Calculate a SHA-256 hash with OpenSSL 1.0.2h

sha256.cpp

#include <cstdint>
#include <vector>
#include <array>

#include <openssl/evp.h>
#include <openssl/sha.h>


namespace {

bool Sha256(
  std::array<uint8_t, SHA256_DIGEST_LENGTH> & out,
  const std::vector<uint8_t> & in
)
{
    auto ctx = EVP_MD_CTX_create();
    if (!ctx)
    {
        return false;
    }
    
    bool result = false;
    for (;;)
    {
        if (EVP_DigestInit(ctx, EVP_sha256()) != 1)
        {
            break;
        }
        
        if (EVP_DigestUpdate(ctx, in.data(), in.size()) != 1)
        {
            break;
        }
        
        if (EVP_DigestFinal(ctx, out.data(), nullptr) != 1)
        {
            break;
        }
        
        result = true;
        break;
    }
    
    EVP_MD_CTX_destroy(ctx);
    
    return result;
}

}