/* ====================================================================

 * Copyright (c) 2008 The OpenSSL Project.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

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 *

 * 1. Redistributions of source code must retain the above copyright

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 * 3. All advertising materials mentioning features or use of this

 *    software must display the following acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"

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 *    openssl-core@openssl.org.

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 * 5. Products derived from this software may not be called "OpenSSL"

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 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"

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 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

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 * ==================================================================== */

#include <assert.h>

#include <string.h>

#include "internal.h"

static_assert(16 % sizeof(size_t) == 0, "block cannot be divided into size_t");

void CRYPTO_ofb128_encrypt(const uint8_t *in, uint8_t *out, size_t len,

                           const AES_KEY *key, uint8_t ivec[16], unsigned *num,

                           block128_f block) {

  assert(key != NULL && ivec != NULL && num != NULL);

  assert(len == 0 || (in != NULL && out != NULL));

  unsigned n = *num;

  while (n && len) {

    *(out++) = *(in++) ^ ivec[n];

    --len;

    n = (n + 1) % 16;

  }

  while (len >= 16) {

    (*block)(ivec, ivec, key);

    CRYPTO_xor16(out, in, ivec);

    len -= 16;

    out += 16;

    in += 16;

    n = 0;

  }

  if (len) {

    (*block)(ivec, ivec, key);

    while (len--) {

      out[n] = in[n] ^ ivec[n];

      ++n;

    }

  }

  *num = n;

}