1 //===- llvm/unittest/Support/CRCTest.cpp - CRC tests ----------------------===//
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-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements unit tests for CRC calculation functions.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "llvm/Support/CRC.h"
14 #include "llvm/ADT/StringExtras.h"
15 #include "gtest/gtest.h"
16 #include <stdlib.h>
17
18 using namespace llvm;
19
20 namespace {
21
TEST(CRCTest,CRC32)22 TEST(CRCTest, CRC32) {
23 EXPECT_EQ(0x414FA339U, llvm::crc32(arrayRefFromStringRef(
24 "The quick brown fox jumps over the lazy dog")));
25
26 // CRC-32/ISO-HDLC test vector
27 // http://reveng.sourceforge.net/crc-catalogue/17plus.htm#crc.cat.crc-32c
28 EXPECT_EQ(0xCBF43926U, llvm::crc32(arrayRefFromStringRef("123456789")));
29
30 // Check the CRC-32 of each byte value, exercising all of CRCTable.
31 for (int i = 0; i < 256; i++) {
32 // Compute CRCTable[i] using Hacker's Delight (2nd ed.) Figure 14-7.
33 uint32_t crc = i;
34 for (int j = 7; j >= 0; j--) {
35 uint32_t mask = -(crc & 1);
36 crc = (crc >> 1) ^ (0xEDB88320 & mask);
37 }
38
39 // CRCTable[i] is the CRC-32 of i without the initial and final bit flips.
40 uint8_t byte = i;
41 EXPECT_EQ(crc, ~llvm::crc32(0xFFFFFFFFU, byte));
42 }
43
44 EXPECT_EQ(0x00000000U, llvm::crc32(arrayRefFromStringRef("")));
45 }
46
47 #if (SIZE_MAX > UINT32_MAX) && defined(EXPENSIVE_CHECKS)
TEST(CRCTest,LargeCRC32)48 TEST(CRCTest, LargeCRC32) {
49 // Check that crc32 can handle inputs with sizes larger than 32 bits.
50 size_t TestSize = (size_t)UINT32_MAX + 42;
51 uint8_t *TestData = (uint8_t*)calloc(TestSize, 1);
52 if (!TestData)
53 GTEST_SKIP();
54
55 // Test expectation generated with:
56 // $ truncate --size=`echo 2^32-1+42 | bc` /tmp/foo
57 // $ crc32 /tmp/foo
58 EXPECT_EQ(0xE46F28FBU, llvm::crc32(ArrayRef(TestData, TestSize)));
59
60 free(TestData);
61 }
62 #endif
63
64 } // end anonymous namespace
65