Return to compress.c CVS log

Up to [local] / src / usr.bin / ssh

i bet a lot of people didn't know what ssh 1.2.16 had a nice license.
well, except for the patent issues.  someone in sweden (forget their
name at the moment) cleaned out most of the patented code, and now
this code removes rsa code.  when this is done, it will link against
libssl, but the work isn't completely done yet.  then we need to bring
this up to modern days, featurewise.

/*

compress.c

Author: Tatu Ylonen <ylo@cs.hut.fi>

Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
                   All rights reserved

Created: Wed Oct 25 22:12:46 1995 ylo

Interface to packet compression for ssh.

*/

#include "includes.h"
RCSID("$Id: compress.c,v 1.1 1999/09/26 20:53:34 deraadt Exp $");

#include "ssh.h"
#include "buffer.h"
#include "zlib.h"

static z_stream incoming_stream;
static z_stream outgoing_stream;

/* Initializes compression; level is compression level from 1 to 9 (as in
   gzip). */

void buffer_compress_init(int level)
{
  debug("Enabling compression at level %d.", level);
  if (level < 1 || level > 9)
    fatal("Bad compression level %d.", level);
  inflateInit(&incoming_stream);
  deflateInit(&outgoing_stream, level);
}

/* Frees any data structures allocated for compression. */

void buffer_compress_uninit()
{
  debug("compress outgoing: raw data %lu, compressed %lu, factor %.2f",
	outgoing_stream.total_in, outgoing_stream.total_out,
	outgoing_stream.total_in == 0 ? 0.0 :
	 (double)outgoing_stream.total_out / outgoing_stream.total_in);
  debug("compress incoming: raw data %lu, compressed %lu, factor %.2f",
	incoming_stream.total_out, incoming_stream.total_in,
	incoming_stream.total_out == 0 ? 0.0 :
	  (double)incoming_stream.total_in / incoming_stream.total_out);
  inflateEnd(&incoming_stream);
  deflateEnd(&outgoing_stream);
}

/* Compresses the contents of input_buffer into output_buffer.  All
   packets compressed using this function will form a single
   compressed data stream; however, data will be flushed at the end of
   every call so that each output_buffer can be decompressed
   independently (but in the appropriate order since they together
   form a single compression stream) by the receiver.  This appends
   the compressed data to the output buffer. */

void buffer_compress(Buffer *input_buffer, Buffer *output_buffer)
{
  char buf[4096];
  int status;

  /* This case is not handled below. */
  if (buffer_len(input_buffer) == 0)
    return;

  /* Input is the contents of the input buffer. */
  outgoing_stream.next_in = buffer_ptr(input_buffer);
  outgoing_stream.avail_in = buffer_len(input_buffer);

  /* Loop compressing until deflate() returns with avail_out != 0. */
  do
    {
      /* Set up fixed-size output buffer. */
      outgoing_stream.next_out = buf;
      outgoing_stream.avail_out = sizeof(buf);

      /* Compress as much data into the buffer as possible. */
      status = deflate(&outgoing_stream, Z_PARTIAL_FLUSH);
      switch (status)
	{
	case Z_OK:
	  /* Append compressed data to output_buffer. */
	  buffer_append(output_buffer, buf,
			sizeof(buf) - outgoing_stream.avail_out);
	  break;
	case Z_STREAM_END:
	  fatal("buffer_compress: deflate returned Z_STREAM_END");
	  /*NOTREACHED*/
	case Z_STREAM_ERROR:
	  fatal("buffer_compress: deflate returned Z_STREAM_ERROR");
	  /*NOTREACHED*/
	case Z_BUF_ERROR:
	  fatal("buffer_compress: deflate returned Z_BUF_ERROR");
	  /*NOTREACHED*/
	default:
	  fatal("buffer_compress: deflate returned %d", status);
	  /*NOTREACHED*/
	}
    }
  while (outgoing_stream.avail_out == 0);
}

/* Uncompresses the contents of input_buffer into output_buffer.  All
   packets uncompressed using this function will form a single
   compressed data stream; however, data will be flushed at the end of
   every call so that each output_buffer.  This must be called for the
   same size units that the buffer_compress was called, and in the
   same order that buffers compressed with that.  This appends the
   uncompressed data to the output buffer. */

void buffer_uncompress(Buffer *input_buffer, Buffer *output_buffer)
{
  char buf[4096];
  int status;

  incoming_stream.next_in = buffer_ptr(input_buffer);
  incoming_stream.avail_in = buffer_len(input_buffer);

  incoming_stream.next_out = buf;
  incoming_stream.avail_out = sizeof(buf);

  for (;;)
    {
      status = inflate(&incoming_stream, Z_PARTIAL_FLUSH);
      switch (status)
	{
	case Z_OK:
	  buffer_append(output_buffer, buf,
			sizeof(buf) - incoming_stream.avail_out);
	  incoming_stream.next_out = buf;
	  incoming_stream.avail_out = sizeof(buf);
	  break;
	case Z_STREAM_END:
	  fatal("buffer_uncompress: inflate returned Z_STREAM_END");
	  /*NOTREACHED*/
	case Z_DATA_ERROR:
	  fatal("buffer_uncompress: inflate returned Z_DATA_ERROR");
	  /*NOTREACHED*/
	case Z_STREAM_ERROR:
	  fatal("buffer_uncompress: inflate returned Z_STREAM_ERROR");
	  /*NOTREACHED*/
	case Z_BUF_ERROR:
	  /* Comments in zlib.h say that we should keep calling inflate()
	     until we get an error.  This appears to be the error that we
	     get. */
	  return;
	case Z_MEM_ERROR:
	  fatal("buffer_uncompress: inflate returned Z_MEM_ERROR");
	  /*NOTREACHED*/
	default:
	  fatal("buffer_uncompress: inflate returned %d", status);
	}
    }
}