/* <!-- copyright */
/*
 * aria2 - The high speed download utility
 *
 * Copyright (C) 2006 Tatsuhiro Tsujikawa
 *
 * 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 "message_digest_helper.h"

#include <array>
#include <cstring>
#include <cstdlib>

#include "MessageDigest.h"
#include "DlAbortEx.h"
#include "message.h"
#include "DefaultDiskWriter.h"
#include "util.h"
#include "fmt.h"

namespace aria2 {

namespace message_digest {

std::string digest(MessageDigest* ctx, const std::shared_ptr<BinaryStream>& bs,
                   int64_t offset, int64_t length)
{
  std::array<unsigned char, 4_k> buf;
  lldiv_t res = lldiv(length, buf.size());
  int64_t iteration = res.quot;
  size_t tail = res.rem;
  for (int64_t i = 0; i < iteration; ++i) {
    ssize_t readLength = bs->readData(buf.data(), buf.size(), offset);
    if ((size_t)readLength != buf.size()) {
      throw DL_ABORT_EX(fmt(EX_FILE_READ, "n/a", "data is too short"));
    }
    ctx->update(buf.data(), readLength);
    offset += readLength;
  }
  if (tail) {
    ssize_t readLength = bs->readData(buf.data(), tail, offset);
    if ((size_t)readLength != tail) {
      throw DL_ABORT_EX(fmt(EX_FILE_READ, "n/a", "data is too short"));
    }
    ctx->update(buf.data(), readLength);
  }
  return ctx->digest();
}

void digest(unsigned char* md, size_t mdLength, MessageDigest* ctx,
            const void* data, size_t length)
{
  size_t reqLength = ctx->getDigestLength();
  if (mdLength < reqLength) {
    throw DL_ABORT_EX(fmt("Insufficient space for storing message digest:"
                          " %lu required, but only %lu is allocated",
                          static_cast<unsigned long>(reqLength),
                          static_cast<unsigned long>(mdLength)));
  }
  ctx->update(data, length);
  ctx->digest(md);
}

} // namespace message_digest

} // namespace aria2