C语言生成随机uuid编码

C语言生成随机uuid编码

#include <stdio.h>
#include <stdlib.h>
 
/**
 * Create random UUID
 *
 * @param buf - buffer to be filled with the uuid string
 */
char *random_uuid( char buf[37] )
{
	const char *c = "89ab";
	char *p = buf;
	int n;
 
	for( n = 0; n < 16; ++n )
	{
		int b = rand()%255;
 
		switch( n )
		{
			case 6:
				sprintf(
					p,
					"4%x",
					b%15 );
				break;
			case 8:
				sprintf(
					p,
					"%c%x",
					c[rand()%strlen( c )],
					b%15 );
				break;
			default:
				sprintf(
					p,
					"%02x",
					b );
				break;
		}
 
		p += 2;
 
		switch( n )
		{
			case 3:
			case 5:
			case 7:
			case 9:
				*p++ = '-';
				break;
		}
	}
 
	*p = 0;
 
	return buf;
}