ocean.util.compress.c.Zip source code

1 /*******************************************************************************
2 
3     Record definitions for the PKZIP archive file format
4 
5     copyright:  Copyright (c) 2016 dunnhumby Germany GmbH. All rights reserved
6 
7 
8 *******************************************************************************/
9 
10 module ocean.util.compress.c.Zip;
11 
12 /*******************************************************************************
13 
14     Signatures of the records in a Zip archive. Each record is preceded by the
15     corresponding signature, except for ZipLocalFileSizeSignature, which is
16     permitted to be missing.
17 
18     All signatures begin with "PK", the initials of Phil Katz, who created the
19     format.
20 
21 *******************************************************************************/
22 
23 static string ZipCentralDirectoryFileHeaderSignature = "PK\x01\x02";
24 
25 /** ditto **/
26 
27 static string ZipLocalFileHeaderSignature = "PK\x03\x04";
28 
29 /** ditto **/
30 
31 static string ZipEndOfCentralDirectorySignature = "PK\x05\x06";
32 
33 /** ditto **/
34 
35 static string ZipLocalFileSizeSignature = "PK\x07\x08";
36 
37 
38 
39 /*******************************************************************************
40 
41     Struct which is stored at the start of each file in the archive
42 
43     This record will always be preceded by a ZipLocalFileHeaderSignature.
44     This is an incomplete, redundant copy of the struct in the central
45     directory.
46 
47 *******************************************************************************/
48 
49 public align(1) struct ZipLocalFileHeaderRecord
50 {
51     align(1):
52     ushort      extract_version;
53     ushort      general_flags;
54     ushort      compression_method;
55     ushort      modification_file_time;
56     ushort      modification_file_date;
57     uint        crc_32;
58     uint        compressed_size;
59     uint        uncompressed_size;
60     ushort      file_name_length;
61     ushort      extra_field_length;
62 
63     /***********************************************************************
64 
65         Returns:
66             true if the CRC and file sizes were not known when the object
67             was written. In this case, the values are stored in a
68             ZipLocalFileSizeRecord after the compressed data. There may or
69             may not be a ZipLocalFileSizeSignature before the record.
70 
71     ***********************************************************************/
72 
73     public final bool isCrcMissing ( )
74     {
75         return (this.general_flags & 0x08 ) == 0x08;
76     }
77 
78 
79     /***************************************************************************
80 
81         Returns:
82             true if and only if the file is compressed using the DEFLATE method
83 
84     ***************************************************************************/
85 
86     public final bool isDeflateCompressed ()
87     {
88         return this.compression_method == 8;
89     }
90 }
91 
92 
93 /*******************************************************************************
94 
95     Struct which is stored at the end of a file if the CRC and length were not
96     known when the file compression began.
97 
98     This struct may optionally be preceded by a ZipLocalFileSizeSignature.
99 
100 *******************************************************************************/
101 
102 public align(1) struct ZipLocalFileSizeRecord
103 {
104     align(1):
105     uint        crc_32;
106     uint        compressed_size;
107     uint        uncompressed_size;
108 }
109 
110 
111 /*******************************************************************************
112 
113     Struct which is stored at the end of the archive. It is followed by a
114     comment of length up to 65535 bytes.
115 
116     This record will always be preceded by a
117     ZipCentralDirectoryFileHeaderSignature.
118 
119 *******************************************************************************/
120 
121 public align(1) struct ZipCentralDirectoryFileHeaderRecord
122 {
123     align(1):
124     ubyte       zip_version;
125     ubyte       file_attribute_type;
126     ushort      extract_version;
127     ushort      general_flags;
128     ushort      compression_method;
129     ushort      modification_file_time;
130     ushort      modification_file_date;
131     uint        crc_32;
132     uint        compressed_size;
133     uint        uncompressed_size;
134     ushort      file_name_length;
135     ushort      extra_field_length;
136     ushort      file_comment_length;
137     ushort      disk_number_start;
138     ushort      internal_file_attributes;
139     uint        external_file_attributes;
140     int         relative_offset_of_local_header;
141 }
142 
143 
144 /*******************************************************************************
145 
146     Struct which is stored at the end of the archive. It is followed by a
147     comment of length up to 65535 bytes.
148 
149     This record will always be preceded by a
150     ZipEndOfCentralDirectorySignature
151 
152 *******************************************************************************/
153 
154 public align(1) struct EndOfCentralDirectoryRecord
155 {
156     align(1):
157     ushort      disk_number;
158     ushort      disk_with_start_of_central_directory;
159     ushort      central_directory_entries_on_this_disk;
160     ushort      central_directory_entries_total;
161     uint        size_of_central_directory;
162     uint        offset_of_start_of_cd_from_starting_disk;
163     ushort      file_comment_length;
164 }