How do I use boost :: hash to get a hash of the contents of a file?
1 answer
No, Boost does not implement MD5. To do this, use the crypto / hash library.
CryptoC ++ is good in my experience.
OpenSSL implements all the popular digests, here's a sample that uses OpenSSL:
#include <openssl/md5.h>
#include <iostream>
#include <iomanip>
// Print the MD5 sum as hex-digits.
void print_md5_sum(unsigned char* md) {
for(unsigned i=0; i <MD5_DIGEST_LENGTH; i++) {
std::cout << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(md[i]);
}
}
#include <string>
#include <vector>
#include <fstream>
int main(int argc, char *argv[]) {
using namespace std;
vector<string> const args(argv+1, argv+argc);
for (auto& fname : args) {
MD5_CTX ctx;
MD5_Init(&ctx);
ifstream ifs(fname, std::ios::binary);
char file_buffer[4096];
while (ifs.read(file_buffer, sizeof(file_buffer)) || ifs.gcount()) {
MD5_Update(&ctx, file_buffer, ifs.gcount());
}
unsigned char digest[MD5_DIGEST_LENGTH] = {};
MD5_Final(digest, &ctx);
print_md5_sum(digest);
std::cout << "\t" << fname << "\n";
}
}
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