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Byte Swaping a structure

I would like to set data elements to a struction and then byte swap the entire structure.
The part that makes it difficult is the struction contains elements of diffrent sizes. Below is an example of a data structure that uses shorts, ints, and chars all in the same structure.
I do not have to perform any word swapping just byte swapping.

Is there some inherent function in C++ like the _swab function that performs this. If not does someone have an example of how to do this. Once the structure is swapped it will be written to a file.

#pragma pack(1)//eliminate padding in structs
typedef struct {
      short            IDMSAReportingMode : 2;
      short            IDMSAReportingSpare : 1;
      short            IDMSATimeFilter : 13;
      short            IDMSAMotionSpare : 4;
      short            IDMSAMotionFilter : 12;
      int            IDMStaleFilterDurationSpare : 13;
      int            IDMStaleFilterDuration : 19;
      int            IDMOldFilterDurationSpare : 13;
      int            IDMOldFilterDuration : 19;
      int            IDMPurgeFilterDurationSpare : 13;
      int            IDMPurgeFilterDuration : 19;
      short            IDMAutoResponseModeSpare : 6;
      short            IDMAutoResponseMode : 2;
      short            IDMChannelTransFlagSpare : 6;
      short            IDMChannelTransFlag : 2;
      char            IDMFSConfigFile[6];
      short            IDMTIInterfaceSpare : 6;
      short            IDMTIInterfaceNum : 2;
      short            IDMTICMSAPortNumSpare : 6;
      short            IDMTICMSAPortNum : 2;
      short            IDMFSInterfaceNumSpare : 6;
      short            IDMFSInterfaceNum : 2;
      short            IDMFSCMSAPortSpare : 6;
      short            IDMFSCMSAPort : 2;
      int            IDMEBC_OWN_URN_Spare : 9;
      int            IDMEBC_OWN_URN : 23;
      int            IDMMulticast_URN_Spare : 9;
      int            IDMMulticast_URN : 23;
      char            IDMTIPassword[8];
      short            IDMFIPRRegNetworkMonitoring : 1;
      short            IDMFIPRRegSystemCoord : 1;
      short            IDMFIPRRegSecurityMsg : 1;
      short            IDMFIPRRegFreetext : 1;
      short            IDMFIPRRegUnitRefQuery : 1;
      short            IDMFIPRRegInfoRequest : 1;
      short            IDMFIPRRegObserverMsnUpdate : 1;
      short            IDMFIPRRegMsgToObserver : 1;
      short            IDMFIPRRegAirborneFireMsn : 1;
      short            IDMFIPRRegBasicWeatherRprt : 1;
      short            IDMFIPRRegMaydayMsg : 1;
      short            IDMFIPRRegSpot_SaluteRprt : 1;
      short            IDMFIPRRegObstacleRprt : 1;
      short            IDMFIPRRegPosRprt : 1;
      short            IDMFIPRRegNBC3Rprt : 1;
      short            IDMFIPRRegREDCONRprt : 1;
      short            IDMFIPRRegThreatWarning : 1;
      short            IDMFIPRRegSitrep : 1;
      short            IDMFIPRRegMOPP : 1;
      short            IDMFIPRRegSupplyPointStatus : 1;
      short            IDMFIPRRegTaskMgmt : 1;
      short            IDMFIPRSpare : 11;
      char            IDMEBC_UTO[64];

} IDM_OPERATOR_CONFIG_TYPE;

jkr

>>Is there some inherent function in C++ like the _swab function that performs this

'_swab()' works like

/* SWAB.C illustrates:
* _swab
*/

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

char from[] = "BADCFEHGJILKNMPORQTSVUXWZY";
char to[] = "..........................";

void main()
{
printf( "Before:\t%s\n\t%s\n\n", from, to );
_swab( from, to, sizeof( from ) );
printf( "After:\t%s\n\t%s\n\n", from, to );
}

jkr

BTW, as I can see, you don *NOT* want to use '_swab()' at all - if your goal is to put the above in non-intel byte order, just swapping the byte is not enough, you need to use the appropriate functions on the bitfield members.

ASKER CERTIFIED SOLUTION

jkr

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