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/**
* Copyright 1981-2007 ECMWF
*
* Licensed under the GNU Lesser General Public License which
* incorporates the terms and conditions of version 3 of the GNU
* General Public License.
* See LICENSE and gpl-3.0.txt for details.
*/
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <sys/sem.h>
#include "sharedmemory.h"
#include "fortdefs.h"
int sharedMemoryCharacteristics( int, int , float , int * , int * , key_t * );
void createSharedMemoryCoefficients( fortint , fortint , fortreal , fortint , key_t , int );
int debugSet = 0;
static char * debugLevel;
fortint SMREAD(
fortreal ** fortranArrayPointer, /* to be attached to shared memory */
fortint * Type, /* SP2LL, SP2QG, .. */
fortint * Truncation, /* spectral truncation */
fortreal * Grid) /* grid spacing or gaussian number */
/*
// Callable from Fortran.
//
*/
/*
C
C---->
C**** SMREAD
C
C Purpose
C -------
C
C This routine gets interpolation coefficients in a shared memory array.
C
C
C Interface
C ---------
C
C ISIZE = SMREAD(KARRAY,KTYPE,KTRUNC,GRID)
C
C
C Input parameters
C ----------------
C
C KTYPE - Type of spectral to grid transformation (SP2LL, SP2QG, ..)
C KTRUNC - Spectral truncation (eg 511 for T511)
C GRID - longitude grid spacing (for lat/long) or gaussian number
C
C
C Output parameters
C -----------------
C
C KARRAY - Pointer to a shared memory array of REALs
C
C Function returns the size (in values) of the shared memory array
C
C
C Common block usage
C ------------------
C
C None.
C
C
C Method
C ------
C
C Looks for coefficients in shared memory.
C Waits on semaphore for coefficients to become available.
C
C
C Externals
C ---------
C
C sharedMemoryCharacteristics - to get key and size for shared memory
C createSharedMemoryCoefficients - creates coefficients if necessary
C
C
C Reference
C ---------
C
C None.
C
C
C Comments
C --------
C
C Environment variable SHARED_DEBUG can be set (1, 2, ..) to give
C diagnostic printout.
C
C
C Author
C ------
C
C J.D.Chambers ECMWF January 2002
C
C
C Modifications
C -------------
C
C None.
C
C----<
C
*/
{
int type = (int) *Type;
int truncation = (int) *Truncation;
float grid = (float) *Grid;
key_t memoryKey;
int size, shmflg, shmid;
char * shmaddr;
int status, i;
fortint numberOfValues = 0;
char mode[] = "00666";
int value, semaphoreId, numlat, returnCode;
union semun {
int val;
struct semid_ds *buf;
ushort *array;
} semvalues;
fortint Numlat;
struct sembuf bufs[1];
/*
// See if DEBUG switched on.
*/
if( ! debugSet ) {
debugLevel = getenv("SHARED_DEBUG");
if( debugLevel == NULL )
debugSet = DEBUGOFF; /* off */
else {
int loop;
for( loop = 0; loop < strlen(debugLevel) ; loop++ ) {
if( ! isdigit(debugLevel[loop]) ) {
printf("Invalid number string in SHARED_DEBUG: %s\n", debugLevel);
printf("SHARED_DEBUG must comprise only digits [0-9].\n");
debugSet = DEBUGOFF;
}
}
debugSet = DEBUGOFF + atoi( debugLevel );
}
if( DEBUG ) printf("SHARED_DEBUG: debug switched on\n");
}
/*
// Get key and size for shared memory (whole globe)
*/
if( DEBUG ) {
printf("SMREAD: type = %d\n",type);
printf("SMREAD: truncation = %d\n",truncation);
printf("SMREAD: grid = %f\n",grid);
}
status = sharedMemoryCharacteristics( type,
truncation,
grid,
&numlat,
&size,
&memoryKey);
if( status ) {
if( DEBUG ) printf("SMREAD: sharedMemoryCharacteristics call failed\n");
return (fortint) 0;
}
Numlat = numlat;
/*
// Wait for the shared memory array to become available
*/
if( DEBUG ) printf("SMREAD: call createSharedMemoryCoefficients with numlat = %d\n", numlat);
createSharedMemoryCoefficients(*Type,*Truncation,*Grid,Numlat,memoryKey,size);
bufs[0].sem_num = 0;
bufs[0].sem_op = -READY_TO_READ;
bufs[0].sem_flg = 0;
semaphoreId = (int) memoryKey;
if( DEBUG )
printf("SMREAD: wait for shared memory semaphore id %0x\n", semaphoreId);
status = semop(semaphoreId,bufs,1);
/*
// Locate shared segment
*/
if( DEBUG ) printf("SMREAD: locate shared memory\n");
shmflg = 0666;
shmid = shmget( memoryKey, (size_t)size, shmflg);
if ( shmid < 0 ) {
perror("shmget error");
return (fortint) 0;
}
/*
// Attach the shared segment to the array pointer
*/
if( DEBUG ) printf("SMREAD: attach shared memory to array\n");
shmaddr = (char *) NULL;
shmflg = 0;
*fortranArrayPointer = (fortreal *) shmat( shmid, shmaddr, shmflg);
if ( *fortranArrayPointer == (fortreal *) -1 ) {
perror("shmat error");
return (fortint) 0;
}
/*
// Set semaphore value to make memory readable for other readers
*/
if( DEBUG ) printf("SMREAD: set semaphore to make memory readable\n");
semvalues.val = READY_TO_READ;
value = semctl((int)semaphoreId, (int)0, (int)SETVAL,semvalues);
/*
// Return the size (in values) of the shared segment
*/
numberOfValues = (fortint) size/sizeof(fortreal);
if( DEBUG )
printf("SMREAD: number of values in shared memory = %d\n", numberOfValues);
return numberOfValues;
}
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