环形缓存滑窗加c语言代码

环形缓存滑窗是一种常见的数据缓存方式，它可以在固定大小的缓冲区中存储数据，并且可以循环使用。当添加数据时，head指针前进；当使用数据时，tail指针向前移动。当到达缓冲区的尾部时，指针又回到缓冲区的起始位置。这种方式可以有效地解决在C语言编程场景中需要对一段不定长数据进行缓存的问题。

以下是一个基于数组的环形缓冲队列的C语言代码示例：

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#define BUFFER_SIZE 5

typedef unsigned char UINT8;
typedef unsigned int UINT32;

UINT8 buffer[BUFFER_SIZE] = {0};
UINT32 head = 0;
UINT32 tail = 0;

void writeRingbuffer(UINT8 *data, UINT32 len)
{
    UINT32 i;
    for(i = 0; i < len; i++)
    {
        buffer[head] = data[i];
        head = (head + 1) % BUFFER_SIZE;
        if(head == tail)
        {
            tail = (tail + 1) % BUFFER_SIZE;
        }
    }
}

UINT32 readRingbuffer(UINT8 *data, UINT32 len)
{
    UINT32 i;
    UINT32 readLen = 0;
    for(i = 0; i < len; i++)
    {
        if(head == tail)
        {
            break;
        }
        data[i] = buffer[tail];
        tail = (tail + 1) % BUFFER_SIZE;
        readLen++;
    }
    return readLen;
}

void releaseRingbuffer()
{
    head = 0;
    tail = 0;
}

int main()
{
    UINT8 c;
    UINT32 readLen,i;
    UINT8 readBuffer[5] = {0};

    printf("Please enter a line>\n");
    do{
        c = getchar();
        putchar(c);
        switch(c)
        {
            case 'Q':
                goto exit;
                break;
            case 'R':
                readLen = readRingbuffer(readBuffer,5);
                printf("readRingbuffer len:%d\n",readLen);
                if(readLen > 0)
                {
                    printf("readRingbuffer:");
                    for(i = 0; i < readLen; i++)
                    {
                        printf("%c ",(UINT8)readBuffer[i]);
                    }
                    printf("\n");
                }
                break;
            default :
                if(c != '\n')
                    writeRingbuffer((UINT8*)&c,1);
                break;
        }
    }while(1);

exit:
    releaseRingbuffer();
    printf("\nexit!\n");
    return 0;
}