c++ protobuf varint 简单编码和解码

#include 
using namespace std;

//  小端存储
int varintEncode(int n, unsigned char *bytes) {
    int idx = 0;
    while (true) {
        // 只有低7位，高位全部为0
        if ((n & ~0x7f) == 0) { // 除低7位，全部为0
            bytes[idx++] = (char) n;
            break;
        } else { // 除低7位，不全部为0
            bytes[idx++] = ((unsigned char) ((n & 0x7f) | 0x80)); // 高1位置1，低7位按位与得到实际值
            n = n >> 7;
        }
    }
    return idx;
}

// 小端恢复
int varintDecode(unsigned char *bytes) {
    int idx = 0;
    int shift = 0;
    int result = 0;
    while (true) {
        unsigned char b = bytes[idx++];
        result |= ((b & 0x7f) << shift);
        // 判断最高位是否为0
        if ((b >> 7) == 0) {
            break;
        }
        shift += 7;
    }
    return result;
}


int main() {
    for (int i = 1; i < 1000000; i++) {
        unsigned char bytes[5]{0};
        if (i != varintDecode(bytes)) {
            cout << "decode error" << endl;
        }
    }
}