1 // This file is part of par2cmdline (a PAR 2.0 compatible file verification and
2 // repair tool). See http://parchive.sourceforge.net for details of PAR 2.0.
3 //
4 // Copyright (c) 2003 Peter Brian Clements
5 //
6 // par2cmdline is free software; you can redistribute it and/or modify
7 // it under the terms of the GNU General Public License as published by
8 // the Free Software Foundation; either version 2 of the License, or
9 // (at your option) any later version.
10 //
11 // par2cmdline is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 //
16 // You should have received a copy of the GNU General Public License
17 // along with this program; if not, write to the Free Software
18 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
19
20 #ifndef __RECOVERYPACKET_H__
21 #define __RECOVERYPACKET_H__
22
23 // The RecoveryPacket object is used to access a specific recovery
24 // packet within a recovery file (for when creating them, or using
25 // them during a repair operation).
26
27 // Because the actual recovery data for the packet may be large, the
28 // RecoveryPacket object only contains a copy of packet header and
29 // exponent value for the block and uses a DataBlock object for
30 // all accesses to the actual recovery data in the packet.
31
32 class RecoveryPacket
33 {
34 public:
35 RecoveryPacket(void);
36 ~RecoveryPacket(void);
37
38 public:
39 // Create a recovery packet for a specified file.
40 void Create(DiskFile *diskfile, // Which file will the packet be stored in
41 u64 offset, // At what offset will the packet be stored
42 u64 blocksize, // How much recovery data will it contain
43 u32 exponent, // What exponent value will be used
44 const MD5Hash &setid); // What is the SetId
45 // Write some data to the recovery data block and update the recovery packet.
46 bool WriteData(u64 position, // Relative position within the data block
47 size_t size, // Size of data to write to block
48 const void *buffer); // Buffer containing the data to write
49 // Finish computing the hash of the recovery packet and write the header to disk.
50 bool WriteHeader(void);
51
52 public:
53 // Load a recovery packet from a specified file
54 bool Load(DiskFile *diskfile, u64 offset, PACKET_HEADER &header);
55
56 public:
57 // Get the lenght of the packet.
58 u64 PacketLength(void) const;
59
60 // The the exponent of the packet.
61 u32 Exponent(void) const;
62
63 // The length of the recovery data
64 u64 BlockSize(void) const;
65
66 // The data block
67 DataBlock* GetDataBlock(void);
68
69 protected:
70 DiskFile *diskfile; // The specific file that this packet is stored in
71 u64 offset; // The offset at which the packet is stored
72
73 RECOVERYBLOCKPACKET packet; // The packet (excluding the actual recovery data)
74
75 MD5Context *packetcontext; // MD5 Context used to compute the packet hash
76
77 DataBlock datablock; // The recovery data block.
78 };
79
PacketLength(void)80 inline u64 RecoveryPacket::PacketLength(void) const
81 {
82 return packet.header.length;
83 }
84
Exponent(void)85 inline u32 RecoveryPacket::Exponent(void) const
86 {
87 return packet.exponent;
88 }
89
BlockSize(void)90 inline u64 RecoveryPacket::BlockSize(void) const
91 {
92 return packet.header.length - sizeof(packet);
93 }
94
GetDataBlock(void)95 inline DataBlock* RecoveryPacket::GetDataBlock(void)
96 {
97 return &datablock;
98 }
99
100 #endif // __RECOVERYPACKET_H__
101