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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /stdio/fwrite.c
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initial import
Diffstat (limited to 'stdio/fwrite.c')
-rw-r--r--stdio/fwrite.c208
1 files changed, 208 insertions, 0 deletions
diff --git a/stdio/fwrite.c b/stdio/fwrite.c
new file mode 100644
index 0000000000..4d012f1779
--- /dev/null
+++ b/stdio/fwrite.c
@@ -0,0 +1,208 @@
+/* Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB.  If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA.  */
+
+#include <ansidecl.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+
+
+/* Write NMEMB chunks of SIZE bytes each from PTR onto STREAM.  */
+size_t
+DEFUN(fwrite, (ptr, size, nmemb, stream),
+      CONST PTR ptr AND size_t size AND
+      size_t nmemb AND register FILE *stream)
+{
+  register CONST unsigned char *p = (CONST unsigned char *) ptr;
+  register size_t to_write = size * nmemb;
+  register size_t written = 0;
+  int newlinep;
+  size_t buffer_space;
+  int default_func;
+
+  if (!__validfp (stream) || !stream->__mode.__write)
+    {
+      errno = EINVAL;
+      return 0;
+    }
+
+  if (ferror (stream))
+    return 0;
+  if (p == NULL || to_write == 0)
+    return 0;
+
+  if (!stream->__seen || stream->__put_limit == stream->__buffer)
+    {
+      /* This stream has never been seen before.
+	 Calling __flshfp will give it a buffer
+	 and I/O functions if it needs them.  */
+      if (__flshfp (stream, *p++) == EOF)
+	return 0;
+      if (--to_write == 0)
+	return 1;
+      else
+	++written;
+    }
+
+  default_func
+    = stream->__room_funcs.__output == __default_room_functions.__output;
+
+  {
+    int save = errno;
+
+    if (__stdio_check_offset (stream) == EOF && errno != ESPIPE)
+      {
+	stream->__error = 1;
+	goto done;
+      }
+
+    errno = save;
+  }
+
+  if (stream->__buffer == NULL && default_func &&
+      stream->__offset == stream->__target)
+  write_through:
+    /* This is an unbuffered stream using the standard output
+       buffer-flushing function, so we just do a straight write.  */
+    {
+      int count = (stream->__io_funcs.__write == NULL ? to_write :
+		   (*stream->__io_funcs.__write) (stream->__cookie,
+						  (CONST char *) p,
+						  to_write));
+      if (count > 0)
+	{
+	  written += count;
+	  if (stream->__offset != -1)
+	    {
+	      stream->__offset += count;
+	      stream->__target = stream->__offset;
+	    }
+	  to_write -= count;
+	  p += count;
+	}
+      else
+	stream->__error = 1;
+      goto done;
+    }
+
+  /* We ignore the end pointer here since we want to find out how much space
+     is really in the buffer, even for a line-buffered stream.  */
+  buffer_space = stream->__bufsize - (stream->__bufp - stream->__buffer);
+
+  newlinep = (stream->__linebuf &&
+	      memchr ((CONST PTR) p, '\n', to_write) != NULL);
+
+  if (newlinep && stream->__bufp == stream->__buffer &&
+      stream->__offset == stream->__target)
+    /* The buffer's empty, and we want to write our data
+       out soon anyway, so just write it straight out.  */
+    goto write_through;
+
+  if (stream->__bufsize == 0 && !default_func)
+    {
+      /* No buffer, and a special function.
+	 We can't do much better than putc.  */
+      while (to_write-- > 0)
+	{
+	  if (__flshfp (stream, *p++) == EOF)
+	    break;
+	  else
+	    ++written;
+	}
+    }
+  else if (!default_func || buffer_space >= to_write)
+  fill_buffer:
+    /* There is enough room in the buffer for everything we
+       want to write or the user has specified his own output
+       buffer-flushing/expanding function.  */
+    while (to_write > 0)
+      {
+	register size_t n = to_write;
+
+	if (n > buffer_space)
+	  n = buffer_space;
+
+	buffer_space -= n;
+
+	written += n;
+	to_write -= n;
+
+	if (n < 20)
+	  while (n-- > 0)
+	    *stream->__bufp++ = *p++;
+	else
+	  {
+	    memcpy ((PTR) stream->__bufp, (PTR) p, n);
+	    stream->__bufp += n;
+	    p += n;
+	  }
+
+	if (buffer_space == 0 || (to_write == 0 && newlinep))
+	  {
+	    /* We've filled the buffer, so flush it.  */
+	    if (fflush (stream) == EOF)
+	      break;
+
+	    /* Reset our record of the space available in the buffer,
+	       since we have just flushed it.  */
+	  check_space:
+	    buffer_space = (stream->__bufsize -
+			    (stream->__bufp - stream->__buffer));
+	    if (buffer_space == 0)
+	      {
+		/* With a custom output-room function, flushing might
+		   not create any buffer space.  Try writing a single
+		   character to create the space.  */
+		if (__flshfp (stream, *p++) == EOF)
+		  goto done;
+		++written;
+		--to_write;
+		goto check_space;
+	      }
+	  }
+      }
+  else
+    {
+      /* It won't all fit in the buffer.  */
+
+      if (stream->__bufp != stream->__buffer)
+	{
+	  /* There are characters in the buffer.  Flush them.  */
+	  if (__flshfp (stream, EOF) == EOF)
+	    goto done;
+	}
+
+      /* The buffer has been flushed.
+	 Now either fill it or write directly.  */
+
+      buffer_space = stream->__bufsize - (stream->__bufp - stream->__buffer);
+
+      if (stream->__offset == stream->__target &&
+	  (buffer_space < to_write || newlinep))
+	/* What we have to write is bigger than the buffer,
+	   or it contains a newline and we're line-buffered,
+	   so write it out.  */
+	goto write_through;
+      else
+	/* It will fit in the buffer.  */
+	goto fill_buffer;
+    }
+
+ done:;
+  return (size_t) written / size;
+}