Format data and automatically allocate memory to be of sufficient length

README.md

maprintf

Format data and automatically allocate memory to be of sufficient length.

This is a care-free alternative to snprintf() with strings of arbitrary length.

Sample

char *buf = maprintf( "%s: %s", key, value );

/* do something with buf */

free( buf );

maprintf.c

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>

#include "maprintf.h"

/**
 * Format data and automatically allocate memory to be of sufficient length
 *
 * @param format - printf format description
 * @param ... - arguments
 */
char *maprintf( const char *format, ... )
{
	va_list ap;
	char *buf;
	int len;
	int req;

	va_start( ap, format );
	len = vsnprintf( NULL, 0, format, ap );
	va_end( ap );

	if( len < 1 ||
		!(buf = (char *)calloc( ++len, sizeof( char ) )) )
		return NULL;

	va_start( ap, format );
	req = vsnprintf( buf, len, format, ap );
	va_end( ap );

	if( req < 0 ||
		req >= len )
	{
		free( buf );
		return NULL;
	}

	return buf;
}

maprintf.h

#ifndef _maprintf_h_
#define _maprintf_h_

char *maprintf( const char *, ... );

#endif