将 MAC 地址字符串转换为字节

• 下载源代码 - 7.37 KB

介绍 

inet_addr 和 inet_ntoa 已经可用于 IP 地址处理。这里，我提供了与此类似的功能，用于处理 MAC 地址。

这段代码片段将 MAC 地址字符串转换为字节数组，并将字节数组转换为 MAC 地址字符串。

背景

我在互联网上搜索过，但没有找到这样的函数，所以在这里发布出来供大家使用。

Using the Code

代码本身即自解释的。

const char cSep = '-'; //Bytes separator in MAC address string like 00-aa-bb-cc-dd-ee

/*
	This function accepts MAC address in string format and returns in bytes. 
	it relies on size of byAddress and it must be greater than 6  bytes.
	If MAC address string is not in valid format, it returns NULL.

	NOTE: tolower function is used and it is locale dependent.
*/

unsigned char* ConverMacAddressStringIntoByte
	(const char *pszMACAddress, unsigned char* pbyAddress)
{
	for (int iConunter = 0; iConunter < 6; ++iConunter)
	{
		unsigned int iNumber = 0;
		char ch;

		//Convert letter into lower case.
		ch = tolower (*pszMACAddress++);

		if ((ch < '0' || ch > '9') && (ch < 'a' || ch > 'f'))
		{
			return NULL;
		}

		//Convert into number. 
		//       a. If character is digit then ch - '0'
		//	b. else (ch - 'a' + 10) it is done 
		//	because addition of 10 takes correct value.
		iNumber = isdigit (ch) ? (ch - '0') : (ch - 'a' + 10);
		ch = tolower (*pszMACAddress);

		if ((iConunter < 5 && ch != cSep) || 
			(iConunter == 5 && ch != '\0' && !isspace (ch)))
		{
			++pszMACAddress;

			if ((ch < '0' || ch > '9') && (ch < 'a' || ch > 'f'))
			{
				return NULL;
			}

			iNumber <<= 4;
			iNumber += isdigit (ch) ? (ch - '0') : (ch - 'a' + 10);
			ch = *pszMACAddress;

			if (iConunter < 5 && ch != cSep)
			{
				return NULL;
			}
		}
		/* Store result.  */
		pbyAddress[iConunter] = (unsigned char) iNumber;
		/* Skip cSep.  */
		++pszMACAddress;
	}
	return pbyAddress;
}

/*
	This function converts Mac Address in Bytes to String format.
	It does not validate any string size and pointers.

	It returns MAC address in string format.
*/

char *ConvertMacAddressInBytesToString(char *pszMACAddress, 
				unsigned char *pbyMacAddressInBytes)
{
	sprintf(pszMACAddress, "%02x%c%02x%c%02x%c%02x%c%02x%c%02x", 
						pbyMacAddressInBytes[0] & 0xff,
						cSep,
						pbyMacAddressInBytes[1]& 0xff, 
						cSep,
						pbyMacAddressInBytes[2]& 0xff, 
						cSep,
						pbyMacAddressInBytes[3]& 0xff, 
						cSep,
						pbyMacAddressInBytes[4]& 0xff, 
						cSep,
						pbyMacAddressInBytes[5]& 0xff);

	return pszMACAddress;
} 

历史

• 2009年4月8日：首次发布