/*
 *	Copyright 2018, University Corporation for Atmospheric Research
 *	See netcdf/COPYRIGHT file for copying and redistribution conditions.
 */
/* $Id: ffio.c,v 1.56 2006/09/15 20:40:30 ed Exp $ */
/* addition by O. Heudecker, AWI-Bremerhaven, 12.3.1998 */
/* added correction by John Sheldon and Hans Vahlenkamp 15.4.1998*/


#if HAVE_CONFIG_H
#include <config.h>
#endif

#include <assert.h>
#include <stdlib.h>
#include <stdio.h>	/* DEBUG */
#include <string.h>
#include <assert.h>
#include <errno.h>
#ifndef NC_NOERR
#define NC_NOERR 0
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#if 0
/* Insertion by O. R. Heudecker, AWI-Bremerhaven 12.3.98 (1 line)*/
#include <ffio.h>
#include <fortran.h>
#endif

#include "ncio.h"
#include "fbits.h"
#include "rnd.h"

#if !defined(NDEBUG) && !defined(X_INT_MAX)
#define  X_INT_MAX 2147483647
#endif
#if 0 /* !defined(NDEBUG) && !defined(X_ALIGN) */
#define  X_ALIGN 4
#endif

#define ALWAYS_NC_SHARE 0 /* DEBUG */

/* Forward */
static int ncio_ffio_filesize(ncio *nciop, off_t *filesizep);
static int ncio_ffio_pad_length(ncio *nciop, off_t length);
static int ncio_ffio_close(ncio *nciop, int doUnlink);


/* Begin OS */

/*
 * What is the preferred I/O block size?
 * (This becomes the default *sizehint == ncp->chunk in the higher layers.)
 * TODO: What is the the best answer here?
 */
static size_t
blksize(int fd)
{
	struct ffc_stat_s sb;
	struct ffsw sw;
#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
#ifdef HAVE_FCNTL_H
	if (fffcntl(fd, FC_STAT, &sb, &sw) > -1)
	{
#ifdef __crayx1
		if(sb.st_blksize > 0)
			return (size_t) sb.st_blksize;
#else
		if(sb.st_oblksize > 0)
			return (size_t) sb.st_oblksize;
#endif
	}
#endif
#endif
	/* else, silent in the face of error */
	return (size_t) 32768;
}

/*
 * Sortof like ftruncate, except won't make the
 * file shorter.
 */
static int
fgrow(const int fd, const off_t len)
{
	struct ffc_stat_s sb;
	struct ffsw sw;
	if (fffcntl(fd, FC_STAT, &sb, &sw) < 0)
		return errno;
	if (len < sb.st_size)
		return NC_NOERR;
	{
		const long dumb = 0;
			/* cache current position */
		const off_t pos = ffseek(fd, 0, SEEK_CUR);
		if(pos < 0)
			return errno;
		if (ffseek(fd, len-sizeof(dumb), SEEK_SET) < 0)
			return errno;
		if(ffwrite(fd, (void *)&dumb, sizeof(dumb)) < 0)
			return errno;
		if (ffseek(fd, pos, SEEK_SET) < 0)
			return errno;
	}
	/* else */
	return NC_NOERR;
}


/*
 * Sortof like ftruncate, except won't make the file shorter.  Differs
 * from fgrow by only writing one byte at designated seek position, if
 * needed.
 */
static int
fgrow2(const int fd, const off_t len)
{
	struct ffc_stat_s sb;
	struct ffsw sw;
	if (fffcntl(fd, FC_STAT, &sb, &sw) < 0)
		return errno;
	if (len <= sb.st_size)
		return NC_NOERR;
	{
	    const char dumb = 0;
	    /* we don't use ftruncate() due to problem with FAT32 file systems */
	    /* cache current position */
	    const off_t pos = ffseek(fd, 0, SEEK_CUR);
	    if(pos < 0)
		return errno;
	    if (ffseek(fd, len-1, SEEK_SET) < 0)
		return errno;
	    if(ffwrite(fd, (void *)&dumb, sizeof(dumb)) < 0)
		return errno;
	    if (ffseek(fd, pos, SEEK_SET) < 0)
		return errno;
	}
	return NC_NOERR;
}
/* End OS */
/* Begin ffio */

static int
ffio_pgout(ncio *const nciop,
	off_t const offset,  const size_t extent,
	const void *const vp, off_t *posp)
{
#ifdef X_ALIGN
	assert(offset % X_ALIGN == 0);
	assert(extent % X_ALIGN == 0);
#endif

	if(*posp != offset)
	{
		if(ffseek(nciop->fd, offset, SEEK_SET) != offset)
		{
			return errno;
		}
		*posp = offset;
	}
	if(ffwrite(nciop->fd, vp, extent) != extent)
	{
		return errno;
	}
	*posp += extent;

	return NC_NOERR;
}


static int
ffio_pgin(ncio *const nciop,
	off_t const offset, const size_t extent,
	void *const vp, size_t *nreadp, off_t *posp)
{
	int status;
	ssize_t nread;

#ifdef X_ALIGN
	assert(offset % X_ALIGN == 0);
	assert(extent % X_ALIGN == 0);
#endif

	if(*posp != offset)
	{
		if(ffseek(nciop->fd, offset, SEEK_SET) != offset)
		{
			status = errno;
			return status;
		}
		*posp = offset;
	}

	errno = 0;
	nread = ffread(nciop->fd, vp, extent);
	if(nread != extent)
	{
		status = errno;
		if(nread == -1 || status != NC_NOERR)
			return status;
		/* else it's okay we read 0. */
	}
	*nreadp = nread;
	*posp += nread;

	return NC_NOERR;
}

/* */

typedef struct ncio_ffio {
	off_t pos;
	/* buffer */
	off_t	bf_offset;
	size_t	bf_extent;
	size_t	bf_cnt;
	void	*bf_base;
} ncio_ffio;


static int
ncio_ffio_rel(ncio *const nciop, off_t offset, int rflags)
{
	ncio_ffio *ffp = (ncio_ffio *)nciop->pvt;
	int status = NC_NOERR;

	assert(ffp->bf_offset <= offset);
	assert(ffp->bf_cnt != 0);
	assert(ffp->bf_cnt <= ffp->bf_extent);
#ifdef X_ALIGN
	assert(offset < ffp->bf_offset + X_ALIGN);
	assert(ffp->bf_cnt % X_ALIGN == 0 );
#endif

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

		status = ffio_pgout(nciop, ffp->bf_offset,
			ffp->bf_cnt,
			ffp->bf_base, &ffp->pos);
		/* if error, invalidate buffer anyway */
	}
	ffp->bf_offset = OFF_NONE;
	ffp->bf_cnt = 0;
	return status;
}


static int
ncio_ffio_get(ncio *const nciop,
		off_t offset, size_t extent,
		int rflags,
		void **const vpp)
{
	ncio_ffio *ffp = (ncio_ffio *)nciop->pvt;
	int status = NC_NOERR;
#ifdef X_ALIGN
	size_t rem;
#endif

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

	assert(extent != 0);
	assert(extent < X_INT_MAX); /* sanity check */

	assert(ffp->bf_cnt == 0);

#ifdef X_ALIGN
	/* round to seekable boundaries */
	rem = offset % X_ALIGN;
	if(rem != 0)
	{
		offset -= rem;
		extent += rem;
	}

	{
		const size_t rndup = extent % X_ALIGN;
		if(rndup != 0)
			extent += X_ALIGN - rndup;
	}

	assert(offset % X_ALIGN == 0);
	assert(extent % X_ALIGN == 0);
#endif

	if(ffp->bf_extent < extent)
	{
		if(ffp->bf_base != NULL)
		{
			free(ffp->bf_base);
			ffp->bf_base = NULL;
			ffp->bf_extent = 0;
		}
		assert(ffp->bf_extent == 0);
		ffp->bf_base = malloc(extent);
		if(ffp->bf_base == NULL)
			return ENOMEM;
		ffp->bf_extent = extent;
	}

	status = ffio_pgin(nciop, offset,
		 extent,
		 ffp->bf_base,
		 &ffp->bf_cnt, &ffp->pos);
	if(status != NC_NOERR)
		return status;

	ffp->bf_offset = offset;

	if(ffp->bf_cnt < extent)
	{
		(void) memset((char *)ffp->bf_base + ffp->bf_cnt, 0,
			extent - ffp->bf_cnt);
		ffp->bf_cnt = extent;
	}


#ifdef X_ALIGN
	*vpp = (char *)ffp->bf_base + rem;
#else
	*vpp = (char *)ffp->bf_base;
#endif
	return NC_NOERR;
}


static int
ncio_ffio_move(ncio *const nciop, off_t to, off_t from,
			size_t nbytes, int rflags)
{
	int status = NC_NOERR;
	off_t lower = from;
	off_t upper = to;
	char *base;
	size_t diff = upper - lower;
	size_t extent = diff + nbytes;

	rflags &= RGN_NOLOCK; /* filter unwanted flags */

	if(to == from)
		return NC_NOERR; /* NOOP */

	if(to > from)
	{
		/* growing */
		lower = from;
		upper = to;
	}
	else
	{
		/* shrinking */
		lower = to;
		upper = from;
	}

	diff = upper - lower;
	extent = diff + nbytes;

	status = ncio_ffio_get(nciop, lower, extent, RGN_WRITE|rflags,
			(void **)&base);

	if(status != NC_NOERR)
		return status;

	if(to > from)
		(void) memmove(base + diff, base, nbytes);
	else
		(void) memmove(base, base + diff, nbytes);

	(void) ncio_ffio_rel(nciop, lower, RGN_MODIFIED);

	return status;
}

#ifdef NOFFFLUSH
/* ncio_ffio_sync_noffflush is only needed if the FFIO global layer is
 * used, because it currently has a bug that causes the PEs to hang
 * RKO 06/26/98
 */
static int
ncio_ffio_sync_noffflush(ncio *const nciop)
{
	struct ffc_stat_s si;	/* for call to fffcntl() */
	struct ffsw ffstatus;	/* to return ffsw.sw_error */
	/* run some innocuous ffio routine to get if any errno */
	if(fffcntl(nciop->fd, FC_STAT, &si, &ffstatus) < 0)
		return ffstatus.sw_error;
	return NC_NOERR;
}
/* this tests to see if the global FFIO layer is being called for
 * returns ~0 if it is, else returns 0
 */
static int
ncio_ffio_global_test(const char *ControlString)
{
	if (strstr(ControlString,"global") != (char *) NULL) {
		return ~0;
	} else {
		return 0;
	}
}
#endif

static int
ncio_ffio_sync(ncio *const nciop)
{
	int test_flush;
#ifdef __crayx1
	struct ffsw stat;
	test_flush = ffflush(nciop->fd,&stat) < 0;
#else
	test_flush = ffflush(nciop->fd) < 0;
#endif
	if(test_flush)
		return errno;
	return NC_NOERR;
}

static void
ncio_ffio_free(void *const pvt)
{
	ncio_ffio *ffp = (ncio_ffio *)pvt;
	if(ffp == NULL)
		return;

	if(ffp->bf_base != NULL)
	{
		free(ffp->bf_base);
		ffp->bf_base = NULL;
		ffp->bf_offset = OFF_NONE;
		ffp->bf_extent = 0;
		ffp->bf_cnt = 0;
	}
}


static int
ncio_ffio_init2(ncio *const nciop, size_t *sizehintp)
{
	ncio_ffio *ffp = (ncio_ffio *)nciop->pvt;

	assert(nciop->fd >= 0);

	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 NC_NOERR;
}


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_filesizefunc **)&nciop->filesize) = ncio_ffio_filesize; /* cast away const */
	*((ncio_pad_lengthfunc **)&nciop->pad_length) = ncio_ffio_pad_length; /* cast away const */
	*((ncio_closefunc **)&nciop->close) = ncio_ffio_close; /* 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_ffio_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 occurred
 * 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 = NC_NOERR;

/* 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 occurred */
		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) snprintf(buffer,sizeof(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
ffio_create(const char *path, int ioflags,
	size_t initialsz,
	off_t igeto, size_t igetsz, size_t *sizehintp,
	void* parameters,
	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_ffio_new(path, ioflags);
	if(nciop == NULL)
		return ENOMEM;

	if ((ControlString = ncio_ffio_assign(path)) == (const char *)NULL) {
		/* an error occurred - 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 != NC_NOERR)
		goto unwind_open;

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

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

	*nciopp = nciop;
	return NC_NOERR;

unwind_open:
	(void) ffclose(fd);
	/* ?? unlink */
	/*FALLTHRU*/
unwind_new:
	ncio_close(nciop,!fIsSet(ioflags, NC_NOCLOBBER));
	return status;
}


int
ffio_open(const char *path,
	int ioflags,
	off_t igeto, size_t igetsz, size_t *sizehintp,
	void* parameters,
	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_ffio_new(path, ioflags);
	if(nciop == NULL)
		return ENOMEM;

	if ((ControlString = ncio_ffio_assign(path)) == (const char *)NULL) {
		/* an error occurred - 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 != NC_NOERR)
		goto unwind_open;

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

	*nciopp = nciop;
	return NC_NOERR;

unwind_open:
	(void) ffclose(fd);
	/*FALLTHRU*/
unwind_new:
	ncio_close(nciop,0);
	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?
 */
static int
ncio_ffio_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 NC_NOERR;
}


/*
 * 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.
 */
static int
ncio_ffio_pad_length(ncio *nciop, off_t length)
{
	int status = NC_NOERR;

	if(nciop == NULL)
		return EINVAL;

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

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

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


static int
ncio_ffio_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 = NC_NOERR;

	if(nciop == NULL)
		return EINVAL;

	status = nciop->sync(nciop);

	(void) ffclose(nciop->fd);

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

	ncio__ffio_free(nciop);

	return status;
}
