86 lines · cpp
1//===-- sanitizer_leb128.cpp ------------------------------------*- C++ -*-===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8#include "sanitizer_common/sanitizer_leb128.h"9 10#include <type_traits>11 12#include "gtest/gtest.h"13#include "sanitizer_common/sanitizer_common.h"14#include "sanitizer_internal_defs.h"15 16namespace __sanitizer {17 18template <typename T>19class Leb128Test : public ::testing::Test {};20 21using Leb128TestTypes = ::testing::Types<u8, u16, u32, u64>;22TYPED_TEST_SUITE(Leb128Test, Leb128TestTypes, );23 24static uptr BitsNeeded(u64 v) {25 if (!v)26 return 1;27 uptr r = 0;28 if (sizeof(uptr) != sizeof(u64)) {29 uptr uptr_bits = 8 * sizeof(uptr);30 while (v >> uptr_bits) {31 r += uptr_bits;32 v >>= uptr_bits;33 }34 }35 return r + MostSignificantSetBitIndex(v) + 1;36}37 38TYPED_TEST(Leb128Test, SignedOverflow) {39 using T = typename std::make_signed<TypeParam>::type;40 u8 buffer[16] = {255};41 T v = -128;42 EXPECT_EQ(buffer + 1, EncodeSLEB128(v, buffer, buffer + 1));43 EXPECT_EQ(buffer + 1, DecodeSLEB128(buffer, buffer + 1, &v));44}45 46TYPED_TEST(Leb128Test, Signed) {47 using T = typename std::make_signed<TypeParam>::type;48 T v = 0;49 for (int i = 0; i < 100; ++i) {50 u8 buffer[16] = {};51 u8* p = EncodeSLEB128(v, std::begin(buffer), std::end(buffer));52 EXPECT_EQ(int(BitsNeeded(v < 0 ? (-v - 1) : v) + 6 + 1) / 7, p - buffer)53 << (int)v;54 T v2;55 u8* p2 = DecodeSLEB128(std::begin(buffer), std::end(buffer), &v2);56 EXPECT_EQ(v, v2);57 EXPECT_EQ(p, p2);58 v = -TypeParam(v) * 3u + 1u;59 }60}61 62TYPED_TEST(Leb128Test, UnsignedOverflow) {63 using T = TypeParam;64 u8 buffer[16] = {255};65 T v = 255;66 EXPECT_EQ(buffer + 1, EncodeULEB128(v, buffer, buffer + 1));67 EXPECT_EQ(buffer + 1, DecodeULEB128(buffer, buffer + 1, &v));68}69 70TYPED_TEST(Leb128Test, Unsigned) {71 using T = TypeParam;72 T v = 0;73 for (int i = 0; i < 100; ++i) {74 u8 buffer[16] = {};75 u8* p = EncodeULEB128(v, std::begin(buffer), std::end(buffer));76 EXPECT_EQ(int(BitsNeeded(v) + 6) / 7, p - buffer);77 T v2;78 u8* p2 = DecodeULEB128(std::begin(buffer), std::end(buffer), &v2);79 EXPECT_EQ(v, v2);80 EXPECT_EQ(p, p2);81 v = v * 3 + 1;82 }83}84 85} // namespace __sanitizer86