1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 2006-2007, 2009-2013 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Infrastructure common to system file reader and writer.
19 Old versions of SPSS limited string variables to a width of
20 255 bytes. For backward compatibility with these older
21 versions, the system file format represents a string longer
22 than 255 bytes, called a "very long string", as a collection
23 of strings no longer than 255 bytes each. The strings
24 concatenated to make a very long string are called its
25 "segments"; for consistency, variables other than very long
26 strings are considered to have a single segment.
28 The interfaces in this file primarily provide support for
29 dealing with very long strings. */
31 #ifndef DATA_SYS_FILE_PRIVATE_H
32 #define DATA_SYS_FILE_PRIVATE_H 1
38 /* ASCII magic numbers. */
39 #define ASCII_MAGIC "$FL2" /* For regular files. */
40 #define ASCII_ZMAGIC "$FL3" /* For ZLIB compressed files. */
42 /* EBCDIC magic number, the same as ASCII_MAGIC but encoded in EBCDIC.
44 No EBCDIC ZLIB compressed files have been observed, so we do not define
45 EBCDIC_ZMAGIC even though the value is obvious. */
46 #define EBCDIC_MAGIC "\x5b\xc6\xd3\xf2"
48 /* Amount of data that ZLIB compressed data blocks typically decompress to. */
49 #define ZBLOCK_SIZE 0x3ff000
51 /* A variable in a system file. */
54 int var_width; /* Variable width (0 to 32767). */
55 int segment_width; /* Segment width (0 to 255). */
56 int case_index; /* Index into case. */
58 /* The following members are interesting only for string
59 variables (width != 0). For numeric variables (width ==
60 0) their values are always 0.
62 Note: width + padding is always a multiple of 8. */
63 int offset; /* Offset within string variable in case. */
64 int padding; /* Number of padding bytes following data. */
67 int sfm_dictionary_to_sfm_vars (const struct dictionary *,
68 struct sfm_var **, size_t *);
70 int sfm_width_to_octs (int width);
71 int sfm_width_to_segments (int width);
73 int sfm_segment_effective_offset (int width, int segment);
74 int sfm_segment_alloc_width (int width, int segment);
76 /* A mapping between an encoding name and a Windows codepage. */
83 extern struct sys_encoding sys_codepage_number_to_name[];
84 extern struct sys_encoding sys_codepage_name_to_number[];
86 int sys_get_codepage_from_encoding (const char *);
87 const char *sys_get_encoding_from_codepage (int);
89 #endif /* data/sys-file-private.h */