xref: /freebsd/contrib/libcbor/src/cbor/internal/encoders.c (revision b5b9517bfe394e55088f5a05882eabae7e9b7b29)
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 
10 #include <string.h>
11 
_cbor_encode_uint8(uint8_t value,unsigned char * buffer,size_t buffer_size,uint8_t offset)12 size_t _cbor_encode_uint8(uint8_t value, unsigned char* buffer,
13                           size_t buffer_size, uint8_t offset) {
14   if (value <= 23) {
15     if (buffer_size >= 1) {
16       buffer[0] = value + offset;
17       return 1;
18     }
19   } else {
20     if (buffer_size >= 2) {
21       buffer[0] = 0x18 + offset;
22       buffer[1] = value;
23       return 2;
24     }
25   }
26   return 0;
27 }
28 
_cbor_encode_uint16(uint16_t value,unsigned char * buffer,size_t buffer_size,uint8_t offset)29 size_t _cbor_encode_uint16(uint16_t value, unsigned char* buffer,
30                            size_t buffer_size, uint8_t offset) {
31   if (buffer_size < 3) {
32     return 0;
33   }
34   buffer[0] = 0x19 + offset;
35 
36 #ifdef IS_BIG_ENDIAN
37   memcpy(buffer + 1, &value, 2);
38 #else
39   buffer[1] = (unsigned char)(value >> 8);
40   buffer[2] = (unsigned char)value;
41 #endif
42 
43   return 3;
44 }
45 
_cbor_encode_uint32(uint32_t value,unsigned char * buffer,size_t buffer_size,uint8_t offset)46 size_t _cbor_encode_uint32(uint32_t value, unsigned char* buffer,
47                            size_t buffer_size, uint8_t offset) {
48   if (buffer_size < 5) {
49     return 0;
50   }
51   buffer[0] = 0x1A + offset;
52 
53 #ifdef IS_BIG_ENDIAN
54   memcpy(buffer + 1, &value, 4);
55 #else
56   buffer[1] = (unsigned char)(value >> 24);
57   buffer[2] = (unsigned char)(value >> 16);
58   buffer[3] = (unsigned char)(value >> 8);
59   buffer[4] = (unsigned char)value;
60 #endif
61 
62   return 5;
63 }
64 
_cbor_encode_uint64(uint64_t value,unsigned char * buffer,size_t buffer_size,uint8_t offset)65 size_t _cbor_encode_uint64(uint64_t value, unsigned char* buffer,
66                            size_t buffer_size, uint8_t offset) {
67   if (buffer_size >= 9) {
68     buffer[0] = 0x1B + offset;
69 
70 #ifdef IS_BIG_ENDIAN
71     memcpy(buffer + 1, &value, 8);
72 #else
73     buffer[1] = (unsigned char)(value >> 56);
74     buffer[2] = (unsigned char)(value >> 48);
75     buffer[3] = (unsigned char)(value >> 40);
76     buffer[4] = (unsigned char)(value >> 32);
77     buffer[5] = (unsigned char)(value >> 24);
78     buffer[6] = (unsigned char)(value >> 16);
79     buffer[7] = (unsigned char)(value >> 8);
80     buffer[8] = (unsigned char)value;
81 #endif
82 
83     return 9;
84   } else
85     return 0;
86 }
87 
_cbor_encode_uint(uint64_t value,unsigned char * buffer,size_t buffer_size,uint8_t offset)88 size_t _cbor_encode_uint(uint64_t value, unsigned char* buffer,
89                          size_t buffer_size, uint8_t offset) {
90   if (value <= UINT16_MAX)
91     if (value <= UINT8_MAX)
92       return _cbor_encode_uint8((uint8_t)value, buffer, buffer_size, offset);
93     else
94       return _cbor_encode_uint16((uint16_t)value, buffer, buffer_size, offset);
95   else if (value <= UINT32_MAX)
96     return _cbor_encode_uint32((uint32_t)value, buffer, buffer_size, offset);
97   else
98     return _cbor_encode_uint64((uint64_t)value, buffer, buffer_size, offset);
99 }
100