/*
* OpenSSL Hash Functions
* (C) 1999-2007,2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/hash.h>
#include <botan/internal/openssl.h>
#include <botan/internal/algo_registry.h>
#include <openssl/evp.h>

namespace Botan {

namespace {

class OpenSSL_HashFunction : public HashFunction
   {
   public:
      void clear() override
         {
         const EVP_MD* algo = EVP_MD_CTX_md(&m_md);
         EVP_DigestInit_ex(&m_md, algo, nullptr);
         }

      const char* provider() const override { return "openssl"; }
      std::string name() const override { return m_name; }

      HashFunction* clone() const override
         {
         const EVP_MD* algo = EVP_MD_CTX_md(&m_md);
         return new OpenSSL_HashFunction(algo, name());
         }

      size_t output_length() const override
         {
         return EVP_MD_size(EVP_MD_CTX_md(&m_md));
         }

      size_t hash_block_size() const override
         {
         return EVP_MD_block_size(EVP_MD_CTX_md(&m_md));
         }

      OpenSSL_HashFunction(const EVP_MD* md, const std::string& name) : m_name(name)
         {
         EVP_MD_CTX_init(&m_md);
         EVP_DigestInit_ex(&m_md, md, nullptr);
         }

      ~OpenSSL_HashFunction()
         {
         EVP_MD_CTX_cleanup(&m_md);
         }

   private:
      void add_data(const byte input[], size_t length) override
         {
         EVP_DigestUpdate(&m_md, input, length);
         }

      void final_result(byte output[]) override
         {
         EVP_DigestFinal_ex(&m_md, output, nullptr);
         const EVP_MD* algo = EVP_MD_CTX_md(&m_md);
         EVP_DigestInit_ex(&m_md, algo, nullptr);
         }

      std::string m_name;
      EVP_MD_CTX m_md;
   };

std::function<HashFunction* (const HashFunction::Spec&)>
make_evp_hash_maker(const EVP_MD* md, const char* algo)
   {
   return [md,algo](const HashFunction::Spec&)
      {
      return new OpenSSL_HashFunction(md, algo);
      };
   }

#define BOTAN_REGISTER_OPENSSL_EVP_HASH(NAME, EVP)                      \
   BOTAN_REGISTER_TYPE(HashFunction, OpenSSL_HashFunction ## EVP, NAME, \
                       make_evp_hash_maker(EVP(), NAME), "openssl", BOTAN_OPENSSL_HASH_PRIO)

#if !defined(OPENSSL_NO_SHA)
   BOTAN_REGISTER_OPENSSL_EVP_HASH("SHA-160", EVP_sha1);
#endif

#if !defined(OPENSSL_NO_SHA256)
   BOTAN_REGISTER_OPENSSL_EVP_HASH("SHA-224", EVP_sha224);
   BOTAN_REGISTER_OPENSSL_EVP_HASH("SHA-256", EVP_sha256);
#endif

#if !defined(OPENSSL_NO_SHA512)
   BOTAN_REGISTER_OPENSSL_EVP_HASH("SHA-384", EVP_sha384);
   BOTAN_REGISTER_OPENSSL_EVP_HASH("SHA-512", EVP_sha512);
#endif

#if !defined(OPENSSL_NO_MD4)
   BOTAN_REGISTER_OPENSSL_EVP_HASH("MD4", EVP_md4);
#endif

#if !defined(OPENSSL_NO_MD5)
   BOTAN_REGISTER_OPENSSL_EVP_HASH("MD5", EVP_md5);
#endif

#if !defined(OPENSSL_NO_RIPEMD)
   BOTAN_REGISTER_OPENSSL_EVP_HASH("RIPEMD-160", EVP_ripemd160);
#endif

}

}