linux 环形缓冲区

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

typedef struct {
    char *buffer;
    int head;
    int tail;
    int size;
    int count;
} CircularBuffer;

CircularBuffer* createBuffer(int size) {
    CircularBuffer *cb = (CircularBuffer*)malloc(sizeof(CircularBuffer));
    cb->buffer = (char*)malloc(size);
    cb->head = 0;
    cb->tail = 0;
    cb->size = size;
    cb->count = 0;
    return cb;
}

void destroyBuffer(CircularBuffer *cb) {
    free(cb->buffer);
    free(cb);
}

int writeBuffer(CircularBuffer *cb, const char *data, int len) {
    if (len > cb->size - cb->count) {
        return -1; // Buffer overflow
    }
    for (int i = 0; i < len; i++) {
        cb->buffer[cb->tail] = data[i];
        cb->tail = (cb->tail + 1) % cb->size;
    }
    cb->count += len;
    return len;
}

int readBuffer(CircularBuffer *cb, char *data, int len) {
    if (len > cb->count) {
        return -1; // Not enough data
    }
    for (int i = 0; i < len; i++) {
        data[i] = cb->buffer[cb->head];
        cb->head = (cb->head + 1) % cb->size;
    }
    cb->count -= len;
    return len;
}

int main() {
    CircularBuffer *cb = createBuffer(10);
    const char *data1 = "Hello";
    const char *data2 = "World";
    writeBuffer(cb, data1, strlen(data1));
    writeBuffer(cb, data2, strlen(data2));
    char readData[10];
    readBuffer(cb, readData, 5);
    readData[5] = '\0';
    printf("Read data: %s\n", readData);
    destroyBuffer(cb);
    return 0;
}