1 files changed, 92 insertions, 0 deletions
diff --git a/media/libjxl/src/lib/jxl/toc_test.cc b/media/libjxl/src/lib/jxl/toc_test.cc
new file mode 100644
index 0000000000..62eec5a101
--- /dev/null
+++ b/media/libjxl/src/lib/jxl/toc_test.cc
@@ -0,0 +1,92 @@
+// Copyright (c) the JPEG XL Project Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "lib/jxl/toc.h"
+
+#include "gtest/gtest.h"
+#include "lib/jxl/aux_out_fwd.h"
+#include "lib/jxl/base/random.h"
+#include "lib/jxl/base/span.h"
+#include "lib/jxl/common.h"
+#include "lib/jxl/enc_toc.h"
+
+namespace jxl {
+namespace {
+
+void Roundtrip(size_t num_entries, bool permute, Rng* rng) {
+  // Generate a random permutation.
+  std::vector<coeff_order_t> permutation(num_entries);
+  std::vector<coeff_order_t> inv_permutation(num_entries);
+  for (size_t i = 0; i < num_entries; i++) {
+    permutation[i] = i;
+    inv_permutation[i] = i;
+  }
+  if (permute) {
+    rng->Shuffle(permutation.data(), permutation.size());
+    for (size_t i = 0; i < num_entries; i++) {
+      inv_permutation[permutation[i]] = i;
+    }
+  }
+
+  // Generate num_entries groups of random (byte-aligned) length
+  std::vector<BitWriter> group_codes(num_entries);
+  for (BitWriter& writer : group_codes) {
+    const size_t max_bits = (*rng)() & 0xFFF;
+    BitWriter::Allotment allotment(&writer, max_bits + kBitsPerByte);
+    size_t i = 0;
+    for (; i + BitWriter::kMaxBitsPerCall < max_bits;
+         i += BitWriter::kMaxBitsPerCall) {
+      writer.Write(BitWriter::kMaxBitsPerCall, 0);
+    }
+    for (; i < max_bits; i += 1) {
+      writer.Write(/*n_bits=*/1, 0);
+    }
+    writer.ZeroPadToByte();
+    AuxOut aux_out;
+    ReclaimAndCharge(&writer, &allotment, 0, &aux_out);
+  }
+
+  BitWriter writer;
+  AuxOut aux_out;
+  ASSERT_TRUE(WriteGroupOffsets(group_codes, permute ? &permutation : nullptr,
+                                &writer, &aux_out));
+
+  BitReader reader(writer.GetSpan());
+  std::vector<uint64_t> group_offsets;
+  std::vector<uint32_t> group_sizes;
+  uint64_t total_size;
+  ASSERT_TRUE(ReadGroupOffsets(num_entries, &reader, &group_offsets,
+                               &group_sizes, &total_size));
+  ASSERT_EQ(num_entries, group_offsets.size());
+  ASSERT_EQ(num_entries, group_sizes.size());
+  EXPECT_TRUE(reader.Close());
+
+  uint64_t prefix_sum = 0;
+  for (size_t i = 0; i < num_entries; ++i) {
+    EXPECT_EQ(prefix_sum, group_offsets[inv_permutation[i]]);
+
+    EXPECT_EQ(0u, group_codes[i].BitsWritten() % kBitsPerByte);
+    prefix_sum += group_codes[i].BitsWritten() / kBitsPerByte;
+
+    if (i + 1 < num_entries) {
+      EXPECT_EQ(
+          group_offsets[inv_permutation[i]] + group_sizes[inv_permutation[i]],
+          group_offsets[inv_permutation[i + 1]]);
+    }
+  }
+  EXPECT_EQ(prefix_sum, total_size);
+}
+
+TEST(TocTest, Test) {
+  Rng rng(0);
+  for (size_t num_entries = 0; num_entries < 10; ++num_entries) {
+    for (bool permute : std::vector<bool>{false, true}) {
+      Roundtrip(num_entries, permute, &rng);
+    }
+  }
+}
+
+}  // namespace
+}  // namespace jxl