X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;ds=inline;f=doc%2Fdev%2Fsystem-file-format.texi;h=a5a89f4ded01672a57c53791d4f81d51ca3bd24f;hb=f0827ef96044219fea423d73147937c4c266827b;hp=484fbb43f1eca08fc089bd0f5ec171215f279403;hpb=80527716392c066fdf72f37729c42089a2174bae;p=pspp

diff --git a/doc/dev/system-file-format.texi b/doc/dev/system-file-format.texi
index 484fbb43f1..a5a89f4ded 100644
--- a/doc/dev/system-file-format.texi
+++ b/doc/dev/system-file-format.texi
@@ -1,3 +1,13 @@
+@c PSPP - a program for statistical analysis.
+@c Copyright (C) 2019 Free Software Foundation, Inc.
+@c Permission is granted to copy, distribute and/or modify this document
+@c under the terms of the GNU Free Documentation License, Version 1.3
+@c or any later version published by the Free Software Foundation;
+@c with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
+@c A copy of the license is included in the section entitled "GNU
+@c Free Documentation License".
+@c
+
 @node System File Format
 @appendix System File Format
 
@@ -6,7 +16,7 @@ that describes how they may be interpreted.  This chapter describes
 the format of a system file.
 
 System files use four data types: 8-bit characters, 32-bit integers,
-64-bit integers, 
+64-bit integers,
 and 64-bit floating points, called here @code{char}, @code{int32},
 @code{int64}, and
 @code{flt64}, respectively.  Data is not necessarily aligned on a word
@@ -316,10 +326,10 @@ so readers should take care to parse dummy variable records in the
 same way as other variable records.
 
 @anchor{Dictionary Index}
-The @dfn{dictionary index} of a variable is its offset in the set of
+The @dfn{dictionary index} of a variable is a 1-based offset in the set of
 variable records, including dummy variable records for long string
-variables.  The first variable record has a dictionary index of 0, the
-second has a dictionary index of 1, and so on.
+variables.  The first variable record has a dictionary index of 1, the
+second has a dictionary index of 2, and so on.
 
 The system file format does not directly support string variables
 wider than 255 bytes.  Such very long string variables are represented
@@ -514,6 +524,10 @@ Format types are defined as follows:
 @tab @code{EDATE}
 @item 39
 @tab @code{SDATE}
+@item 40
+@tab @code{MTIME}
+@item 41
+@tab @code{YMDHMS}
 @end multitable
 @end quotation
 
@@ -596,7 +610,7 @@ Number of variables that the associated value labels from the value
 label record are to be applied.
 
 @item int32 vars[];
-A list of dictionary indexes of variables to which to apply the value
+A list of 1-based dictionary indexes of variables to which to apply the value
 labels (@pxref{Dictionary Index}).  There are @code{var_count}
 elements.
 
@@ -1572,9 +1586,10 @@ value @var{code} - @var{bias}, where
 variable @code{bias} from the file header.  For example,
 code 105 with bias 100.0 (the normal value) indicates a numeric variable
 of value 5.
-One file has been seen written by SPSS 14 that contained such a code
-in a @emph{string} field with the value 0 (after the bias is
-subtracted) as a way of encoding null bytes.
+
+A code of 0 (after subtracting the bias) in a string field encodes
+null bytes.  This is unusual, since a string field normally encodes
+text data, but it exists in real system files.
 
 @item 252
 End of file.  This code may or may not appear at the end of the data
@@ -1636,7 +1651,7 @@ The number of bytes in the ZLIB data trailer.  This and the previous
 field sum to the size of the system file in bytes.
 @end table
 
-The data header is followed by @code{(ztrailer_ofs - 24) / 24} ZLIB
+The data header is followed by @code{(ztrailer_len - 24) / 24} ZLIB
 compressed data blocks.  Each ZLIB compressed data block begins with a
 ZLIB header as specified in RFC@tie{}1950, e.g.@: hex bytes @code{78
 01} (the only header yet observed in practice).  Each block
@@ -1673,7 +1688,7 @@ been observed so far.
 
 @item int32 n_blocks;
 The number of ZLIB compressed data blocks, always exactly
-@code{(ztrailer_ofs - 24) / 24}.
+@code{(ztrailer_len - 24) / 24}.
 @end table
 
 The fixed header is followed by @code{n_blocks} 24-byte ZLIB data