# RingBufferBytes

**Repository Path**: wylkd1991/ringbufferbytes-cpp

## Basic Information

- **Project Name**: RingBufferBytes
- **Description**: C++实现以字节为单位的环形缓冲区，实现之初用于收发TCP数据;
同样适用于以流为呈现形式的数据收发。如：串口、CAN
- **Primary Language**: C++
- **License**: MIT
- **Default Branch**: master
- **Homepage**: https://ganrui.flowus.cn
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 1
- **Created**: 2022-11-02
- **Last Updated**: 2022-11-02

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# RingBufferBytes

#### 介绍
已使用mutex对读写指针进行保护，适用于多线程通信
若用于串口等硬件类数据收发，mutex可用中断屏蔽相关代码代替

```txt
/**
 *
 *------------------------------------------------------------------------
 * eg.1 有1个数据
 * 0 1 2                    pM=Max-1=m_mask
 * [*|_|_|_|_|______________|_]Max
 * R W
 *
 *
 * eg.2 W=R, 空情况
 * 0 1 2                    pM=Max-1=m_mask
 * [_|_|_|_|_|______________|_]Max
 *   R
 *   W
 *
 *
 * eg.3 W+1=R, 满情况(为区分空情况，最满状态，需要空余一个单位(字节)
 * 0 1 2                 pM=Max-1=m_mask
 * [*|*|*****|_|*|*****|*|*]Max
 *           W R
 *
 *
 * eg.3.1 (W+1)%M=R, 满情况(为区分空情况，最满状态，需要空余一个单位(字节))
 * 0 1 2                 pM=Max-1=m_mask
 * [*|*|*****|*|*|*****|*|_]Max
 * R                     W
 *
 *
 *
 * eg.4 W>R的情况
 * 0 1                         pM=Max-1=m_mask
 * [_|_|_|*|*|*****|*|*|_|_|_|_|_]Max
 *       R             W
 *
 * eg.5 W<R的情况
 * 0 1 2                     pM=Max-1=m_mask
 * [*|*|*|*|*|_|_____|_|*|*|*|*]Max
 *           W         R
 *------------------------------------------------------------------------
 *
 *剩余空间：
 *1) R=W, L=M
 *2) R>W, L=R-W
 *3) R<W, L=R-W+M
 *综合3种情况：
 *        L=(R-W+M)%M
 *考滤满情况，必需要空余一个存储单位(Byte):
 *        L=(R-W+M-1)%M
 *
 * ----------
 *
 * 缓存区中数据大小：N
 *  L + N = M-1
 *  N = M-1 - L
 *  N = M-1 - (R-W+M-1)%M
 *  N = M-1 - (R-W+M-1)%M
 *----------------------------------------------------------------------------
 *
 *取余操作“%”，简化流程
 * M = m_maxSize
 * X % M = X & m_mask;
 *
 **/
```

#### 使用说明


参考test()代码
```cpp


void RingBufferBytes::test()
{
    RingBufferBytes buffer;
    buffer.setBufferSizePower(5);

    char wb[] = "0123456789abcdef0";
    printf("buffer size:%d\n", buffer.getBufferSize());

    printf("will write 17 byte:%s \n", wb);
    int ret = buffer.writeBytes(wb, 17);
    printf("write success bytes:%d\n", ret);
    printf("now buffer data:%d, free:%d\n", buffer.getDataSize(), buffer.getFreeSize());

    char rb[64] = {0};
    printf("want read 20 bytes.\n");
    ret = buffer.readBytes(rb, 20);
    printf("read %d bytes ok.\n", ret);
    printf("buffer left data:%d, free:%d\n", buffer.getDataSize(), buffer.getFreeSize());
    printf("buffer now:\n");
    buffer.printhex(0, 32);


    printf("will write 17 byte:%s \n", wb);
    ret = buffer.writeBytes(wb, 17);
    printf("write success bytes:%d\n", ret);
    printf("now buffer data:%d, free:%d\n", buffer.getDataSize(), buffer.getFreeSize());


    printf("will write 17 byte:%s \n", wb);
    ret = buffer.writeBytes(wb, 17);
    printf("write success bytes:%d\n", ret);
    printf("now buffer data:%d, free:%d\n", buffer.getDataSize(), buffer.getFreeSize());



    printf("want read 20 bytes.\n");
    ret = buffer.readBytes(rb, 20);
    printf("read %d bytes ok.\n", ret);
    printf("buffer left data:%d, free:%d\n", buffer.getDataSize(), buffer.getFreeSize());
    printf("buffer now:\n");
    buffer.printhex(0, 32);

    printf("want read 20 bytes.\n");
    ret = buffer.readBytes(rb, 20);
    printf("read %d bytes ok.\n", ret);
    printf("buffer left data:%d, free:%d\n", buffer.getDataSize(), buffer.getFreeSize());
    printf("buffer now:\n");
    buffer.printhex(0, 32);
}
```

打印效果:
---
```shell
buffer size:31
will write 17 byte:0123456789abcdef0 
write success bytes:17
now buffer data:17, free:14
want read 20 bytes.
read 17 bytes ok.
buffer left data:0, free:31
buffer now:

 0  1  2  3  4  5  6  7       8  9  a  b  c  d  e  f
-------------------------------------------------------
 30 31 32 33 34 35 36 37     38 39 61 62 63 64 65 66
 30 53 74 72 69 6E 67 00     00 00 6F 00 00 00 00 00
will write 17 byte:0123456789abcdef0 
write success bytes:17
now buffer data:17, free:14
will write 17 byte:0123456789abcdef0 
write success bytes:14
now buffer data:31, free:0
want read 20 bytes.
read 20 bytes ok.
buffer left data:11, free:20
buffer now:

 0  1  2  3  4  5  6  7       8  9  a  b  c  d  e  f
-------------------------------------------------------
 66 30 30 31 32 33 34 35     36 37 38 39 61 62 63 64
 30 30 31 32 33 34 35 36     37 38 39 61 62 63 64 65
want read 20 bytes.
read 11 bytes ok.
buffer left data:0, free:31
buffer now:

 0  1  2  3  4  5  6  7       8  9  a  b  c  d  e  f
-------------------------------------------------------
 66 30 30 31 32 33 34 35     36 37 38 39 61 62 63 64
 30 30 31 32 33 34 35 36     37 38 39 61 62 63 64 65
```