iostream.c

一个类似windows

/*
 * I/O streams.
 * Copyright (c) 1998 New Generation Software (NGS) Oy
 *
 * Author: Markku Rossi <[e-mail]>
 */

/*
 * This 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.
 *
 * This 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 this library; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA
 */

/*
 * $Source: /cygdrive/c/RCVS/CVS/ReactOS/reactos/lib/kjs/ksrc/iostream.c,v $
 * $Id: iostream.c 21681 2006-04-21 15:00:24Z peterw $
 */

#include "jsint.h"

/*
 * Types and definitions.
 */

#define DEFAULT_BUFFER_SIZE 4096

/*
 * Global functions.
 */

JSIOStream *
js_iostream_new ()
{
  JSIOStream *stream;

  stream = js_calloc (NULL, 1, sizeof (*stream));
  if (stream == NULL)
    return NULL;

  stream->buflen = DEFAULT_BUFFER_SIZE;
  stream->buffer = js_malloc (NULL, stream->buflen);
  if (stream->buffer == NULL)
    {
      js_free (stream);
      return NULL;
    }

  return stream;
}

size_t
js_iostream_read (JSIOStream *stream, void *ptr, size_t size)
{
  size_t total = 0;
  int got;

  if (stream->writep)
    {
      /* We have buffered output data. */
      if (js_iostream_flush (stream) == EOF)
	return 0;

      assert (stream->writep == 0);
    }

  while (size > 0)
    {
      /* First, take everything from the buffer. */
      if (stream->bufpos < stream->data_in_buf)
	{
	  got = stream->data_in_buf - stream->bufpos;

	  if (size < got)
	    got = size;

	  memcpy (ptr, stream->buffer + stream->bufpos, got);

	  stream->bufpos += got;
	  size -= got;
	  ptr = (void *)((unsigned char *)ptr + got);
	  total += got;
	}
      else
	{
	  if (stream->at_eof)
	    /* EOF seen, can't read more. */
	    break;

	  js_iostream_fill_buffer (stream);
	}
    }

  return total;
}


size_t
js_iostream_write (JSIOStream *stream, void *ptr, size_t size)
{
  int i;

  for( i = 0; size > i; i++ )
    DbgPrint("%c", ((char *)ptr)[i]);

  return i;
}


int
js_iostream_flush (JSIOStream *stream)
{
  return 0;
}

int
js_iostream_unget (JSIOStream *stream, int byte)
{
  return 0;
}

int
js_iostream_close (JSIOStream *stream)
{
  int result = 0;

  if (stream == NULL)
    return result;

  if (js_iostream_flush (stream) == EOF)
    result = EOF;

  if (stream->close)
    (*stream->close) (stream->context);

  js_free (stream->buffer);
  js_free (stream);

  return result;
}


int
js_iostream_seek (JSIOStream *stream, long offset, int whence)
{
  int result;

  if (js_iostream_flush (stream) == EOF)
    return -1;

  result = (*stream->seek) (stream->context, offset, whence);
  if (result == 0)
    /* Successful.  Clear the eof flag. */
    stream->at_eof = 0;

  return result;
}


long
js_iostream_get_position (JSIOStream *stream)
{
  long pos;

  /* Flush the possible buffered output. */
  if (js_iostream_flush (stream) == EOF)
    return -1;

  pos = (*stream->get_position) (stream->context);
  if (pos < 0)
    return pos;

  /*
   * The logical position if at <bufpos>, the context's idea is at
   * <data_in_buf>.  Adjust.
   */
  return pos - (stream->data_in_buf - stream->bufpos);
}


long
js_iostream_get_length (JSIOStream *stream)
{
  /* Flush the possible buffered output. */
  if (js_iostream_flush (stream) == EOF)
    return -1;

  return (*stream->get_length) (stream->context);
}


void
js_iostream_fill_buffer (JSIOStream *stream)
{
  if (stream->read == NULL)
    {
      stream->at_eof = 1;
      return;
    }

  stream->data_in_buf = (*stream->read) (stream->context, stream->buffer,
					 stream->buflen, &stream->error);
  stream->bufpos = 0;
  if (stream->data_in_buf == 0)
    stream->at_eof = 1;
}