Initial version of astc-codec for open source release

Contains an implementation of an ASTC decoder that is able to pass the
dEQP ASTC LDR tests.

astc-codec has no external dependencies for the main library, only for
test code, and is licensed under the Apache license.

Components:

include/ - Public API that can decode ASTC LDR data into a RGBA UNORM8
buffer.

src/base/ - Base library with common functionality not directly related
to ASTC decoding.  Contains a uint128 implementation, BitStream for
reading/writing bits with a primitive (or uint128 type), Optional
implementation (to not take a dependency on C++17), and more.

src/decoder/ - Internal implementation of the ASTC decoder.

src/base/test/, src/decoder/test/ - Unit tests (and a fuzzing test) for
the astc decoder.

src/decoder/testdata/ - Sample ASTC images and golden image results for
testing.

src/decoder/tools/ - A tool to inspect contents of an ASTC file.

third_party/ - Third party libraries, only used for tests.

Change-Id: Ia98e5a7dc847daa3d3a48c5e62d94b8fb1cb98bd

1 files changed, 38 insertions, 0 deletions

diff --git a/src/decoder/weight_infill.h b/src/decoder/weight_infill.h
new file mode 100644
index 0000000..4a09d35
--- /dev/null
+++ b/src/decoder/weight_infill.h
@@ -0,0 +1,38 @@
+// 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_WEIGHT_INFILL_H_
+#define ASTC_CODEC_DECODER_WEIGHT_INFILL_H_
+
+#include "src/decoder/footprint.h"
+
+#include <vector>
+
+namespace astc_codec {
+
+// Returns the number of bits used to represent the weight grid at the target
+// dimensions and weight range.
+int CountBitsForWeights(int weight_dim_x, int weight_dim_y,
+                        int target_weight_range);
+
+// Performs weight infill of a grid of weights of size |dim_x * dim_y|. The
+// weights are fit using the algorithm laid out in Section C.2.18 of the ASTC
+// specification. Weights are expected to be passed unquantized and the returned
+// grid will be unquantized as well (i.e. each weight within the range [0, 64]).
+std::vector<int> InfillWeights(const std::vector<int>& weights,
+                               Footprint footprint, int dim_x, int dim_y);
+
+}  // namespace astc_codec
+
+#endif  // ASTC_CODEC_DECODER_WEIGHT_INFILL_H_