/* poly1305-update.c

   Copyright (C) 2022 Niels Möller

   This file is part of GNU Nettle.

   GNU Nettle is free software: you can redistribute it and/or

   modify it under the terms of either:

     * the GNU Lesser General Public License as published by the Free

       Software Foundation; either version 3 of the License, or (at your

       option) any later version.

   or

     * 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.

   or both in parallel, as here.

   GNU Nettle 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 copies of the GNU General Public License and

   the GNU Lesser General Public License along with this program.  If

   not, see http://www.gnu.org/licenses/.

*/

#if HAVE_CONFIG_H

#include "config.h"

#endif

#include "poly1305.h"

#include "poly1305-internal.h"

#include "md-internal.h"

#if HAVE_NATIVE_fat_poly1305_blocks

const uint8_t *

_nettle_poly1305_blocks_c(struct poly1305_ctx *ctx,

         size_t blocks, const uint8_t *m);

const uint8_t *

_nettle_poly1305_blocks_c(struct poly1305_ctx *ctx,

         size_t blocks, const uint8_t *m)

{

  for (; blocks; blocks--, m += POLY1305_BLOCK_SIZE)

    _nettle_poly1305_block(ctx, m, 1);

  return m;

}

#endif

unsigned

_nettle_poly1305_update (struct poly1305_ctx *ctx,

       uint8_t *block, unsigned index,

       size_t length, const uint8_t *m)

{

  if (!length)

    return index;

  if (index > 0)

    {

      /* Try to fill partial block */

      MD_FILL_OR_RETURN_INDEX (POLY1305_BLOCK_SIZE, block, index,

             length, m);

      _nettle_poly1305_block(ctx, block, 1);

    }

#if HAVE_NATIVE_poly1305_blocks

  m = _nettle_poly1305_blocks (ctx, length >> 4, m);

  length &= 15;

#else

  for (; length >= POLY1305_BLOCK_SIZE;

       length -= POLY1305_BLOCK_SIZE, m += POLY1305_BLOCK_SIZE)

    _nettle_poly1305_block (ctx, m, 1);

#endif

  memcpy (block, m, length);

  return length;

}