Change "union value" to dynamically allocate long strings.

[pspp-builds.git] / src / data / sys-file-private.h

diff --git a/src/data/sys-file-private.h b/src/data/sys-file-private.h
index ee93706fb54118b4b7887f46d26b44fb87e45191..e839cd6ac02008ab5fec2ee08feffcfbdcad003f 100644 (file)
--- a/src/data/sys-file-private.h
+++ b/src/data/sys-file-private.h
@@ -1,29 +1,63 @@
-/* PSPP - computes sample statistics.
-   Copyright (C) 2006 Free Software Foundation, Inc.
+/* PSPP - a program for statistical analysis.
+   Copyright (C) 2006, 2007, 2009 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or
-   modify it under the terms of the GNU General Public License as
-   published by the Free Software Foundation; either version 2 of the
-   License, or (at your option) any later version.
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
 
-   This program is distributed in the hope that it will be useful, but
-   WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   General Public License for more details.
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-   02110-1301, USA. */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+
+/* Infrastructure common to system file reader and writer.
+
+   Old versions of SPSS limited string variables to a width of
+   255 bytes.  For backward compatibility with these older
+   versions, the system file format represents a string longer
+   than 255 bytes, called a "very long string", as a collection
+   of strings no longer than 255 bytes each.  The strings
+   concatenated to make a very long string are called its
+   "segments"; for consistency, variables other than very long
+   strings are considered to have a single segment.
+
+   The interfaces in this file primarily provide support for
+   dealing with very long strings.  */
 
 #ifndef DATA_SYS_FILE_PRIVATE_H
 #define DATA_SYS_FILE_PRIVATE_H 1
 
-/* This nonsense is required for SPSS compatibility. */
+#include <stddef.h>
+
+struct dictionary;
+
+/* A variable in a system file. */
+struct sfm_var
+  {
+    int var_width;              /* Variable width (0 to 32767). */
+    int segment_width;          /* Segment width (0 to 255). */
+    int case_index;             /* Index into case. */
+
+    /* The following members are interesting only for string
+       variables (width != 0).  For numeric variables (width ==
+       0) their values are always 0.
+
+       Note: width + padding is always a multiple of 8. */
+    int offset;                 /* Offset within string variable in case. */
+    int padding;                /* Number of padding bytes following data. */
+  };
+
+int sfm_dictionary_to_sfm_vars (const struct dictionary *,
+                                struct sfm_var **, size_t *);
 
-#define MIN_VERY_LONG_STRING 256
-#define EFFECTIVE_LONG_STRING_LENGTH (MIN_VERY_LONG_STRING - 4)
+int sfm_width_to_octs (int width);
+int sfm_width_to_segments (int width);
 
-int sfm_width_to_bytes (int width);
+int sfm_segment_effective_offset (int width, int segment);
+int sfm_segment_alloc_width (int width, int segment);
 
 #endif /* data/sys-file-private.h */