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node_modules/react-native/ReactCommon/react/renderer/css/CSSRatio.h

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+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+#include <optional>
+#include <variant>
+
+#include <react/renderer/css/CSSDataType.h>
+#include <react/renderer/css/CSSNumber.h>
+#include <react/renderer/css/CSSValueParser.h>
+
+namespace facebook::react {
+
+/**
+ * Representation of CSS <ratio> data type
+ * https://www.w3.org/TR/css-values-4/#ratios
+ */
+struct CSSRatio {
+  float numerator{};
+  float denominator{};
+
+  constexpr bool operator==(const CSSRatio &rhs) const = default;
+
+  constexpr bool isDegenerate() const
+  {
+    // If either number in the <ratio> is 0 or infinite, it represents a
+    // degenerate ratio (and, generally, won’t do anything).
+    // https://www.w3.org/TR/css-values-4/#ratios
+    return numerator == 0.0f || numerator == std::numeric_limits<float>::infinity() || denominator == 0.0f ||
+        denominator == std::numeric_limits<float>::infinity();
+  }
+};
+
+template <>
+struct CSSDataTypeParser<CSSRatio> {
+  static constexpr auto consume(CSSSyntaxParser &parser) -> std::optional<CSSRatio>
+  {
+    // <ratio> = <number [0,∞]> [ / <number [0,∞]> ]?
+    // https://www.w3.org/TR/css-values-4/#ratio
+    auto numerator = parseNextCSSValue<CSSNumber>(parser);
+    if (!std::holds_alternative<CSSNumber>(numerator)) {
+      return {};
+    }
+
+    auto numeratorValue = std::get<CSSNumber>(numerator).value;
+    if (numeratorValue >= 0) {
+      auto denominator = peekNextCSSValue<CSSNumber>(parser, CSSDelimiter::Solidus);
+      if (std::holds_alternative<CSSNumber>(denominator) && std::get<CSSNumber>(denominator).value >= 0) {
+        parseNextCSSValue<CSSNumber>(parser, CSSDelimiter::Solidus);
+        return CSSRatio{.numerator = numeratorValue, .denominator = std::get<CSSNumber>(denominator).value};
+      }
+
+      return CSSRatio{.numerator = numeratorValue, .denominator = 1.0f};
+    }
+
+    return {};
+  }
+};
+
+static_assert(CSSDataType<CSSRatio>);
+
+} // namespace facebook::react