unsigned

Using char as an unsigned 16 bit value in Java?

こ雲淡風輕ζ 提交于 2019-12-10 11:37:06
问题 I need an unsigned 8 bit integer in Java, and char seems to be the only thing close to that. Although it's double the size, it's unsigned which makes it practical for what I want to use it for (writing a basic emulator which requires unsigned bytes). The problem is that I've heard other programmers say that one shouldn't use char in that manner and should just use int or so. Is this true, and why so? 回答1: If you need an unsigned 8 bit integer then use byte . It's easy to make it unsigned in

BMP文件格式学习总结

*爱你&永不变心* 提交于 2019-12-10 06:22:35
一个BMP文件可以包含4部分 1,文件头是14字节长的数据结构,定义如下: typedef struct _BFHEADER { unsigned short magic; unsigned int size; unsigned int reserved; unsigned int bitOffset; }bfHeader; 2.bmp 信息结构,结构定义如下: typedef struct _bmpInfoHead { unsigned int headSize; unsigned int width; unsigned int height; unsigned short planes; unsigned short bpp; unsigned int compress; unsigned int imageSize; unsigned int PelsPerMeterX; unsigned int PelsPerMeterY; unsigned int ClrUsed; unsigned int ClrImportant; unsigned int RedMask; unsigned int GreenMask; unsigned int BlueMask; unsigned int AlphaMask; unsigned int CsType; unsigned int

Linux的tasklet函数详解

房东的猫 提交于 2019-12-10 05:49:50
tasklet主要用在中断函数中。它对于中断处理特别有用,由于硬件中断必须尽快处理, 但大部分的数据管理可以延后到以后安全的时间执行。所以可以使用tasklet。 tasklet的使用比较简单,只需要定义tasklet及其处理函数并将两者关联即可,在定义时可以采用两种形式。 例子: struct tasklet_struct my_tasklet ; Void my_tasklet_func ( unsigned long ) ; 第一种: DECLARE_TASKLET ( my_tasklet , my_tasklet_func , data ) 代码DECLARE_TASKLET实现了定义名称为my_tasklet的tasklet并将其与my_tasklet_func这个函数绑定,而传入这个函数的参数为data。 第二种: tasklet_init ( & my_tasklet , my_tasklet_func , data ) ; 需要调度tasklet的时候引用一个 tasklet_schedule ( ) 函数就能使系统在适当的时候进行调度,如下所示 tasklet_schedule ( & my_tasklet ) tasklet以一个数据结构形式存在,使用前必须被初始化。初始化能够通过调用一个特定函数或者通过使用某些宏定义声明结构: # include

KMP算法--待定

故事扮演 提交于 2019-12-10 02:36:37
https://blog.csdn.net/slimmm/article/details/83989811 KMP算法 准备搞压缩看他文章 不清楚干啥的 先放着这 #include <stdio.h> #include <string.h>//memset #include <stdlib.h>//free #include <stddef.h> #define uint8_t unsigned char #define uint16_t unsigned short #define uint32_t unsigned int #define uint64_t unsigned long long #define uLong unsigned long typedef unsigned char uchar; typedef unsigned short ushort; typedef unsigned int uint; #define TEST_STR 0 //选择测试对象是字符串还是数组 typedef struct KMP { uchar *src; //源数据 uchar *dst; //要求匹配的数据 ushort sLen; //源数据长度 ushort pLen; //匹配数据长度 ushort coord; //匹配到数据记录其坐标 ushort matchLen

Linux字符设备动态申请设备号

独自空忆成欢 提交于 2019-12-10 00:55:25
alloc_chrdev_region是一个函数语句,头文件是<linux/fs.h>,可以动态分配设备编号。int alloc_chrdev_region(dev_t *dev,unsigned int -firstminor,unsigned int -count,char *name); dev_t *dev:用于返回的设备号参数 unsigned int -firstminor:默认为0 unsigned int -count:请求连续设备号的个数 char *name:待注册的设备名称在不再使用时释放这些设备编号void unregister_chrdev_region(dev_t from, unsigned int count); //////////////////////////////////////////////////////////////////////// dev_t dev = 0; ret = alloc_chrdev_region(&dev, 0, 1,DEVICE_NAME); if(ret<0) { printk(KERN_ERR "register_chrdev_region error\r\n"); goto alloc_err; } ///////////////////////////////////////////////////

Cocoa数据类型(NSString等)

雨燕双飞 提交于 2019-12-09 16:24:59
Cocoa框架中的数据类型 1 NSRange: typedef struct _NSRange{ unsigned int location; unsigned int length; }NSRange; location:表示范围的起始点 length:表示范围中所含元素的个数 作用: 用以表示相关事物的范围,如字符串中的字符范围或者是数组中元素的范围. 1.1 创建方式: 1.1.1 直接赋值 NSRnage range; range.location = 0; range.length = 4; 1.1.2 定义的同时进行初始化 NSRange range = {0,4}; 1.1.3 使用Cocoa提供的 API NSMakeRange();来创建: NSRange range = NSMakeRange(0,4); 使用NSMakeRange(location,length)来创建NSRange的好处是:可以在任何可以使用函数的地方使用它。 例如:[anObject flarbulateWithRange: NSMakeRange(0,4)]; 类似于C++中的anObject.flarbulateWithRange(NSMakeRange(0,4)); 2几何数据类型: typedef struct _NSPoint{ float x; float y;

The importance of declaring a variable as unsigned

旧城冷巷雨未停 提交于 2019-12-09 14:58:26
问题 Is it important to declare a variable as unsigned if you know it should never be negative? Does it help prevent anything other than negative numbers being fed into a function that shouldn't have them? 回答1: Declaring variables for semantically non-negative values as unsigned is a good style and good programming practice. However, keep in mind that it doesn't prevent you from making errors. If is perfectly legal to assign negative values to unsigned integers, with the value getting implicitly

Why Is Comparing if an Unsigned Int >= 0 a “Pointless Comparison”?

白昼怎懂夜的黑 提交于 2019-12-09 14:09:28
问题 I got warning: Pe186 "Pointless comparison of unsigned int with zero" when I tried to compile the following code: for(clLoop = cpLoopStart; clLoop >= 0; clLoop--) { //Do something } I don't understand why. I could understand, if I were looking for a value less than zero, since an unsigned int can never be negative. But all I am looking for here is if it is equal to zero, which an unsigned int certainly can be. I could even see this error if in this loop I tried to pre-decrement instead of

Initialize unsigned byte array using hex number

喜欢而已 提交于 2019-12-09 05:59:45
问题 I know that unsigned byte is missing in Java Then how can I initialize the byte array using integer from 0 to 255 (in hex) ? final byte assoc_resp_msg_int[] = new byte[] { 0xe3, 0x00, //APDU CHOICE Type(AareApdu) 0x00, 0x2c, //CHOICE.length = 44 0x00, 0x00, //result=accept 0x50, 0x79, //data-proto-id = 20601 0x00, 0x26, //data-proto-info length = 38 0x80, 0x00, 0x00, 0x00, //protocolVersion 0x80, 0x00, //encoding rules = MDER 0x80, 0x00, 0x00, 0x00, //nomenclatureVersion 0x00, 0x00, 0x00,

Get the signed/unsigned variant of an integer template parameter without explicit traits

怎甘沉沦 提交于 2019-12-09 05:08:45
问题 I am looking to define a template class whose template parameter will always be an integer type. The class will contain two members, one of type T , and the other as the unsigned variant of type T -- i.e. if T == int , then T_Unsigned == unsigned int . My first instinct was to do this: template <typename T> class Range { typedef unsigned T T_Unsigned; // does not compile public: Range(T min, T_Unsigned range); private: T m_min; T_Unsigned m_range; }; But it doesn't work. I then thought about