Line data    Source code

       1             : /* Copyright (c) 2004, Roger Dingledine.
       2             :  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
       3             :  * Copyright (c) 2007-2021, The Tor Project, Inc. */
       4             : /* See LICENSE for licensing information */
       5             : 
       6             : /**
       7             :  * \file compress_none.c
       8             :  * \brief Compression backend for identity compression.
       9             :  *
      10             :  * We actually define this backend so that we can treat the identity transform
      11             :  * as another case of compression.
      12             :  *
      13             :  * This module should never be invoked directly. Use the compress module
      14             :  * instead.
      15             :  **/
      16             : 
      17             : #include "orconfig.h"
      18             : 
      19             : #include "lib/log/log.h"
      20             : #include "lib/compress/compress.h"
      21             : #include "lib/compress/compress_none.h"
      22             : #include "lib/intmath/cmp.h"
      23             : 
      24             : #include <string.h>
      25             : 
      26             : /** Transfer some bytes using the identity transformation.  Read up to
      27             :  * *<b>in_len</b> bytes from *<b>in</b>, and write up to *<b>out_len</b> bytes
      28             :  * to *<b>out</b>, adjusting the values as we go.  If <b>finish</b> is true,
      29             :  * we've reached the end of the input.
      30             :  *
      31             :  * Return TOR_COMPRESS_DONE if we've finished the entire
      32             :  * compression/decompression.
      33             :  * Return TOR_COMPRESS_OK if we're processed everything from the input.
      34             :  * Return TOR_COMPRESS_BUFFER_FULL if we're out of space on <b>out</b>.
      35             :  * Return TOR_COMPRESS_ERROR if the stream is corrupt.
      36             :  */
      37             : tor_compress_output_t
      38          88 : tor_cnone_compress_process(char **out, size_t *out_len,
      39             :                            const char **in, size_t *in_len,
      40             :                            int finish)
      41             : {
      42          88 :   size_t n_to_copy = MIN(*in_len, *out_len);
      43             : 
      44          88 :   memcpy(*out, *in, n_to_copy);
      45          88 :   *out += n_to_copy;
      46          88 :   *in += n_to_copy;
      47          88 :   *out_len -= n_to_copy;
      48          88 :   *in_len -= n_to_copy;
      49          88 :   if (*in_len == 0) {
      50          72 :     return finish ? TOR_COMPRESS_DONE : TOR_COMPRESS_OK;
      51             :   } else {
      52             :     return TOR_COMPRESS_BUFFER_FULL;
      53             :   }
      54             : }