在int和反之亦然嵌入字符 [英] embedding chars in int and vice versa
问题描述
我的智能卡上，我可以存储字节（16的倍数）。
如果我做的：保存（字节数组，长度）然后我可以做接收（字节数组，长度）
我想我会得到字节数组中存储我相同的顺序。
现在，我有这样的问题。我意识到，如果我这个存储卡上的整数，
和其他一些机（带不同字节）读取它，它可能会得到错误的数据。
所以，我想，也许解决方案是我的总是此卡上存储数据，在一个小
端的方式，和总是检索小端方式中的数据（我会写的应用程序来读写，所以我可以自由地跨preT的数字，因为我喜欢。）。这可能吗？
这里是我想出了：
I have smart card on which I can store bytes (multiple of 16).
If I do: Save(byteArray, length) then I can do Receive(byteArray,length)
and I think I will get byte array in the same order I stored.
Now, I have such issue. I realized if I store integer on this card,
and some other machine (with different endianness) reads it, it may get wrong data.
So, I thought maybe solution is I always store data on this card, in a little
endian way, and always retrieve the data in a little endian way (I will write apps to read and write, so I am free to interpret numbers as I like.). Is this possible?
Here is something I have come up with:
嵌入整数字符数组：
int x;
unsigned char buffer[250];
buffer[0] = LSB(x);
buffer[1] = LSB(x>>8);
buffer[2] = LSB(x>>16);
buffer[3] = LSB(x>>24);
重要的是我认为的 LSB 函数应该返回至少显著字节计较机，的字节序的怎么会这样LSB的功能是什么样子？
Important is I think that LSB function should return the least significant byte regardless of the endiannes of the machine, how would such LSB function look like?
现在，重建整数（像这样）：
Now, to reconstruct the integer (something like this):
int x = buffer[0] | (buffer[1]<<8) | (buffer[2]<<16) | (buffer[3]<<24);
正如我说我要这个工作，不管是谁读取它，并将其写入机器的字节序的。将这项工作？
As I said I want this to work, regardless of the endiannes of the machine who reads it and writes it. Will this work?
推荐答案
如果你的C库是POSIX兼容的，那么您有可到底该怎么做你正在尝试code标准功能。 ntohl ， ntohs和， htonl ， htons （网络到主机长，网络到主机短，...）。如果你想编译它的大端或小端架构，你没有这样的方式来改变你的code。该功能在 ARPA / inet.h 定义（见的 http://linux.die.net/man/3/ntohl ）。
If your C library is posix compliant, then you have standard functions available to do exactly what you are trying to code. ntohl, ntohs, htonl, htons (network to host long, network to host short, ...). That way you don't have to change your code if you want to compile it for a big-endian or for a little-endian architecture. The functions are defined in arpa/inet.h (see http://linux.die.net/man/3/ntohl).
这篇关于在int和反之亦然嵌入字符的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
