/*
boost-crc-bug-demo.cpp
Written by U.Mutlu on 2015-07-09-Th
Compile:
g++ -O2 -Wall -std=gnu++11 boost-crc-bug-demo.cpp
Run:
./a.out
Output:
crc("The quick brown fox jumps over the lazy dog")=414fa339
crc("The quick brown fox ")=88b075e2
crc("The quick brown fox jumps over the lazy dog")=4ac56d0f
ERROR
See also:
http://www.boost.org/doc/libs/1_58_0/libs/crc/crc.html#usage
Conclusion:
It doesn't do what it should and also advertises; ie. there's a bug
*/
#include
#include
#include <iostream>
int main()
{
uint32_t expected;
{
const std::string sTxt = "The quick brown fox jumps over the lazy dog";
boost::crc_optimal<32, 0x04C11DB7, 0xFFFFFFFF, 0xFFFFFFFF, true, true> crc;
crc.process_bytes(sTxt.data(), sTxt.size());
std::cout << "crc(\"" << sTxt << "\")=" << std::hex << crc.checksum() <<
std::endl;
// save the result for the following test
expected = crc.checksum();
}
// test: doing the same as above, but now in 2 steps, ie. chunk- or
blockwise:
std::string sTxt;
uint32_t result = 0xFFFFFFFF;
for (size_t i = 0; i <= 1; ++i)
{
sTxt += !i ? "The quick brown fox "
: "jumps over the lazy dog";
// using the special ctor for initial remainder stored in "result"
boost::crc_optimal<32, 0x04C11DB7, 0xFFFFFFFF, 0xFFFFFFFF, true, true>
crc(result);
crc.process_bytes(sTxt.data(), sTxt.size());
std::cout << "crc(\"" << sTxt << "\")=" << std::hex << crc.checksum() <<
std::endl;
result = crc.checksum();
}
// eval:
const std::string sRes = result == expected ? "SUCCESS" : "ERROR";
std::cout << sRes << std::endl;
return 0;
}
