
     use crate::Color;
 
     macro_rules! test {

src/colors.rs

@@ -199,7 +199,7 @@ pub fn from_str(text: &str) -> Option<Color> {
 //
 // https://github.com/sfackler/rust-phf
 
-use std::hash::Hasher;
+use core::hash::Hasher;
 
 pub struct Map<V: 'static> {
     pub key: u64,

src/directional_position.rs

@@ -2,6 +2,8 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use crate::{Error, Length, LengthUnit, Stream};
+use alloc::string::ToString;
+use alloc::vec;
 
 /// List of all SVG directional positions.
 #[derive(Clone, Copy, PartialEq, Eq, Debug)]
@@ -52,7 +54,7 @@ impl From<DirectionalPosition> for Length {
     }
 }
 
-impl std::str::FromStr for DirectionalPosition {
+impl core::str::FromStr for DirectionalPosition {
     type Err = Error;
 
     #[inline]
@@ -108,7 +110,7 @@ impl Stream<'_> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     macro_rules! test_p {
         ($name:ident, $text:expr, $result:expr) => (

src/enable_background.rs

@@ -19,7 +19,7 @@ pub enum EnableBackground {
     },
 }
 
-impl std::str::FromStr for EnableBackground {
+impl core::str::FromStr for EnableBackground {
     type Err = Error;
 
     fn from_str(text: &str) -> Result<Self, Self::Err> {
@@ -71,7 +71,7 @@ impl std::str::FromStr for EnableBackground {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     #[test]
     fn parse_1() {

src/error.rs

@@ -1,6 +1,10 @@
 // Copyright 2018 the SVG Types Authors
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
+use alloc::string::String;
+use alloc::vec;
+use alloc::vec::Vec;
+
 /// List of all errors.
 #[derive(Debug, PartialEq, Eq)]
 pub enum Error {
@@ -46,8 +50,8 @@ pub enum Error {
     InvalidNumber(usize),
 }
 
-impl std::fmt::Display for Error {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+impl core::fmt::Display for Error {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         match *self {
             Error::UnexpectedEndOfStream => {
                 write!(f, "unexpected end of stream")
@@ -93,7 +97,7 @@ impl std::fmt::Display for Error {
     }
 }
 
-impl std::error::Error for Error {
+impl core::error::Error for Error {
     fn description(&self) -> &str {
         "an SVG data parsing error"
     }

src/filter_functions.rs

@@ -73,8 +73,8 @@ impl From<Error> for FilterValueListParserError {
     }
 }
 
-impl std::fmt::Display for FilterValueListParserError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+impl core::fmt::Display for FilterValueListParserError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         match *self {
             FilterValueListParserError::PercentageValue(pos) => {
                 write!(f, "a percentage value detected at position {}", pos)
@@ -102,7 +102,7 @@ impl std::fmt::Display for FilterValueListParserError {
     }
 }
 
-impl std::error::Error for FilterValueListParserError {
+impl core::error::Error for FilterValueListParserError {
     fn description(&self) -> &str {
         "filter-value-list parsing error"
     }

src/font.rs

@@ -3,7 +3,11 @@
 
 use crate::stream::{ByteExt, Stream};
 use crate::Error;
-use std::fmt::Display;
+use alloc::format;
+use alloc::string::{String, ToString};
+use alloc::vec;
+use alloc::vec::Vec;
+use core::fmt::Display;
 
 /// Parses a list of font families and generic families from a string.
 pub fn parse_font_families(text: &str) -> Result<Vec<FontFamily>, Error> {
@@ -36,7 +40,7 @@ pub enum FontFamily {
 }
 
 impl Display for FontFamily {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
         let str = match self {
             FontFamily::Monospace => "monospace".to_string(),
             FontFamily::Serif => "serif".to_string(),

src/length.rs

@@ -64,7 +64,7 @@ impl Default for Length {
     }
 }
 
-impl std::str::FromStr for Length {
+impl core::str::FromStr for Length {
     type Err = Error;
 
     #[inline]
@@ -187,7 +187,7 @@ impl Iterator for LengthListParser<'_> {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     macro_rules! test_p {
         ($name:ident, $text:expr, $result:expr) => (

src/lib.rs

@@ -51,11 +51,14 @@
 None.
 */
 
+#![cfg_attr(all(not(feature = "std"), not(test)), no_std)]
 #![forbid(unsafe_code)]
 #![deny(missing_docs)]
 #![deny(missing_debug_implementations)]
 #![deny(missing_copy_implementations)]
 
+extern crate alloc;
+
 macro_rules! matches {
     ($expression:expr, $($pattern:tt)+) => {
         match $expression {

src/number.rs

@@ -1,15 +1,15 @@
 // Copyright 2018 the SVG Types Authors
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
-use std::str::FromStr;
+use core::str::FromStr;
 
 use crate::{ByteExt, Error, Stream};
 
 /// An [SVG number](https://www.w3.org/TR/SVG2/types.html#InterfaceSVGNumber).
 #[derive(Clone, Copy, PartialEq, Debug)]
 pub struct Number(pub f64);
 
-impl std::str::FromStr for Number {
+impl core::str::FromStr for Number {
     type Err = Error;
 
     fn from_str(text: &str) -> Result<Self, Self::Err> {

src/paint.rs

@@ -1,7 +1,7 @@
 // Copyright 2018 the SVG Types Authors
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
-use std::str::FromStr;
+use core::str::FromStr;
 
 use crate::{Color, Error, Stream};
 

src/paint_order.rs

@@ -2,6 +2,8 @@
 // SPDX-License-Identifier: Apache-2.0 OR MIT
 
 use crate::stream::Stream;
+use alloc::vec;
+use alloc::vec::Vec;
 
 /// [`paint-order`] property variants.
 ///
@@ -45,7 +47,7 @@ impl From<[PaintOrderKind; 3]> for PaintOrder {
     }
 }
 
-impl std::str::FromStr for PaintOrder {
+impl core::str::FromStr for PaintOrder {
     type Err = ();
 
     /// Parses `PaintOrder` from a string.
@@ -112,7 +114,7 @@ impl std::str::FromStr for PaintOrder {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use std::str::FromStr;
+    use core::str::FromStr;
 
     #[test]
     fn parse_1() {