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llvm-mirror/unittests/Support/CRCTest.cpp
Hans Wennborg ab9f34b755 Make llvm::crc32() work also for input sizes larger than 32 bits.
The problem was noticed by the Chrome OS toolchain folks
(crbug.com/1048445) because llvm-objcopy --add-gnu-debuglink would
insert the wrong checksum when processing a binary larger than 4 GB.
That use case regressed in 1e1e3ba2526 when we started using
llvm::crc32() in more places.

Differential revision: https://reviews.llvm.org/D74039
2020-02-05 21:32:11 +01:00

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//===- llvm/unittest/Support/CRCTest.cpp - CRC 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
//
//===----------------------------------------------------------------------===//
//
// This file implements unit tests for CRC calculation functions.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/CRC.h"
#include "llvm/ADT/StringExtras.h"
#include "gtest/gtest.h"
#include <stdlib.h>
using namespace llvm;
namespace {
TEST(CRCTest, CRC32) {
EXPECT_EQ(0x414FA339U, llvm::crc32(arrayRefFromStringRef(
"The quick brown fox jumps over the lazy dog")));
// CRC-32/ISO-HDLC test vector
// http://reveng.sourceforge.net/crc-catalogue/17plus.htm#crc.cat.crc-32c
EXPECT_EQ(0xCBF43926U, llvm::crc32(arrayRefFromStringRef("123456789")));
// Check the CRC-32 of each byte value, exercising all of CRCTable.
for (int i = 0; i < 256; i++) {
// Compute CRCTable[i] using Hacker's Delight (2nd ed.) Figure 14-7.
uint32_t crc = i;
for (int j = 7; j >= 0; j--) {
uint32_t mask = -(crc & 1);
crc = (crc >> 1) ^ (0xEDB88320 & mask);
}
// CRCTable[i] is the CRC-32 of i without the initial and final bit flips.
uint8_t byte = i;
EXPECT_EQ(crc, ~llvm::crc32(0xFFFFFFFFU, byte));
}
EXPECT_EQ(0x00000000U, llvm::crc32(arrayRefFromStringRef("")));
}
#if (SIZE_MAX > UINT32_MAX) && defined(EXPENSIVE_CHECKS)
TEST(CRCTest, LargeCRC32) {
// Check that crc32 can handle inputs with sizes larger than 32 bits.
size_t TestSize = (size_t)UINT32_MAX + 42;
uint8_t *TestData = (uint8_t*)calloc(TestSize, 1);
if (!TestData)
return;
// Test expectation generated with:
// $ truncate --size=`echo 2^32-1+42 | bc` /tmp/foo
// $ crc32 /tmp/foo
EXPECT_EQ(0xE46F28FBU, llvm::crc32(makeArrayRef(TestData, TestSize)));
free(TestData);
}
#endif
} // end anonymous namespace