如下函数，是从文件中获取特定的数据保存到Buf，如何修改成从一个缓冲区（char inBuf[]）中获取数据保存到Buf？
int getNextNal(FILE* inpf, unsigned char* Buf)
{
    int pos = 0;
    int StartCodeFound = 0;
    int info2 = 0;
    int info3 = 0;

    while(!feof(inpf) && (Buf[pos++]=fgetc(inpf))==0);

    while (!StartCodeFound)
    {
        if (feof (inpf))
        {
            return pos-1;
        }
        Buf[pos++] = fgetc (inpf);
        info3 = FindStartCode(&Buf[pos-4], 3);
        if(info3 != 1)
            info2 = FindStartCode(&Buf[pos-3], 2);
        StartCodeFound = (info2 == 1 || info3 == 1);
    }
    fseek (inpf, -4, SEEK_CUR);
    return pos - 4;
}