编程

Test PHP Carve for JPG files

I am just making a little PHP program/page for fun. My ultimate aim is to allow myself to upload an image file to my, mysql database. Then call that file into a string in ASCII, then carve that file for a JPG file I created. To test this I used the program FTK Imager along with my web server and the

Powershell: Inherited classes calling Parent's empty constructors, even when passed objects

In powershell 5 I'm running into a strange inheritance problem with classes. I want to enforce that we are passed an object during setup like [class]::new($mailbox_object) , and I was intending to do this by causing [class]::new() to throw an error if it's associated object isn't assigned (say by a

LTE的CQI即下行码率计算

1、CQI的定义   CQI-Channel Quality Indication,信道质量指示,CQI由UE测量所得,因此,CQI一般指的是下行信道质量。eNodeB根据CQI信息选择合适的调度算法和下行数据块大小,以保证UE在不同的无线环境下获取最佳的下行性能。 2、引入CQI的原因   PDSCH支持三种编码方式:QPSK、16QAM及64QAM,其对应三种星座图,从而所需要的信道条件...

快慢指针

学习体会 例题:快速找到未知长度的单链表的中间节点? 解法一(暴击法):遍历一遍单链表,得到单链表的长度,再遍历一半即可。O(n+n1/2) 解法二(快慢指针):设两个指针,一个指针的速度是另一个指针的两倍(一个是“1”,一个是“2”)。 ...

oracle内核原理-读取buffer解析

1 搜索buffer过程如下: 根据要访问的文件号,块号,计算hash值。 根据hash值,找到对应的bucket。 搜索(在CBC的保护下) bucket的链表,查找哪个 BH为目标BH. 找到对应的BH,开始修改buffer pin锁,完成后释放CBC。 在buffer pin锁保护下,读取BA。 按照BA访问buffer 以上为oracle逻辑读过程,如果未找到,则需要发生物理读...