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 "encoders.h"
9 #include <string.h>
10 
11 size_t _cbor_encode_uint8(uint8_t value, unsigned char *buffer,
12                           size_t buffer_size, uint8_t offset) {
13   if (value <= 23) {
14     if (buffer_size >= 1) {
15       buffer[0] = value + offset;
16       return 1;
17     }
18   } else {
19     if (buffer_size >= 2) {
20       buffer[0] = 0x18 + offset;
21       buffer[1] = value;
22       return 2;
23     }
24   }
25   return 0;
26 }
27 
28 size_t _cbor_encode_uint16(uint16_t value, unsigned char *buffer,
29                            size_t buffer_size, uint8_t offset) {
30   if (buffer_size >= 3) {
31     buffer[0] = 0x19 + offset;
32 
33 #ifdef IS_BIG_ENDIAN
34     memcpy(buffer + 1, &value, 2);
35 #else
36     buffer[1] = (unsigned char)(value >> 8);
37     buffer[2] = (unsigned char)value;
38 #endif
39 
40     return 3;
41   } else
42     return 0;
43 }
44 
45 size_t _cbor_encode_uint32(uint32_t value, unsigned char *buffer,
46                            size_t buffer_size, uint8_t offset) {
47   if (buffer_size >= 5) {
48     buffer[0] = 0x1A + offset;
49 
50 #ifdef IS_BIG_ENDIAN
51     memcpy(buffer + 1, &value, 4);
52 #else
53     buffer[1] = (unsigned char)(value >> 24);
54     buffer[2] = (unsigned char)(value >> 16);
55     buffer[3] = (unsigned char)(value >> 8);
56     buffer[4] = (unsigned char)value;
57 #endif
58 
59     return 5;
60   } else
61     return 0;
62 }
63 
64 size_t _cbor_encode_uint64(uint64_t value, unsigned char *buffer,
65                            size_t buffer_size, uint8_t offset) {
66   if (buffer_size >= 9) {
67     buffer[0] = 0x1B + offset;
68 
69 #ifdef IS_BIG_ENDIAN
70     memcpy(buffer + 1, &value, 8);
71 #else
72     buffer[1] = (unsigned char)(value >> 56);
73     buffer[2] = (unsigned char)(value >> 48);
74     buffer[3] = (unsigned char)(value >> 40);
75     buffer[4] = (unsigned char)(value >> 32);
76     buffer[5] = (unsigned char)(value >> 24);
77     buffer[6] = (unsigned char)(value >> 16);
78     buffer[7] = (unsigned char)(value >> 8);
79     buffer[8] = (unsigned char)value;
80 #endif
81 
82     return 9;
83   } else
84     return 0;
85 }
86 
87 size_t _cbor_encode_uint(uint64_t value, unsigned char *buffer,
88                          size_t buffer_size, uint8_t offset) {
89   if (value <= UINT16_MAX)
90     if (value <= UINT8_MAX)
91       return _cbor_encode_uint8((uint8_t)value, buffer, buffer_size, offset);
92     else
93       return _cbor_encode_uint16((uint16_t)value, buffer, buffer_size, offset);
94   else if (value <= UINT32_MAX)
95     return _cbor_encode_uint32((uint32_t)value, buffer, buffer_size, offset);
96   else
97     return _cbor_encode_uint64((uint64_t)value, buffer, buffer_size, offset);
98 }
99