Echtzeitdatenverarbeitung/include/rtai_nam2num.h
2020-10-26 10:38:48 +01:00

137 lines
3.5 KiB
C

/**
* @ingroup shm
* @ingroup lxrt
* @ingroup tasklets
* @file
*
* Conversion between 6 characters strings and unsigned long identifiers.
*
* Convert a 6 characters string to un unsigned long, and vice versa, to be used
* as an dentifier for RTAI services, symmetrically available in user and kernel
* space, e.g. @ref shm "shared memory" and @ref lxrt "LXRT and LXRT-INFORMED".
*
* @author Paolo Mantegazza
*
* @note Copyright &copy; 1999-2013 Paolo Mantegazza <mantegazza@aero.polimi.it>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifndef _RTAI_NAM2NUM_H
#define _RTAI_NAM2NUM_H
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
#include <rtai_types.h>
#ifdef __KERNEL__
#include <linux/ctype.h>
#include <linux/string.h>
#define NAM2NUM_PROTO(type, name, arglist) static inline type name arglist
#else
#include <ctype.h>
#include <string.h>
#define NAM2NUM_PROTO RTAI_PROTO
#endif
#define MAX_NAM2NUM 4096000003UL // nam2num("$$$$$$") + 2
/**
* Convert a 6 characters string to an unsigned long.
*
* Converts a 6 characters string name containing an alpha numeric identifier
* to its corresponding unsigned long identifier.
*
* @param name is the name to be converted.
*
* Allowed characters are:
* - english letters (no difference between upper and lower case, the latter
* will always be translated to upper case);
* - decimal digits;
* - '_', '@', '.' and another character of your choice, the latter will
* always be treated as a $ and converted back as such by num2nam().
*
* @return the unsigned long associated with @a name.
*/
NAM2NUM_PROTO(unsigned long, nam2num, (const char *name))
{
unsigned long retval = 0;
int c, i;
for (i = 0; i < 6; i++) {
if (!(c = name[i])) {
break;
}
if (islower(c)) {
c += (10 - 'a');
} else if (isupper(c)) {
c += (10 - 'A');
} else if (isdigit(c)) {
c -= '0';
} else {
c = c == '_' ? 36 : c == '@' ? 37 : c == '.' ? 38 : 39;
}
retval = retval*40 + c;
}
return i > 0 ? retval + 2 : 0xFFFFFFFF;
}
/**
* Convert an unsigned long identifier back to its corresponding 6 characters
* string.
*
* @param num is the unsigned long identifier whose alphanumeric name string has
* to be evaluated;
*
* @param name is a pointer to a 6 characters buffer where the identifier will
* be returned. Recall to dimension it at least to 7.
*/
NAM2NUM_PROTO(void, num2nam, (unsigned long num, char *name))
{
int c, i, k, q;
if (num >= MAX_NAM2NUM) {
strncpy(name, "|null|", 7);
return;
}
i = 5;
num -= 2;
while (num && i >= 0) {
q = num/40;
c = num - q*40;
num = q;
if (c < 36) {
name[i--] = c > 9 ? c + 'A' - 10 : c + '0';
} else {
name[i--] = c == 36 ? '_' : c == 37 ? '@' : c == 38 ? '.' : '$';
}
}
for (k = 0; i < 5; k++) {
name[k] = name[++i];
}
name[k] = 0;
}
#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* !_RTAI_NAM2NUM_H */