/* coap_encode.c -- encoding and decoding of CoAP data types

 *

 * Copyright (C) 2010-2026 Olaf Bergmann <bergmann@tzi.org>

 *

 * SPDX-License-Identifier: BSD-2-Clause

 *

 * This file is part of the CoAP library libcoap. Please see

 * README for terms of use.

 */

/**

 * @file coap_encode.c

 * @brief Encoding and decoding Coap data types functions

 */

#include "coap3/coap_libcoap_build.h"

/* Carsten suggested this when fls() is not available: */

#ifndef HAVE_FLS

int

coap_fls(unsigned int i) {

  return coap_flsll(i);

}

#endif

#ifndef HAVE_FLSLL

int

coap_flsll(long long j) {

  unsigned long long i = (unsigned long long)j;

  int n;

  for (n = 0; i; n++)

    i >>= 1;

  return n;

}

#endif

unsigned int

coap_decode_var_bytes(const uint8_t *buf, size_t len) {

  unsigned int i, n = 0;

  for (i = 0; i < len; ++i)

    n = (n << 8) + buf[i];

  return n;

}

unsigned int

coap_encode_var_safe(uint8_t *buf, size_t length, unsigned int val) {

  unsigned int n, i;

  if (val == 0)

    return 0;

  for (n = 0, i = val; i && n < sizeof(val); ++n)

    i >>= 8;

  if (n > length) {

    assert(n <= length);

    return 0;

  }

  i = n;

  while (i) {

    i--;

    buf[i] = val & 0xff;

    val >>= 8;

  }

  return n;

}

uint64_t

coap_decode_var_bytes8(const uint8_t *buf, size_t len) {

  unsigned int i;

  uint64_t n = 0;

  for (i = 0; i < len && i < sizeof(uint64_t); ++i)

    n = (n << 8) + buf[i];

  return n;

}

unsigned int

coap_encode_var_safe8(uint8_t *buf, size_t length, uint64_t val) {

  unsigned int n, i;

  uint64_t tval = val;

  if (val == 0)

    return 0;

  for (n = 0; tval && n < sizeof(val); ++n)

    tval >>= 8;

  if (n > length) {

    assert(n <= length);

    return 0;

  }

  i = n;

  while (i) {

    i--;

    buf[i] = val & 0xff;

    val >>= 8;

  }

  return n;

}