make the dbase entry stricter so that it has less chance misidentifying

xbase memo files (Joerg Jenderek)

diff --git a/magic/Magdir/database b/magic/Magdir/database
index 071a1156485b4db3ad03c2b9f7e34b71a5d32758..9578c0fc33216ef113717c569850c4f2a15a53ee 100644 (file)
--- a/magic/Magdir/database
+++ b/magic/Magdir/database
@@ -1,6 +1,6 @@
 
 #------------------------------------------------------------------------------
-# $File: database,v 1.55 2019/04/19 00:42:27 christos Exp $
+# $File: database,v 1.56 2019/06/14 20:12:00 christos Exp $
 # database:  file(1) magic for various databases
 #
 # extracted from header/code files by Graeme Wilford (eep2gw@ee.surrey.ac.uk)
@@ -149,7 +149,6 @@
 # updated by Joerg Jenderek at Feb 2013
 # https://www.dbase.com/Knowledgebase/INT/db7_file_fmt.htm
 # https://www.clicketyclick.dk/databases/xbase/format/dbf.html
-# http://home.f1.htw-berlin.de/scheibl/db/intern/dBase.htm
 # inspect VVYYMMDD , where 1<= MM <= 12 and 1<= DD <= 31
 0      ubelong&0x0000FFFF              <0x00000C20
 # skip Infocom game Z-machine
@@ -339,7 +338,7 @@
 # next free block index is positive
 >>>0           ulelong         >0
 # skip many JPG. ZIP, BZ2 by test for reserved bytes NULL , 0|2 , 0|1 , low byte of block size
->>>>17         ubelong&0xFFfdFE00      0x00000000
+>>>>17         ubelong&0xFFfdFEff      0x00000000
 # skip many RAR by test for low byte 0 ,high byte 0|2|even of block size, 0|a|e|d7 , 0|64h
 >>>>>20                ubelong&0xFF01209B      0x00000000
 # dBASE III
@@ -355,36 +354,34 @@
 >>>>>>>>>6     ubeshort        >0
 # skip emacs.PIF
 >>>>>>>>>>4    ushort          0
->>>>>>>>>>>0   use             foxpro-memo-print
+# check for valid FoxPro field type
+>>>>>>>>>>>512 ubelong         <3
+>>>>>>>>>>>>0  use             foxpro-memo-print
 # dBASE III DBT , garbage
->>>>>>>>>6     ubeshort        0
-# skip MM*DD*.bin by test for for reserved NULL byte
->>>>>>>>>>510  ubeshort        0
-# skip TK-DOS11.img image by looking for memo text
->>>>>>>>>>>512 ubelong         <0xfeffff03
-# skip EFI executables by looking for memo text
->>>>>>>>>>>>512        ubelong         >0x1F202020
->>>>>>>>>>>>>513 ubyte         >0
+# skip WORD1XW.DOC with improbably high free block index
+>>>>>>>>>0     lelong          <2205083
 # unusual dBASE III DBT like adressen.dbt
->>>>>>>>>>>>>>0        use             dbase3-memo-print
+>>>>>>>>>>0    use             dbase3-memo-print
 # dBASE III DBT like angest.dbt, or garbage PCX DBF
 >>>>>>>>8      ubelong         !0
 # skip PCX and some DBF by test for for reserved NULL bytes
 >>>>>>>>>510   ubeshort        0
-# skip some DBF by test of invalid version
->>>>>>>>>>0    ubyte           >5
->>>>>>>>>>>0   ubyte           <48
->>>>>>>>>>>>0  use             dbase3-memo-print
+# skip AI070GEP.EPS with improbably high free block index
+>>>>>>>>>>0    lelong          <458766
+>>>>>>>>>>>0   use             dbase3-memo-print
 # dBASE IV DBT with positive block size
 >>>>>>>20      uleshort        >0
 # dBASE IV DBT with valid block length like 512, 1024
 # multiple of 2 in between 16 and 16 K ,implies upper and lower bits are zero
->>>>>>>>20     uleshort&0x800f 0
+# skip also 3600h 3E00h size
+>>>>>>>>20     uleshort&0xE00f 0
 >>>>>>>>>0     use             dbase4-memo-print
 
 #              Print the information of dBase III DBT memo file
 0      name                            dbase3-memo-print
 >0     ubyte                   x               dBase III DBT
+!:mime application/x-dbt
+!:ext  dbt
 # instead 3 as version number 0 for unusual examples like biblio.dbt
 >16    ubyte                   !3              \b, version number %u
 # Number of next available block for appending data
@@ -395,6 +392,7 @@
 >20    uleshort                !0              \b, block length %u
 # dBase III memo field terminated by \032\032
 >512   string                  >\0             \b, 1st item "%s"
+# https://www.clicketyclick.dk/databases/xbase/format/dbt.html
 #              Print the information of dBase IV DBT memo file
 0      name                            dbase4-memo-print
 >0             lelong          x               dBase IV DBT
@@ -433,9 +431,12 @@
 # length of memo field
 >>4            lelong          x               \b, field length %d
 >>>8           string          >\0             \b, 1st used item "%s"
+# http://www.dbfree.org/webdocs/1-documentation/0018-developers_stuff_(advanced)/os_related_stuff/xbase_file_format.htm
 #              Print the information of FoxPro FPT memo file
 0      name                            foxpro-memo-print
 >0             belong          x               FoxPro FPT
+!:mime application/x-fpt
+!:ext  fpt
 # Size of blocks for FoxPro ( 64,256 )
 >6             ubeshort        x               \b, blocks size %u
 # next available block