/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2013 Nils Maier
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * In addition, as a special exception, the copyright holders give
 * permission to link the code of portions of this program with the
 * OpenSSL library under certain conditions as described in each
 * individual source file, and distribute linked combinations
 * including the two.
 * You must obey the GNU General Public License in all respects
 * for all of the code used other than OpenSSL.  If you modify
 * file(s) with this exception, you may extend this exception to your
 * version of the file(s), but you are not obligated to do so.  If you
 * do not wish to do so, delete this exception statement from your
 * version.  If you delete this exception statement from all source
 * files in the program, then also delete it here.
 */
/* copyright --> */

#include "MessageDigestImpl.h"

#include <gcrypt.h>

namespace aria2 {

namespace {
template<int hash>
class MessageDigestBase : public MessageDigestImpl {
private:
  struct Deleter {
    void operator()(gcry_md_hd_t ctx) {
      if (ctx) {
        gcry_md_close(ctx);
      }
    }
  };

public:
  MessageDigestBase()
  {
    gcry_md_hd_t ctx = nullptr;
    gcry_md_open(&ctx, hash, 0);
    ctx_.reset(ctx);
    reset();
  }

  virtual ~MessageDigestBase() {}

  static size_t length()
  {
    return ::gcry_md_get_algo_dlen(hash);
  }

  virtual size_t getDigestLength() const CXX11_OVERRIDE
  {
    return ::gcry_md_get_algo_dlen(hash);
  }

  virtual void reset() CXX11_OVERRIDE {
    ::gcry_md_reset(ctx_.get());
  }

  virtual void update(const void* data, size_t length) CXX11_OVERRIDE
  {
    auto bytes = reinterpret_cast<const uint8_t*>(data);
    while (length) {
      size_t l = std::min(length, (size_t)std::numeric_limits<uint32_t>::max());
      gcry_md_write(ctx_.get(), bytes, length);
      length -= l;
      bytes += l;
    }
  }

  virtual void digest(unsigned char* md) CXX11_OVERRIDE
  {
    ::memcpy(md, gcry_md_read(ctx_.get(), 0), getDigestLength());
  }

private:
  std::unique_ptr<std::remove_pointer<gcry_md_hd_t>::type, Deleter> ctx_;
};

typedef MessageDigestBase<GCRY_MD_MD5> MessageDigestMD5;
typedef MessageDigestBase<GCRY_MD_SHA1> MessageDigestSHA1;
typedef MessageDigestBase<GCRY_MD_SHA224> MessageDigestSHA224;
typedef MessageDigestBase<GCRY_MD_SHA256> MessageDigestSHA256;
typedef MessageDigestBase<GCRY_MD_SHA384> MessageDigestSHA384;
typedef MessageDigestBase<GCRY_MD_SHA512> MessageDigestSHA512;
} // namespace

std::unique_ptr<MessageDigestImpl> MessageDigestImpl::sha1()
{
  return std::unique_ptr<MessageDigestImpl>(new MessageDigestSHA1());
}

MessageDigestImpl::hashes_t MessageDigestImpl::hashes = {
  { "sha-1", make_hi<MessageDigestSHA1>() },
  { "sha-224", make_hi<MessageDigestSHA224>() },
  { "sha-256", make_hi<MessageDigestSHA256>() },
  { "sha-384", make_hi<MessageDigestSHA384>() },
  { "sha-512", make_hi<MessageDigestSHA512>() },
  { "md5", make_hi<MessageDigestMD5>() },
};

} // namespace aria2