Logo Search packages:      
Sourcecode: labplot version File versions

posixio.c

/*
 *    Copyright 1996, University Corporation for Atmospheric Research
 *    See netcdf/COPYRIGHT file for copying and redistribution conditions.
 */
/* $Id: posixio.c,v 1.68 1999/08/24 17:18:19 steve Exp $ */

#include "ncconfig.h"
#include <assert.h>
#include <stdlib.h>
#include <errno.h>
#ifndef ENOERR
#define ENOERR 0
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#ifdef _MSC_VER /* Microsoft Compilers */
#include <io.h>
#else
#include <unistd.h>
#endif

#ifndef SEEK_SET
#define SEEK_SET 0
#define SEEK_CUR 1
#define SEEK_END 2
#endif

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

/* #define INSTRUMENT 1 */
#if INSTRUMENT /* debugging */
#undef NDEBUG
#include <stdio.h>
#include "instr.h"
#endif

#undef MIN  /* system may define MIN somewhere and complain */
#define MIN(mm,nn) (((mm) < (nn)) ? (mm) : (nn))

#if !defined(NDEBUG) && !defined(X_INT_MAX)
#define  X_INT_MAX 2147483647
#endif

#if 0 /* !defined(NDEBUG) && !defined(X_ALIGN) */
#define  X_ALIGN 4
#else
#undef X_ALIGN
#endif

/*
 * Define the following for debugging.
 */
/* #define ALWAYS_NC_SHARE 1 */

/* Begin OS */

static int ncio_px_sync(ncio *const nciop);

#ifndef POSIXIO_DEFAULT_PAGESIZE
#define POSIXIO_DEFAULT_PAGESIZE 4096
#endif
/*
 * What is the system pagesize?
 */
static size_t
pagesize(void)
{
/* Hmm, aren't standards great? */
#if defined(_SC_PAGE_SIZE) && !defined(_SC_PAGESIZE)
#define _SC_PAGESIZE _SC_PAGE_SIZE
#endif

#ifdef _SC_PAGESIZE
      {
            const long pgsz = sysconf(_SC_PAGESIZE);
            if(pgsz > 0)
                  return (size_t) pgsz;
            /* else, silent in the face of error */
      }
#elif defined(HAVE_GETPAGESIZE)
      return (size_t) getpagesize();
#endif
      return (size_t) POSIXIO_DEFAULT_PAGESIZE;
}

/*
 * What is the preferred I/O block size?
 */
static size_t
blksize(int fd)
{
#if defined(HAVE_ST_BLKSIZE)
      struct stat sb;
      if (fstat(fd, &sb) > -1)
      {
            if(sb.st_blksize >= 8192)
                  return (size_t) sb.st_blksize;
            return 8192;
      }
      /* else, silent in the face of error */
#endif
      return (size_t) 2 * pagesize();
}


/*
 * Sortof like ftruncate, except won't make the
 * file shorter.
 */
static int
fgrow(const int fd, const off_t len)
{
      struct stat sb;
      if (fstat(fd, &sb) < 0)
            return errno;
      if (len < sb.st_size)
            return ENOERR;
#if defined(HAVE_FTRUNCATE)
      if (ftruncate(fd, len) < 0)
            return errno;
#else
      {
            const long dumb = 0;
                  /* cache current position */
            const off_t pos = lseek(fd, 0, SEEK_CUR);
            if(pos < 0)
                  return errno;
            if (lseek(fd, len-sizeof(dumb), SEEK_SET) < 0)
                  return errno;
            if(write(fd, &dumb, sizeof(dumb)) < 0)
                  return errno;
            if (lseek(fd, pos, SEEK_SET) < 0)
                  return errno;
      }
#endif /* HAVE_FTRUNCATE */
      /* else */
      return ENOERR;
}

/* End OS */
/* Begin px */

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

      assert(*posp == OFF_NONE || *posp == lseek(nciop->fd, 0, SEEK_CUR));

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

      return ENOERR;
}


static int
px_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

      assert(*posp == OFF_NONE || *posp == lseek(nciop->fd, 0, SEEK_CUR));

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

      errno = 0;
      nread = read(nciop->fd, vp, extent);
      if(nread != (ssize_t) extent)
      {
            status = errno;
            if(nread == -1 || status != ENOERR)
                  return status;
            /* else it's okay we read less than asked for */
            (void) memset((char *)vp + nread, 0, (ssize_t)extent - nread);
      }
      *nreadp = nread;
      *posp += nread;

      return ENOERR;
}


typedef struct ncio_px {
      size_t blksz;
      off_t pos;
      /* buffer */
      off_t bf_offset; 
      size_t      bf_extent;
      size_t      bf_cnt;
      void  *bf_base;
      int   bf_rflags;
      int   bf_refcount;
      /* chain for double buffering in px_move */
      struct ncio_px *slave;
} ncio_px;


/*ARGSUSED*/
static int
px_rel(ncio_px *const pxp, off_t offset, int rflags)
{
      assert(pxp->bf_offset <= offset
             && offset < pxp->bf_offset + (off_t) pxp->bf_extent);
      assert(pIf(fIsSet(rflags, RGN_MODIFIED),
            fIsSet(pxp->bf_rflags, RGN_WRITE)));

      if(fIsSet(rflags, RGN_MODIFIED))
      {
            fSet(pxp->bf_rflags, RGN_MODIFIED);
      }
      pxp->bf_refcount--;

      return ENOERR;
}

static int
ncio_px_rel(ncio *const nciop, off_t offset, int rflags)
{
      ncio_px *const pxp = (ncio_px *)nciop->pvt;

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

      return px_rel(pxp, offset, rflags);
}

static int
px_get(ncio *const nciop, ncio_px *const pxp,
            off_t offset, size_t extent,
            int rflags,
            void **const vpp)
{
      int status = ENOERR;

      const off_t blkoffset = _RNDDOWN(offset, (off_t)pxp->blksz);
      size_t diff = (size_t)(offset - blkoffset);
      size_t blkextent = _RNDUP(diff + extent, pxp->blksz);
      
      assert(extent != 0);
      assert(extent < X_INT_MAX); /* sanity check */
      assert(offset >= 0); /* sanity check */
      assert(offset < X_INT_MAX); /* sanity check */

      if(2 * pxp->blksz < blkextent)
            return E2BIG; /* TODO: temporary kludge */
      if(pxp->bf_offset == OFF_NONE)
      {
            /* Uninitialized */
            if(pxp->bf_base == NULL)
            {
                  assert(pxp->bf_extent == 0);
                  assert(blkextent <= 2 * pxp->blksz);
                  pxp->bf_base = malloc(2 * pxp->blksz);
                  if(pxp->bf_base == NULL)
                        return ENOMEM;
            }
            goto pgin;
      }
      /* else */
      assert(blkextent <= 2 * pxp->blksz);

      if(blkoffset == pxp->bf_offset)
      {
            /* hit */
            if(blkextent > pxp->bf_extent) 
            {
                  /* page in upper */
                  void *const middle =
                        (void *)((char *)pxp->bf_base + pxp->blksz);
                  assert(pxp->bf_extent == pxp->blksz);
                  status = px_pgin(nciop,
                         pxp->bf_offset + (off_t)pxp->blksz,
                         pxp->blksz,
                         middle,
                         &pxp->bf_cnt,
                         &pxp->pos);
                  if(status != ENOERR)
                        return status;
                  pxp->bf_extent = 2 * pxp->blksz;
                  pxp->bf_cnt += pxp->blksz;
            }
            goto done;
      }
      /* else */

      if(pxp->bf_extent > pxp->blksz
             && blkoffset == pxp->bf_offset + pxp->blksz)
      {
            /* hit in upper half */
            if(blkextent == pxp->blksz)
            {
                  /* all in upper half, no fault needed */
                  diff += pxp->blksz;
                  goto done;
            }
            /* else */
            if(pxp->bf_cnt > pxp->blksz)
            {
                  /* data in upper half */
                  void *const middle =
                        (void *)((char *)pxp->bf_base + pxp->blksz);
                  assert(pxp->bf_extent == 2 * pxp->blksz);
                  if(fIsSet(pxp->bf_rflags, RGN_MODIFIED))
                  {
                        /* page out lower half */
                        assert(pxp->bf_refcount <= 0);
                        status = px_pgout(nciop,
                              pxp->bf_offset,
                              pxp->blksz,
                              pxp->bf_base,
                              &pxp->pos);
                        if(status != ENOERR)
                              return status;
                  }
                  pxp->bf_cnt -= pxp->blksz;
                  /* copy upper half into lower half */
                  (void) memcpy(pxp->bf_base, middle, pxp->bf_cnt);
            }
            pxp->bf_offset = blkoffset;
            /* pxp->bf_extent = pxp->blksz; */

            assert(blkextent == 2 * pxp->blksz);
            {
                  /* page in upper */
                  void *const middle =
                        (void *)((char *)pxp->bf_base + pxp->blksz);
                  status = px_pgin(nciop,
                         pxp->bf_offset + (off_t)pxp->blksz,
                         pxp->blksz,
                         middle,
                         &pxp->bf_cnt,
                         &pxp->pos);
                  if(status != ENOERR)
                        return status;
                  pxp->bf_extent = 2 * pxp->blksz;
                  pxp->bf_cnt += pxp->blksz;
            }
            goto done;
      }
      /* else */

      if(blkoffset == pxp->bf_offset - pxp->blksz)
      {
            /* wants the page below */
            void *const middle =
                  (void *)((char *)pxp->bf_base + pxp->blksz);
            size_t upper_cnt = 0;
            if(pxp->bf_cnt > pxp->blksz)
            {
                  /* data in upper half */
                  assert(pxp->bf_extent == 2 * pxp->blksz);
                  if(fIsSet(pxp->bf_rflags, RGN_MODIFIED))
                  {
                        /* page out upper half */
                        assert(pxp->bf_refcount <= 0);
                        status = px_pgout(nciop,
                              pxp->bf_offset + (off_t)pxp->blksz,
                              pxp->bf_cnt - pxp->blksz,
                              middle,
                              &pxp->pos);
                        if(status != ENOERR)
                              return status;
                  }
                  pxp->bf_cnt = pxp->blksz;
                  pxp->bf_extent = pxp->blksz;
            }
            if(pxp->bf_cnt > 0)
            {
                  /* copy lower half into upper half */
                  (void) memcpy(middle, pxp->bf_base, pxp->blksz);
                  upper_cnt = pxp->bf_cnt;
            }
            /* read page below into lower half */
            status = px_pgin(nciop,
                   blkoffset,
                   pxp->blksz,
                   pxp->bf_base,
                   &pxp->bf_cnt,
                   &pxp->pos);
            if(status != ENOERR)
                  return status;
            pxp->bf_offset = blkoffset;
            if(upper_cnt != 0)
            {
                  pxp->bf_extent = 2 * pxp->blksz;
                  pxp->bf_cnt = pxp->blksz + upper_cnt;
            }
            else
            {
                  pxp->bf_extent = pxp->blksz;
            }
            goto done;
      }
      /* else */

      /* no overlap */
      if(fIsSet(pxp->bf_rflags, RGN_MODIFIED))
      {
            assert(pxp->bf_refcount <= 0);
            status = px_pgout(nciop,
                  pxp->bf_offset,
                  pxp->bf_cnt,
                  pxp->bf_base,
                  &pxp->pos);
            if(status != ENOERR)
                  return status;
            pxp->bf_rflags = 0;
      }

pgin:
      status = px_pgin(nciop,
             blkoffset,
             blkextent,
             pxp->bf_base,
             &pxp->bf_cnt,
             &pxp->pos);
      if(status != ENOERR)
            return status;
       pxp->bf_offset = blkoffset;
       pxp->bf_extent = blkextent;

done:
      extent += diff;
      if(pxp->bf_cnt < extent)
            pxp->bf_cnt = extent;
      assert(pxp->bf_cnt <= pxp->bf_extent);

      pxp->bf_rflags |= rflags;
      pxp->bf_refcount++;

      *vpp = (char *)pxp->bf_base + diff;
      return ENOERR;
}

static int
ncio_px_get(ncio *const nciop, 
            off_t offset, size_t extent,
            int rflags,
            void **const vpp) /* NULL => force read */
{
      ncio_px *const pxp = (ncio_px *)nciop->pvt;
      
      if(fIsSet(rflags, RGN_WRITE) && !fIsSet(nciop->ioflags, NC_WRITE))
            return EPERM; /* attempt to write readonly file */

      /*
         * If the base of the stream buffer is NULL, then a read is forced
         * for synchronization purposes (see fault_v1hs() in v1hpg.c).  The
         * implementation is based on ncio_spx_rel() in this file.
       */
      if (*vpp == NULL)
      {
          ncio_px_sync(nciop);
          pxp->bf_offset = OFF_NONE;
          pxp->bf_cnt = 0;
      }

      /* reclaim space used in move */
      if(pxp->slave != NULL)
      {
            if(pxp->slave->bf_base != NULL)
            {
                  free(pxp->slave->bf_base);
                  pxp->slave->bf_base = NULL;
                  pxp->slave->bf_extent = 0;
                  pxp->slave->bf_offset = OFF_NONE;
            }
            free(pxp->slave);
            pxp->slave = NULL;
      }
      return px_get(nciop, pxp, offset, extent, rflags, vpp);
}


/* ARGSUSED */
static int
px_double_buffer(ncio *const nciop, off_t to, off_t from,
                  size_t nbytes, int rflags)
{
      ncio_px *const pxp = (ncio_px *)nciop->pvt;
      int status = ENOERR;
      void *src;
      void *dest;
      
#if INSTRUMENT
fprintf(stderr, "\tdouble_buffr %ld %ld %ld\n",
             (long)to, (long)from, (long)nbytes);
#endif
      status = px_get(nciop, pxp, to, nbytes, RGN_WRITE,
                  &dest);
      if(status != ENOERR)
            return status;

      if(pxp->slave == NULL)
      {
            pxp->slave = (ncio_px *) malloc(sizeof(ncio_px));
            if(pxp->slave == NULL)
                  return ENOMEM;

            pxp->slave->blksz = pxp->blksz;
            /* pos done below */
            pxp->slave->bf_offset = pxp->bf_offset; 
            pxp->slave->bf_extent = pxp->bf_extent;
            pxp->slave->bf_cnt = pxp->bf_cnt;
            pxp->slave->bf_base = malloc(2 * pxp->blksz);
            if(pxp->slave->bf_base == NULL)
                  return ENOMEM;
            (void) memcpy(pxp->slave->bf_base, pxp->bf_base,
                   pxp->bf_extent);
            pxp->slave->bf_rflags = 0;
            pxp->slave->bf_refcount = 0;
            pxp->slave->slave = NULL;
      }
      
      pxp->slave->pos = pxp->pos;
      status = px_get(nciop, pxp->slave, from, nbytes, 0,
                  &src);
      if(status != ENOERR)
            return status;
      if(pxp->pos != pxp->slave->pos)
      {
            /* position changed, sync */
            pxp->pos = pxp->slave->pos;
      }

      (void) memcpy(dest, src, nbytes);

      (void)px_rel(pxp->slave, from, 0);
      (void)px_rel(pxp, to, RGN_MODIFIED);
      
      return status;
}

static int
ncio_px_move(ncio *const nciop, off_t to, off_t from,
                  size_t nbytes, int rflags)
{
      ncio_px *const pxp = (ncio_px *)nciop->pvt;
      int status = ENOERR;
      off_t lower;      
      off_t upper;
      char *base;
      size_t diff;
      size_t extent;

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

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

      if(to > from)
      {
            /* growing */
            lower = from;     
            upper = to;
      }
      else
      {
            /* shrinking */
            lower = to;
            upper = from;
      }
      diff = (size_t)(upper - lower);
      extent = diff + nbytes;

#if INSTRUMENT
fprintf(stderr, "ncio_px_move %ld %ld %ld %ld %ld\n",
             (long)to, (long)from, (long)nbytes, (long)lower, (long)extent);
#endif
      if(extent > pxp->blksz)
      {
            size_t remaining = nbytes;

if(to > from)
{
            off_t frm = from + nbytes;
            off_t toh = to + nbytes;
            for(;;)
            {
                  size_t loopextent = MIN(remaining, pxp->blksz);
                  frm -= loopextent;
                  toh -= loopextent;

                  status = px_double_buffer(nciop, toh, frm,
                              loopextent, rflags) ;
                  if(status != ENOERR)
                        return status;
                  remaining -= loopextent;

                  if(remaining == 0)
                        break; /* normal loop exit */
            }
}
else
{
            for(;;)
            {
                  size_t loopextent = MIN(remaining, pxp->blksz);

                  status = px_double_buffer(nciop, to, from,
                              loopextent, rflags) ;
                  if(status != ENOERR)
                        return status;
                  remaining -= loopextent;

                  if(remaining == 0)
                        break; /* normal loop exit */
                  to += loopextent;
                  from += loopextent;
            }
}
            return ENOERR;
      }
      
#if INSTRUMENT
fprintf(stderr, "\tncio_px_move small\n");
#endif
      status = px_get(nciop, pxp, lower, extent, RGN_WRITE|rflags,
                  (void **)&base);

      if(status != ENOERR)
            return status;

      if(to > from)
            (void) memmove(base + diff, base, nbytes); 
      else
            (void) memmove(base, base + diff, nbytes); 
            
      (void) px_rel(pxp, lower, RGN_MODIFIED);

      return status;
}


static int
ncio_px_sync(ncio *const nciop)
{
      ncio_px *const pxp = (ncio_px *)nciop->pvt;
      int status = ENOERR;
      if(fIsSet(pxp->bf_rflags, RGN_MODIFIED))
      {
            assert(pxp->bf_refcount <= 0);
            status = px_pgout(nciop, pxp->bf_offset,
                  pxp->bf_cnt,
                  pxp->bf_base, &pxp->pos);
            if(status != ENOERR)
                  return status;
            pxp->bf_rflags = 0;
      }
      return status;
}

static void
ncio_px_free(void *const pvt)
{
      ncio_px *const pxp = (ncio_px *)pvt;
      if(pxp == NULL)
            return;

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


static int
ncio_px_init2(ncio *const nciop, size_t *sizehintp, int isNew)
{
      ncio_px *const pxp = (ncio_px *)nciop->pvt;
      const size_t bufsz = 2 * *sizehintp;

      assert(nciop->fd >= 0);

      pxp->blksz = *sizehintp;

      assert(pxp->bf_base == NULL);

      /* this is separate allocation because it may grow */
      pxp->bf_base = malloc(bufsz);
      if(pxp->bf_base == NULL)
            return ENOMEM;
      /* else */
      pxp->bf_cnt = 0;
      if(isNew)
      {
            /* save a read */
            pxp->pos = 0;
            pxp->bf_offset = 0;
            pxp->bf_extent = bufsz;
            (void) memset(pxp->bf_base, 0, pxp->bf_extent);
      }
      return ENOERR;
}


static void
ncio_px_init(ncio *const nciop)
{
      ncio_px *const pxp = (ncio_px *)nciop->pvt;

      *((ncio_relfunc **)&nciop->rel) = ncio_px_rel; /* cast away const */
      *((ncio_getfunc **)&nciop->get) = ncio_px_get; /* cast away const */
      *((ncio_movefunc **)&nciop->move) = ncio_px_move; /* cast away const */
      *((ncio_syncfunc **)&nciop->sync) = ncio_px_sync; /* cast away const */
      *((ncio_freefunc **)&nciop->free) = ncio_px_free; /* cast away const */

      pxp->blksz = 0;
      pxp->pos = -1;
      pxp->bf_offset = OFF_NONE;
      pxp->bf_extent = 0;
      pxp->bf_rflags = 0;
      pxp->bf_refcount = 0;
      pxp->bf_base = NULL;
      pxp->slave = NULL;

}

/* Begin spx */

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


/*ARGSUSED*/
static int
ncio_spx_rel(ncio *const nciop, off_t offset, int rflags)
{
      ncio_spx *const pxp = (ncio_spx *)nciop->pvt;
      int status = ENOERR;

      assert(pxp->bf_offset <= offset);
      assert(pxp->bf_cnt != 0);
      assert(pxp->bf_cnt <= pxp->bf_extent);
#ifdef X_ALIGN
      assert(offset < pxp->bf_offset + X_ALIGN);
      assert(pxp->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 = px_pgout(nciop, pxp->bf_offset,
                  pxp->bf_cnt,
                  pxp->bf_base, &pxp->pos);
            /* if error, invalidate buffer anyway */
      }
      pxp->bf_offset = OFF_NONE;
      pxp->bf_cnt = 0;
      return status;
}


static int
ncio_spx_get(ncio *const nciop,
            off_t offset, size_t extent,
            int rflags,
            void **const vpp)
{
      ncio_spx *const pxp = (ncio_spx *)nciop->pvt;
      int status = ENOERR;
#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(offset < X_INT_MAX); /* sanity check */

      assert(pxp->bf_cnt == 0);

#ifdef X_ALIGN
      rem = (size_t)(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(pxp->bf_extent < extent)
      {
            if(pxp->bf_base != NULL)
            {
                  free(pxp->bf_base);
                  pxp->bf_base = NULL;
                  pxp->bf_extent = 0;
            }
            assert(pxp->bf_extent == 0);
            pxp->bf_base = malloc(extent);
            if(pxp->bf_base == NULL)
                  return ENOMEM;
            pxp->bf_extent = extent;
      }

      status = px_pgin(nciop, offset,
             extent,
             pxp->bf_base,
             &pxp->bf_cnt, &pxp->pos);
      if(status != ENOERR)
            return status;

      pxp->bf_offset = offset;

      if(pxp->bf_cnt < extent)
            pxp->bf_cnt = extent;

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


#if 0
/*ARGSUSED*/
static int
strategy(ncio *const nciop, off_t to, off_t offset,
                  size_t extent, int rflags)
{
      static ncio_spx pxp[1];
      int status = ENOERR;
#ifdef X_ALIGN
      size_t rem;
#endif
      
      assert(extent != 0);
      assert(extent < X_INT_MAX); /* sanity check */
      assert(offset < X_INT_MAX); /* sanity check */
#if INSTRUMENT
fprintf(stderr, "strategy %ld at %ld to %ld\n",
       (long)extent, (long)offset, (long)to);
#endif


#ifdef X_ALIGN
      rem = (size_t)(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(pxp->bf_extent < extent)
      {
            if(pxp->bf_base != NULL)
            {
                  free(pxp->bf_base);
                  pxp->bf_base = NULL;
                  pxp->bf_extent = 0;
            }
            assert(pxp->bf_extent == 0);
            pxp->bf_base = malloc(extent);
            if(pxp->bf_base == NULL)
                  return ENOMEM;
            pxp->bf_extent = extent;
      }

      status = px_pgin(nciop, offset,
             extent,
             pxp->bf_base,
             &pxp->bf_cnt, &pxp->pos);
      if(status != ENOERR)
            return status;

      pxp->bf_offset = to; /* TODO: XALIGN */
      
      if(pxp->bf_cnt < extent)
            pxp->bf_cnt = extent;

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

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

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

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

      diff = (size_t)(upper - lower);
      extent = diff + nbytes;

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

      if(status != ENOERR)
            return status;

      if(to > from)
            (void) memmove(base + diff, base, nbytes); 
      else
            (void) memmove(base, base + diff, nbytes); 
            
      (void) ncio_spx_rel(nciop, lower, RGN_MODIFIED);

      return status;
}


/*ARGSUSED*/
static int
ncio_spx_sync(ncio *const nciop)
{
      /* NOOP */
      return ENOERR;
}

static void
ncio_spx_free(void *const pvt)
{
      ncio_spx *const pxp = (ncio_spx *)pvt;
      if(pxp == NULL)
            return;

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


static int
ncio_spx_init2(ncio *const nciop, const size_t *const sizehintp)
{
      ncio_spx *const pxp = (ncio_spx *)nciop->pvt;

      assert(nciop->fd >= 0);

      pxp->bf_extent = *sizehintp;

      assert(pxp->bf_base == NULL);

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


static void
ncio_spx_init(ncio *const nciop)
{
      ncio_spx *const pxp = (ncio_spx *)nciop->pvt;

      *((ncio_relfunc **)&nciop->rel) = ncio_spx_rel; /* cast away const */
      *((ncio_getfunc **)&nciop->get) = ncio_spx_get; /* cast away const */
      *((ncio_movefunc **)&nciop->move) = ncio_spx_move; /* cast away const */
      *((ncio_syncfunc **)&nciop->sync) = ncio_spx_sync; /* cast away const */
      *((ncio_freefunc **)&nciop->free) = ncio_spx_free; /* cast away const */

      pxp->pos = -1;
      pxp->bf_offset = OFF_NONE;
      pxp->bf_extent = 0;
      pxp->bf_cnt = 0;
      pxp->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))
            sz_ncio_pvt = sizeof(ncio_spx);
      else
            sz_ncio_pvt = sizeof(ncio_px);

      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);

      if(fIsSet(ioflags, NC_SHARE))
            ncio_spx_init(nciop);
      else
            ncio_px_init(nciop);

      return nciop;
}


/* Public below this point */

#define NCIO_MINBLOCKSIZE 256
#define NCIO_MAXBLOCKSIZE 268435456 /* sanity check, about X_SIZE_T_MAX/8 */

#ifdef S_IRUSR
#define NC_DEFAULT_CREAT_MODE \
        (S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH) /* 0666 */

#else
#define NC_DEFAULT_CREAT_MODE 0666
#endif

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;
      int oflags = (O_RDWR|O_CREAT);
      int fd;
      int status;

      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(fIsSet(ioflags, NC_NOCLOBBER))
            fSet(oflags, O_EXCL);
      else
            fSet(oflags, O_TRUNC);
#ifdef O_BINARY
      fSet(oflags, O_BINARY);
#endif
#ifdef vms
      fd = open(path, oflags, NC_DEFAULT_CREAT_MODE, "ctx=stm");
#else
      /* Should we mess with the mode based on NC_SHARE ?? */
      fd = open(path, oflags, NC_DEFAULT_CREAT_MODE);
#endif
#if 0
      (void) fprintf(stderr, "ncio_create(): path=\"%s\"\n", path);
      (void) fprintf(stderr, "ncio_create(): oflags=0x%x\n", oflags);
#endif
      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);
      }

      if(fIsSet(nciop->ioflags, NC_SHARE))
            status = ncio_spx_init2(nciop, sizehintp);
      else
            status = ncio_px_init2(nciop, sizehintp, 1);

      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) close(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;
      int oflags = fIsSet(ioflags, NC_WRITE) ? O_RDWR : O_RDONLY;
      int fd;
      int status;

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

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

#ifdef O_BINARY
      fSet(oflags, O_BINARY);
#endif
#ifdef vms
      fd = open(path, oflags, 0, "ctx=stm");
#else
      fd = open(path, oflags, 0);
#endif
      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);
      }

      if(fIsSet(nciop->ioflags, NC_SHARE))
            status = ncio_spx_init2(nciop, sizehintp);
      else
            status = ncio_px_init2(nciop, sizehintp, 0);

      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) close(fd);
      /*FALLTHRU*/
unwind_new:
      ncio_free(nciop);
      return status;
}


int 
ncio_close(ncio *nciop, int doUnlink)
{
      int status = ENOERR;

      if(nciop == NULL)
            return EINVAL;

      status = nciop->sync(nciop);

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

      ncio_free(nciop);

      return status;
}

Generated by  Doxygen 1.6.0   Back to index