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, 141 insertions, 0 deletions

diff --git a/src/base/test/bit_stream_test.cpp b/src/base/test/bit_stream_test.cpp
new file mode 100644
index 0000000..0c4b3c9
--- /dev/null
+++ b/src/base/test/bit_stream_test.cpp
@@ -0,0 +1,141 @@
+// 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.
+
+#include "src/base/bit_stream.h"
+
+#include <gtest/gtest.h>
+
+namespace astc_codec {
+namespace base {
+
+namespace {
+  static constexpr uint64_t kAllBits = 0xFFFFFFFFFFFFFFFF;
+  static constexpr uint64_t k40Bits = 0x000000FFFFFFFFFF;
+}
+
+TEST(BitStream, Decode) {
+  {
+    BitStream<uint64_t> stream(0, 1);
+
+    uint64_t bits = kAllBits;
+    EXPECT_TRUE(stream.GetBits(1, &bits));
+    EXPECT_EQ(bits, 0);
+    EXPECT_FALSE(stream.GetBits(1, &bits));
+  }
+
+  {
+    BitStream<uint64_t> stream(0b1010101010101010, 32);
+    EXPECT_EQ(stream.Bits(), 32);
+
+    uint64_t bits = 0;
+    EXPECT_TRUE(stream.GetBits(1, &bits));
+    EXPECT_EQ(bits, 0);
+
+    EXPECT_TRUE(stream.GetBits(3, &bits));
+    EXPECT_EQ(bits, 0b101);
+
+    EXPECT_TRUE(stream.GetBits(8, &bits));
+    EXPECT_EQ(bits, 0b10101010);
+
+    EXPECT_EQ(stream.Bits(), 20);
+
+    EXPECT_TRUE(stream.GetBits(20, &bits));
+    EXPECT_EQ(bits, 0b1010);
+    EXPECT_EQ(stream.Bits(), 0);
+  }
+
+  {
+    BitStream<uint64_t> stream(kAllBits, 64);
+    EXPECT_EQ(stream.Bits(), 64);
+
+    uint64_t bits = 0;
+    EXPECT_TRUE(stream.GetBits(64, &bits));
+    EXPECT_EQ(bits, kAllBits);
+    EXPECT_EQ(stream.Bits(), 0);
+  }
+
+  {
+    BitStream<uint64_t> stream(kAllBits, 64);
+    EXPECT_EQ(stream.Bits(), 64);
+
+    uint64_t bits = 0;
+    EXPECT_TRUE(stream.GetBits(40, &bits));
+    EXPECT_EQ(bits, k40Bits);
+    EXPECT_EQ(stream.Bits(), 24);
+  }
+
+  {
+    BitStream<uint64_t> stream(kAllBits, 32);
+
+    uint64_t bits = 0;
+    EXPECT_TRUE(stream.GetBits(0, &bits));
+    EXPECT_EQ(bits, 0);
+    EXPECT_TRUE(stream.GetBits(32, &bits));
+    EXPECT_EQ(bits, k40Bits & 0xFFFFFFFF);
+    EXPECT_TRUE(stream.GetBits(0, &bits));
+    EXPECT_EQ(bits, 0);
+    EXPECT_EQ(stream.Bits(), 0);
+  }
+}
+
+TEST(BitStream, Encode) {
+  {
+    BitStream<uint64_t> stream;
+
+    stream.PutBits(0, 1);
+    stream.PutBits(0b11, 2);
+    EXPECT_EQ(stream.Bits(), 3);
+
+    uint64_t bits = 0;
+    EXPECT_TRUE(stream.GetBits(3, &bits));
+    EXPECT_EQ(bits, 0b110);
+  }
+
+  {
+    BitStream<uint64_t> stream;
+
+    uint64_t bits = 0;
+    stream.PutBits(kAllBits, 64);
+    EXPECT_EQ(stream.Bits(), 64);
+
+    EXPECT_TRUE(stream.GetBits(64, &bits));
+    EXPECT_EQ(bits, kAllBits);
+    EXPECT_EQ(stream.Bits(), 0);
+  }
+
+  {
+    BitStream<uint64_t> stream;
+    stream.PutBits(kAllBits, 40);
+
+    uint64_t bits = 0;
+    EXPECT_TRUE(stream.GetBits(40, &bits));
+    EXPECT_EQ(bits, k40Bits);
+    EXPECT_EQ(stream.Bits(), 0);
+  }
+
+  {
+    BitStream<uint64_t> stream;
+    stream.PutBits(0, 0);
+    stream.PutBits(kAllBits, 32);
+    stream.PutBits(0, 0);
+
+    uint64_t bits = 0;
+    EXPECT_TRUE(stream.GetBits(32, &bits));
+    EXPECT_EQ(bits, k40Bits & 0xFFFFFFFF);
+    EXPECT_EQ(stream.Bits(), 0);
+  }
+}
+
+}  // namespace base
+}  // namespace astc_codec