12eaa0fe61
VLQ encoding was implemented in TranslationArray and Sparkplug PC <-> bytecode mapping. This CL introduces new VLQ helper methods used in both. Bug: v8:11429 Change-Id: I89d9777eab4ad28f08e5957421b63df07e37f9cc Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2704674 Reviewed-by: Igor Sheludko <ishell@chromium.org> Reviewed-by: Toon Verwaest <verwaest@chromium.org> Reviewed-by: Jakob Gruber <jgruber@chromium.org> Commit-Queue: Patrick Thier <pthier@chromium.org> Cr-Commit-Position: refs/heads/master@{#73054}
124 lines
3.7 KiB
C++
124 lines
3.7 KiB
C++
// Copyright 2021 the V8 project authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "src/base/vlq.h"
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#include <cmath>
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#include <limits>
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#include "src/base/memory.h"
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#include "test/unittests/test-utils.h"
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#include "testing/gtest-support.h"
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namespace v8 {
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namespace base {
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int ExpectedBytesUsed(int64_t value, bool is_signed) {
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uint64_t bits = value;
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if (is_signed) {
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bits = (value < 0 ? -value : value) << 1;
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}
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int num_bits = 0;
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while (bits != 0) {
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num_bits++;
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bits >>= 1;
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}
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return std::max(1, static_cast<int>(ceil(static_cast<float>(num_bits) / 7)));
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}
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void TestVLQUnsignedEquals(uint32_t value) {
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std::vector<byte> buffer;
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VLQEncodeUnsigned(&buffer, value);
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byte* data_start = buffer.data();
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int index = 0;
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int expected_bytes_used = ExpectedBytesUsed(value, false);
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EXPECT_EQ(buffer.size(), static_cast<size_t>(expected_bytes_used));
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EXPECT_EQ(value, VLQDecodeUnsigned(data_start, &index));
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EXPECT_EQ(index, expected_bytes_used);
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}
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void TestVLQEquals(int32_t value) {
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std::vector<byte> buffer;
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VLQEncode(&buffer, value);
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byte* data_start = buffer.data();
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int index = 0;
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int expected_bytes_used = ExpectedBytesUsed(value, true);
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EXPECT_EQ(buffer.size(), static_cast<size_t>(expected_bytes_used));
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EXPECT_EQ(value, VLQDecode(data_start, &index));
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EXPECT_EQ(index, expected_bytes_used);
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}
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TEST(VLQ, Unsigned) {
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TestVLQUnsignedEquals(0);
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TestVLQUnsignedEquals(1);
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TestVLQUnsignedEquals(63);
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TestVLQUnsignedEquals(64);
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TestVLQUnsignedEquals(127);
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TestVLQUnsignedEquals(255);
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TestVLQUnsignedEquals(256);
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}
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TEST(VLQ, Positive) {
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TestVLQEquals(0);
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TestVLQEquals(1);
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TestVLQEquals(63);
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TestVLQEquals(64);
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TestVLQEquals(127);
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TestVLQEquals(255);
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TestVLQEquals(256);
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}
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TEST(VLQ, Negative) {
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TestVLQEquals(-1);
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TestVLQEquals(-63);
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TestVLQEquals(-64);
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TestVLQEquals(-127);
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TestVLQEquals(-255);
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TestVLQEquals(-256);
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}
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TEST(VLQ, LimitsUnsigned) {
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TestVLQEquals(std::numeric_limits<uint8_t>::max());
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TestVLQEquals(std::numeric_limits<uint8_t>::max() - 1);
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TestVLQEquals(std::numeric_limits<uint8_t>::max() + 1);
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TestVLQEquals(std::numeric_limits<uint16_t>::max());
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TestVLQEquals(std::numeric_limits<uint16_t>::max() - 1);
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TestVLQEquals(std::numeric_limits<uint16_t>::max() + 1);
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TestVLQEquals(std::numeric_limits<uint32_t>::max());
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TestVLQEquals(std::numeric_limits<uint32_t>::max() - 1);
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}
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TEST(VLQ, LimitsSigned) {
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TestVLQEquals(std::numeric_limits<int8_t>::max());
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TestVLQEquals(std::numeric_limits<int8_t>::max() - 1);
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TestVLQEquals(std::numeric_limits<int8_t>::max() + 1);
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TestVLQEquals(std::numeric_limits<int16_t>::max());
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TestVLQEquals(std::numeric_limits<int16_t>::max() - 1);
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TestVLQEquals(std::numeric_limits<int16_t>::max() + 1);
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TestVLQEquals(std::numeric_limits<int32_t>::max());
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TestVLQEquals(std::numeric_limits<int32_t>::max() - 1);
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TestVLQEquals(std::numeric_limits<int8_t>::min());
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TestVLQEquals(std::numeric_limits<int8_t>::min() - 1);
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TestVLQEquals(std::numeric_limits<int8_t>::min() + 1);
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TestVLQEquals(std::numeric_limits<int16_t>::min());
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TestVLQEquals(std::numeric_limits<int16_t>::min() - 1);
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TestVLQEquals(std::numeric_limits<int16_t>::min() + 1);
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// int32_t::min() is not supported.
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TestVLQEquals(std::numeric_limits<int32_t>::min() + 1);
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}
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TEST(VLQ, Random) {
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static constexpr int RANDOM_RUNS = 50;
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base::RandomNumberGenerator rng(::testing::FLAGS_gtest_random_seed);
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for (int i = 0; i < RANDOM_RUNS; ++i) {
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TestVLQUnsignedEquals(rng.NextInt(std::numeric_limits<int32_t>::max()));
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}
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for (int i = 0; i < RANDOM_RUNS; ++i) {
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TestVLQEquals(rng.NextInt());
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}
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}
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} // namespace base
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} // namespace v8
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