import newlib-2000-02-17 snapshot

newlib/libc/stdio/fvwrite.c

@@ -0,0 +1,195 @@
+/* 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;
+}