Ç - 格式化的MAC地址 [英] C - formatting MAC address

问题描述

我目前正在与一些解析MAC地址的工作。我给出的输出不包括前导零（像这样）。

I am currently working with parsing some MAC addresses. I am given an output that does not include leading zeros (like so).

char* host = "0:25:25:0:25:25";

和我想，像这样进行格式化

and I would like to format it like so

char* host = "00:25:25:00:25:25";

什么是去了解最简单的方法？

What would be the easiest way to go about this?

对于那些想知道，我现在用的是libpcap的图书馆。

For those wondering, I am using the libpcap library.

推荐答案

我可能会丢失在问题的东西。假设你知道这是一个有效的MAC，输入字符串是这样解析的，你有没有考虑简单的东西如：

I may be missing something in the question. Assuming you know it is a valid MAC, and the input string is thus parsable, have you considered something as simple as:

char* host1 = "0:25:25:0:AB:25";
char *host2 = "0:1:02:3:0a:B";
char result[19];
int a,b,c,d,e,f;

// the question sample
if (sscanf(host1, "%x:%x:%x:%x:%x:%x", &a,&b,&c,&d,&e, &f) == 6)
    sprintf(result, "%02X:%02X:%02X:%02X:%02X:%02X", a,b,c,d,e,f);
printf("host1: %s\n", result);

// a more daunting sample
if (sscanf(host2, "%x:%x:%x:%x:%x:%x", &a,&b,&c,&d,&e, &f) == 6)
    sprintf(result, "%02X:%02X:%02X:%02X:%02X:%02X", a,b,c,d,e,f);
printf("host2: %s\n", result);

输出

host1: 00:25:25:00:AB:25
host2: 00:01:02:03:0A:0B

显然，对于超偏执，你会希望确保 A-F 都是＆LT; 255，这可能是preferable。最根本的原因，我preFER这种性能不是一个关键问题是多的你可能不会在你的问题考虑的事情。它可以处理所有的

Obviously for the ultra-paranoid you would want to make sure a-f are all < 255, which is probably preferable. The fundamental reasons I prefer this where performance isn't a critical issue are the many things you may not be considering in your question. It handles all of

N的
1. 铅值，其中 N 取值的任何的十六进制数字;不只是零。例如：5：，0


2. 中旬值：N：，再次在相同的条件为：（1）上述之下。例如：：A：，0：


3. 尾值：N。再次，相同的条件（1）以上下。例如：：B，：0


4. 十六进制数字无关时看书;它的工作原理与两个大写和小写数字字符。


5. 最重要的是，什么也不做（除了大写十六进制丘壑），如果你输入的字符串已正确格式化。

1. Lead values of "n:", where n s any hex digit; not just zero. Examples: "5:", "0:"
2. Mid values of ":n:", again under the same conditions as (1) above. Examples: ":A:", ":0:"
3. Tail values of ":n". once more, under the same conditions as (1) above. Examples: ":b", ":0"
4. Hex-digit agnostic when reading; it works with both upper and lower case digit chars.
5. Most important, does nothing (except upper-case the hex vals) if you're input string is already properly formatted.

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