linux 串口驱动里缓冲区

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <termios.h>

#define BUFFER_SIZE 1024

typedef struct {
    char buffer[BUFFER_SIZE];
    int head;
    int tail;
} CircularBuffer;

void cb_init(CircularBuffer *cb) {
    cb->head = 0;
    cb->tail = 0;
}

int cb_is_empty(CircularBuffer *cb) {
    return cb->head == cb->tail;
}

int cb_is_full(CircularBuffer *cb) {
    return (cb->head + 1) % BUFFER_SIZE == cb->tail;
}

void cb_write(CircularBuffer *cb, char data) {
    if (!cb_is_full(cb)) {
        cb->buffer[cb->head] = data;
        cb->head = (cb->head + 1) % BUFFER_SIZE;
    }
}

char cb_read(CircularBuffer *cb) {
    if (!cb_is_empty(cb)) {
        char data = cb->buffer[cb->tail];
        cb->tail = (cb->tail + 1) % BUFFER_SIZE;
        return data;
    }
    return '\0';
}

int main() {
    int fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY);
    if (fd == -1) {
        perror("Failed to open serial port");
        return -1;
    }

    struct termios options;
    tcgetattr(fd, &options);
    cfsetispeed(&options, B9600);
    cfsetospeed(&options, B9600);
    options.c_cflag |= (CLOCAL | CREAD);
    options.c_cflag &= ~PARENB;
    options.c_cflag &= ~CSTOPB;
    options.c_cflag &= ~CSIZE;
    options.c_cflag |= CS8;
    options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
    options.c_oflag &= ~OPOST;
    tcsetattr(fd, TCSANOW, &options);

    CircularBuffer rx_buffer;
    cb_init(&rx_buffer);

    while (1) {
        if (read(fd, &data, 1) > 0) {
            cb_write(&rx_buffer, data);
            if (!cb_is_empty(&rx_buffer)) {
                printf("%c", cb_read(&rx_buffer));
            }
        }
    }

    close(fd);
    return 0;
}