[Help]方法在C ++中将short数组连接到unsigned long [英] [Help] method to concatenate shorts array to unsigned long in C++

问题描述

Hello Everyone，



我想连接成一个unsigned long以下的short数组，并能够解析它以重建short数组。





我怎么能缩小它并避免溢出？

非常感谢你提前。

祝你好运。

MiQi



我的尝试：



以下是我到目前为止：

 短 exp [ 10 ]; 
 exp [ 0 ] =  1 ; exp [ 1 ] =  0 ; exp [ 2 ] =  -   2 ; exp [ 3 ] =  0 ; exp [ 4 ] =  -   1 ; exp [ 5 ] =  0 ; exp [ 6 ] =  2 ; exp [ 7 ] =  0 ; exp [ 8 ] =  0 ; exp [ 9 ] =  1 ; 
 
  for （ int  index =  0 ; index<  sizeof （exp）/  sizeof （ short ）; index ++）
 {
  if （index％ 2  ==  0 ）
 exp [index] =  5 ;  //   0101  
  else  exp [index] =  -   5 ;  //   1101  
} 
 
 LARGE_INTEGER uiCode; 
 uiCode.QuadPart =  0 ; 
  for （index =  0 ; index<  sizeof （exp）/  sizeof （ short ）; index ++）
 { 
 uiCode.QuadPart = uiCode.QuadPart | （exp [index]& 0x000f）; 
 uiCode.QuadPart = uiCode.QuadPart<<  4 ; 
} 
 
 LARGE_INTEGER uiExpectedCode; 
 uiExpectedCode.QuadPart = uiCode.QuadPart / LONG_MAX; 
 
 LARGE_INTEGER uiResiduCode; 
 uiResiduCode.QuadPart = uiCode.QuadPart％LONG_MAX; 
 
  long  SchrinkedCode = ??; 

解决方案

< blockquote>目前还不是很清楚你想要实现什么但是有一些可能的错误。



这里-5不是二进制1101：

 else exp [index] = -5; // 1101 

-5是十六进制0xFFFB。所以最低的4位是1011.



将半字节（4位值）转换为四边形部分的循环应该首先转移：

 for（index = 0; index< sizeof（exp）/ sizeof（short）; index ++）
 {
 uiCode.QuadPart<< = 4; 
 uiCode.QuadPart | =（exp [index]& 0x000f）; 
} 

否则最低的四位将始终为零，高位可能会被移出。



最后一个提示。可以根据定义初始化数组：

 short exp [10] = {1,0，-2,0，-1,0,2,0,0,1} ; 

Hello Everyone,

I would like to concatenate into an unsigned long the following shorts array and be able to decompact it to rebuild the shorts array.


How could I schrink it and avoid overflow ?
Thank you very much in advance.
Best regards.
MiQi

What I have tried:

Here is what I have so far:

short exp[10];
exp[0] = 1; exp[1] = 0; exp[2] = -2; exp[3] = 0; exp[4] = -1; exp[5] = 0; exp[6] = 2; exp[7] = 0; exp[8] = 0; exp[9] = 1;

for (int index = 0; index < sizeof(exp) / sizeof(short); index++)
{
   if (index % 2 == 0)
      exp[index] = 5;   // 0101
   else exp[index] = -5;// 1101
}

LARGE_INTEGER uiCode;
uiCode.QuadPart = 0;
for (index = 0; index < sizeof(exp) / sizeof(short); index++)
{
  uiCode.QuadPart = uiCode.QuadPart | (exp[index] & 0x000f);
  uiCode.QuadPart = uiCode.QuadPart << 4;
}
            
LARGE_INTEGER uiExpectedCode;
uiExpectedCode.QuadPart = uiCode.QuadPart / LONG_MAX;

LARGE_INTEGER uiResiduCode;
uiResiduCode.QuadPart = uiCode.QuadPart % LONG_MAX;

long SchrinkedCode =  ??;

解决方案

It is not quite clear what you want to achieve but there are some possible errors.

Here -5 is not binary 1101:

else exp[index] = -5;// 1101

-5 is hex 0xFFFB. So the lowest 4 bits are 1011.

The loop to shift the nibbles (4 bit values) into the quad part should probably shift first:

for (index = 0; index < sizeof(exp) / sizeof(short); index++)
{
  uiCode.QuadPart <<= 4;
  uiCode.QuadPart |= (exp[index] & 0x000f);
}

Otherwise the lowest four bits will be always zero and the upper bits may get shifted out.

Finally a tip. Arrays can be initialised upon definition:

short exp[10] = { 1, 0, -2, 0, -1, 0, 2, 0, 0, 1 };

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