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 #include "par2cmdline.h"
21
22 #ifdef _MSC_VER
23 #ifdef _DEBUG
24 #undef THIS_FILE
25 static char THIS_FILE[]=__FILE__;
26 #define new DEBUG_NEW
27 #endif
28 #endif
29
30 // Construct the main packet from the source files and the block size
31
Create(vector<Par2CreatorSourceFile * > & sourcefiles,u64 _blocksize)32 bool MainPacket::Create(vector<Par2CreatorSourceFile*> &sourcefiles, u64 _blocksize)
33 {
34 recoverablefilecount = totalfilecount =(u32)sourcefiles.size();
35 blocksize = _blocksize;
36
37 // Allocate memory for the main packet with enough fileid entries
38 MAINPACKET *packet = (MAINPACKET *)AllocatePacket(sizeof(MAINPACKET) + totalfilecount * sizeof(MD5Hash));
39
40 // Record the details we already know in the packet
41 packet->header.magic = packet_magic;
42 packet->header.length = packetlength;
43 //packet->header.hash; // Compute shortly
44 //packet->header.setid; // Compute shortly
45 packet->header.type = mainpacket_type;
46
47 packet->blocksize = _blocksize;
48 packet->recoverablefilecount = totalfilecount;
49 //packet->fileid; // Compute shortly
50
51 // Sort the source files according to their fileid values
52 if (totalfilecount > 1)
53 {
54 sort(sourcefiles.begin(), sourcefiles.end(), Par2CreatorSourceFile::CompareLess);
55 }
56
57 // Store the fileid values in the main packet
58 vector<Par2CreatorSourceFile*>::const_iterator sourcefile;
59 MD5Hash *hash;
60 for ((sourcefile=sourcefiles.begin()),(hash=packet->fileid);
61 sourcefile!=sourcefiles.end();
62 ++sourcefile, ++hash)
63 {
64 *hash = (*sourcefile)->FileId();
65 }
66
67 // Compute the set_id_hash
68 MD5Context setidcontext;
69 setidcontext.Update(&packet->blocksize, packetlength - offsetof(MAINPACKET, blocksize));
70 setidcontext.Final(packet->header.setid);
71
72 // Compute the packet_hash
73 MD5Context packetcontext;
74 packetcontext.Update(&packet->header.setid, packetlength - offsetof(MAINPACKET, header.setid));
75 packetcontext.Final(packet->header.hash);
76
77 return true;
78 }
79
80 // Load a main packet from a specified file
81
Load(DiskFile * diskfile,u64 offset,PACKET_HEADER & header)82 bool MainPacket::Load(DiskFile *diskfile, u64 offset, PACKET_HEADER &header)
83 {
84 // Is the packet large enough
85 if (header.length < sizeof(MAINPACKET))
86 {
87 return false;
88 }
89
90 // Is there a whole number of fileid values
91 if (0 < (header.length - sizeof(MAINPACKET)) % sizeof(MD5Hash))
92 {
93 return false;
94 }
95
96 // Is the packet too large
97 if (header.length > sizeof(MAINPACKET) + 32768 * sizeof(MD5Hash))
98 {
99 return false;
100 }
101
102 // Compute the total number of entries in the fileid array
103 totalfilecount = (u32)(((size_t)header.length - sizeof(MAINPACKET)) / sizeof(MD5Hash));
104
105 MAINPACKET *packet = (MAINPACKET *)AllocatePacket((size_t)header.length);
106
107 packet->header = header;
108
109 // Read the rest of the packet from disk
110 if (!diskfile->Read(offset + sizeof(PACKET_HEADER),
111 &packet->blocksize,
112 (size_t)packet->header.length - sizeof(PACKET_HEADER)))
113 return false;
114
115 // Does the packet have enough fileid values
116 recoverablefilecount = packet->recoverablefilecount;
117 if (recoverablefilecount > totalfilecount)
118 {
119 return false;
120 }
121
122 // Is the block size valid
123 blocksize = packet->blocksize;
124 if (blocksize == 0 || (blocksize & 3) != 0)
125 {
126 return false;
127 }
128
129 return true;
130 }
131