2 This file is part of GNUnet.
3 (C) 2009 Christian Grothoff (and other contributing authors)
5 GNUnet is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published
7 by the Free Software Foundation; either version 3, or (at your
8 option) any later version.
10 GNUnet is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with GNUnet; see the file COPYING. If not, write to the
17 Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 Boston, MA 02111-1307, USA.
23 * @brief Merkle-tree-ish-CHK file encoding for GNUnet
24 * @see https://gnunet.org/encoding
25 * @author Krista Bennett
26 * @author Christian Grothoff
29 * - decide if this API should be made public (gnunet_fs_service.h)
30 * or remain "internal" (but with exported symbols?)
32 #ifndef GNUNET_FS_TREE_H
33 #define GNUNET_FS_TREE_H
38 * Compute the depth of the CHK tree.
40 * @param flen file length for which to compute the depth
41 * @return depth of the tree, always > 0. A depth of 1 means only a DBLOCK.
43 unsigned int GNUNET_FS_compute_depth (uint64_t flen);
47 * Calculate how many bytes of payload a block tree of the given
48 * depth MAY correspond to at most (this function ignores the fact that
49 * some blocks will only be present partially due to the total file
50 * size cutting some blocks off at the end).
52 * @param depth depth of the block. depth==0 is a DBLOCK.
53 * @return number of bytes of payload a subtree of this depth may correspond to
55 uint64_t GNUNET_FS_tree_compute_tree_size (unsigned int depth);
59 * Compute how many bytes of data should be stored in
60 * the specified block.
62 * @param fsize overall file size, must be > 0.
63 * @param offset offset in the original data corresponding
64 * to the beginning of the tree induced by the block;
66 * @param depth depth of the node in the tree, 0 for DBLOCK
67 * @return number of bytes stored in this node
70 GNUNET_FS_tree_calculate_block_size (uint64_t fsize,
71 uint64_t offset, unsigned int depth);
75 * Context for an ECRS-based file encoder that computes
76 * the Merkle-ish-CHK tree.
78 struct GNUNET_FS_TreeEncoder;
82 * Function called asking for the current (encoded)
83 * block to be processed. After processing the
84 * client should either call "GNUNET_FS_tree_encode_next"
85 * or (on error) "GNUNET_FS_tree_encode_finish".
88 * @param chk content hash key for the block
89 * @param offset offset of the block
90 * @param depth depth of the block, 0 for DBLOCKs
91 * @param type type of the block (IBLOCK or DBLOCK)
92 * @param block the (encrypted) block
93 * @param block_size size of block (in bytes)
95 typedef void (*GNUNET_FS_TreeBlockProcessor) (void *cls,
96 const struct ContentHashKey * chk,
99 enum GNUNET_BLOCK_Type type,
101 uint16_t block_size);
105 * Function called with information about our
106 * progress in computing the tree encoding.
109 * @param offset where are we in the file
110 * @param pt_block plaintext of the currently processed block
111 * @param pt_size size of pt_block
112 * @param depth depth of the block in the tree, 0 for DBLOCKS
114 typedef void (*GNUNET_FS_TreeProgressCallback) (void *cls,
116 const void *pt_block,
122 * Initialize a tree encoder. This function will call "proc" and
123 * "progress" on each block in the tree. Once all blocks have been
124 * processed, "cont" will be scheduled. The "reader" will be called
125 * to obtain the (plaintext) blocks for the file. Note that this
126 * function will actually never call "proc"; the "proc" function must
127 * be triggered by calling "GNUNET_FS_tree_encoder_next" to trigger
128 * encryption (and calling of "proc") for each block.
130 * @param h the global FS context
131 * @param size overall size of the file to encode
132 * @param cls closure for reader, proc, progress and cont
133 * @param reader function to call to read plaintext data
134 * @param proc function to call on each encrypted block
135 * @param progress function to call with progress information
136 * @param cont function to call when done
137 * @return tree encoder context
139 struct GNUNET_FS_TreeEncoder *GNUNET_FS_tree_encoder_create (struct
145 GNUNET_FS_TreeBlockProcessor
147 GNUNET_FS_TreeProgressCallback
149 GNUNET_SCHEDULER_Task
154 * Encrypt the next block of the file (and
155 * call proc and progress accordingly; or
156 * of course "cont" if we have already completed
157 * encoding of the entire file).
159 * @param te tree encoder to use
161 void GNUNET_FS_tree_encoder_next (struct GNUNET_FS_TreeEncoder *te);
165 * Clean up a tree encoder and return information
166 * about the resulting URI or an error message.
168 * @param te the tree encoder to clean up
169 * @param uri set to the resulting URI (if encoding finished)
170 * @param emsg set to an error message (if an error occured
171 * within the tree encoder; if this function is called
172 * prior to completion and prior to an internal error,
173 * both "*uri" and "*emsg" will be set to NULL).
175 void GNUNET_FS_tree_encoder_finish (struct GNUNET_FS_TreeEncoder *te,
176 struct GNUNET_FS_Uri **uri, char **emsg);
180 /* the functions below will be needed for persistence
181 but are not yet implemented -- FIXME... */
183 * Get data that would be needed to resume
184 * the encoding later.
186 * @param te encoding to resume
187 * @param data set to the resume data
188 * @param size set to the size of the resume data
190 void GNUNET_FS_tree_encoder_resume_get_data (const struct GNUNET_FS_TreeEncoder
191 *te, void **data, size_t * size);
195 * Reset tree encoder to point previously
196 * obtained for resuming.
198 * @param te encoding to resume
199 * @param data the resume data
200 * @param size the size of the resume data
202 void GNUNET_FS_tree_encoder_resume (struct GNUNET_FS_TreeEncoder *te,
203 const void *data, size_t size);
208 /* end of fs_tree.h */