1 files changed, 211 insertions, 0 deletions
diff --git a/third_party/aom/test/ans_test.cc b/third_party/aom/test/ans_test.cc
new file mode 100644
index 000000000..a553a9e84
--- /dev/null
+++ b/third_party/aom/test/ans_test.cc
@@ -0,0 +1,211 @@
+/*
+ * 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 <assert.h>
+#include <math.h>
+#include <stdio.h>
+#include <ctime>
+#include <utility>
+#include <vector>
+
+#include "third_party/googletest/src/googletest/include/gtest/gtest.h"
+
+#include "test/acm_random.h"
+#include "aom_dsp/ansreader.h"
+#include "aom_dsp/buf_ans.h"
+
+namespace {
+typedef std::vector<std::pair<uint8_t, bool> > PvVec;
+
+const int kPrintStats = 0;
+// Use a small buffer size to exercise ANS window spills or buffer growth
+const int kBufAnsSize = 1 << 8;
+
+PvVec abs_encode_build_vals(int iters) {
+  PvVec ret;
+  libaom_test::ACMRandom gen(0x30317076);
+  double entropy = 0;
+  for (int i = 0; i < iters; ++i) {
+    uint8_t p;
+    do {
+      p = gen.Rand8();
+    } while (p == 0);  // zero is not a valid coding probability
+    bool b = gen.Rand8() < p;
+    ret.push_back(std::make_pair(static_cast<uint8_t>(p), b));
+    if (kPrintStats) {
+      double d = p / 256.;
+      entropy += -d * log2(d) - (1 - d) * log2(1 - d);
+    }
+  }
+  if (kPrintStats) printf("entropy %f\n", entropy);
+  return ret;
+}
+
+bool check_rabs(const PvVec &pv_vec, uint8_t *buf) {
+  BufAnsCoder a;
+  aom_buf_ans_alloc(&a, NULL, kBufAnsSize);
+  buf_ans_write_init(&a, buf);
+
+  std::clock_t start = std::clock();
+  for (PvVec::const_iterator it = pv_vec.begin(); it != pv_vec.end(); ++it) {
+    buf_rabs_write(&a, it->second, 256 - it->first);
+  }
+  aom_buf_ans_flush(&a);
+  std::clock_t enc_time = std::clock() - start;
+  int offset = buf_ans_write_end(&a);
+  aom_buf_ans_free(&a);
+  bool okay = true;
+  AnsDecoder d;
+#if ANS_MAX_SYMBOLS
+  d.window_size = kBufAnsSize;
+#endif
+  if (ans_read_init(&d, buf, offset)) return false;
+  start = std::clock();
+  for (PvVec::const_iterator it = pv_vec.begin(); it != pv_vec.end(); ++it) {
+    okay = okay && (rabs_read(&d, 256 - it->first) != 0) == it->second;
+  }
+  std::clock_t dec_time = std::clock() - start;
+  if (!okay) return false;
+  if (kPrintStats)
+    printf("uABS size %d enc_time %f dec_time %f\n", offset,
+           static_cast<float>(enc_time) / CLOCKS_PER_SEC,
+           static_cast<float>(dec_time) / CLOCKS_PER_SEC);
+  return ans_read_end(&d) != 0;
+}
+
+const aom_cdf_prob spareto65[] = { 8320, 6018, 4402, 3254, 4259,
+                                   3919, 2057, 492,  45,   2 };
+
+const int kRansSymbols =
+    static_cast<int>(sizeof(spareto65) / sizeof(spareto65[0]));
+
+struct rans_sym {
+  aom_cdf_prob prob;
+  aom_cdf_prob cum_prob;  // not-inclusive
+};
+
+std::vector<int> ans_encode_build_vals(rans_sym *const tab, int iters) {
+  aom_cdf_prob sum = 0;
+  for (int i = 0; i < kRansSymbols; ++i) {
+    tab[i].cum_prob = sum;
+    tab[i].prob = spareto65[i];
+    sum += spareto65[i];
+  }
+  std::vector<int> p_to_sym;
+  for (int i = 0; i < kRansSymbols; ++i) {
+    p_to_sym.insert(p_to_sym.end(), tab[i].prob, i);
+  }
+  assert(p_to_sym.size() == RANS_PRECISION);
+  std::vector<int> ret;
+  libaom_test::ACMRandom gen(18543637);
+  for (int i = 0; i < iters; ++i) {
+    int sym =
+        p_to_sym[((gen.Rand8() << 8) + gen.Rand8()) & (RANS_PRECISION - 1)];
+    ret.push_back(sym);
+  }
+  return ret;
+}
+
+void rans_build_dec_tab(const struct rans_sym sym_tab[],
+                        aom_cdf_prob *dec_tab) {
+  unsigned int sum = 0;
+  for (int i = 0; sum < RANS_PRECISION; ++i) {
+    dec_tab[i] = sum += sym_tab[i].prob;
+  }
+}
+
+bool check_rans(const std::vector<int> &sym_vec, const rans_sym *const tab,
+                uint8_t *buf) {
+  BufAnsCoder a;
+  aom_buf_ans_alloc(&a, NULL, kBufAnsSize);
+  buf_ans_write_init(&a, buf);
+  aom_cdf_prob dec_tab[kRansSymbols];
+  rans_build_dec_tab(tab, dec_tab);
+
+  std::clock_t start = std::clock();
+  for (std::vector<int>::const_iterator it = sym_vec.begin();
+       it != sym_vec.end(); ++it) {
+    buf_rans_write(&a, tab[*it].cum_prob, tab[*it].prob);
+  }
+  aom_buf_ans_flush(&a);
+  std::clock_t enc_time = std::clock() - start;
+  int offset = buf_ans_write_end(&a);
+  aom_buf_ans_free(&a);
+  bool okay = true;
+  AnsDecoder d;
+#if ANS_MAX_SYMBOLS
+  d.window_size = kBufAnsSize;
+#endif
+  if (ans_read_init(&d, buf, offset)) return false;
+  start = std::clock();
+  for (std::vector<int>::const_iterator it = sym_vec.begin();
+       it != sym_vec.end(); ++it) {
+    okay &= rans_read(&d, dec_tab) == *it;
+  }
+  std::clock_t dec_time = std::clock() - start;
+  if (!okay) return false;
+  if (kPrintStats)
+    printf("rANS size %d enc_time %f dec_time %f\n", offset,
+           static_cast<float>(enc_time) / CLOCKS_PER_SEC,
+           static_cast<float>(dec_time) / CLOCKS_PER_SEC);
+  return ans_read_end(&d) != 0;
+}
+
+class AbsTestFix : public ::testing::Test {
+ protected:
+  static void SetUpTestCase() { pv_vec_ = abs_encode_build_vals(kNumBools); }
+  virtual void SetUp() { buf_ = new uint8_t[kNumBools / 8]; }
+  virtual void TearDown() { delete[] buf_; }
+  static const int kNumBools = 100000000;
+  static PvVec pv_vec_;
+  uint8_t *buf_;
+};
+PvVec AbsTestFix::pv_vec_;
+
+class AnsTestFix : public ::testing::Test {
+ protected:
+  static void SetUpTestCase() {
+    sym_vec_ = ans_encode_build_vals(rans_sym_tab_, kNumSyms);
+  }
+  virtual void SetUp() { buf_ = new uint8_t[kNumSyms / 2]; }
+  virtual void TearDown() { delete[] buf_; }
+  static const int kNumSyms = 25000000;
+  static std::vector<int> sym_vec_;
+  static rans_sym rans_sym_tab_[kRansSymbols];
+  uint8_t *buf_;
+};
+std::vector<int> AnsTestFix::sym_vec_;
+rans_sym AnsTestFix::rans_sym_tab_[kRansSymbols];
+
+TEST_F(AbsTestFix, Rabs) { EXPECT_TRUE(check_rabs(pv_vec_, buf_)); }
+TEST_F(AnsTestFix, Rans) {
+  EXPECT_TRUE(check_rans(sym_vec_, rans_sym_tab_, buf_));
+}
+TEST(AnsTest, FinalStateSerialization) {
+  for (unsigned i = L_BASE; i < L_BASE * IO_BASE; ++i) {
+    uint8_t buf[8];
+    AnsCoder c;
+    ans_write_init(&c, buf);
+    c.state = i;
+    const int written_size = ans_write_end(&c);
+    ASSERT_LT(static_cast<size_t>(written_size), sizeof(buf));
+    AnsDecoder d;
+#if ANS_MAX_SYMBOLS
+    // There is no real data window here because no symbols are sent through
+    // ans (only synthetic states), so use a dummy value
+    d.window_size = 1024;
+#endif
+    const int read_init_status = ans_read_init(&d, buf, written_size);
+    EXPECT_EQ(read_init_status, 0);
+    EXPECT_EQ(d.state, i);
+  }
+}
+}  // namespace