65 lines
2.0 KiB
C++
65 lines
2.0 KiB
C++
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//===- llvm/unittest/Support/CRCTest.cpp - CRC tests ----------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements unit tests for CRC calculation functions.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/CRC.h"
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#include "llvm/ADT/StringExtras.h"
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#include "gtest/gtest.h"
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#include <stdlib.h>
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using namespace llvm;
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namespace {
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TEST(CRCTest, CRC32) {
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EXPECT_EQ(0x414FA339U, llvm::crc32(arrayRefFromStringRef(
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"The quick brown fox jumps over the lazy dog")));
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// CRC-32/ISO-HDLC test vector
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// http://reveng.sourceforge.net/crc-catalogue/17plus.htm#crc.cat.crc-32c
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EXPECT_EQ(0xCBF43926U, llvm::crc32(arrayRefFromStringRef("123456789")));
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// Check the CRC-32 of each byte value, exercising all of CRCTable.
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for (int i = 0; i < 256; i++) {
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// Compute CRCTable[i] using Hacker's Delight (2nd ed.) Figure 14-7.
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uint32_t crc = i;
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for (int j = 7; j >= 0; j--) {
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uint32_t mask = -(crc & 1);
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crc = (crc >> 1) ^ (0xEDB88320 & mask);
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}
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// CRCTable[i] is the CRC-32 of i without the initial and final bit flips.
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uint8_t byte = i;
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EXPECT_EQ(crc, ~llvm::crc32(0xFFFFFFFFU, byte));
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}
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EXPECT_EQ(0x00000000U, llvm::crc32(arrayRefFromStringRef("")));
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}
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#if (SIZE_MAX > UINT32_MAX) && defined(EXPENSIVE_CHECKS)
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TEST(CRCTest, LargeCRC32) {
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// Check that crc32 can handle inputs with sizes larger than 32 bits.
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size_t TestSize = (size_t)UINT32_MAX + 42;
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uint8_t *TestData = (uint8_t*)calloc(TestSize, 1);
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if (!TestData)
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return;
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// Test expectation generated with:
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// $ truncate --size=`echo 2^32-1+42 | bc` /tmp/foo
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// $ crc32 /tmp/foo
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EXPECT_EQ(0xE46F28FBU, llvm::crc32(makeArrayRef(TestData, TestSize)));
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free(TestData);
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}
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#endif
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} // end anonymous namespace
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