rework send frames and init client

Reviewed-on: #5

.gitignore

@@ -0,0 +1,9 @@
+hdlc1.c
+hdlc1.h
+hdlc_frame.c
+hdlc_frame.h
+main1.c
+uart.c
+uart.h
+
+!./hdlc

.idea/.gitignore

@@ -0,0 +1,8 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/untitled1.iml" filepath="$PROJECT_DIR$/.idea/untitled1.iml" />
+    </modules>
+  </component>
+</project>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

CMakeLists.txt

@@ -0,0 +1,6 @@
+cmake_minimum_required(VERSION 3.25)
+project(untitled1 C)
+
+set(CMAKE_C_STANDARD 11)
+
+add_executable(untitled1 hdlc/fcs.h hdlc/fcs.c hdlc/hdlc.h hdlc/hdlc.c hdlc/main.c hdlc/client.c)

UART/circular_buf.c

@@ -1,36 +0,0 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include "circular_buf.h"
-
-
-void clear_buffer(struct circular_buffer* cb) {
-	cb->buf_head = 0;
-	cb->buf_tail = 0;
-}
-// Проверка, пустой ли буфер
-int buffer_empty(const struct circular_buffer* cb) {
-	return cb->buf_head == cb->buf_tail;
-}
-// Проверка, заполнен ли буфер
-int buffer_full(const struct circular_buffer* cb) {
-	return (cb->buf_tail + 1) % BUFFER_SIZE == cb->buf_head; //проверяем следующее число, если оно будет совпадать с индексом головы то будет false, при совпадении вывод true
-}
-// Запись в буфер
-void write_buffer(struct circular_buffer* cb, int value) {
-	if (buffer_full(cb)) { // проверяем, заполнен ли буфер
-		return;
-	}
-	cb->buffer[cb->buf_tail] = value;// записываем значение в элемент массива в хвост
-	cb->buf_tail = (cb->buf_tail + 1) % BUFFER_SIZE;// присваивается cb->buf_tail, обновляется его значение на следующий индекс в буфере
-}
-// Чтение элемента
-int read_buffer(struct circular_buffer* cb) {
-	if (buffer_empty(cb)) { // проверка на пустоту
-		return -1;// -1  как индикатор в случае ошибки
-	}
-	int value = cb->buffer[cb->buf_head]; // чтение по индексу головы
-	cb->buf_head = (cb->buf_head + 1) % BUFFER_SIZE; // увеличиваем индекс на 1
-	return value;
-}
-
-

UART/circular_buf.h

@@ -1,18 +0,0 @@
-#ifndef CIRCULAR_BUFFER_H
-#define CIRCULAR_BUFFER_H
-
-#define BUFFER_SIZE 32
-
-struct circular_buffer{
-	unsigned char buffer[BUFFER_SIZE];
-	unsigned char buf_head;
-	unsigned char buf_tail;
-};
-
-void clear_buffer(struct circular_buffer* cb);
-int buffer_empty(const struct circular_buffer* cb);
-int buffer_full(const struct circular_buffer* cb);
-void write_buffer(struct circular_buffer* cb, int value);
-int read_buffer(struct circular_buffer* cb);
-
-#endif /* CIRCULAR_BUFFER_H */

UART/uart.c

@@ -1,63 +0,0 @@
-#include <avr/io.h>
-#include <avr/interrupt.h>
-#include <stdint.h>
-#include <string.h>
-#include "circular_buf.h"
-#include "uart.h"
-
-struct circular_buffer uartRxBuffer;
-struct circular_buffer uartTxBuffer;
-
-void UART_init(void) {
-	UCSR0B = (1 << RXEN0) | (1 << TXEN0) | (1 << RXCIE0) | (1<<TXCIE0) | (1 << UDRIE0); // прерывание по приему и передаче
-	UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
-	UBRR0H = 0;
-	UBRR0L = 103;
-}
-
-void UART_send(uint8_t* data, size_t length) {
-	for (size_t i = 0; i < length; i++) {
-		if (!buffer_full(&uartTxBuffer)) {
-			write_buffer(&uartTxBuffer, data[i]);
-			} else {
-			break; // если буфер передачи заполнен, то отправка прерывается
-		}
-	}
-	UCSR0B |= (1 << TXCIE0); // включаем прерывание по завершении передачи
-	clear_buffer(&uartTxBuffer);
-}
-
-// Получение данных из буфера
-int UART_receive(uint8_t* data, size_t length) {
-    char overflow = 0;  // Флаг переполнения, который устанавливается, если превышен размер массива 
-    uint32_t byteCount = 0;  // Счетчик байтов, принятых из буфера приема
-    // Пока буфер приема не пуст и не превышен лимит длины массива,
-    // функция продолжает читать байты из буфера и сохранять их в массив data.
-    while (!buffer_empty(&uartRxBuffer) && byteCount < length) {
-        int reader = read_buffer(&uartRxBuffer);  // Прием и запись символа в переменную
-        data[byteCount] = reader;  // Запись в массив с индексом byteCount
-        byteCount++;
-    }
-    // Проверка переполнения
-    if (byteCount > length) {
-        overflow = 1;
-    }
-	clear_buffer(&uartRxBuffer);
-    return overflow ? -1 : byteCount;  // Возвращает количество успешно принятых байт или -1 в случае переполнения
-}
-
-// прерывание по завершению приема
-ISR(USART_RX_vect) {
-	uint8_t data = UDR0; // читаем из регистра UDR0
-	if (!buffer_full(&uartRxBuffer)) {
-		write_buffer(&uartRxBuffer, data);// записываем символ в буфер приема
-	}
-}
-
-ISR(USART_TX_vect) {
-	if (!buffer_empty(&uartTxBuffer)) {
-		UDR0 = read_buffer(&uartTxBuffer);
-	} else {
-		UCSR0B &= ~(1 << TXCIE0); // отключаем прерывание, когда все данные отправлены
-	}
-}

UART/uart.h

@@ -1,13 +0,0 @@
-#ifndef UART_H
-#define UART_H
-#include <stdint.h> 
-#include <stddef.h>
-
-#define F_CPU 16000000
-
-void UART_init(void);
-void UART_send(uint8_t* data, size_t length);
-int UART_receive(uint8_t* data, size_t length);
-
-
-#endif /* UART_H */

hdlc/client.c

@@ -0,0 +1,147 @@
+#include "client.h"
+#include "hdlc.h"
+#include "stdio.h"
+
+#define CONNECT_FRAME_PERIOD 200
+#define SIZE_DATA_BUFFER 64
+#define COUNT_BUFFERS 4
+
+#define ERR_INVALID_DATA_SIZE -1
+#define ERR_ALL_BUFFERS_FILL -2
+#define ERR_INVALID_PARAMS -3
+#define ERR_INVALID_STATE -4
+#define ERR_FRAME_TIME_OUT -5
+#define ERR_INVALID_SEQ_NUMBER_FRAME -6
+#define ERR_TIMEOUT_ANSWER -7
+
+uint8_t buffer_data[COUNT_BUFFERS][SIZE_DATA_BUFFER];
+
+int init_hdlc_client(int count_buffers, int size_data_buffer, int connecting_frame_timeout, struct Client* client){
+    if (count_buffers <= 0){
+        return ERR_INVALID_PARAMS;
+    }
+
+    if (size_data_buffer <= 0){
+        return ERR_INVALID_PARAMS;
+    }
+
+    if (connecting_frame_timeout <= 0){
+        return ERR_INVALID_PARAMS;
+    }
+
+    client->state = IDLE_STATE;
+    client->connecting_frame_timeout = connecting_frame_timeout;
+    client->count_buffers = count_buffers;
+    client->size_data_buffer = size_data_buffer;
+    client->number_seq_frame = 0;
+
+    for (int i = 0; i < sizeof(buffer_data); i++){
+        for (int x = 0; x < sizeof(buffer_data[i]); x++){
+            buffer_data[i][x] = -1;
+        }
+    }
+    return 0;
+}
+
+void connect(struct Client* client){
+    client->state = CONNECTING;
+}
+
+int send_data(struct Client* client, uint8_t* data, size_t data_len){
+    if (client->state != READY_STATE){
+        return ERR_INVALID_STATE;
+    }
+
+    if (client->size_data_buffer < data_len){
+        return ERR_INVALID_DATA_SIZE;
+    }
+
+    for(int i = 0; i < COUNT_BUFFERS; i++){
+        if (buffer_data[i][0] == -1){
+            for (int x = 0; x < data_len; x++){
+                buffer_data[i][x] = data[x];
+            }
+        }
+
+        if (i == COUNT_BUFFERS - 1){
+            return ERR_ALL_BUFFERS_FILL;
+        }
+    }
+
+    client->state = RECIVING;
+};
+
+int get_frame(struct Client *client, uint8_t buffer[], size_t lenBuffer) {
+    hdlc_control_t control_send;
+
+    switch (client->state) {
+        case CONNECTING:
+            if (client->connecting_frame_timeout <= 0){
+                control_send.frame = S_FRAME;
+                control_send.seq_no = 1;
+                client->number_seq_frame = control_send.seq_no;
+
+                int ret = hdlc_frame_data(&control_send, NULL, 0, buffer, &lenBuffer);
+                if (ret < 0){
+                    printf("err in get_frame ACK: %d\n", ret);
+                }
+
+                client->connecting_frame_timeout = CONNECT_FRAME_PERIOD;
+            }
+            break;
+        case READY_STATE:
+            control_send.frame = I_FRAME;
+            control_send.seq_no = 1;
+            for(int i = 0; i < COUNT_BUFFERS; i++){
+                if (buffer_data[i][0] == -1){
+                    int ret = hdlc_frame_data(&control_send, buffer_data[i], SIZE_DATA_BUFFER, buffer, &lenBuffer);
+                    if (ret < 0){
+                        printf("err in get_frame DATA: %d\n", ret);
+                    }
+                }
+
+                if (i == COUNT_BUFFERS - 1){
+                    return ERR_ALL_BUFFERS_FILL;
+                }
+            }
+            break;
+    }
+
+//   Yf
+
+    return 0;
+}
+
+int hdlc_get_raw_data(struct Client* client, uint8_t buffer[], size_t len_buffer){
+    if (client->connecting_frame_timeout <= 0){
+        return ERR_FRAME_TIME_OUT;
+    }
+
+    hdlc_control_t recv_control;
+    uint8_t recive[len_buffer];
+
+    int ret = hdlc_get_data(&recv_control, buffer, len_buffer, recive,
+                            &len_buffer);
+    if (recv_control.seq_no != client->number_seq_frame){
+        return ERR_INVALID_SEQ_NUMBER_FRAME;
+    }
+
+    if (ret < 0 && client->connecting_frame_timeout < 0){
+        return ERR_TIMEOUT_ANSWER;
+    }
+
+    switch (recv_control.frame) {
+        case S_FRAME:
+            client->state = READY_STATE;
+            break;
+        case I_FRAME:
+            break;
+        case S_FRAME_NACK:
+            break;
+    }
+    return 0;
+}
+
+void hdlc_timeout_handler(struct Client* client, int delta_time){
+    client->connecting_frame_timeout -= delta_time;
+}

hdlc/client.h

@@ -0,0 +1,33 @@
+#ifndef CLIENT_H
+#define CLIENT_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+enum HDLCState {
+    UNINITIALIZED_STATE = 0,  // состояние до инцилизации
+    IDLE_STATE, // Состояние ожидания начала
+    READY_STATE, // Состояние принятия
+    CONNECTING, // состояние соединения
+    DISCONNECTING, // состояния отключения
+    RECIVING // состояние приема и отправки
+};
+
+struct Client{
+    enum HDLCState state;
+    int connecting_frame_timeout; //-1
+    int size_data_buffer;
+    int count_buffers;
+    int number_seq_frame;
+};
+
+//название функций
+int init_hdlc_client(int count_buffers, int size_data_buffer, int connecting_frame_timeout, struct Client* client);
+void connect(struct Client* client);
+int send_data(struct Client* client, uint8_t* data, size_t data_len);
+int get_frame(struct Client *client, uint8_t buffer[], size_t lenBuffer);
+//принимает буффер с уарта
+int hdlc_get_raw_data(struct Client* client, uint8_t buffer[], size_t len_buffer);
+void hdlc_timeout_handler(struct Client* client, int delta_time);
+
+#endif //CLIENT_H

hdlc/fcs.c

@@ -0,0 +1,41 @@
+#include "fcs.h"
+
+/*
+ *    CRC-Type:     CRC16 CCIT
+ *    Polynomial:   0x1021 (x^16+x^12+x^5+1)
+ *    Lookup Table: Reflected
+ */
+static const unsigned short fcstab[256] = {
+        0x0000, 0x1189, 0x2312, 0x329b,
+        0x4624, 0x57ad, 0x6536, 0x74bf, 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c,
+        0xdbe5, 0xe97e, 0xf8f7, 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c,
+        0x75b7, 0x643e, 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff,
+        0xe876, 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
+        0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, 0x3183,
+        0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, 0xbdcb, 0xac42,
+        0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, 0x4204, 0x538d, 0x6116,
+        0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, 0xce4c, 0xdfc5, 0xed5e, 0xfcd7,
+        0x8868, 0x99e1, 0xab7a, 0xbaf3, 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1,
+        0x0528, 0x37b3, 0x263a, 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960,
+        0xbbfb, 0xaa72, 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630,
+        0x17b9, 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
+        0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, 0xffcf,
+        0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, 0x8408, 0x9581,
+        0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, 0x0840, 0x19c9, 0x2b52,
+        0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, 0x9489, 0x8500, 0xb79b, 0xa612,
+        0xd2ad, 0xc324, 0xf1bf, 0xe036, 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5,
+        0x4f6c, 0x7df7, 0x6c7e, 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7,
+        0xc03c, 0xd1b5, 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74,
+        0x5dfd, 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
+        0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, 0xc60c,
+        0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, 0x4a44, 0x5bcd,
+        0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, 0xd68d, 0xc704, 0xf59f,
+        0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, 0x5ac5, 0x4b4c, 0x79d7, 0x685e,
+        0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a,
+        0xb0a3, 0x8238, 0x93b1, 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb,
+        0x0e70, 0x1ff9, 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9,
+        0x8330, 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78 };
+
+FCS_SIZE calc_fcs(FCS_SIZE fcs, unsigned char value) {
+    return (fcs >> 8) ^ fcstab[(fcs ^ value) & 0xff];
+}

hdlc/fcs.h

@@ -0,0 +1,18 @@
+#ifndef FCS_H
+#define FCS_H
+
+#define FCS_INIT_VALUE 0xFFFF /* FCS initialization value. */
+#define FCS_GOOD_VALUE 0xF0B8 /* FCS value for valid frames. */
+#define FCS_INVERT_MASK 0xFFFF /* Invert the FCS value accordingly to the specification */
+#define FCS_SIZE unsigned short
+
+/**
+ * Calculates a new FCS based on the current value and value of data.
+ *
+ * @param fcs Current FCS value
+ * @param value The value to be added
+ * @returns Calculated FCS value
+ */
+FCS_SIZE calc_fcs(FCS_SIZE fcs, unsigned char value);
+
+#endif

hdlc/hdlc.c

@@ -0,0 +1,261 @@
+#include "hdlc.h"
+
+// HDLC Control field bit positions
+#define HDLC_CONTROL_S_OR_U_FRAME_BIT 0
+#define HDLC_CONTROL_SEND_SEQ_NO_BIT 1
+#define HDLC_CONTROL_S_FRAME_TYPE_BIT 2
+#define HDLC_CONTROL_POLL_BIT 4
+#define HDLC_CONTROL_RECV_SEQ_NO_BIT 5
+
+// HDLC Control type definitions
+#define HDLC_CONTROL_TYPE_RECEIVE_READY 0
+#define HDLC_CONTROL_TYPE_RECEIVE_NOT_READY 1
+#define HDLC_CONTROL_TYPE_REJECT 2
+#define HDLC_CONTROL_TYPE_SELECTIVE_REJECT 3
+
+static hdlc_state_t hdlc_state = {
+        .control_escape = 0,
+        .fcs = FCS_INIT_VALUE,
+        .start_index = -1,
+        .end_index = -1,
+        .src_index = 0,
+        .dest_index = 0,
+};
+
+int hdlc_set_state(hdlc_state_t *state) {
+    if (!state) {
+        return -EINVAL;
+    }
+
+    hdlc_state = *state;
+    return 0;
+}
+
+
+int hdlc_get_state(hdlc_state_t *state) {
+    if (!state) {
+        return -EINVAL;
+    }
+
+    *state = hdlc_state;
+    return 0;
+}
+
+void hdlc_escape_value(char value, char *dest, int *dest_index) {
+    // Check and escape the value if needed
+    if ((value == HDLC_FLAG_SEQUENCE) || (value == HDLC_CONTROL_ESCAPE)) {
+        dest[(*dest_index)++] = HDLC_CONTROL_ESCAPE;
+        value ^= 0x20;
+    }
+
+    // Add the value to the destination buffer and increment destination index
+    dest[(*dest_index)++] = value;
+}
+
+hdlc_control_t hdlc_get_control_type(unsigned char control) {
+    hdlc_control_t value;
+
+    // Check if the frame is a S-frame (or U-frame)
+    if (control & (1 << HDLC_CONTROL_S_OR_U_FRAME_BIT)) {
+        // Check if S-frame type is a Receive Ready (ACK)
+        if (((control >> HDLC_CONTROL_S_FRAME_TYPE_BIT) & 0x3)
+            == HDLC_CONTROL_TYPE_RECEIVE_READY) {
+            value.frame = S_FRAME;
+        } else {
+            // Assume it is an NACK since Receive Not Ready, Selective Reject and U-frames are not supported
+            value.frame = S_FRAME_NACK;
+        }
+
+        // Add the receive sequence number from the S-frame (or U-frame)
+        value.seq_no = (control >> HDLC_CONTROL_RECV_SEQ_NO_BIT);
+    } else {
+        // It must be an I-frame so add the send sequence number (receive sequence number is not used)
+        value.frame = I_FRAME;
+        value.seq_no = (control >> HDLC_CONTROL_SEND_SEQ_NO_BIT);
+    }
+
+    return value;
+}
+
+unsigned char hdlc_frame_control_type(hdlc_control_t *control) {
+    unsigned char value = 0;
+
+    switch (control->frame) {
+        case I_FRAME:
+            // Create the HDLC I-frame control byte with Poll bit set
+            value |= (control->seq_no << HDLC_CONTROL_SEND_SEQ_NO_BIT);
+            value |= (1 << HDLC_CONTROL_POLL_BIT);
+            break;
+        case S_FRAME:
+            // Create the HDLC Receive Ready S-frame control byte with Poll bit cleared
+            value |= (control->seq_no << HDLC_CONTROL_RECV_SEQ_NO_BIT);
+            value |= (1 << HDLC_CONTROL_S_OR_U_FRAME_BIT);
+            break;
+        case S_FRAME_NACK:
+            // Create the HDLC Receive Ready S-frame control byte with Poll bit cleared
+            value |= (control->seq_no << HDLC_CONTROL_RECV_SEQ_NO_BIT);
+            value |= (HDLC_CONTROL_TYPE_REJECT << HDLC_CONTROL_S_FRAME_TYPE_BIT);
+            value |= (1 << HDLC_CONTROL_S_OR_U_FRAME_BIT);
+            break;
+    }
+
+    return value;
+}
+
+void hdlc_get_data_reset() {
+    hdlc_get_data_reset_with_state(&hdlc_state);
+}
+
+void hdlc_get_data_reset_with_state(hdlc_state_t *state) {
+    state->fcs = FCS_INIT_VALUE;
+    state->start_index = state->end_index = -1;
+    state->src_index = state->dest_index = 0;
+    state->control_escape = 0;
+}
+
+//int hdlc_get_data(hdlc_control_t *control, const char *src,
+//                    unsigned int src_len, char *dest, unsigned int *dest_len)
+int hdlc_get_data(hdlc_control_t *control, uint8_t *src,
+                  size_t src_len, uint8_t *dest, size_t *dest_len){
+    return hdlc_get_data_with_state(&hdlc_state, control, src, src_len, dest, dest_len);
+}
+
+//int hdlc_get_data_with_state(hdlc_state_t *state, hdlc_control_t *control, const char *src,
+//                               unsigned int src_len, char *dest, unsigned int *dest_len)
+int hdlc_get_data_with_state(hdlc_state_t *state, hdlc_control_t *control, uint8_t *src,
+                             size_t src_len, uint8_t *dest, size_t *dest_len){
+    int ret;
+    char value;
+    unsigned int i;
+
+    // Make sure that all parameters are valid
+    if (!state || !control || !src || !dest || !dest_len) {
+        return -EINVAL;
+    }
+
+    // Run through the data bytes
+    for (i = 0; i < src_len; i++) {
+        // First find the start flag sequence
+        if (state->start_index < 0) {
+            if (src[i] == HDLC_FLAG_SEQUENCE) {
+                // Check if an additional flag sequence byte is present
+                if ((i < (src_len - 1)) && (src[i + 1] == HDLC_FLAG_SEQUENCE)) {
+                    // Just loop again to silently discard it (accordingly to HDLC)
+                    continue;
+                }
+
+                state->start_index = state->src_index;
+            }
+        } else {
+            // Check for end flag sequence
+            if (src[i] == HDLC_FLAG_SEQUENCE) {
+                // Check if an additional flag sequence byte is present or earlier received
+                if (((i < (src_len - 1)) && (src[i + 1] == HDLC_FLAG_SEQUENCE))
+                    || ((state->start_index + 1) == state->src_index)) {
+                    // Just loop again to silently discard it (accordingly to HDLC)
+                    continue;
+                }
+
+                state->end_index = state->src_index;
+                break;
+            } else if (src[i] == HDLC_CONTROL_ESCAPE) {
+                state->control_escape = 1;
+            } else {
+                // Update the value based on any control escape received
+                if (state->control_escape) {
+                    state->control_escape = 0;
+                    value = src[i] ^ 0x20;
+                } else {
+                    value = src[i];
+                }
+
+                // Now update the FCS value
+                state->fcs = calc_fcs(state->fcs, value);
+
+                if (state->src_index == state->start_index + 2) {
+                    // Control field is the second byte after the start flag sequence
+                    *control = hdlc_get_control_type(value);
+                } else if (state->src_index > (state->start_index + 2)) {
+                    // Start adding the data values after the Control field to the buffer
+                    dest[state->dest_index++] = value;
+                }
+            }
+        }
+        state->src_index++;
+    }
+
+    // Check for invalid frame (no start or end flag sequence)
+    if ((state->start_index < 0) || (state->end_index < 0)) {
+        // Return no message and make sure destination length is 0
+        *dest_len = 0;
+        ret = -ENOMSG;
+    } else {
+        // A frame is at least 4 bytes in size and has a valid FCS value
+        if ((state->end_index < (state->start_index + 4))
+            || (state->fcs != FCS_GOOD_VALUE)) {
+            // Return FCS error and indicate that data up to end flag sequence in buffer should be discarded
+            *dest_len = i;
+            ret = -EIO;
+        } else {
+            // Return success and indicate that data up to end flag sequence in buffer should be discarded
+            *dest_len = state->dest_index - sizeof(state->fcs);
+            ret = i;
+        }
+
+        // Reset values for next frame
+        hdlc_get_data_reset_with_state(state);
+    }
+
+    return ret;
+}
+
+//int hdlc_frame_data(hdlc_control_t *control, const char *src,
+//                      unsigned int src_len, char *dest, unsigned int *dest_len)
+int hdlc_frame_data(hdlc_control_t *control, uint8_t *src,
+                    size_t src_len, uint8_t *dest, size_t *dest_len){
+    unsigned int i;
+    int dest_index = 0;
+    unsigned char value = 0;
+    FCS_SIZE fcs = FCS_INIT_VALUE;
+
+    // Make sure that all parameters are valid
+    if (!control || (!src && (src_len > 0)) || !dest || !dest_len) {
+        return -EINVAL;
+    }
+
+    // Start by adding the start flag sequence
+    dest[dest_index++] = HDLC_FLAG_SEQUENCE;
+
+    // Add the all-station address from HDLC (broadcast)
+    fcs = calc_fcs(fcs, HDLC_ALL_STATION_ADDR);
+    hdlc_escape_value(HDLC_ALL_STATION_ADDR, dest, &dest_index);
+
+    // Add the framed control field value
+    value = hdlc_frame_control_type(control);
+    fcs = calc_fcs(fcs, value);
+    hdlc_escape_value(value, dest, &dest_index);
+
+    // Only DATA frames should contain data
+    if (control->frame == I_FRAME) {
+        // Calculate FCS and escape data
+        for (i = 0; i < src_len; i++) {
+            fcs = calc_fcs(fcs, src[i]);
+            hdlc_escape_value(src[i], dest, &dest_index);
+        }
+    }
+
+    // Invert the FCS value accordingly to the specification
+    fcs ^= FCS_INVERT_MASK;
+
+    // Run through the FCS bytes and escape the values
+    for (i = 0; i < sizeof(fcs); i++) {
+        value = ((fcs >> (8 * i)) & 0xFF);
+        hdlc_escape_value(value, dest, &dest_index);
+    }
+
+    // Add end flag sequence and update length of frame
+    dest[dest_index++] = HDLC_FLAG_SEQUENCE;
+    *dest_len = dest_index;
+
+    return 0;
+}

hdlc/hdlc.h

@@ -0,0 +1,126 @@
+//
+// Created by 79513 on 15.12.2023.
+//
+
+#ifndef HDLC_H
+#define HDLC_H
+
+#include "fcs.h"
+#include <errno.h>
+#include "stdint.h"
+
+/** HDLC start/end flag sequence */
+#define HDLC_FLAG_SEQUENCE 0x7E
+
+/** HDLC control escape value */
+#define HDLC_CONTROL_ESCAPE 0x7D
+
+/** HDLC all station address */
+#define HDLC_ALL_STATION_ADDR 0xFF
+
+/** Supported HDLC frame types */
+typedef enum {
+    I_FRAME,
+    S_FRAME,
+    S_FRAME_NACK,
+} hdlc_frame_t;
+
+/** Control field information */
+typedef struct {
+    hdlc_frame_t frame;
+    unsigned char seq_no :3;
+} hdlc_control_t;
+
+/** Variables used in hdlc_get_data and hdlc_get_data_with_state
+ * to keep track of received buffers
+ */
+typedef struct {
+    char control_escape;
+    FCS_SIZE fcs;
+    int start_index;
+    int end_index;
+    int src_index;
+    int dest_index;
+} hdlc_state_t;
+
+/**
+ * Set the hdlc state
+ *
+ * @param[in] state The new hdlc state to be used
+ * @retval 0 Success
+ * @retval -EINVAL Invalid parameter
+ */
+int hdlc_set_state(hdlc_state_t *state);
+
+/**
+ * Get current hdlc state
+ *
+ * @param[out] state Current hdlc state
+ * @retval 0 Success
+ * @retval -EINVAL Invalid parameter
+ */
+int hdlc_get_state(hdlc_state_t *state);
+
+/**
+ * Retrieves data from specified buffer containing the HDLC frame. Frames can be
+ * parsed from multiple buffers e.g. when received via UART.
+ *
+ * @param[out] control Control field structure with frame type and sequence number
+ * @param[in] src Source buffer with frame
+ * @param[in] src_len Source buffer length
+ * @param[out] dest Destination buffer (should be able to contain max frame size)
+ * @param[out] dest_len Destination buffer length
+ * @retval >=0 Success (size of returned value should be discarded from source buffer)
+ * @retval -EINVAL Invalid parameter
+ * @retval -ENOMSG Invalid message
+ * @retval -EIO Invalid FCS (size of dest_len should be discarded from source buffer)
+ *
+ * @see hdlc_get_data_with_state
+ */
+int hdlc_get_data(hdlc_control_t *control, uint8_t *src,
+                    size_t src_len, uint8_t *dest, size_t *dest_len);
+
+/**
+ * Retrieves data from specified buffer containing the HDLC frame. Frames can be
+ * parsed from multiple buffers e.g. when received via UART.
+ *
+ * This function is a variation of @ref hdlc_get_data
+ * The difference is only in first argument: hdlc_state_t *state
+ * Data under that pointer is used to keep track of internal buffers.
+ *
+ * @see hdlc_get_data
+ */
+int hdlc_get_data_with_state(hdlc_state_t *state, hdlc_control_t *control, uint8_t *src,
+                             size_t src_len, uint8_t *dest, size_t *dest_len);
+
+/**
+ * Resets values used in yahdlc_get_data function to keep track of received buffers
+ */
+void hdlc_get_data_reset();
+
+/**
+ * This is a variation of @ref hdlc_get_data_reset
+ * Resets state values that are under the pointer provided as argument
+ *
+ * This function need to be called before the first call to hdlc_get_data_with_state
+ * when custom state storage is used.
+ *
+ * @see hdlc_get_data_reset
+ */
+void hdlc_get_data_reset_with_state(hdlc_state_t *state);
+
+/**
+ * Creates HDLC frame with specified data buffer.
+ *
+ * @param[in] control Control field structure with frame type and sequence number
+ * @param[in] src Source buffer with data
+ * @param[in] src_len Source buffer length
+ * @param[out] dest Destination buffer (should be bigger than source buffer)
+ * @param[out] dest_len Destination buffer length
+ * @retval 0 Success
+ * @retval -EINVAL Invalid parameter
+ */
+int hdlc_frame_data(hdlc_control_t *control, uint8_t *src,
+                      size_t src_len, uint8_t *dest, size_t *dest_len);
+
+#endif //HDLC_H

hdlc/main.c

@@ -0,0 +1,164 @@
+//#include "hdlc.h"
+#include "stdio.h"
+#include "client.h"
+#include <stdlib.h>
+#include <inttypes.h>
+
+int main(){
+    struct Client hdlc;
+    init_hdlc_client(2, 64, 200, &hdlc);
+    connect(&hdlc);
+    uint8_t frame_data[8];
+    uint8_t buffer_for_ex[8];
+    get_frame(&hdlc, frame_data, sizeof(frame_data));
+
+    for (int i = 0; i < 200; i++){
+        hdlc_timeout_handler(&hdlc, 1);
+        hdlc_get_raw_data(&hdlc, buffer_for_ex, sizeof(buffer_for_ex));
+    }
+
+    get_frame(&hdlc, frame_data, sizeof(frame_data));
+    int i = hdlc_get_raw_data(&hdlc, frame_data, sizeof(frame_data));
+    printf("%d", i);
+
+
+//    uint8_t send[64];
+//    uint8_t buffer[134];
+//    for (int i = 0; i < sizeof(send); i++) {
+//        send[i] = (uint8_t) (rand() % 0x70);
+//    }
+//    send_data(&hdlc, send, sizeof(send_data));
+//    //get_frame(&hdlc, buffer, sizeof(buffer), send_data, sizeof(send_data));
+//
+//    hdlc_get_raw_data(&hdlc, buffer, sizeof(buffer));
+
+    // test 1
+
+//    int ret;
+//    uint8_t frame_data[8], recv_data[8];
+//    size_t i, frame_length = 0, recv_length = 0;
+//    hdlc_control_t control_send, control_recv;
+
+//    // Run through the supported sequence numbers (3-bit)
+//    for (i = 0; i <= 7; i++) {
+//        // Initialize the control field structure with frame type and sequence number
+//        control_send.frame = HDLC_FRAME_ACK;
+//        control_send.seq_no = i;
+//
+//        // Create an empty frame with the control field information
+//        ret = hdlc_frame_data(&control_send, NULL, 0, frame_data, &frame_length);
+//
+//        // Get the data from the frame
+//        ret = hdlc_get_data(&control_recv, frame_data, frame_length, recv_data,
+//                              &recv_length);
+//
+//        // Result should be frame_length minus start flag to be discarded and no bytes received
+//        if(ret != (int )frame_length - 1){
+//            printf("err");
+//        }
+//    }
+//    if (recv_length != 0){
+//        printf("err2");
+//    }
+//
+//    if (control_send.frame != control_recv.frame){
+//        printf("err3");
+//    }
+//
+//    if (control_send.seq_no != control_recv.seq_no){
+//        printf("err4");
+//    }
+
+    // test 2
+
+    // Run through the supported sequence numbers (3-bit)
+//    for (i = 0; i <= 7; i++) {
+//        // Initialize the control field structure with frame type and sequence number
+//        control_send.frame = HDLC_FRAME_DATA;
+//        control_send.seq_no = i;
+//
+//        char* input = "311";
+//        uint8_t data = (uint8_t)atoi(input);
+//
+//        // Create an empty frame with the control field information
+//        ret = hdlc_frame_data(&control_send, &data, 3, frame_data, &frame_length);
+//        if (ret != 0){
+//            printf("err123\n");
+//        }
+//
+//        // Get the data from the frame
+//        ret = hdlc_get_data(&control_recv, frame_data, frame_length, recv_data,
+//                            &recv_length);
+//
+//        // Result should be frame_length minus start flag to be discarded and no bytes received
+//        if(ret != (int )frame_length - 1){
+//            printf("err333\n");
+//        }
+//        if (recv_length != 0){
+//            printf("err2\n");
+//        }
+//
+//        // Verify the control field information
+//        if (control_send.frame != control_recv.frame){
+//            printf("err3\n");
+//        }
+//
+//        if (control_send.seq_no != control_recv.seq_no){
+//            printf("err4\n");
+//        }
+//    }
+
+//    int ret;
+//    hdlc_control_t control;
+//    uint8_t send_data[512], frame_data[530], recv_data[530];
+//    size_t i, frame_length = 0, recv_length = 0, buf_length = 16;
+//
+//    // Initialize data to be send with random values (up to 0x70 to keep below the values to be escaped)
+//    for (i = 0; i < sizeof(send_data); i++) {
+//        send_data[i] = (uint8_t) (rand() % 0x70);
+//    }
+//
+//    // Initialize control field structure and create frame
+//    control.frame = HDLC_FRAME_DATA;
+//    ret = hdlc_frame_data(&control, send_data, sizeof(send_data), frame_data,
+//                            &frame_length);
+//
+//    // Check that frame length is maximum 2 bytes larger than data due to escape of FCS value
+//    if(frame_length >= ((sizeof(send_data) + 6) + 2)){
+//        printf("1");
+//    }
+//    if(ret != 0){
+//        printf("2");
+//    }
+//
+//    // Run though the different buffers (simulating decode of buffers from UART)
+//    for (i = 0; i <= sizeof(send_data); i += buf_length) {
+//        // Decode the data
+//        ret = hdlc_get_data(&control, &frame_data[i], buf_length, recv_data,
+//                              &recv_length);
+//
+//        printf("%zu: %s\n", i, recv_data);
+//
+//        if (i < sizeof(send_data)) {
+//            // All chunks until the last should return no message and zero length
+//            if (ret != -ENOMSG){
+//                printf("3");
+//            }
+//            if (recv_length != 0){
+//                printf("1231");
+//            }
+//        } else {
+//            if (ret > 7){
+//                printf("332");
+//            }
+//            if (recv_length != sizeof(send_data)){
+//                printf("88888");
+//            }
+//            // The last chunk should return max 6 frame bytes - 1 start flag sequence byte + 2 byte for the possible
+//            // escaped FCS = 7 bytes
+////            BOOST_CHECK(ret <= 7);
+////            BOOST_CHECK_EQUAL(recv_length, sizeof(send_data));
+//            //printf("5");
+//        }
+//    }
+}