LibWeb: Implement CSS Frequency class

This corresponds to `<frequency>` in the grammar.

1 files changed, 86 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/CSS/Frequency.cpp b/Userland/Libraries/LibWeb/CSS/Frequency.cpp
new file mode 100644
index 0000000000..31d1eb3ab4
--- /dev/null
+++ b/Userland/Libraries/LibWeb/CSS/Frequency.cpp
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2022, Sam Atkins <atkinssj@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "Frequency.h"
+#include <LibWeb/CSS/StyleValue.h>
+
+namespace Web::CSS {
+
+Frequency::Frequency(int value, Type type)
+    : m_type(type)
+    , m_value(value)
+{
+}
+
+Frequency::Frequency(float value, Type type)
+    : m_type(type)
+    , m_value(value)
+{
+}
+
+Frequency Frequency::make_calculated(NonnullRefPtr<CalculatedStyleValue> calculated_style_value)
+{
+    Frequency frequency { 0, Type::Calculated };
+    frequency.m_calculated_style = move(calculated_style_value);
+    return frequency;
+}
+
+Frequency Frequency::make_hertz(float value)
+{
+    return { value, Type::Hz };
+}
+
+Frequency Frequency::percentage_of(Percentage const& percentage) const
+{
+    VERIFY(!is_calculated());
+
+    return Frequency { percentage.as_fraction() * m_value, m_type };
+}
+
+String Frequency::to_string() const
+{
+    if (is_calculated())
+        return m_calculated_style->to_string();
+    return String::formatted("{}{}", m_value, unit_name());
+}
+
+float Frequency::to_hertz() const
+{
+    switch (m_type) {
+    case Type::Calculated:
+        return m_calculated_style->resolve_frequency()->to_hertz();
+    case Type::Hz:
+        return m_value;
+    case Type::kHz:
+        return m_value * 1000;
+    }
+    VERIFY_NOT_REACHED();
+}
+
+StringView Frequency::unit_name() const
+{
+    switch (m_type) {
+    case Type::Calculated:
+        return "calculated"sv;
+    case Type::Hz:
+        return "hz"sv;
+    case Type::kHz:
+        return "khz"sv;
+    }
+    VERIFY_NOT_REACHED();
+}
+
+Optional<Frequency::Type> Frequency::unit_from_name(StringView name)
+{
+    if (name.equals_ignoring_case("hz"sv)) {
+        return Type::Hz;
+    } else if (name.equals_ignoring_case("khz"sv)) {
+        return Type::kHz;
+    }
+    return {};
+}
+
+}