1 /*
2 * Copyright (c) 2011 Petteri Aimonen
3 * Copyright (c) 2021 Basalte bv
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 */
7
8 #include <zephyr/kernel.h>
9 #include <zephyr/sys/printk.h>
10
11 #include <pb_encode.h>
12 #include <pb_decode.h>
13 #include "src/simple.pb.h"
14
encode_message(uint8_t * buffer,size_t buffer_size,size_t * message_length)15 bool encode_message(uint8_t *buffer, size_t buffer_size, size_t *message_length)
16 {
17 bool status;
18
19 /* Allocate space on the stack to store the message data.
20 *
21 * Nanopb generates simple struct definitions for all the messages.
22 * - check out the contents of simple.pb.h!
23 * It is a good idea to always initialize your structures
24 * so that you do not have garbage data from RAM in there.
25 */
26 SimpleMessage message = SimpleMessage_init_zero;
27
28 /* Create a stream that will write to our buffer. */
29 pb_ostream_t stream = pb_ostream_from_buffer(buffer, buffer_size);
30
31 /* Fill in the lucky number */
32 message.lucky_number = 13;
33 for (int i = 0; i < CONFIG_SAMPLE_BUFFER_SIZE; ++i) {
34 message.buffer[i] = (uint8_t)(i * 2);
35 }
36 #ifdef CONFIG_SAMPLE_UNLUCKY_NUMBER
37 message.unlucky_number = 42;
38 #endif
39
40 /* Now we are ready to encode the message! */
41 status = pb_encode(&stream, SimpleMessage_fields, &message);
42 *message_length = stream.bytes_written;
43
44 if (!status) {
45 printk("Encoding failed: %s\n", PB_GET_ERROR(&stream));
46 }
47
48 return status;
49 }
50
decode_message(uint8_t * buffer,size_t message_length)51 bool decode_message(uint8_t *buffer, size_t message_length)
52 {
53 bool status;
54
55 /* Allocate space for the decoded message. */
56 SimpleMessage message = SimpleMessage_init_zero;
57
58 /* Create a stream that reads from the buffer. */
59 pb_istream_t stream = pb_istream_from_buffer(buffer, message_length);
60
61 /* Now we are ready to decode the message. */
62 status = pb_decode(&stream, SimpleMessage_fields, &message);
63
64 /* Check for errors... */
65 if (status) {
66 /* Print the data contained in the message. */
67 printk("Your lucky number was %d!\n", (int)message.lucky_number);
68 printk("Buffer contains: ");
69 for (int i = 0; i < CONFIG_SAMPLE_BUFFER_SIZE; ++i) {
70 printk("%s%d", ((i == 0) ? "" : ", "), (int) message.buffer[i]);
71 }
72 printk("\n");
73 #ifdef CONFIG_SAMPLE_UNLUCKY_NUMBER
74 printk("Your unlucky number was %d!\n", (int)message.unlucky_number);
75 #endif
76 } else {
77 printk("Decoding failed: %s\n", PB_GET_ERROR(&stream));
78 }
79
80 return status;
81 }
82
main(void)83 int main(void)
84 {
85 /* This is the buffer where we will store our message. */
86 uint8_t buffer[SimpleMessage_size];
87 size_t message_length;
88
89 /* Encode our message */
90 if (!encode_message(buffer, sizeof(buffer), &message_length)) {
91 return 0;
92 }
93
94 /* Now we could transmit the message over network, store it in a file or
95 * wrap it to a pigeon's leg.
96 */
97
98 /* But because we are lazy, we will just decode it immediately. */
99 decode_message(buffer, message_length);
100 return 0;
101 }
102
