unittests/Support/DataExtractorTest.cpp - llvm-project/llvm - Git at Google

 //===- llvm/unittest/Support/DataExtractorTest.cpp - DataExtractor tests --===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/Support/DataExtractor.h"
 #include "llvm/Testing/Support/Error.h"
 #include "gtest/gtest.h"
 using namespace llvm;

 namespace {

 const char numberData[] = "\x80\x90\xFF\xFF\x80\x00\x00\x00";
 const char leb128data[] = "\xA6\x49";
 const char bigleb128data[] = "\xAA\xA9\xFF\xAA\xFF\xAA\xFF\x4A";

 TEST(DataExtractorTest, OffsetOverflow) {
   DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
   EXPECT_FALSE(DE.isValidOffsetForDataOfSize(-2U, 5));
 }

 TEST(DataExtractorTest, UnsignedNumbers) {
   DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
   uint64_t offset = 0;

   EXPECT_EQ(0x80U, DE.getU8(&offset));
   EXPECT_EQ(1U, offset);
   offset = 0;
   EXPECT_EQ(0x8090U, DE.getU16(&offset));
   EXPECT_EQ(2U, offset);
   offset = 0;
   EXPECT_EQ(0x8090FFFFU, DE.getU32(&offset));
   EXPECT_EQ(4U, offset);
   offset = 0;
   EXPECT_EQ(0x8090FFFF80000000ULL, DE.getU64(&offset));
   EXPECT_EQ(8U, offset);
   offset = 0;
   EXPECT_EQ(0x8090FFFF80000000ULL, DE.getAddress(&offset));
   EXPECT_EQ(8U, offset);
   offset = 0;

   uint32_t data[2];
   EXPECT_EQ(data, DE.getU32(&offset, data, 2));
   EXPECT_EQ(0x8090FFFFU, data[0]);
   EXPECT_EQ(0x80000000U, data[1]);
   EXPECT_EQ(8U, offset);
   offset = 0;

   // Now for little endian.
   DE = DataExtractor(StringRef(numberData, sizeof(numberData)-1), true, 4);
   EXPECT_EQ(0x9080U, DE.getU16(&offset));
   EXPECT_EQ(2U, offset);
   offset = 0;
   EXPECT_EQ(0xFFFF9080U, DE.getU32(&offset));
   EXPECT_EQ(4U, offset);
   offset = 0;
   EXPECT_EQ(0x80FFFF9080ULL, DE.getU64(&offset));
   EXPECT_EQ(8U, offset);
   offset = 0;
   EXPECT_EQ(0xFFFF9080U, DE.getAddress(&offset));
   EXPECT_EQ(4U, offset);
   offset = 0;

   EXPECT_EQ(data, DE.getU32(&offset, data, 2));
   EXPECT_EQ(0xFFFF9080U, data[0]);
   EXPECT_EQ(0x80U, data[1]);
   EXPECT_EQ(8U, offset);
 }

 TEST(DataExtractorTest, SignedNumbers) {
   DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
   uint64_t offset = 0;

   EXPECT_EQ(-128, DE.getSigned(&offset, 1));
   EXPECT_EQ(1U, offset);
   offset = 0;
   EXPECT_EQ(-32624, DE.getSigned(&offset, 2));
   EXPECT_EQ(2U, offset);
   offset = 0;
   EXPECT_EQ(-2137980929, DE.getSigned(&offset, 4));
   EXPECT_EQ(4U, offset);
   offset = 0;
   EXPECT_EQ(-9182558167379214336LL, DE.getSigned(&offset, 8));
   EXPECT_EQ(8U, offset);
 }

 TEST(DataExtractorTest, Strings) {
   const char stringData[] = "hellohello\0hello";
   DataExtractor DE(StringRef(stringData, sizeof(stringData)-1), false, 8);
   uint64_t offset = 0;

   EXPECT_EQ(stringData, DE.getCStr(&offset));
   EXPECT_EQ(11U, offset);
   EXPECT_EQ(nullptr, DE.getCStr(&offset));
   EXPECT_EQ(11U, offset);

   DataExtractor::Cursor C(0);
   EXPECT_EQ(stringData, DE.getCStr(C));
   EXPECT_EQ(11U, C.tell());
   EXPECT_EQ(nullptr, DE.getCStr(C));
   EXPECT_EQ(11U, C.tell());
   EXPECT_THAT_ERROR(
       C.takeError(),
       FailedWithMessage("no null terminated string at offset 0xb"));
 }

 TEST(DataExtractorTest, LEB128) {
   DataExtractor DE(StringRef(leb128data, sizeof(leb128data)-1), false, 8);
   uint64_t offset = 0;

   EXPECT_EQ(9382ULL, DE.getULEB128(&offset));
   EXPECT_EQ(2U, offset);
   offset = 0;
   EXPECT_EQ(-7002LL, DE.getSLEB128(&offset));
   EXPECT_EQ(2U, offset);

   DataExtractor BDE(StringRef(bigleb128data, sizeof(bigleb128data)-1), false,8);
   offset = 0;
   EXPECT_EQ(42218325750568106ULL, BDE.getULEB128(&offset));
   EXPECT_EQ(8U, offset);
   offset = 0;
   EXPECT_EQ(-29839268287359830LL, BDE.getSLEB128(&offset));
   EXPECT_EQ(8U, offset);
 }

 TEST(DataExtractorTest, LEB128_error) {
   DataExtractor DE(StringRef("\x81"), false, 8);
   uint64_t Offset = 0;
   EXPECT_EQ(0U, DE.getULEB128(&Offset));
   EXPECT_EQ(0U, Offset);

   Offset = 0;
   EXPECT_EQ(0U, DE.getSLEB128(&Offset));
   EXPECT_EQ(0U, Offset);

   DataExtractor::Cursor C(0);
   EXPECT_EQ(0U, DE.getULEB128(C));
   EXPECT_THAT_ERROR(
       C.takeError(),
       FailedWithMessage("unable to decode LEB128 at offset 0x00000000: "
                         "malformed uleb128, extends past end"));

   C = DataExtractor::Cursor(0);
   EXPECT_EQ(0U, DE.getSLEB128(C));
   EXPECT_THAT_ERROR(
       C.takeError(),
       FailedWithMessage("unable to decode LEB128 at offset 0x00000000: "
                         "malformed sleb128, extends past end"));

   // Show non-zero offsets are reported appropriately.
   C = DataExtractor::Cursor(1);
   EXPECT_EQ(0U, DE.getULEB128(C));
   EXPECT_THAT_ERROR(
       C.takeError(),
       FailedWithMessage("unable to decode LEB128 at offset 0x00000001: "
                         "malformed uleb128, extends past end"));
 }

 TEST(DataExtractorTest, Cursor_tell) {
   DataExtractor DE(StringRef("AB"), false, 8);
   DataExtractor::Cursor C(0);
   // A successful read operation advances the cursor
   EXPECT_EQ('A', DE.getU8(C));
   EXPECT_EQ(1u, C.tell());

   // An unsuccessful one doesn't.
   EXPECT_EQ(0u, DE.getU16(C));
   EXPECT_EQ(1u, C.tell());

   // And neither do any subsequent operations.
   EXPECT_EQ(0, DE.getU8(C));
   EXPECT_EQ(1u, C.tell());

   consumeError(C.takeError());
 }

 TEST(DataExtractorTest, Cursor_takeError) {
   DataExtractor DE(StringRef("AB"), false, 8);
   DataExtractor::Cursor C(0);
   // Initially, the cursor is in the "success" state.
   EXPECT_THAT_ERROR(C.takeError(), Succeeded());

   // It remains "success" after a successful read.
   EXPECT_EQ('A', DE.getU8(C));
   EXPECT_THAT_ERROR(C.takeError(), Succeeded());

   // An unsuccessful read sets the error state.
   EXPECT_EQ(0u, DE.getU32(C));
   EXPECT_THAT_ERROR(C.takeError(), Failed());

   // Once set the error sticks until explicitly cleared.
   EXPECT_EQ(0u, DE.getU32(C));
   EXPECT_EQ(0, DE.getU8(C));
   EXPECT_THAT_ERROR(C.takeError(), Failed());

   // At which point reads can be succeed again.
   EXPECT_EQ('B', DE.getU8(C));
   EXPECT_THAT_ERROR(C.takeError(), Succeeded());
 }

 TEST(DataExtractorTest, Cursor_chaining) {
   DataExtractor DE(StringRef("ABCD"), false, 8);
   DataExtractor::Cursor C(0);

   // Multiple reads can be chained without trigerring any assertions.
   EXPECT_EQ('A', DE.getU8(C));
   EXPECT_EQ('B', DE.getU8(C));
   EXPECT_EQ('C', DE.getU8(C));
   EXPECT_EQ('D', DE.getU8(C));
   // And the error checked at the end.
   EXPECT_THAT_ERROR(C.takeError(), Succeeded());
 }

 #if defined(GTEST_HAS_DEATH_TEST) && defined(_DEBUG) &&                        \
     LLVM_ENABLE_ABI_BREAKING_CHECKS
 TEST(DataExtractorDeathTest, Cursor) {
   DataExtractor DE(StringRef("AB"), false, 8);

   // Even an unused cursor must be checked for errors:
   EXPECT_DEATH(DataExtractor::Cursor(0),
                "Success values must still be checked prior to being destroyed");

   {
     auto C = std::make_unique<DataExtractor::Cursor>(0);
     EXPECT_EQ(0u, DE.getU32(*C));
     // It must also be checked after an unsuccessful operation.
     // destruction.
     EXPECT_DEATH(C.reset(), "unexpected end of data");
     EXPECT_THAT_ERROR(C->takeError(), Failed());
   }
   {
     auto C = std::make_unique<DataExtractor::Cursor>(0);
     EXPECT_EQ('A', DE.getU8(*C));
     // Same goes for a successful one.
     EXPECT_DEATH(
         C.reset(),
         "Success values must still be checked prior to being destroyed");
     EXPECT_THAT_ERROR(C->takeError(), Succeeded());
   }
   {
     auto C = std::make_unique<DataExtractor::Cursor>(0);
     EXPECT_EQ('A', DE.getU8(*C));
     EXPECT_EQ(0u, DE.getU32(*C));
     // Even if a successful operation is followed by an unsuccessful one.
     EXPECT_DEATH(C.reset(), "unexpected end of data");
     EXPECT_THAT_ERROR(C->takeError(), Failed());
   }
   {
     auto C = std::make_unique<DataExtractor::Cursor>(0);
     EXPECT_EQ(0u, DE.getU32(*C));
     EXPECT_EQ(0, DE.getU8(*C));
     // Even if an unsuccessful operation is followed by one that would normally
     // succeed.
     EXPECT_DEATH(C.reset(), "unexpected end of data");
     EXPECT_THAT_ERROR(C->takeError(), Failed());
   }
 }
 #endif

 TEST(DataExtractorTest, getU8_vector) {
   DataExtractor DE(StringRef("AB"), false, 8);
   DataExtractor::Cursor C(0);
   SmallVector<uint8_t, 2> S;

   DE.getU8(C, S, 4);
   EXPECT_THAT_ERROR(C.takeError(), Failed());
   EXPECT_EQ("", toStringRef(S));

   DE.getU8(C, S, 2);
   EXPECT_THAT_ERROR(C.takeError(), Succeeded());
   EXPECT_EQ("AB", toStringRef(S));

   C = DataExtractor::Cursor(0x47);
   DE.getU8(C, S, 2);
   EXPECT_THAT_ERROR(
       C.takeError(),
       FailedWithMessage("offset 0x47 is beyond the end of data at 0x2"));
 }

 TEST(DataExtractorTest, getU24) {
   DataExtractor DE(StringRef("ABCD"), false, 8);
   DataExtractor::Cursor C(0);

   EXPECT_EQ(0x414243u, DE.getU24(C));
   EXPECT_EQ(0u, DE.getU24(C));
   EXPECT_EQ(3u, C.tell());
   EXPECT_THAT_ERROR(C.takeError(), Failed());
 }

 TEST(DataExtractorTest, skip) {
   DataExtractor DE(StringRef("AB"), false, 8);
   DataExtractor::Cursor C(0);

   DE.skip(C, 4);
   EXPECT_THAT_ERROR(C.takeError(), Failed());
   EXPECT_EQ(0u, C.tell());

   DE.skip(C, 2);
   EXPECT_THAT_ERROR(C.takeError(), Succeeded());
   EXPECT_EQ(2u, C.tell());
 }

 TEST(DataExtractorTest, eof) {
   DataExtractor DE(StringRef("A"), false, 8);
   DataExtractor::Cursor C(0);

   EXPECT_FALSE(DE.eof(C));

   EXPECT_EQ(0, DE.getU16(C));
   EXPECT_FALSE(DE.eof(C));
   EXPECT_THAT_ERROR(C.takeError(), Failed());

   EXPECT_EQ('A', DE.getU8(C));
   EXPECT_TRUE(DE.eof(C));
   EXPECT_THAT_ERROR(C.takeError(), Succeeded());
 }

 TEST(DataExtractorTest, size) {
   uint8_t Data[] = {'A', 'B', 'C', 'D'};
   DataExtractor DE1(StringRef(reinterpret_cast<char *>(Data), sizeof(Data)),
                     false, 8);
   EXPECT_EQ(DE1.size(), sizeof(Data));
   DataExtractor DE2(ArrayRef<uint8_t>(Data), false, 8);
   EXPECT_EQ(DE2.size(), sizeof(Data));
 }

 TEST(DataExtractorTest, FixedLengthString) {
   const char Data[] = "hello\x00\x00\x00world  \thola\x00";
   DataExtractor DE(StringRef(Data, sizeof(Data)-1), false, 8);
   uint64_t Offset = 0;
   StringRef Str;
   // Test extracting too many bytes doesn't modify Offset and returns None.
   Str = DE.getFixedLengthString(&Offset, sizeof(Data));
   EXPECT_TRUE(Str.empty());
   EXPECT_EQ(Offset, 0u);

   // Test extracting a fixed width C string with trailing NULL characters.
   Str = DE.getFixedLengthString(&Offset, 8);
   EXPECT_EQ(Offset, 8u);
   EXPECT_EQ(Str.size(), 5u);
   EXPECT_EQ(Str, "hello");
   // Test extracting a fixed width C string with trailing space and tab
   // characters.
   Str = DE.getFixedLengthString(&Offset, 8, " \t");
   EXPECT_EQ(Offset, 16u);
   EXPECT_EQ(Str.size(), 5u);
   EXPECT_EQ(Str, "world");
   // Now extract a normal C string.
   Str = DE.getCStrRef(&Offset);
   EXPECT_EQ(Str.size(), 4u);
   EXPECT_EQ(Str, "hola");
 }


 TEST(DataExtractorTest, GetBytes) {
   // Use data with an embedded NULL character for good measure.
   const char Data[] = "\x01\x02\x00\x04";
   StringRef Bytes(Data, sizeof(Data)-1);
   DataExtractor DE(Bytes, false, 8);
   uint64_t Offset = 0;
   StringRef Str;
   // Test extracting too many bytes doesn't modify Offset and returns None.
   Str = DE.getBytes(&Offset, sizeof(Data));
   EXPECT_TRUE(Str.empty());
   EXPECT_EQ(Offset, 0u);
   // Test extracting 4 bytes from the stream.
   Str = DE.getBytes(&Offset, 4);
   EXPECT_EQ(Offset, 4u);
   EXPECT_EQ(Str.size(), 4u);
   EXPECT_EQ(Str, Bytes);

   DataExtractor::Cursor C(0);
   EXPECT_EQ(StringRef("\x01\x02"), DE.getBytes(C, 2));
   EXPECT_EQ(StringRef("\x00\x04", 2), DE.getBytes(C, 2));
   EXPECT_EQ(StringRef(), DE.getBytes(C, 2));
   EXPECT_EQ(StringRef(), DE.getBytes(C, 2));
   EXPECT_EQ(4u, C.tell());
   EXPECT_THAT_ERROR(C.takeError(), Failed());
 }

 }
	//===- llvm/unittest/Support/DataExtractorTest.cpp - DataExtractor tests --===//
	//
	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
	// See https://llvm.org/LICENSE.txt for license information.
	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/Support/DataExtractor.h"
	#include "llvm/Testing/Support/Error.h"
	#include "gtest/gtest.h"
	using namespace llvm;

	namespace {

	const char numberData[] = "\x80\x90\xFF\xFF\x80\x00\x00\x00";
	const char leb128data[] = "\xA6\x49";
	const char bigleb128data[] = "\xAA\xA9\xFF\xAA\xFF\xAA\xFF\x4A";

	TEST(DataExtractorTest, OffsetOverflow) {
	DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
	EXPECT_FALSE(DE.isValidOffsetForDataOfSize(-2U, 5));
	}

	TEST(DataExtractorTest, UnsignedNumbers) {
	DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
	uint64_t offset = 0;

	EXPECT_EQ(0x80U, DE.getU8(&offset));
	EXPECT_EQ(1U, offset);
	offset = 0;
	EXPECT_EQ(0x8090U, DE.getU16(&offset));
	EXPECT_EQ(2U, offset);
	offset = 0;
	EXPECT_EQ(0x8090FFFFU, DE.getU32(&offset));
	EXPECT_EQ(4U, offset);
	offset = 0;
	EXPECT_EQ(0x8090FFFF80000000ULL, DE.getU64(&offset));
	EXPECT_EQ(8U, offset);
	offset = 0;
	EXPECT_EQ(0x8090FFFF80000000ULL, DE.getAddress(&offset));
	EXPECT_EQ(8U, offset);
	offset = 0;

	uint32_t data[2];
	EXPECT_EQ(data, DE.getU32(&offset, data, 2));
	EXPECT_EQ(0x8090FFFFU, data[0]);
	EXPECT_EQ(0x80000000U, data[1]);
	EXPECT_EQ(8U, offset);
	offset = 0;

	// Now for little endian.
	DE = DataExtractor(StringRef(numberData, sizeof(numberData)-1), true, 4);
	EXPECT_EQ(0x9080U, DE.getU16(&offset));
	EXPECT_EQ(2U, offset);
	offset = 0;
	EXPECT_EQ(0xFFFF9080U, DE.getU32(&offset));
	EXPECT_EQ(4U, offset);
	offset = 0;
	EXPECT_EQ(0x80FFFF9080ULL, DE.getU64(&offset));
	EXPECT_EQ(8U, offset);
	offset = 0;
	EXPECT_EQ(0xFFFF9080U, DE.getAddress(&offset));
	EXPECT_EQ(4U, offset);
	offset = 0;

	EXPECT_EQ(data, DE.getU32(&offset, data, 2));
	EXPECT_EQ(0xFFFF9080U, data[0]);
	EXPECT_EQ(0x80U, data[1]);
	EXPECT_EQ(8U, offset);
	}

	TEST(DataExtractorTest, SignedNumbers) {
	DataExtractor DE(StringRef(numberData, sizeof(numberData)-1), false, 8);
	uint64_t offset = 0;

	EXPECT_EQ(-128, DE.getSigned(&offset, 1));
	EXPECT_EQ(1U, offset);
	offset = 0;
	EXPECT_EQ(-32624, DE.getSigned(&offset, 2));
	EXPECT_EQ(2U, offset);
	offset = 0;
	EXPECT_EQ(-2137980929, DE.getSigned(&offset, 4));
	EXPECT_EQ(4U, offset);
	offset = 0;
	EXPECT_EQ(-9182558167379214336LL, DE.getSigned(&offset, 8));
	EXPECT_EQ(8U, offset);
	}

	TEST(DataExtractorTest, Strings) {
	const char stringData[] = "hellohello\0hello";
	DataExtractor DE(StringRef(stringData, sizeof(stringData)-1), false, 8);
	uint64_t offset = 0;

	EXPECT_EQ(stringData, DE.getCStr(&offset));
	EXPECT_EQ(11U, offset);
	EXPECT_EQ(nullptr, DE.getCStr(&offset));
	EXPECT_EQ(11U, offset);

	DataExtractor::Cursor C(0);
	EXPECT_EQ(stringData, DE.getCStr(C));
	EXPECT_EQ(11U, C.tell());
	EXPECT_EQ(nullptr, DE.getCStr(C));
	EXPECT_EQ(11U, C.tell());
	EXPECT_THAT_ERROR(
	C.takeError(),
	FailedWithMessage("no null terminated string at offset 0xb"));
	}

	TEST(DataExtractorTest, LEB128) {
	DataExtractor DE(StringRef(leb128data, sizeof(leb128data)-1), false, 8);
	uint64_t offset = 0;

	EXPECT_EQ(9382ULL, DE.getULEB128(&offset));
	EXPECT_EQ(2U, offset);
	offset = 0;
	EXPECT_EQ(-7002LL, DE.getSLEB128(&offset));
	EXPECT_EQ(2U, offset);

	DataExtractor BDE(StringRef(bigleb128data, sizeof(bigleb128data)-1), false,8);
	offset = 0;
	EXPECT_EQ(42218325750568106ULL, BDE.getULEB128(&offset));
	EXPECT_EQ(8U, offset);
	offset = 0;
	EXPECT_EQ(-29839268287359830LL, BDE.getSLEB128(&offset));
	EXPECT_EQ(8U, offset);
	}

	TEST(DataExtractorTest, LEB128_error) {
	DataExtractor DE(StringRef("\x81"), false, 8);
	uint64_t Offset = 0;
	EXPECT_EQ(0U, DE.getULEB128(&Offset));
	EXPECT_EQ(0U, Offset);

	Offset = 0;
	EXPECT_EQ(0U, DE.getSLEB128(&Offset));
	EXPECT_EQ(0U, Offset);

	DataExtractor::Cursor C(0);
	EXPECT_EQ(0U, DE.getULEB128(C));
	EXPECT_THAT_ERROR(
	C.takeError(),
	FailedWithMessage("unable to decode LEB128 at offset 0x00000000: "
	"malformed uleb128, extends past end"));

	C = DataExtractor::Cursor(0);
	EXPECT_EQ(0U, DE.getSLEB128(C));
	EXPECT_THAT_ERROR(
	C.takeError(),
	FailedWithMessage("unable to decode LEB128 at offset 0x00000000: "
	"malformed sleb128, extends past end"));

	// Show non-zero offsets are reported appropriately.
	C = DataExtractor::Cursor(1);
	EXPECT_EQ(0U, DE.getULEB128(C));
	EXPECT_THAT_ERROR(
	C.takeError(),
	FailedWithMessage("unable to decode LEB128 at offset 0x00000001: "
	"malformed uleb128, extends past end"));
	}

	TEST(DataExtractorTest, Cursor_tell) {
	DataExtractor DE(StringRef("AB"), false, 8);
	DataExtractor::Cursor C(0);
	// A successful read operation advances the cursor
	EXPECT_EQ('A', DE.getU8(C));
	EXPECT_EQ(1u, C.tell());

	// An unsuccessful one doesn't.
	EXPECT_EQ(0u, DE.getU16(C));
	EXPECT_EQ(1u, C.tell());

	// And neither do any subsequent operations.
	EXPECT_EQ(0, DE.getU8(C));
	EXPECT_EQ(1u, C.tell());

	consumeError(C.takeError());
	}

	TEST(DataExtractorTest, Cursor_takeError) {
	DataExtractor DE(StringRef("AB"), false, 8);
	DataExtractor::Cursor C(0);
	// Initially, the cursor is in the "success" state.
	EXPECT_THAT_ERROR(C.takeError(), Succeeded());

	// It remains "success" after a successful read.
	EXPECT_EQ('A', DE.getU8(C));
	EXPECT_THAT_ERROR(C.takeError(), Succeeded());

	// An unsuccessful read sets the error state.
	EXPECT_EQ(0u, DE.getU32(C));
	EXPECT_THAT_ERROR(C.takeError(), Failed());

	// Once set the error sticks until explicitly cleared.
	EXPECT_EQ(0u, DE.getU32(C));
	EXPECT_EQ(0, DE.getU8(C));
	EXPECT_THAT_ERROR(C.takeError(), Failed());

	// At which point reads can be succeed again.
	EXPECT_EQ('B', DE.getU8(C));
	EXPECT_THAT_ERROR(C.takeError(), Succeeded());
	}

	TEST(DataExtractorTest, Cursor_chaining) {
	DataExtractor DE(StringRef("ABCD"), false, 8);
	DataExtractor::Cursor C(0);

	// Multiple reads can be chained without trigerring any assertions.
	EXPECT_EQ('A', DE.getU8(C));
	EXPECT_EQ('B', DE.getU8(C));
	EXPECT_EQ('C', DE.getU8(C));
	EXPECT_EQ('D', DE.getU8(C));
	// And the error checked at the end.
	EXPECT_THAT_ERROR(C.takeError(), Succeeded());
	}

	#if defined(GTEST_HAS_DEATH_TEST) && defined(_DEBUG) && \
	LLVM_ENABLE_ABI_BREAKING_CHECKS
	TEST(DataExtractorDeathTest, Cursor) {
	DataExtractor DE(StringRef("AB"), false, 8);

	// Even an unused cursor must be checked for errors:
	EXPECT_DEATH(DataExtractor::Cursor(0),
	"Success values must still be checked prior to being destroyed");

	{
	auto C = std::make_unique<DataExtractor::Cursor>(0);
	EXPECT_EQ(0u, DE.getU32(*C));
	// It must also be checked after an unsuccessful operation.
	// destruction.
	EXPECT_DEATH(C.reset(), "unexpected end of data");
	EXPECT_THAT_ERROR(C->takeError(), Failed());
	}
	{
	auto C = std::make_unique<DataExtractor::Cursor>(0);
	EXPECT_EQ('A', DE.getU8(*C));
	// Same goes for a successful one.
	EXPECT_DEATH(
	C.reset(),
	"Success values must still be checked prior to being destroyed");
	EXPECT_THAT_ERROR(C->takeError(), Succeeded());
	}
	{
	auto C = std::make_unique<DataExtractor::Cursor>(0);
	EXPECT_EQ('A', DE.getU8(*C));
	EXPECT_EQ(0u, DE.getU32(*C));
	// Even if a successful operation is followed by an unsuccessful one.
	EXPECT_DEATH(C.reset(), "unexpected end of data");
	EXPECT_THAT_ERROR(C->takeError(), Failed());
	}
	{
	auto C = std::make_unique<DataExtractor::Cursor>(0);
	EXPECT_EQ(0u, DE.getU32(*C));
	EXPECT_EQ(0, DE.getU8(*C));
	// Even if an unsuccessful operation is followed by one that would normally
	// succeed.
	EXPECT_DEATH(C.reset(), "unexpected end of data");
	EXPECT_THAT_ERROR(C->takeError(), Failed());
	}
	}
	#endif

	TEST(DataExtractorTest, getU8_vector) {
	DataExtractor DE(StringRef("AB"), false, 8);
	DataExtractor::Cursor C(0);
	SmallVector<uint8_t, 2> S;

	DE.getU8(C, S, 4);
	EXPECT_THAT_ERROR(C.takeError(), Failed());
	EXPECT_EQ("", toStringRef(S));

	DE.getU8(C, S, 2);
	EXPECT_THAT_ERROR(C.takeError(), Succeeded());
	EXPECT_EQ("AB", toStringRef(S));

	C = DataExtractor::Cursor(0x47);
	DE.getU8(C, S, 2);
	EXPECT_THAT_ERROR(
	C.takeError(),
	FailedWithMessage("offset 0x47 is beyond the end of data at 0x2"));
	}

	TEST(DataExtractorTest, getU24) {
	DataExtractor DE(StringRef("ABCD"), false, 8);
	DataExtractor::Cursor C(0);

	EXPECT_EQ(0x414243u, DE.getU24(C));
	EXPECT_EQ(0u, DE.getU24(C));
	EXPECT_EQ(3u, C.tell());
	EXPECT_THAT_ERROR(C.takeError(), Failed());
	}

	TEST(DataExtractorTest, skip) {
	DataExtractor DE(StringRef("AB"), false, 8);
	DataExtractor::Cursor C(0);

	DE.skip(C, 4);
	EXPECT_THAT_ERROR(C.takeError(), Failed());
	EXPECT_EQ(0u, C.tell());

	DE.skip(C, 2);
	EXPECT_THAT_ERROR(C.takeError(), Succeeded());
	EXPECT_EQ(2u, C.tell());
	}

	TEST(DataExtractorTest, eof) {
	DataExtractor DE(StringRef("A"), false, 8);
	DataExtractor::Cursor C(0);

	EXPECT_FALSE(DE.eof(C));

	EXPECT_EQ(0, DE.getU16(C));
	EXPECT_FALSE(DE.eof(C));
	EXPECT_THAT_ERROR(C.takeError(), Failed());

	EXPECT_EQ('A', DE.getU8(C));
	EXPECT_TRUE(DE.eof(C));
	EXPECT_THAT_ERROR(C.takeError(), Succeeded());
	}

	TEST(DataExtractorTest, size) {
	uint8_t Data[] = {'A', 'B', 'C', 'D'};
	DataExtractor DE1(StringRef(reinterpret_cast<char *>(Data), sizeof(Data)),
	false, 8);
	EXPECT_EQ(DE1.size(), sizeof(Data));
	DataExtractor DE2(ArrayRef<uint8_t>(Data), false, 8);
	EXPECT_EQ(DE2.size(), sizeof(Data));
	}

	TEST(DataExtractorTest, FixedLengthString) {
	const char Data[] = "hello\x00\x00\x00world \thola\x00";
	DataExtractor DE(StringRef(Data, sizeof(Data)-1), false, 8);
	uint64_t Offset = 0;
	StringRef Str;
	// Test extracting too many bytes doesn't modify Offset and returns None.
	Str = DE.getFixedLengthString(&Offset, sizeof(Data));
	EXPECT_TRUE(Str.empty());
	EXPECT_EQ(Offset, 0u);

	// Test extracting a fixed width C string with trailing NULL characters.
	Str = DE.getFixedLengthString(&Offset, 8);
	EXPECT_EQ(Offset, 8u);
	EXPECT_EQ(Str.size(), 5u);
	EXPECT_EQ(Str, "hello");
	// Test extracting a fixed width C string with trailing space and tab
	// characters.
	Str = DE.getFixedLengthString(&Offset, 8, " \t");
	EXPECT_EQ(Offset, 16u);
	EXPECT_EQ(Str.size(), 5u);
	EXPECT_EQ(Str, "world");
	// Now extract a normal C string.
	Str = DE.getCStrRef(&Offset);
	EXPECT_EQ(Str.size(), 4u);
	EXPECT_EQ(Str, "hola");
	}


	TEST(DataExtractorTest, GetBytes) {
	// Use data with an embedded NULL character for good measure.
	const char Data[] = "\x01\x02\x00\x04";
	StringRef Bytes(Data, sizeof(Data)-1);
	DataExtractor DE(Bytes, false, 8);
	uint64_t Offset = 0;
	StringRef Str;
	// Test extracting too many bytes doesn't modify Offset and returns None.
	Str = DE.getBytes(&Offset, sizeof(Data));
	EXPECT_TRUE(Str.empty());
	EXPECT_EQ(Offset, 0u);
	// Test extracting 4 bytes from the stream.
	Str = DE.getBytes(&Offset, 4);
	EXPECT_EQ(Offset, 4u);
	EXPECT_EQ(Str.size(), 4u);
	EXPECT_EQ(Str, Bytes);

	DataExtractor::Cursor C(0);
	EXPECT_EQ(StringRef("\x01\x02"), DE.getBytes(C, 2));
	EXPECT_EQ(StringRef("\x00\x04", 2), DE.getBytes(C, 2));
	EXPECT_EQ(StringRef(), DE.getBytes(C, 2));
	EXPECT_EQ(StringRef(), DE.getBytes(C, 2));
	EXPECT_EQ(4u, C.tell());
	EXPECT_THAT_ERROR(C.takeError(), Failed());
	}

	}