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/* No user fns here.  Pesch 15apr92. */

/*

 * Copyright (c) 1990 The Regents of the University of California.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms are permitted

 * provided that the above copyright notice and this paragraph are

 * duplicated in all such forms and that any documentation,

 * advertising materials, and other materials related to such

 * distribution and use acknowledge that the software was developed

 * by the University of California, Berkeley.  The name of the

 * University may not be used to endorse or promote products derived

 * from this software without specific prior written permission.

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

 */

#include <stdio.h>

#include <string.h>

#include "local.h"

#include "fvwrite.h"

#define MIN(a, b) ((a) < (b) ? (a) : (b))

#define COPY(n)   (void) memmove((void *) fp->_p, (void *) p, (size_t) (n))

#define GETIOV(extra_work) \

  while (len == 0) \

    { \

      extra_work; \

      p = iov->iov_base; \

      len = iov->iov_len; \

      iov++; \

    }

/*

 * Write some memory regions.  Return zero on success, EOF on error.

 *

 * This routine is large and unsightly, but most of the ugliness due

 * to the three different kinds of output buffering is handled here.

 */

int

__sfvwrite (fp, uio)

     register FILE *fp;

     register struct __suio *uio;

{

  register size_t len;

  register _CONST char *p;

  register struct __siov *iov;

  register int w, s;

  char *nl;

  int nlknown, nldist;

  if ((len = uio->uio_resid) == 0)

    return 0;

  /* make sure we can write */

  if (cantwrite (fp))

    return EOF;

  iov = uio->uio_iov;

  len = 0;

  if (fp->_flags & __SNBF)

    {

      /*

       * Unbuffered: write up to BUFSIZ bytes at a time.

       */

      do

        {

          GETIOV (;);

          w = (*fp->_write) (fp->_cookie, p, MIN (len, BUFSIZ));

          if (w <= 0)

            goto err;

          p += w;

          len -= w;

        }

      while ((uio->uio_resid -= w) != 0);

    }

  else if ((fp->_flags & __SLBF) == 0)

    {

      /*

       * Fully buffered: fill partially full buffer, if any,

       * and then flush.  If there is no partial buffer, write

       * one _bf._size byte chunk directly (without copying).

       *

       * String output is a special case: write as many bytes

       * as fit, but pretend we wrote everything.  This makes

       * snprintf() return the number of bytes needed, rather

       * than the number used, and avoids its write function

       * (so that the write function can be invalid).

       */

      do

        {

          GETIOV (;);

          w = fp->_w;

          if (fp->_flags & __SSTR)

            {

              if (len < w)

                w = len;

              COPY (w);         /* copy MIN(fp->_w,len), */

              fp->_w -= w;

              fp->_p += w;

              w = len;          /* but pretend copied all */

            }

          else if (fp->_p > fp->_bf._base && len > w)

            {

              /* fill and flush */

              COPY (w);

              /* fp->_w -= w; *//* unneeded */

              fp->_p += w;

              if (fflush (fp))

                goto err;

            }

          else if (len >= (w = fp->_bf._size))

            {

              /* write directly */

              w = (*fp->_write) (fp->_cookie, p, w);

              if (w <= 0)

                goto err;

            }

          else

            {

              /* fill and done */

              w = len;

              COPY (w);

              fp->_w -= w;

              fp->_p += w;

            }

          p += w;

          len -= w;

        }

      while ((uio->uio_resid -= w) != 0);

    }

  else

    {

      /*

       * Line buffered: like fully buffered, but we

       * must check for newlines.  Compute the distance

       * to the first newline (including the newline),

       * or `infinity' if there is none, then pretend

       * that the amount to write is MIN(len,nldist).

       */

      nlknown = 0;

      do

        {

          GETIOV (nlknown = 0);

          if (!nlknown)

            {

              nl = memchr ((void *) p, '\n', len);

              nldist = nl ? nl + 1 - p : len + 1;

              nlknown = 1;

            }

          s = MIN (len, nldist);

          w = fp->_w + fp->_bf._size;

          if (fp->_p > fp->_bf._base && s > w)

            {

              COPY (w);

              /* fp->_w -= w; */

              fp->_p += w;

              if (fflush (fp))

                goto err;

            }

          else if (s >= (w = fp->_bf._size))

            {

              w = (*fp->_write) (fp->_cookie, p, w);

              if (w <= 0)

                goto err;

            }

          else

            {

              w = s;

              COPY (w);

              fp->_w -= w;

              fp->_p += w;

            }

          if ((nldist -= w) == 0)

            {

              /* copied the newline: flush and forget */

              if (fflush (fp))

                goto err;

              nlknown = 0;

            }

          p += w;

          len -= w;

        }

      while ((uio->uio_resid -= w) != 0);

    }

  return 0;

err:

  fp->_flags |= __SERR;

  return EOF;

}