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diff --git a/src/decoder/footprint.h b/src/decoder/footprint.h
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+// Copyright 2018 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ASTC_CODEC_DECODER_FOOTPRINT_H_
+#define ASTC_CODEC_DECODER_FOOTPRINT_H_
+
+#include "include/astc-codec/astc-codec.h"
+#include "src/base/optional.h"
+
+#include <cstddef>
+
+namespace astc_codec {
+
+// An ASTC texture can be encoded with varying choices in block size. A set of
+// predefined block sizes are specified in the ASTC specification. These are
+// referred to in the literature as "footprints" available to an encoder when
+// constructing an ASTC bitstream. This class provides various utility functions
+// for interacting with these footprints.
+class Footprint {
+ public:
+  Footprint() = delete;
+  Footprint(const Footprint& footprint) = default;
+
+  // Return the footprint type.
+  FootprintType Type() const { return footprint_; }
+
+  // Return logical descriptions of the dimensions.
+  int Width() const { return width_; }
+  int Height() const { return height_; }
+
+  // Returns the number of pixels for a block with this footprint.
+  int NumPixels() const { return width_ * height_; }
+
+  // Returns the number of bytes needed to store an ASTC encoded image with the
+  // given width and height.
+  size_t StorageRequirements(int width, int height) const;
+
+  // Returns the number of bits used per pixel.
+  float Bitrate() const;
+
+  static constexpr int NumValidFootprints() {
+    return static_cast<int>(FootprintType::kCount);
+  }
+
+  bool operator==(const Footprint& other) const {
+    return footprint_ == other.footprint_;
+  }
+
+  // These are the valid and available ASTC footprints.
+  static Footprint Get4x4() { return Footprint(FootprintType::k4x4); }
+  static Footprint Get5x4() { return Footprint(FootprintType::k5x4); }
+  static Footprint Get5x5() { return Footprint(FootprintType::k5x5); }
+  static Footprint Get6x5() { return Footprint(FootprintType::k6x5); }
+  static Footprint Get6x6() { return Footprint(FootprintType::k6x6); }
+  static Footprint Get8x5() { return Footprint(FootprintType::k8x5); }
+  static Footprint Get8x6() { return Footprint(FootprintType::k8x6); }
+  static Footprint Get8x8() { return Footprint(FootprintType::k8x8); }
+  static Footprint Get10x5() { return Footprint(FootprintType::k10x5); }
+  static Footprint Get10x6() { return Footprint(FootprintType::k10x6); }
+  static Footprint Get10x8() { return Footprint(FootprintType::k10x8); }
+  static Footprint Get10x10() { return Footprint(FootprintType::k10x10); }
+  static Footprint Get12x10() { return Footprint(FootprintType::k12x10); }
+  static Footprint Get12x12() { return Footprint(FootprintType::k12x12); }
+
+  // Constructs a footprint from a string of the form "NxM", or no value if
+  // width and height are not a valid footprint.
+  static base::Optional<Footprint> Parse(const char* footprint_string);
+
+  // Returns a footprint corresponding to a block of the given width and height,
+  // or no value if it does not.
+  static base::Optional<Footprint> FromDimensions(int width, int height);
+
+  // Returns a Footprint for the given FootprintType.
+  static base::Optional<Footprint> FromFootprintType(FootprintType type);
+
+ private:
+  // The only constructor.
+  explicit Footprint(FootprintType footprint);
+
+  // Returns the valid footprint for the width and height if possible.
+  static base::Optional<FootprintType> GetValidFootprintForDimensions(
+      int width, int height);
+
+  // Returns the associated dimension for the given valid footprint.
+  static int GetWidthForFootprint(FootprintType footprint);
+  static int GetHeightForFootprint(FootprintType footprint);
+
+  FootprintType footprint_;
+  int width_;
+  int height_;
+};
+
+}  // namespace astc_codec
+
+#endif  // ASTC_CODEC_DECODER_FOOTPRINT_H_