1/*
2 * Copyright (c) 2014-2020 Pavel Kalvoda <me@pavelkalvoda.com>
3 *
4 * libcbor is free software; you can redistribute it and/or modify
5 * it under the terms of the MIT license. See LICENSE for details.
6 */
7
8#include "loaders.h"
9#include <math.h>
10#include <string.h>
11
12uint8_t _cbor_load_uint8(cbor_data source) { return (uint8_t)*source; }
13
14uint16_t _cbor_load_uint16(const unsigned char *source) {
15#ifdef IS_BIG_ENDIAN
16  uint16_t result;
17  memcpy(&result, source, 2);
18  return result;
19#else
20  return ((uint16_t) * (source + 0) << 8) + (uint8_t) * (source + 1);
21#endif
22}
23
24uint32_t _cbor_load_uint32(const unsigned char *source) {
25#ifdef IS_BIG_ENDIAN
26  uint32_t result;
27  memcpy(&result, source, 4);
28  return result;
29#else
30  return ((uint32_t) * (source + 0) << 0x18) +
31         ((uint32_t) * (source + 1) << 0x10) +
32         ((uint16_t) * (source + 2) << 0x08) + (uint8_t) * (source + 3);
33#endif
34}
35
36uint64_t _cbor_load_uint64(const unsigned char *source) {
37#ifdef IS_BIG_ENDIAN
38  uint64_t result;
39  memcpy(&result, source, 8);
40  return result;
41#else
42  return ((uint64_t) * (source + 0) << 0x38) +
43         ((uint64_t) * (source + 1) << 0x30) +
44         ((uint64_t) * (source + 2) << 0x28) +
45         ((uint64_t) * (source + 3) << 0x20) +
46         ((uint32_t) * (source + 4) << 0x18) +
47         ((uint32_t) * (source + 5) << 0x10) +
48         ((uint16_t) * (source + 6) << 0x08) + (uint8_t) * (source + 7);
49#endif
50}
51
52/* As per https://www.rfc-editor.org/rfc/rfc8949.html#name-half-precision */
53float _cbor_decode_half(unsigned char *halfp) {
54  int half = (halfp[0] << 8) + halfp[1];
55  int exp = (half >> 10) & 0x1f;
56  int mant = half & 0x3ff;
57  double val;
58  if (exp == 0)
59    val = ldexp(mant, -24);
60  else if (exp != 31)
61    val = ldexp(mant + 1024, exp - 25);
62  else
63    val = mant == 0 ? INFINITY : NAN;
64  return (float)(half & 0x8000 ? -val : val);
65}
66
67float _cbor_load_half(cbor_data source) {
68  /* Discard const */
69  return _cbor_decode_half((unsigned char *)source);
70}
71
72float _cbor_load_float(cbor_data source) {
73  union _cbor_float_helper helper = {.as_uint = _cbor_load_uint32(source)};
74  return helper.as_float;
75}
76
77double _cbor_load_double(cbor_data source) {
78  union _cbor_double_helper helper = {.as_uint = _cbor_load_uint64(source)};
79  return helper.as_double;
80}
81