X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;ds=sidebyside;f=doc%2Fdev%2Fsystem-file-format.texi;h=500d74f66556fcff16d9ef14cf547a2375b8ee2e;hb=66cf88eb930344d1c18c90d25cb9fdacd9912502;hp=e52b9571166a25b477a8f6263f34d0960b9f0423;hpb=f518002b6673e3bcc030c903378d5d75f64697ea;p=pspp

diff --git a/doc/dev/system-file-format.texi b/doc/dev/system-file-format.texi
index e52b957116..500d74f665 100644
--- a/doc/dev/system-file-format.texi
+++ b/doc/dev/system-file-format.texi
@@ -222,6 +222,12 @@ pspp 0.1.4 - sparc-sun-solaris2.5.2}.  The string is truncated if it
 would be longer than 60 characters; otherwise it is padded on the right
 with spaces.
 
+The product name field allow readers to behave differently based on
+quirks in the way that particular software writes system files.
+@xref{Value Labels Records}, for the detail of the quirk that the PSPP
+system file reader tolerates in files written by ReadStat, which has
+@code{https://github.com/WizardMac/ReadStat} in @code{prod_name}.
+
 @anchor{layout_code}
 @item int32 layout_code;
 Normally set to 2, although a few system files have been spotted in
@@ -310,10 +316,10 @@ 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
@@ -508,6 +514,10 @@ 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
 
@@ -524,6 +534,14 @@ numeric and short string variables only.  Long string variables may
 have value labels, but their value labels are recorded using a
 different record type (@pxref{Long String Value Labels Record}).
 
+ReadStat (@pxref{File Header Record}) writes value labels that label a
+single value more than once.  In more detail, it emits value labels
+whose values are longer than string variables' widths, that are
+identical in the actual width of the variable, e.g.@: labels for
+values @code{ABC123} and @code{ABC456} for a string variable with
+width 3.  For files written by this software, PSPP ignores such
+labels.
+
 The value label record has the following format:
 
 @example
@@ -582,7 +600,7 @@ 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.
 
@@ -606,9 +624,7 @@ Record type.  Always set to 6.
 
 @item int32 n_lines;
 Number of lines of documents present.  This should be greater than
-zero, but the system file writer that identifies itself as
-@url{https://github.com/WizardMac/ReadStat} writes document records
-with zero @code{n_lines}.
+zero, but ReadStats writes system files with zero @code{n_lines}.
 
 @item char lines[][80];
 Document lines.  The number of elements is defined by @code{n_lines}.
@@ -1560,9 +1576,10 @@ 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