unsigned

剑指offer#16.数值的整数次方

陌路散爱 提交于 2019-12-02 02:37:38
数值的整数次方:给定一个double类型的浮点数base和int类型的整数exponent。求base的exponent次方。 保证base和exponent不同时为0 解法一:使用循环来求 分析:注意考虑特殊情况,当底数为0,如果指数是正整数,则可以返回1,如果底数为0,指数是负整数,那么就会出错,而且如果底数不是0,指数是负整数,则返回的应该是底数和正整数运算结果的倒数。因此要考虑齐全。 double PowerWithUnsignedExponent(double base,unsigned int exponent){ double result = 1.0; for(int i=1;i<=exponent;i++) result *= base; return result; } double Power(double base, int exponent) { g_InvalidInput = true; if(base - 0.0 <= 1e-6 && exponent < 0){ g_InvalidInput = false; return 0.0; } unsigned int absExponent = (unsigned int)exponent; if(exponent<0){ absExponent = (unsigned int)(-exponent);

C# Unsigned bytes Encryption to Java Signed bytes Decryption

女生的网名这么多〃 提交于 2019-12-02 02:35:01
I have an application in C# that encrypt part of my files (because they are big files) using RijndaelManaged. So I convert my file to byte arrays and encrypt only a part of it. Then I want to decrypt the file using Java. So I have to decrypt only part of the file (means those bytes) that was encrypted in C#. Here the problem comes. Because in C# we have unsigned bytes and in Java we have signed bytes . So my encryption and decryption not working the way I want. In C# I have joined the encrypted bytes and normal bytes together and saved them with File.WriteAllBytes . So I can't use sbyte here

Why does << 32 not result in 0 in javascript?

牧云@^-^@ 提交于 2019-12-02 02:25:44
This is false: (0xffffffff << 31 << 1) === (0xffffffff << 32) It seems like it should be true. Adding >>> 0 anywhere does not change this. Why is this and how can I correctly write code that handles << 32 ? The shift operators always effectively has a right operand in the range 0-31. From the Mozilla docs : Shift operators convert their operands to 32-bit integers in big-endian order and return a result of the same type as the left operand. The right operand should be less than 32, but if not only the low five bits will be used . Or from the ECMAscript 5 standard : The production

用户系统设计与实现

╄→гoц情女王★ 提交于 2019-12-02 01:53:05
用户系统,主要分为账号体系和用户信息两大类。账号体系包括,登陆验证、注册、第三方授权、以及权限管理。用户信息包括,用户地理位置、用户属性、用户设备信息、还有用户日志信息。本文会介绍用户模块的具体落地方案。 登陆验证 在一般项目账号体系中,一般会要求支持手机、邮箱、账号、QQ、微信、微博实现登陆。后面三种方式都是基于第三方授权后,完成的身份验证。手机、邮箱、账号则是相对传统的登录方式。 用户身份与登录的授权方式是独立开的,即用户uid和登录方式是一对多的关系。举例来说,用户A在使用微博授权登陆后,服务端鉴别身份信息为uid=123。用户A下次使用微信登陆,服务端鉴别身份同样为uid=123。不存在同一用户A拥有多个账号信息的现象。登陆授权表设计如下。 12345678910111213 //用户授权表CREATE TABLE `user_auth` ( `id` bigint(20) NOT NULL AUTO_INCREMENT, `uid` bigint(20) unsigned NOT NULL DEFAULT '0' COMMENT '用户id', `identity_type` tinyint(4) unsigned NOT NULL DEFAULT '1' COMMENT '1手机号 2邮箱 3用户名 4qq 5微信 6腾讯微博 7新浪微博', `identifier`

Swift converting signed array of Int [int8] to unsigned array of Int [UInt8]

谁说我不能喝 提交于 2019-12-02 00:47:15
问题 How to convert signed array of [Int8] to unsigned array of [UInt8]. let arryData: [Int8] = [-108, 11, -107, -14, 35, -57, -116, 118, 54, 91, 12, 67, 21, 29, -44, 111] I just want to convert this above into array of Unsigned [UInt8]. How to achieve this in swift.? Thanks in advance. 回答1: If your intention is to convert signed 8-bit integers to unsigned ones with the same bit representation (e.g. -1 -> 255 ): let intArray: [Int8] = [0, 1, 2, 127, -1, -2, -128] let uintArray = intArray.map {

mysql中bigint、int、mediumint、smallint 和 tinyint的取值范

删除回忆录丶 提交于 2019-12-01 23:43:17
mysql数据库设计,其中,对于数据性能优化,字段类型考虑很重要,搜集了些资料,整理分享出来,这篇为有关mysql整型bigint、int、mediumint、smallint 和 tinyint的语法介绍,如下: 1、bigint 从 -2^63 (-9223372036854775808) 到 2^63-1 (9223372036854775807) 的整型数据(所有数字),无符号的范围是0到 18446744073709551615。一位为 8 个字节。 2、int 一个正常大小整数。有符号的范围是-2^31 (-2,147,483,648) 到 2^31 - 1 (2,147,483,647) 的整型数据(所有数字),无符号的范围是0到4294967295。一位大小为 4 个字节。 int 的 SQL-92 同义词为 integer。 3、mediumint 一个中等大小整数,有符号的范围是-8388608到8388607,无符号的范围是0到16777215。 一位大小为3个字节。 4、smallint 一个小整数。有符号的范围是-2^15 (-32,768) 到 2^15 - 1 (32,767) 的整型数据,无符号的范围是0到65535。一位大小为 2 个字节。MySQL提供的功能已经绰绰有余,而且由于MySQL是开放源码软件,因此可以大大降低总体拥有成本。 5

Bran的内核开发教程(bkerndev)-06 全局描述符表(GDT)

烂漫一生 提交于 2019-12-01 23:21:08
全局描述符表(GDT)   在386平台各种保护措施中最重要的就是全局描述符表(GDT)。GDT为内存的某些部分定义了基本的访问权限。我们可以使用GDT中的一个索引来生成段冲突异常, 让内核终止执行异常的进程。现代操作系统大多使用"分页"的内存模式来实现该功能, 它更具通用性和灵活性。GDT还定义了内存中的的某个部分是可执行程序还是实际的数据。GDT还可定义任务状态段(TSS)。TSS一般在基于硬件的多任务处理中使用, 所以我们在此并不做讨论。需要注意的是TSS并不是启用多任务的唯一方法。   注意GRUB已经为你安装了一个GDT, 如果我们重写了加载GRUB的内存区域, 将会丢弃它的GDT, 这会导致"三重错误(Triple fault)"。简单的说, 它将重置机器。为了防止该问题的发生, 我们应该在已知可以访问的内存中构建自己的GDT, 并告诉处理器它在哪里, 最后使用我们的新索引加载处理器的CS、DS、ES、FS和GS寄存器。CS寄存器就是代码段, 它告诉处理器执行当前代码的访问权限在GDT中的偏移量。DS寄存器的作用类似, 但是数据段, 定义了当前数据的访问权限的偏移量。ES、FS和GS是备用的DS寄存器, 对我们并不重要。   GDT本身是64位的长索引列表。这些索引定义了内存中可访问区域的起始位置和大小界限, 以及与该索引关联的访问权限。通常第一个索引,

WriteUp-i春秋-溯源

不打扰是莪最后的温柔 提交于 2019-12-01 22:45:01
一个简单的逆向qwq 叫你输入key,给出提示信息 -- 无壳 C++编写 老规矩:拖IDA 搜索fail找到了main函数 这个main流程有点复杂qwq 我们看看它的伪代码: 全代码: 1 _DWORD *__fastcall sub_401D90(_DWORD *a1, _DWORD *a2) 2 { 3 _DWORD *v2; // esi 4 _DWORD *v3; // ebx 5 int v4; // eax 6 signed int v5; // edi 7 int v6; // ecx 8 int v7; // eax 9 void (__thiscall ***v8)(_DWORD, signed int); // eax 10 bool v9; // cf 11 _BYTE *v10; // eax 12 int v11; // ecx 13 int v12; // eax 14 unsigned int v13; // edi 15 int i; // eax 16 char v15; // dl 17 unsigned int v16; // edi 18 _DWORD *v17; // eax 19 _DWORD *v18; // eax 20 int v19; // eax 21 bool v20; // zf 22 int v21; // eax

Java and unsigned Bytes [duplicate]

北慕城南 提交于 2019-12-01 22:16:18
问题 This question already has answers here : What is the best way to work around the fact that ALL Java bytes are signed? (7 answers) Closed 10 months ago . I need to make use of an array of unsigned bytes. I need to send certain characters over the network to a server and some of these characters are greater that 127. I have a simplified version of the code below to try and understand the concept: int i= 160; byte j = (byte) i; System.out.println((byte)i); System.out.println(j); and this gives

Swift converting signed array of Int [int8] to unsigned array of Int [UInt8]

百般思念 提交于 2019-12-01 22:08:55
How to convert signed array of [Int8] to unsigned array of [UInt8]. let arryData: [Int8] = [-108, 11, -107, -14, 35, -57, -116, 118, 54, 91, 12, 67, 21, 29, -44, 111] I just want to convert this above into array of Unsigned [UInt8]. How to achieve this in swift.? Thanks in advance. If your intention is to convert signed 8-bit integers to unsigned ones with the same bit representation (e.g. -1 -> 255 ): let intArray: [Int8] = [0, 1, 2, 127, -1, -2, -128] let uintArray = intArray.map { UInt8(bitPattern: $0) } print(uintArray) // [0, 1, 2, 127, 255, 254, 128] [Int8] -> [UInt8] You haven't