1 files changed, 173 insertions, 0 deletions
diff --git a/media/libaom/src/test/boolcoder_test.cc b/media/libaom/src/test/boolcoder_test.cc
new file mode 100644
index 000000000..680ec1877
--- /dev/null
+++ b/media/libaom/src/test/boolcoder_test.cc
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2016, Alliance for Open Media. All rights reserved
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "third_party/googletest/src/googletest/include/gtest/gtest.h"
+
+#include "test/acm_random.h"
+#include "aom/aom_integer.h"
+#include "aom_dsp/bitreader.h"
+#include "aom_dsp/bitwriter.h"
+
+using libaom_test::ACMRandom;
+
+namespace {
+const int num_tests = 10;
+}  // namespace
+
+TEST(AV1, TestBitIO) {
+  ACMRandom rnd(ACMRandom::DeterministicSeed());
+  for (int n = 0; n < num_tests; ++n) {
+    for (int method = 0; method <= 7; ++method) {  // we generate various proba
+      const int kBitsToTest = 1000;
+      uint8_t probas[kBitsToTest];
+
+      for (int i = 0; i < kBitsToTest; ++i) {
+        const int parity = i & 1;
+        /* clang-format off */
+        probas[i] =
+          (method == 0) ? 0 : (method == 1) ? 255 :
+          (method == 2) ? 128 :
+          (method == 3) ? rnd.Rand8() :
+          (method == 4) ? (parity ? 0 : 255) :
+            // alternate between low and high proba:
+            (method == 5) ? (parity ? rnd(128) : 255 - rnd(128)) :
+            (method == 6) ?
+            (parity ? rnd(64) : 255 - rnd(64)) :
+            (parity ? rnd(32) : 255 - rnd(32));
+        /* clang-format on */
+      }
+      for (int bit_method = 0; bit_method <= 3; ++bit_method) {
+        const int random_seed = 6432;
+        const int kBufferSize = 10000;
+        ACMRandom bit_rnd(random_seed);
+        aom_writer bw;
+        uint8_t bw_buffer[kBufferSize];
+        aom_start_encode(&bw, bw_buffer);
+
+        int bit = (bit_method == 0) ? 0 : (bit_method == 1) ? 1 : 0;
+        for (int i = 0; i < kBitsToTest; ++i) {
+          if (bit_method == 2) {
+            bit = (i & 1);
+          } else if (bit_method == 3) {
+            bit = bit_rnd(2);
+          }
+          aom_write(&bw, bit, static_cast<int>(probas[i]));
+        }
+
+        aom_stop_encode(&bw);
+
+        aom_reader br;
+        aom_reader_init(&br, bw_buffer, bw.pos);
+        bit_rnd.Reset(random_seed);
+        for (int i = 0; i < kBitsToTest; ++i) {
+          if (bit_method == 2) {
+            bit = (i & 1);
+          } else if (bit_method == 3) {
+            bit = bit_rnd(2);
+          }
+          GTEST_ASSERT_EQ(aom_read(&br, probas[i], NULL), bit)
+              << "pos: " << i << " / " << kBitsToTest
+              << " bit_method: " << bit_method << " method: " << method;
+        }
+      }
+    }
+  }
+}
+
+#define FRAC_DIFF_TOTAL_ERROR 0.18
+
+TEST(AV1, TestTell) {
+  const int kBufferSize = 10000;
+  aom_writer bw;
+  uint8_t bw_buffer[kBufferSize];
+  const int kSymbols = 1024;
+  // Coders are noisier at low probabilities, so we start at p = 4.
+  for (int p = 4; p < 256; p++) {
+    double probability = p / 256.;
+    aom_start_encode(&bw, bw_buffer);
+    for (int i = 0; i < kSymbols; i++) {
+      aom_write(&bw, 0, p);
+    }
+    aom_stop_encode(&bw);
+    aom_reader br;
+    aom_reader_init(&br, bw_buffer, bw.pos);
+    uint32_t last_tell = aom_reader_tell(&br);
+    uint32_t last_tell_frac = aom_reader_tell_frac(&br);
+    double frac_diff_total = 0;
+    GTEST_ASSERT_GE(aom_reader_tell(&br), 0u);
+    GTEST_ASSERT_LE(aom_reader_tell(&br), 1u);
+    ASSERT_FALSE(aom_reader_has_overflowed(&br));
+    for (int i = 0; i < kSymbols; i++) {
+      aom_read(&br, p, NULL);
+      uint32_t tell = aom_reader_tell(&br);
+      uint32_t tell_frac = aom_reader_tell_frac(&br);
+      GTEST_ASSERT_GE(tell, last_tell)
+          << "tell: " << tell << ", last_tell: " << last_tell;
+      GTEST_ASSERT_GE(tell_frac, last_tell_frac)
+          << "tell_frac: " << tell_frac
+          << ", last_tell_frac: " << last_tell_frac;
+      // Frac tell should round up to tell.
+      GTEST_ASSERT_EQ(tell, (tell_frac + 7) >> 3);
+      last_tell = tell;
+      frac_diff_total +=
+          fabs(((tell_frac - last_tell_frac) / 8.0) + log2(probability));
+      last_tell_frac = tell_frac;
+    }
+    const uint32_t expected = (uint32_t)(-kSymbols * log2(probability));
+    // Last tell should be close to the expected value.
+    GTEST_ASSERT_LE(last_tell, expected + 20) << " last_tell: " << last_tell;
+    // The average frac_diff error should be pretty small.
+    GTEST_ASSERT_LE(frac_diff_total / kSymbols, FRAC_DIFF_TOTAL_ERROR)
+        << " frac_diff_total: " << frac_diff_total;
+    ASSERT_FALSE(aom_reader_has_overflowed(&br));
+  }
+}
+
+TEST(AV1, TestHasOverflowed) {
+  const int kBufferSize = 10000;
+  aom_writer bw;
+  uint8_t bw_buffer[kBufferSize];
+  const int kSymbols = 1024;
+  // Coders are noisier at low probabilities, so we start at p = 4.
+  for (int p = 4; p < 256; p++) {
+    aom_start_encode(&bw, bw_buffer);
+    for (int i = 0; i < kSymbols; i++) {
+      aom_write(&bw, 1, p);
+    }
+    aom_stop_encode(&bw);
+    aom_reader br;
+    aom_reader_init(&br, bw_buffer, bw.pos);
+    ASSERT_FALSE(aom_reader_has_overflowed(&br));
+    for (int i = 0; i < kSymbols; i++) {
+      GTEST_ASSERT_EQ(aom_read(&br, p, NULL), 1);
+      ASSERT_FALSE(aom_reader_has_overflowed(&br));
+    }
+    // In the worst case, the encoder uses just a tiny fraction of the last
+    // byte in the buffer. So to guarantee that aom_reader_has_overflowed()
+    // returns true, we have to consume very nearly 8 additional bits of data.
+    // In the worse case, one of the bits in that byte will be 1, and the rest
+    // will be zero. Once we are past that 1 bit, when the probability of
+    // reading zero symbol from aom_read() is high, each additional symbol read
+    // will consume very little additional data (in the case that p == 255,
+    // approximately -log_2(255/256) ~= 0.0056 bits). In that case it would
+    // take around 178 calls to consume more than 8 bits. That is only an upper
+    // bound. In practice we are not guaranteed to hit the worse case and can
+    // get away with 174 calls.
+    for (int i = 0; i < 174; i++) {
+      aom_read(&br, p, NULL);
+    }
+    ASSERT_TRUE(aom_reader_has_overflowed(&br));
+  }
+}