--- trunk/IsisDB.pm 2004/12/31 07:16:02 26 +++ trunk/IsisDB.pm 2005/01/05 15:46:26 32 @@ -9,7 +9,7 @@ BEGIN { use Exporter (); use vars qw ($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS); - $VERSION = 0.08; + $VERSION = 0.09; @ISA = qw (Exporter); #Give a hoot don't pollute, do not export more than needed by default @EXPORT = qw (); @@ -30,14 +30,15 @@ isisdb => './cds/cds', ); - for(my $mfn = 1; $mfn <= $isis->{'maxmfn'}; $mfn++) { + for(my $mfn = 1; $mfn <= $isis->count; $mfn++) { print $isis->to_ascii($mfn),"\n"; } =head1 DESCRIPTION This module will read ISIS databases created by DOS CDS/ISIS, WinIsis or -IsisMarc. It can be used as perl-only alternative to OpenIsis module. +IsisMarc. It can be used as perl-only alternative to OpenIsis module which +seems to depriciate it's old C bindings for perl. It can create hash values from data in ISIS database (using C), ASCII dump (using C) or just hash with field names and packed @@ -50,7 +51,7 @@ It also has support for identifiers (only if ISIS database is created by IsisMarc), see C. -This will module will always be slower than OpenIsis module which use C +This module will always be slower than OpenIsis module which use C library. However, since it's written in perl, it's platform independent (so you don't need C compiler), and can be easily modified. I hope that it creates data structures which are easier to use than ones created by @@ -122,8 +123,6 @@ =back -It will also set C<$isis-E{'maxmfn'}> which is maximum MFN stored in database. - =cut sub new { @@ -198,9 +197,6 @@ read($self->{'fileMST'}, $buff, 4); $self->{'NXTMFN'}=unpack("l",$buff) || carp "NXTNFN is zero"; - # save maximum MFN - $self->{'maxmfn'} = $self->{'NXTMFN'} - 1; - @@ -212,13 +208,29 @@ $self ? return $self : return undef; } +=head2 count + +Return number of records in database + + print $isis->count; + +=cut + +sub count { + my $self = shift; + return $self->{'NXTMFN'} - 1; +} + =head2 read_cnt -This function is not really used by module, but can be useful to find info -about your index (if debugging it for example). +Read content of C<.CNT> file and return hash containing it. print Dumper($isis->read_cnt); +This function is not used by module (C<.CNT> files are not required for this +module to work), but it can be useful to examine your index (while debugging +for example). + =cut sub read_cnt { @@ -230,36 +242,6 @@ open(fileCNT, $self->{cnt_file}) || croak "can't read '$self->{cnt_file}': $!"; - # There is two 26 Bytes fixed lenght records - - # 0: IDTYPE BTree type 16 - # 2: ORDN Nodes Order 16 - # 4: ORDF Leafs Order 16 - # 6: N Number of Memory buffers for nodes 16 - # 8: K Number of buffers for first level index 16 - # 10: LIV Current number of Index Levels 16 - # 12: POSRX* Pointer to Root Record in N0x 32 - # 16: NMAXPOS* Next Available position in N0x 32 - # 20: FMAXPOS* Next available position in L0x 32 - # 24: ABNORMAL Formal BTree normality indicator 16 - # length: 26 bytes - - sub unpack_cnt { - my $self = shift; - - my @flds = qw(ORDN ORDF N K LIV POSRX NMAXPOS FMAXPOS ABNORMAL); - - my $buff = shift || return; - my @arr = unpack("ssssssllls", $buff); - - print STDERR "unpack_cnt: ",join(" ",@arr),"\n" if ($self->{'debug'}); - - my $IDTYPE = shift @arr; - foreach (@flds) { - $self->{cnt}->{$IDTYPE}->{$_} = abs(shift @arr); - } - } - my $buff; read(fileCNT, $buff, 26); @@ -273,6 +255,45 @@ return $self->{cnt}; } +=head2 unpack_cnt + +Unpack one of two 26 bytes fixed length record in C<.CNT> file. + +Here is definition of record: + + off key description size + 0: IDTYPE BTree type s + 2: ORDN Nodes Order s + 4: ORDF Leafs Order s + 6: N Number of Memory buffers for nodes s + 8: K Number of buffers for first level index s + 10: LIV Current number of Index Levels s + 12: POSRX Pointer to Root Record in N0x l + 16: NMAXPOS Next Available position in N0x l + 20: FMAXPOS Next available position in L0x l + 24: ABNORMAL Formal BTree normality indicator s + length: 26 bytes + +This will fill C<$self> object under C with hash. It's used by C. + +=cut + +sub unpack_cnt { + my $self = shift; + + my @flds = qw(ORDN ORDF N K LIV POSRX NMAXPOS FMAXPOS ABNORMAL); + + my $buff = shift || return; + my @arr = unpack("ssssssllls", $buff); + + print STDERR "unpack_cnt: ",join(" ",@arr),"\n" if ($self->{'debug'}); + + my $IDTYPE = shift @arr; + foreach (@flds) { + $self->{cnt}->{$IDTYPE}->{$_} = abs(shift @arr); + } +} + =head2 fetch Read record with selected MFN @@ -420,11 +441,11 @@ =head2 to_ascii -Dump ASCII output of record with specified MFN +Returns ASCII output of record with specified MFN print $isis->to_ascii(42); -It outputs something like this: +This outputs something like this: 210 ^aNew York^cNew York University press^dcop. 1988 990 2140 @@ -461,7 +482,7 @@ my $hash = $isis->to_hash($mfn); -It has ability to convert characters (using C from ISIS +It has ability to convert characters (using C) from ISIS database before creating structures enabling character re-mapping or quick fix-up of data. @@ -557,7 +578,18 @@ =head1 BUGS -This module has been very lightly tested. Use with caution and report bugs. +Some parts of CDS/ISIS documentation are not detailed enough to exmplain +some variations in input databases which has been tested with this module. +When I was in doubt, I assumed that OpenIsis's implementation was right +(except for obvious bugs). + +However, every effort has been made to test this module with as much +databases (and programs that create them) as possible. + +I would be very greatful for success or failure reports about usage of this +module with databases from programs other than WinIsis and IsisMarc. I had +tested this against ouput of one C-based application, but I don't +know any details about it's version. =head1 AUTHOR