ffio.c

一个用来实现偏微分方程中网格的计算库

	ffp->bf_extent = *sizehintp;

	assert(ffp->bf_base == NULL);

	/* this is separate allocation because it may grow */
	ffp->bf_base = malloc(ffp->bf_extent);
	if(ffp->bf_base == NULL)
	{
		ffp->bf_extent = 0;
		return ENOMEM;
	}
	/* else */
	return ENOERR;
}


static void
ncio_ffio_init(ncio *const nciop)
{
	ncio_ffio *ffp = (ncio_ffio *)nciop->pvt;

	*((ncio_relfunc **)&nciop->rel) = ncio_ffio_rel; /* cast away const */
	*((ncio_getfunc **)&nciop->get) = ncio_ffio_get; /* cast away const */
	*((ncio_movefunc **)&nciop->move) = ncio_ffio_move; /* cast away const */
	*((ncio_syncfunc **)&nciop->sync) = ncio_ffio_sync; /* cast away const */
	*((ncio_freefunc **)&nciop->free) = ncio_ffio_free; /* cast away const */

	ffp->pos = -1;
	ffp->bf_offset = OFF_NONE;
	ffp->bf_extent = 0;
	ffp->bf_cnt = 0;
	ffp->bf_base = NULL;
}

/* */

static void
ncio_free(ncio *nciop)
{
	if(nciop == NULL)
		return;

	if(nciop->free != NULL)
		nciop->free(nciop->pvt);
	
	free(nciop);
}


static ncio *
ncio_new(const char *path, int ioflags)
{
	size_t sz_ncio = M_RNDUP(sizeof(ncio));
	size_t sz_path = M_RNDUP(strlen(path) +1);
	size_t sz_ncio_pvt;
	ncio *nciop;
 
#if ALWAYS_NC_SHARE /* DEBUG */
	fSet(ioflags, NC_SHARE);
#endif

	if(fIsSet(ioflags, NC_SHARE))
		fprintf(stderr, "NC_SHARE not implemented for ffio\n");

	sz_ncio_pvt = sizeof(ncio_ffio);

	nciop = (ncio *) malloc(sz_ncio + sz_path + sz_ncio_pvt);
	if(nciop == NULL)
		return NULL;
	
	nciop->ioflags = ioflags;
	*((int *)&nciop->fd) = -1; /* cast away const */

	nciop->path = (char *) ((char *)nciop + sz_ncio);
	(void) strcpy((char *)nciop->path, path); /* cast away const */

				/* cast away const */
	*((void **)&nciop->pvt) = (void *)(nciop->path + sz_path);

	ncio_ffio_init(nciop);

	return nciop;
}

/* put all the FFIO assign specific code here
 * returns a pointer to an internal static char location
 * which may change when the function is called again
 * if the returned pointer is NULL this indicates that an error occured
 * check errno for the netCDF error value
 */
/* prototype fortran subroutines */
#ifdef __crayx1
void ASNQFILE(const char *filename, const char *attribute, int *istat, int flen, int alen);
void ASNFILE(const char *filename, const char *attribute, int *istat, int flen, int alen);
#else
void ASNQFILE(_fcd filename, _fcd attribute, int *istat);
void ASNFILE(_fcd filename, _fcd attribute, int *istat);
#endif

#define BUFLEN 256
static const char *
ncio_ffio_assign(const char *filename) {
	static char buffer[BUFLEN];
	int istat;
#ifndef __crayx1
	_fcd fnp, fbp;
#endif
	char *envstr;
	char *xtra_assign;
	char emptystr='\0';

/* put things into known states */
	memset(buffer,'\0',BUFLEN);
	errno = ENOERR;

/* set up Fortran character pointers */
#ifdef __crayx1
	ASNQFILE(filename, buffer, &istat, strlen(filename)+1, BUFLEN);
#else
	fnp = _cptofcd((char *)filename, strlen(filename));
	fbp = _cptofcd(buffer, BUFLEN);

/* see if the user has "assigned" to this file */
	ASNQFILE(fnp, fbp, &istat);
#endif
	if (istat == 0) {	/* user has already specified an assign */
		return buffer;
	} else if (istat > 0 || istat < -1) {	/* error occured */
		errno = EINVAL;
		return (const char *) NULL;
	} /* istat = -1 -> no assign for file */
	envstr = getenv("NETCDF_FFIOSPEC");
	if(envstr == (char *) NULL) {
		 envstr = "bufa:336:2";		/* this should be macroized */
	}
	
	/* Insertion by Olaf Heudecker, AWI-Bremerhaven, 12.8.1998
	   to allow more versatile FFIO-assigns */
	/* this is unnecessary and could have been included
	 * into the NETCDF_FFIOSPEC environment variable */
	xtra_assign = getenv("NETCDF_XFFIOSPEC");
	if(xtra_assign == (char *) NULL) {
		xtra_assign=&emptystr;
	}
	if (strlen(envstr)+strlen(xtra_assign) + 4 > BUFLEN) {
	/* Error: AssignCommand too long */
		errno=E2BIG;
		return (const char *) NULL;
	}
	(void) sprintf(buffer,"-F %s %s", envstr,xtra_assign);
#ifdef __crayx1
	ASNFILE(filename, buffer, &istat, strlen(filename)+1, strlen(buffer)+1);
#else
	fbp = _cptofcd(buffer, strlen(buffer));
	ASNFILE(fnp, fbp, &istat);
#endif
	if (istat == 0) {	/* success */
		return buffer;
	} else {		/* error */
		errno = EINVAL;
		return (const char *) NULL;
	}
}

/* Public below this point */

/* TODO: Is this reasonable for this platform? */
static const size_t NCIO_MINBLOCKSIZE = 256;
static const size_t NCIO_MAXBLOCKSIZE = 268435456; /* sanity check, about X_SIZE_T_MAX/8 */

int
ncio_create(const char *path, int ioflags,
	size_t initialsz,
	off_t igeto, size_t igetsz, size_t *sizehintp,
	ncio **nciopp, void **const igetvpp)
{
	ncio *nciop;
	const char *ControlString;
	int oflags = (O_RDWR|O_CREAT|O_TRUNC);
	int fd;
	int status;
	struct ffsw stat;

	if(initialsz < (size_t)igeto + igetsz)
		initialsz = (size_t)igeto + igetsz;

	fSet(ioflags, NC_WRITE);

	if(path == NULL || *path == 0)
		return EINVAL;

	nciop = ncio_new(path, ioflags);
	if(nciop == NULL)
		return ENOMEM;

	if ((ControlString = ncio_ffio_assign(path)) == (const char *)NULL) {
		/* an error occured - just punt */
		status = errno;
		goto unwind_new;
	}
#ifdef NOFFFLUSH
	/* test whether the global layer is being called for
	 * this file ... if so then can't call FFIO ffflush()
	 * RKO 06/26/98
	 */
	if (strstr(ControlString,"global") != (char *) NULL) {
		/* use no ffflush version */
		*((ncio_syncfunc **)&nciop->sync)
			= ncio_ffio_sync_noffflush;
	}
#endif
	if(fIsSet(ioflags, NC_NOCLOBBER))
		fSet(oflags, O_EXCL);

	/* Orig: fd = ffopens(path, oflags, 0666, 0, &stat, ControlString); */
	fd = ffopen(path, oflags, 0666, 0, &stat);
	if(fd < 0)
	{
		status = errno;
		goto unwind_new;
	}
	*((int *)&nciop->fd) = fd; /* cast away const */

	if(*sizehintp < NCIO_MINBLOCKSIZE || *sizehintp > NCIO_MAXBLOCKSIZE)
	{
		/* Use default */
		*sizehintp = blksize(fd);
	}
	else
	{
		*sizehintp = M_RNDUP(*sizehintp);
	}

	status = ncio_ffio_init2(nciop, sizehintp);
	if(status != ENOERR)
		goto unwind_open;

	if(initialsz != 0)
	{
		status = fgrow(fd, (off_t)initialsz);
		if(status != ENOERR)
			goto unwind_open;
	}

	if(igetsz != 0)
	{
		status = nciop->get(nciop,
				igeto, igetsz,
                        	RGN_WRITE,
                        	igetvpp);
		if(status != ENOERR)
			goto unwind_open;
	}

	*nciopp = nciop;
	return ENOERR;

unwind_open:
	(void) ffclose(fd);
	/* ?? unlink */
	/*FALLTHRU*/
unwind_new:
	ncio_free(nciop);
	return status;
}


int
ncio_open(const char *path,
	int ioflags,
	off_t igeto, size_t igetsz, size_t *sizehintp,
	ncio **nciopp, void **const igetvpp)
{
	ncio *nciop;
	const char *ControlString;
	int oflags = fIsSet(ioflags, NC_WRITE) ? O_RDWR : O_RDONLY;
	int fd;
	int status;
	struct ffsw stat;

	if(path == NULL || *path == 0)
		return EINVAL;

	nciop = ncio_new(path, ioflags);
	if(nciop == NULL)
		return ENOMEM;

	if ((ControlString = ncio_ffio_assign(path)) == (const char *)NULL) {
		/* an error occured - just punt */
		status = errno;
		goto unwind_new;
	}
#ifdef NOFFFLUSH
	/* test whether the global layer is being called for
	 * this file ... if so then can't call FFIO ffflush()
	 * RKO 06/26/98
	 */
	if (strstr(ControlString,"global") != (char *) NULL) {
		/* use no ffflush version */
		*((ncio_syncfunc **)&nciop->sync)
			= ncio_ffio_sync_noffflush;
	}
#endif

	/* Orig: fd = ffopens(path, oflags, 0, 0, &stat, ControlString); */
	fd = ffopen(path, oflags, 0, 0, &stat);

	if(fd < 0)
	{
		status = errno;
		goto unwind_new;
	}
	*((int *)&nciop->fd) = fd; /* cast away const */

	if(*sizehintp < NCIO_MINBLOCKSIZE || *sizehintp > NCIO_MAXBLOCKSIZE)
	{
		/* Use default */
		*sizehintp = blksize(fd);
	}
	else
	{
		*sizehintp = M_RNDUP(*sizehintp);
	}

	status = ncio_ffio_init2(nciop, sizehintp);
	if(status != ENOERR)
		goto unwind_open;

	if(igetsz != 0)
	{
		status = nciop->get(nciop,
				igeto, igetsz,
                        	0,
                        	igetvpp);
		if(status != ENOERR)
			goto unwind_open;
	}

	*nciopp = nciop;
	return ENOERR;

unwind_open:
	(void) ffclose(fd);
	/*FALLTHRU*/
unwind_new:
	ncio_free(nciop);
	return status;
}


/* 
 * Get file size in bytes.  
 * Is use of ffseek() really necessary, or could we use standard fstat() call
 * and get st_size member?
 */
int
ncio_filesize(ncio *nciop, off_t *filesizep)
{
    off_t filesize, current, reset;

    if(nciop == NULL)
	return EINVAL;

    current = ffseek(nciop->fd, 0, SEEK_CUR);  /* save current */
    *filesizep = ffseek(nciop->fd, 0, SEEK_END); /* get size */
    reset = ffseek(nciop->fd, current, SEEK_SET); /* reset */ 

    if(reset != current)
	return EINVAL;
    return ENOERR;
}


/*
 * Sync any changes to disk, then extend file so its size is length.
 * This is only intended to be called before close, if the file is
 * open for writing and the actual size does not match the calculated
 * size, perhaps as the result of having been previously written in
 * NOFILL mode.
 */
int
ncio_pad_length(ncio *nciop, off_t length)
{
	int status = ENOERR;

	if(nciop == NULL)
		return EINVAL;

	if(!fIsSet(nciop->ioflags, NC_WRITE))
	        return EPERM; /* attempt to write readonly file */

	status = nciop->sync(nciop);
	if(status != ENOERR)
	        return status;

	status = fgrow2(nciop->fd, length);
	if(status != ENOERR)
	        return errno;
	return ENOERR;
}


int 
ncio_close(ncio *nciop, int doUnlink)
{
	/*
         * TODO: I believe this function is lacking the de-assignment of the
         * Fortran LUN assigned by ASNFILE in ncio_ffio_assign(...) -- SRE
         * 2002-07-10.
	 */

	int status = ENOERR;

	if(nciop == NULL)
		return EINVAL;

	status = nciop->sync(nciop);

	(void) ffclose(nciop->fd);
	
	if(doUnlink)
		(void) unlink(nciop->path);

	ncio_free(nciop);

	return status;
}