/* ================================================================
 * jb_ringbuffer.c  —  环形缓冲区实现
 * ================================================================
 */
#include "jb_ringbuffer.h"

/* ── 初始化 ── */
void jbRbInit(jb_ringbuffer_t *rb)
{
    if (!rb)
    {
        return;
    }
    rb->write = rb->read = rb->count = 0;
}

/* ── 压入一个字节 ── */
void jbRbPush(jb_ringbuffer_t *rb, uint8_t byte)
{
    if (!rb)
    {
        return;
    }
    if (rb->count >= JB_RB_CAPACITY)
    {
        return;   /* 已满 — 丢弃 */
    }
    rb->buf[rb->write] = byte;
    rb->write = (rb->write + 1) % JB_RB_CAPACITY;
    rb->count++;
}

/* ── 弹出一个字节 ── */
uint8_t jbRbPop(jb_ringbuffer_t *rb)
{
    if (!rb || rb->count == 0)
    {
        return 0;
    }
    uint8_t byte = rb->buf[rb->read];
    rb->read = (rb->read + 1) % JB_RB_CAPACITY;
    rb->count--;
    return byte;
}

/* ── 查看指定偏移字节（不消费）── */
uint8_t jbRbPeek(const jb_ringbuffer_t *rb, uint16_t offset)
{
    if (!rb || offset >= rb->count)
    {
        return 0;
    }
    uint16_t idx = (rb->read + offset) % JB_RB_CAPACITY;
    return rb->buf[idx];
}

/* ── 可读字节数 ── */
uint16_t jbRbAvailable(const jb_ringbuffer_t *rb)
{
    if (!rb)
    {
        return 0;
    }
    return rb->count;
}

/* ── 清空缓冲区 ── */
void jbRbClear(jb_ringbuffer_t *rb)
{
    if (!rb)
    {
        return;
    }
    rb->write = rb->read = rb->count = 0;
}