feat: complete no-std support

Author: boquanfu

Cargo.toml

@@ -23,9 +23,10 @@ encoding_rs = "0.8"
 cssparser-macros = { path = "./macros", version = "0.6.1" }
 dtoa-short = "0.3"
 itoa = "1.0"
-phf = { version = "0.11.2", features = ["macros"] }
+phf = { version = "0.11.2", features = ["macros"], default-features = false }
 serde = { version = "1.0", features = ["derive"], optional = true }
 smallvec = "1.0"
+libm = "0.2.8"
 
 [profile.profiling]
 inherits = "release"
@@ -37,7 +38,7 @@ bench = []
 dummy_match_byte = []
 # Useful for skipping tests when execution is slow, e.g., under miri
 skip_long_tests = []
-std = []
+std = ["phf/std"]
 
 [workspace]
 members = [".", "./macros", "./color"]

src/color.rs

@@ -41,7 +41,7 @@ pub fn clamp_unit_f32(val: f32) -> u8 {
 /// Round and clamp a single number to a u8.
 #[inline]
 pub fn clamp_floor_256_f32(val: f32) -> u8 {
-    val.round().clamp(0., 255.) as u8
+    crate::math::f32_round(val).clamp(0., 255.) as u8
 }
 
 /// Serialize the alpha copmonent of a color according to the specification.
@@ -65,9 +65,9 @@ pub fn serialize_color_alpha(
     dest.write_str(if legacy_syntax { ", " } else { " / " })?;
 
     // Try first with two decimal places, then with three.
-    let mut rounded_alpha = (alpha * 100.).round() / 100.;
+    let mut rounded_alpha = crate::math::f32_round(alpha * 100.) / 100.;
     if clamp_unit_f32(rounded_alpha) != clamp_unit_f32(alpha) {
-        rounded_alpha = (alpha * 1000.).round() / 1000.;
+        rounded_alpha = crate::math::f32_round(alpha * 1000.) / 1000.;
     }
 
     rounded_alpha.to_css(dest)

src/lib.rs

@@ -103,6 +103,7 @@ mod nth;
 mod parser;
 mod serializer;
 mod unicode_range;
+mod math;
 
 #[cfg(test)]
 mod size_of_tests;

src/math.rs

@@ -0,0 +1,21 @@
+
+pub(crate) fn f32_trunc(val: f32) -> f32 {
+    #[cfg(feature = "std")]
+    { val.round() }
+    #[cfg(not(feature = "std"))]
+    { libm::roundf(val) }
+}
+
+pub(crate) fn f32_round(val: f32) -> f32 {
+    #[cfg(feature = "std")]
+    { val.round() }
+    #[cfg(not(feature = "std"))]
+    { libm::roundf(val) }
+}
+
+pub(crate) fn f64_pow(a: f64, b: f64) -> f64 {
+    #[cfg(feature = "std")]
+    { f64::powf(a, b) }
+    #[cfg(not(feature = "std"))]
+    { libm::pow(a, b) }
+}

src/serializer.rs

@@ -49,7 +49,7 @@ where
         dtoa_short::write(dest, value)?
     };
 
-    if int_value.is_none() && value.fract() == 0. && !notation.decimal_point && !notation.scientific
+    if int_value.is_none() && value == crate::math::f32_trunc(value) && !notation.decimal_point && !notation.scientific
     {
         dest.write_str(".0")?;
     }

src/tokenizer.rs

@@ -1083,7 +1083,7 @@ fn consume_numeric<'a>(tokenizer: &mut Tokenizer<'a>) -> Token<'a> {
                 break;
             }
         }
-        value *= f64::powf(10., sign * exponent);
+        value *= crate::math::f64_pow(10., sign * exponent);
     }
 
     let int_value = if is_integer {