src/lib/compress/compress.h

   1 /* Copyright (c) 2003, 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.h
   8  * \brief Headers for compress.c
   9  **/
  10
  11 #ifndef TOR_COMPRESS_H
  12 #define TOR_COMPRESS_H
  13
  14 #include <stddef.h>
  15 #include "lib/testsupport/testsupport.h"
  16
  17 /** Enumeration of what kind of compression to use.  Only ZLIB_METHOD and
  18  * GZIP_METHOD is guaranteed to be supported by the compress/uncompress
  19  * functions here. Call tor_compress_supports_method() to check if a given
  20  * compression schema is supported by Tor. */
  21 typedef enum compress_method_t {
  22   NO_METHOD=0, // This method must be first.
  23   GZIP_METHOD=1,
  24   ZLIB_METHOD=2,
  25   LZMA_METHOD=3,
  26   ZSTD_METHOD=4,
  27   UNKNOWN_METHOD=5, // This method must be last. Add new ones in the middle.
  28 } compress_method_t;
  29
  30 /**
  31  * Enumeration to define tradeoffs between memory usage and compression level.
  32  * BEST_COMPRESSION saves the most bandwidth; LOW_COMPRESSION saves the most
  33  * memory.
  34  **/
  35 typedef enum compression_level_t {
  36   BEST_COMPRESSION, HIGH_COMPRESSION, MEDIUM_COMPRESSION, LOW_COMPRESSION
  37 } compression_level_t;
  38
  39 int tor_compress(char **out, size_t *out_len,
  40                  const char *in, size_t in_len,
  41                  compress_method_t method);
  42
  43 int tor_uncompress(char **out, size_t *out_len,
  44                    const char *in, size_t in_len,
  45                    compress_method_t method,
  46                    int complete_only,
  47                    int protocol_warn_level);
  48
  49 compress_method_t detect_compression_method(const char *in, size_t in_len);
  50
  51 MOCK_DECL(int,tor_compress_is_compression_bomb,(size_t size_in,
  52                                                 size_t size_out));
  53
  54 int tor_compress_supports_method(compress_method_t method);
  55 unsigned tor_compress_get_supported_method_bitmask(void);
  56 const char *compression_method_get_name(compress_method_t method);
  57 const char *compression_method_get_human_name(compress_method_t method);
  58 compress_method_t compression_method_get_by_name(const char *name);
  59
  60 const char *tor_compress_version_str(compress_method_t method);
  61
  62 const char *tor_compress_header_version_str(compress_method_t method);
  63
  64 size_t tor_compress_get_total_allocation(void);
  65
  66 /** Return values from tor_compress_process; see that function's documentation
  67  * for details. */
  68 typedef enum {
  69   TOR_COMPRESS_OK,
  70   TOR_COMPRESS_DONE,
  71   TOR_COMPRESS_BUFFER_FULL,
  72   TOR_COMPRESS_ERROR
  73 } tor_compress_output_t;
  74
  75 /** Internal state for an incremental compression/decompression. */
  76 typedef struct tor_compress_state_t tor_compress_state_t;
  77
  78 tor_compress_state_t *tor_compress_new(int compress,
  79                                        compress_method_t method,
  80                                        compression_level_t level);
  81
  82 tor_compress_output_t tor_compress_process(tor_compress_state_t *state,
  83                                            char **out, size_t *out_len,
  84                                            const char **in, size_t *in_len,
  85                                            int finish);
  86 void tor_compress_free_(tor_compress_state_t *state);
  87 #define tor_compress_free(st) \
  88   FREE_AND_NULL(tor_compress_state_t, tor_compress_free_, (st))
  89
  90 size_t tor_compress_state_size(const tor_compress_state_t *state);
  91
  92 int tor_compress_init(void);
  93 void tor_compress_log_init_warnings(void);
  94
  95 struct buf_t;
  96 int buf_add_compress(struct buf_t *buf, struct tor_compress_state_t *state,
  97                      const char *data, size_t data_len, int done);
  98
  99 #endif /* !defined(TOR_COMPRESS_H) */