#include "uart_ring_buffer.h"

static volatile uint8_t uart_rx_buffer[UART_RX_BUFFER_SIZE];
static volatile uint16_t uart_rx_write = 0;
static volatile uint16_t uart_rx_read = 0;

void uart_ring_buffer_init(void) {
    uart_rx_write = 0;
    uart_rx_read = 0;
}

uint16_t uart_rx_available(void) {
    return (uart_rx_write + UART_RX_BUFFER_SIZE - uart_rx_read) % UART_RX_BUFFER_SIZE;
}

int uart_rx_get(void) {
    if (uart_rx_read == uart_rx_write) return -1; // 空
    uint8_t data = uart_rx_buffer[uart_rx_read];
    uart_rx_read = (uart_rx_read + 1) % UART_RX_BUFFER_SIZE;
    return data;
}

void uart_rx_put(uint8_t data) {
    uint16_t next = (uart_rx_write + 1) % UART_RX_BUFFER_SIZE;
    if (next != uart_rx_read) { // 缓冲区未满
        uart_rx_buffer[uart_rx_write] = data;
        uart_rx_write = next;
    }
}

void uart_rx_clear(void) {
    uart_rx_write = 0;
    uart_rx_read = 0;
}