| 1 | #
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| 2 | # PDF::Core.pm, version 1.11 February 2000 antro
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| 3 | #
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| 4 | # Copyright (c) 1998 - 2000 Antonio Rosella Italy [email protected], Johannes Blach [email protected]
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| 5 | #
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| 6 | # Free usage under the same Perl Licence condition.
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| 7 | #
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| 8 |
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| 9 | package PDF::Core;
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| 10 |
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| 11 | $PDF::Core::VERSION = "1.11";
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| 12 |
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| 13 | =pod
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| 14 |
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| 15 | =head1 NAME
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| 16 |
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| 17 | PDF::Core - Core Library for PDF library
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| 18 |
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| 19 | =head1 SYNOPSIS
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| 20 |
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| 21 | use PDF::Core;
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| 22 |
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| 23 | $pdf=PDF::Core->new ;
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| 24 | $pdf=PDF->new(filename);
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| 25 |
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| 26 | $res= $pdf->GetObject($ref);
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| 27 |
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| 28 | $name = UnQuoteName($pdfname);
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| 29 | $string = UnQuoteString($pdfstring);
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| 30 |
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| 31 | $pdfname = QuoteName($name);
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| 32 | $pdfhexstring = QuoteHexString($string);
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| 33 | $pdfstring = QuoteString($string);
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| 34 |
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| 35 | $obj = PDFGetPrimitive (filehandle, \$offset);
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| 36 | $line = PDFGetLine (filehandle, \$offset);
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| 37 |
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| 38 |
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| 39 | =head1 DESCRIPTION
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| 40 |
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| 41 | The main purpose of the PDF::Core library is to provide the data structure
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| 42 | and the constructor for the more general PDF library.
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| 43 |
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| 44 | =cut
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| 45 |
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| 46 | require 5.005;
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| 47 | use strict;
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| 48 | use Carp;
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| 49 | use Exporter ();
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| 50 |
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| 51 | use vars qw(@ISA @EXPORT_OK $UseObjectCache);
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| 52 |
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| 53 | @ISA = qw(Exporter);
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| 54 |
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| 55 | @EXPORT_OK = qw( GetObject );
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| 56 |
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| 57 | #
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| 58 | # Object caching
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| 59 | #
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| 60 | # If this variable is true, all processed objects will be added to the
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| 61 | # object cache. If only header information of a PDF are read or very
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| 62 | # big PDF are processed, turning off the cache reduces the memory usage.
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| 63 | #
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| 64 | $UseObjectCache = 1;
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| 65 |
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| 66 |
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| 67 | #################################################################
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| 68 | #
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| 69 | # Helper functions
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| 70 | #
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| 71 | #################################################################
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| 72 |
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| 73 | =pod
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| 74 |
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| 75 | =head1 Helper functions
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| 76 |
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| 77 | This functions are not part of the class, but perform useful services.
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| 78 |
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| 79 | =cut
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| 80 |
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| 81 | #
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| 82 | # Modification by johi: 18.12.1999
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| 83 | #
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| 84 |
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| 85 | #################################################################
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| 86 | =pod
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| 87 |
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| 88 | =head2 UnQuoteName ( string )
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| 89 |
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| 90 | This function processes quoted characters in a PDF-name. PDF-names returned by
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| 91 | B<GetObject> are already processed by this function.
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| 92 |
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| 93 | Returns a string.
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| 94 |
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| 95 | =cut
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| 96 |
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| 97 | sub UnQuoteName ($)
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| 98 | {
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| 99 | my $value = shift;
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| 100 | $value =~ s/#([\da-f]{2})/chr(hex($1))/ige;
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| 101 | return $value;
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| 102 | }
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| 103 |
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| 104 | #################################################################
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| 105 | =pod
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| 106 |
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| 107 | =head2 UnQuoteString ( string )
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| 108 |
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| 109 | This function extracts the text from PDF-strings and PDF-hexstrings.
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| 110 | It will process all quoted characters and remove the enclosing braces.
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| 111 |
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| 112 | WARNING: The current version doesn't handle unicode strings properly.
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| 113 |
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| 114 | Returns a string.
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| 115 |
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| 116 | =cut
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| 117 |
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| 118 | sub UnQuoteString ($)
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| 119 | {
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| 120 | #
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| 121 | # Translate quoted character.
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| 122 | #
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| 123 | my $param = shift;
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| 124 | my $value;
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| 125 | if (($value) = $param =~ m/^<(.*)>$/)
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| 126 | {
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| 127 | $value =~ tr/0-9A-Fa-f//cd;
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| 128 | $value .= "0" if (length ($value) % 2);
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| 129 | $value =~ s/([\da-f]{2})/chr(hex($1))/ige;
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| 130 | }
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| 131 | elsif (($value) = $param =~ m/^\((.*)\)$/)
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| 132 | {
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| 133 | my %quoted = ("n" => "\n", "r" => "\r",
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| 134 | "t" => "\t", "b" => "\b",
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| 135 | "f" => "\f", "\\" => "\\",
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| 136 | "(" => "(", ")" => ")");
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| 137 | $value =~ s/\\([nrtbf\\()]|[0-7]{1,3})/
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| 138 | defined ($quoted{$1}) ? $quoted{$1} : chr(oct($1))/gex;
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| 139 | }
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| 140 | else
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| 141 | {
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| 142 | $value = $param;
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| 143 | }
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| 144 |
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| 145 | return $value;
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| 146 | }
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| 147 |
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| 148 | #################################################################
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| 149 | =pod
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| 150 |
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| 151 | =head2 QuoteName ( string )
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| 152 |
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| 153 | This function quotes problematic characters in a PDF-name. This
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| 154 | function should be used before writing a PDF-name back to a PDF-file.
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| 155 |
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| 156 | Returns a string.
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| 157 |
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| 158 | =cut
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| 159 |
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| 160 | sub QuoteName ($)
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| 161 | {
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| 162 | my $value = shift;
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| 163 | $value =~ s/(?<!\A)([\x00-\x20\x7f-\xff%()\[\]<>\/{}#])/
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| 164 | sprintf ("#%2.2X", ord($1))/gex;
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| 165 | return $value;
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| 166 | }
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| 167 |
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| 168 | #################################################################
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| 169 | =pod
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| 170 |
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| 171 | =head2 QuoteHexString ( string )
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| 172 |
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| 173 | This function translates a string into a PDF-hexstring.
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| 174 |
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| 175 | Returns a string.
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| 176 |
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| 177 | =cut
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| 178 |
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| 179 | sub QuoteHexString ($)
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| 180 | {
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| 181 | my $value = shift;
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| 182 |
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| 183 | $value =~ s/(.)/sprintf ("%2.2X", ord($1))/ge;
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| 184 | return ("<" . $value . ">");
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| 185 | }
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| 186 |
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| 187 | #################################################################
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| 188 | =pod
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| 189 |
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| 190 | =head2 QuoteString ( string )
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| 191 |
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| 192 | This function translates a string into a PDF-string. Problematic
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| 193 | character will be quoted.
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| 194 |
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| 195 | WARNING: The current version doesn't handle unicode strings properly.
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| 196 |
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| 197 | Returns a string.
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| 198 |
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| 199 | =cut
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| 200 |
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| 201 | sub QuoteString ($)
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| 202 | {
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| 203 | #
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| 204 | # Only \character style quotes will be added. The really important
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| 205 | # characters to quote are: ()\
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| 206 | #
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| 207 | my $value = shift;
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| 208 |
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| 209 | my %quote = ("\n" => "\\n", "\r" => "\\r",
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| 210 | "\t" => "\\t", "\b" => "\\b",
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| 211 | "\f" => "\\f", "\\" => "\\\\",
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| 212 | "(" => "\\(", ")" => "\\)");
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| 213 | $value =~ s/([\n\r\t\b\f\\()])/$quote{$1}/g;
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| 214 | return ("(" . $value . ")");
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| 215 | }
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| 216 |
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| 217 | #################################################################
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| 218 | =pod
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| 219 |
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| 220 | =head2 PDFGetPrimitive ( filehandle, offset )
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| 221 |
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| 222 | This internal function is used while parsing a PDF-file. If you are
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| 223 | not writing extentions for this library and are parsing some special
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| 224 | parts of the PDF-file, stay away and use B<GetObject> instead.
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| 225 |
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| 226 | This function has many quirks and limitations. Check the source for details.
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| 227 |
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| 228 | =cut
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| 229 |
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| 230 | sub PDFGetPrimitive (*\$)
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| 231 | {
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| 232 | my $fd = shift;
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| 233 | my $offset = shift;
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| 234 |
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| 235 | binmode $fd;
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| 236 | seek $fd, $$offset, 0;
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| 237 |
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| 238 | my $state = 0;
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| 239 | my $buffer;
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| 240 | my @collector;
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| 241 | my $lastchar;
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| 242 |
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| 243 | while ()
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| 244 | {
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| 245 | # File offset is positioned on start of stream.
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| 246 | last if ($state == -4);
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| 247 |
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| 248 | $state = 0;
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| 249 |
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| 250 | # Process last element
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| 251 | if ($#collector >= 0)
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| 252 | {
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| 253 | my $lastvalue = $collector[$#collector];
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| 254 |
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| 255 | if ($lastvalue eq "R")
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| 256 | {
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| 257 | # Process references
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| 258 | if ($#collector >= 2
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| 259 | && $collector[$#collector - 1] =~ m/\d+/
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| 260 | && $collector[$#collector - 2] =~ m/\d+/)
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| 261 | {
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| 262 | $collector[$#collector - 2] .= join (" ",
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| 263 | "", @collector[$#collector - 1, $#collector]);
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| 264 | $#collector -= 2;
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| 265 | }
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| 266 | else
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| 267 | {
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| 268 | carp "Bad reference at offset ", $$offset;
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| 269 | }
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| 270 | }
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| 271 | elsif ($lastvalue eq "endobj")
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| 272 | {
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| 273 | # End of object
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| 274 | last;
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| 275 | }
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| 276 | elsif ($lastvalue eq "stream")
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| 277 | {
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| 278 | # End of object
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| 279 | $state = -4;
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| 280 | }
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| 281 | }
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| 282 |
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| 283 | # Set state for next element
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| 284 | if ($buffer eq "[")
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| 285 | {
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| 286 | # Read array
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| 287 | $buffer = "";
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| 288 | push @collector, [ PDFGetPrimitive ($fd, $offset) ];
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| 289 | }
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| 290 | elsif ($buffer eq "<<")
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| 291 | {
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| 292 | # Read dictionary
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| 293 | $buffer = "";
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| 294 | push @collector, { PDFGetPrimitive ($fd, $offset) };
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| 295 | }
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| 296 | elsif ($buffer eq "(")
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| 297 | {
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| 298 | # Here comes a string
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| 299 | $state = 1;
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| 300 | $lastchar = "";
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| 301 | }
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| 302 | elsif ($buffer eq "<")
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| 303 | {
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| 304 | # Here comes a hex string
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| 305 | $state = -1;
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| 306 | }
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| 307 | elsif ($buffer eq ">")
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| 308 | {
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| 309 | # Wait for next > to terminate dictionary
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| 310 | $state = -2;
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| 311 | }
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| 312 | elsif ($buffer eq "%")
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| 313 | {
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| 314 | # Skip comments
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| 315 | $state = -3;
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| 316 | $buffer = "";
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| 317 | }
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| 318 | elsif ($buffer eq "]")
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| 319 | {
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| 320 | last;
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| 321 | }
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| 322 | elsif ($buffer eq ">>")
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| 323 | {
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| 324 | last;
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| 325 | }
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| 326 |
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| 327 | # Read next item
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| 328 | while (read ($fd, $_, 1))
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| 329 | {
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| 330 | $$offset++;
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| 331 |
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| 332 | if ($state == 0)
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| 333 | {
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| 334 | # Normal mode
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| 335 | if (m/[^\x00-\x20\x7f-\xff%()\[\]<>\/]/)
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| 336 | {
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| 337 | # Normal character inside a name or number
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| 338 | $buffer .= $_;
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| 339 | }
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| 340 | elsif (m/[\/\(\[\]\<\>%]/)
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| 341 | {
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| 342 | if ($buffer ne "")
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| 343 | {
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| 344 | # A new item starts
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| 345 | if ($buffer =~ m/^\//)
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| 346 | {
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| 347 | push @collector, UnQuoteName ($buffer);
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| 348 | }
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| 349 | else
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| 350 | {
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| 351 | push @collector, $buffer;
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| 352 | }
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| 353 | }
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| 354 | $buffer = $_;
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| 355 | last;
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| 356 | }
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| 357 | elsif (m/\s/)
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| 358 | {
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| 359 | # All kind of whitespaces are ignored
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| 360 | if ($buffer ne "")
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| 361 | {
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| 362 | # The old item is done starts
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| 363 | if ($buffer =~ m/^\//)
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| 364 | {
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| 365 | push @collector, UnQuoteName ($buffer);
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| 366 | }
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| 367 | else
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| 368 | {
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| 369 | push @collector, $buffer;
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| 370 | }
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| 371 | $buffer = "";
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| 372 | last;
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| 373 | }
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| 374 | }
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| 375 | else
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| 376 | {
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| 377 | # Strange character. Should not exist.
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| 378 | # Complain and move on.
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| 379 | carp "Strange character '", $_, "' at offset ",
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| 380 | $$offset, " in mode ", $state, " detected";
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| 381 | $buffer .= $_;
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| 382 | }
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| 383 | }
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| 384 | elsif ($state > 0)
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| 385 | {
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| 386 | # We have a string
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| 387 |
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| 388 | if ($lastchar =~ m/\\[\r\n]+/ && m/[^\r\n]/)
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| 389 | {
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| 390 | # Clean up after line continuation
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| 391 | $lastchar = "";
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| 392 | }
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| 393 |
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| 394 | if ($lastchar =~ m/\\[\r\n]*/)
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| 395 | {
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| 396 | # Process character after backslash
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| 397 | if (m/[\r\n]/)
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| 398 | {
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| 399 | # end of line
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| 400 | $lastchar .= $_;
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| 401 | }
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| 402 | else
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| 403 | {
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| 404 | # Just a quote
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| 405 | $buffer .= $lastchar . $_;
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| 406 | $lastchar = "";
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| 407 | }
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| 408 | }
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| 409 | else
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| 410 | {
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| 411 | if ($_ eq "\\")
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| 412 | {
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| 413 | # Quoted string starts
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| 414 | $lastchar = $_;
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| 415 | }
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| 416 | elsif ($_ eq "(")
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| 417 | {
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| 418 | # Count braces
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| 419 | $buffer .= $_;
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| 420 | $state ++;
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| 421 | }
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| 422 | elsif ($_ eq ")")
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| 423 | {
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| 424 | # End of string
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| 425 | $buffer .= $_;
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| 426 | unless (-- $state)
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| 427 | {
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| 428 | push @collector, $buffer;
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| 429 | $buffer = "";
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| 430 | last;
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| 431 | }
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| 432 | }
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| 433 | else
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| 434 | {
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| 435 | $buffer .= $_;
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| 436 | }
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| 437 | }
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| 438 | }
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| 439 | elsif ($state == -1)
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| 440 | {
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| 441 | if (m/[0-9a-f\s]/i)
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| 442 | {
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| 443 | # Hex character
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| 444 | $buffer .= $_;
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| 445 | }
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| 446 | elsif ($_ eq ">")
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| 447 | {
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| 448 | # End of string
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| 449 | $buffer .= $_;
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| 450 | push @collector, $buffer;
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| 451 | $buffer = "";
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| 452 | last;
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| 453 | }
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| 454 | elsif ($_ eq "<" && $buffer eq "<")
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| 455 | {
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| 456 | # This is not a string, but a dictionary instead
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| 457 | $buffer .= $_;
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| 458 | last;
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| 459 | }
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| 460 | else
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| 461 | {
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| 462 | # Should not be there. Complain and add it to the $buffer
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| 463 | carp "Bad character '", $_ , "' in hex string";
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| 464 | $buffer .= $_;
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| 465 | }
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| 466 | }
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| 467 | elsif ($state == -2)
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| 468 | {
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| 469 | # Wait for second > to terminate dictionary
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| 470 |
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| 471 | # Some sanity checks
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| 472 | carp "Character '", $_, "' appeared while waiting for '>'"
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| 473 | if ($_ ne ">");
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| 474 | carp "Buffer contains '", $buffer, "' and not '>'"
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| 475 | if ($buffer ne ">");
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| 476 |
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| 477 | $buffer = ">>";
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| 478 | last;
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| 479 | }
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| 480 | elsif ($state == -3)
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| 481 | {
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| 482 | # Skip comments;
|
|---|
| 483 | last if (m/[\r\n]/);
|
|---|
| 484 | }
|
|---|
| 485 | elsif ($state == -4)
|
|---|
| 486 | {
|
|---|
| 487 | # Wait for newline to start stream
|
|---|
| 488 |
|
|---|
| 489 | if ($_ eq "\n")
|
|---|
| 490 | {
|
|---|
| 491 | # Some sanity checks
|
|---|
| 492 | carp "Text '", $buffer,
|
|---|
| 493 | "' appeared while waiting for start of stream"
|
|---|
| 494 | if ($buffer ne "");
|
|---|
| 495 |
|
|---|
| 496 | $buffer = "";
|
|---|
| 497 | last;
|
|---|
| 498 | }
|
|---|
| 499 | elsif (m/\S/)
|
|---|
| 500 | {
|
|---|
| 501 | $buffer .= $_;
|
|---|
| 502 | }
|
|---|
| 503 | }
|
|---|
| 504 | else
|
|---|
| 505 | {
|
|---|
| 506 | # Unhandled status. Complain and reset
|
|---|
| 507 | carp "Unhandled status ", $state;
|
|---|
| 508 | }
|
|---|
| 509 | }
|
|---|
| 510 | if ($_ eq "")
|
|---|
| 511 | {
|
|---|
| 512 | # Unhandled status. Complain and reset
|
|---|
| 513 | carp "Premature end of file reached";
|
|---|
| 514 |
|
|---|
| 515 | if ($buffer ne "")
|
|---|
| 516 | {
|
|---|
| 517 | push @collector, $buffer;
|
|---|
| 518 | $buffer = "";
|
|---|
| 519 | }
|
|---|
| 520 | last;
|
|---|
| 521 | }
|
|---|
| 522 | }
|
|---|
| 523 |
|
|---|
| 524 | return @collector;
|
|---|
| 525 | }
|
|---|
| 526 |
|
|---|
| 527 | #################################################################
|
|---|
| 528 | =pod
|
|---|
| 529 |
|
|---|
| 530 | =head2 PDFGetline ( filehandle, offset )
|
|---|
| 531 |
|
|---|
| 532 | This internal function was used to read a line from a PDF-file. It has
|
|---|
| 533 | many limitations and you should stay away from it, if you don't know
|
|---|
| 534 | what you are doing. Use B<GetObject> or B<PDFGetPrimitive> instead.
|
|---|
| 535 |
|
|---|
| 536 | =cut
|
|---|
| 537 |
|
|---|
| 538 | sub PDFGetline {
|
|---|
| 539 | #
|
|---|
| 540 | # BUG WARNING:
|
|---|
| 541 | #
|
|---|
| 542 | # This function returns only one line, which doesn't mean anything most of the
|
|---|
| 543 | # time. Except for the fileheader and the xref-table, linebreaks can (and will!)
|
|---|
| 544 | # occur everywhere in a PDF and are just whitespace. You may find only part of a
|
|---|
| 545 | # PDF-primitve on one line, or more than one of them.
|
|---|
| 546 | #
|
|---|
| 547 | # If you want to read PDF-Primitves, use the function PDFGetPrimitive instead.
|
|---|
| 548 | #
|
|---|
| 549 | my $fd = shift;
|
|---|
| 550 | my $offset=shift;
|
|---|
| 551 |
|
|---|
| 552 | my $buffer;
|
|---|
| 553 | my $endflag=1;
|
|---|
| 554 |
|
|---|
| 555 | binmode $fd;
|
|---|
| 556 | seek $fd, $$offset, 0;
|
|---|
| 557 |
|
|---|
| 558 | read($fd,$buffer,2);
|
|---|
| 559 | $buffer =~ s/^\r?\n?// ;
|
|---|
| 560 |
|
|---|
| 561 | $$offset +=2;
|
|---|
| 562 |
|
|---|
| 563 | while ($endflag) {
|
|---|
| 564 | read($fd,$_,1);
|
|---|
| 565 | $$offset++;
|
|---|
| 566 | $endflag = 0 if ( $_ eq "\r" || $_ eq "\n");
|
|---|
| 567 | $buffer = $buffer . $_ ;
|
|---|
| 568 | }
|
|---|
| 569 | return $buffer;
|
|---|
| 570 | }
|
|---|
| 571 |
|
|---|
| 572 | #################################################################
|
|---|
| 573 | #
|
|---|
| 574 | # Constructors
|
|---|
| 575 | #
|
|---|
| 576 | #################################################################
|
|---|
| 577 |
|
|---|
| 578 | =pod
|
|---|
| 579 |
|
|---|
| 580 | =head1 Constructor
|
|---|
| 581 |
|
|---|
| 582 | =cut
|
|---|
| 583 |
|
|---|
| 584 | #################################################################
|
|---|
| 585 | =pod
|
|---|
| 586 |
|
|---|
| 587 | =head2 new ( [ filename ] )
|
|---|
| 588 |
|
|---|
| 589 | This is the constructor of a new PDF object. If the filename is
|
|---|
| 590 | missing, it returns an empty PDF descriptor ( can be filled with
|
|---|
| 591 | $pdf->TargetFile). Otherwise, It acts as the B<PDF::Parse::TargetFile>
|
|---|
| 592 | method.
|
|---|
| 593 |
|
|---|
| 594 | =cut
|
|---|
| 595 |
|
|---|
| 596 | sub new {
|
|---|
| 597 |
|
|---|
| 598 | my %PDF_Fields = (
|
|---|
| 599 | File_Name => undef, # Name of file
|
|---|
| 600 | File_Handler => undef, # Open handle to file
|
|---|
| 601 | Header => undef, # Identification string
|
|---|
| 602 |
|
|---|
| 603 | Objects => [], # Offset of objects
|
|---|
| 604 | Gen_Num => [], # Genereation number of objects
|
|---|
| 605 | Object_Length => [], # Length of processed objects
|
|---|
| 606 | Object_Cache => {}, # Cache for objects.
|
|---|
| 607 | Page => [], # Information about all pages. Useful.
|
|---|
| 608 |
|
|---|
| 609 | Updated => 0, # Is the PDF updated
|
|---|
| 610 | Last_XRef_Offset => undef, # File offset of active Xref table
|
|---|
| 611 | Trailer => {}, # Content of active trailer
|
|---|
| 612 | Info => {}, # Content of active info object
|
|---|
| 613 | Catalog => {}, # Content of catalog
|
|---|
| 614 | PageTree => {}, # Content of root page
|
|---|
| 615 | );
|
|---|
| 616 | my $that = shift;
|
|---|
| 617 | my $class=ref($that) || $that ;
|
|---|
| 618 | my $self = \%PDF_Fields ;
|
|---|
| 619 | my $buf2=bless $self, $class;
|
|---|
| 620 | if ( @_ ) { # I have the filename
|
|---|
| 621 | $buf2->TargetFile($_[0]) ;
|
|---|
| 622 | }
|
|---|
| 623 | return bless $self, $class;
|
|---|
| 624 | };
|
|---|
| 625 |
|
|---|
| 626 | #################################################################
|
|---|
| 627 | sub DESTROY {
|
|---|
| 628 | #
|
|---|
| 629 | # Close the file if not empty
|
|---|
| 630 | #
|
|---|
| 631 | my $self = shift;
|
|---|
| 632 | close ( $self->{File_Handler} ) if $self->{File_Handler} ;
|
|---|
| 633 | }
|
|---|
| 634 |
|
|---|
| 635 | #################################################################
|
|---|
| 636 | #
|
|---|
| 637 | # Methods
|
|---|
| 638 | #
|
|---|
| 639 | #################################################################
|
|---|
| 640 |
|
|---|
| 641 | =pod
|
|---|
| 642 |
|
|---|
| 643 | =head1 Methods
|
|---|
| 644 |
|
|---|
| 645 | The available methods are:
|
|---|
| 646 |
|
|---|
| 647 | =cut
|
|---|
| 648 |
|
|---|
| 649 | #################################################################
|
|---|
| 650 | =pod
|
|---|
| 651 |
|
|---|
| 652 | =head2 GetObject (reference)
|
|---|
| 653 |
|
|---|
| 654 | This methods returns the PDF-object for B<reference>. The string
|
|---|
| 655 | B<reference> must match the regular expression /^\d+ \d+ R$/,
|
|---|
| 656 | where the first number is the object number, the second number the
|
|---|
| 657 | generation number.
|
|---|
| 658 |
|
|---|
| 659 | The return value is a PDF-primitive, the type depends on the content
|
|---|
| 660 | of the object:
|
|---|
| 661 |
|
|---|
| 662 | =over
|
|---|
| 663 |
|
|---|
| 664 | =item B<undef>
|
|---|
| 665 |
|
|---|
| 666 | The object could not be found or an error. Not all referenced objects
|
|---|
| 667 | need to be present in a PDF-file. This value can be ignored.
|
|---|
| 668 |
|
|---|
| 669 | =item B<Hash Reference>
|
|---|
| 670 |
|
|---|
| 671 | If (UNIVERSAL::isa ($retval, "HASH") is true, the object is a
|
|---|
| 672 | PDF-dictionary. The keys of the hash should be either a PDF name (eg:
|
|---|
| 673 | /MediaBox) or a generated value like Stream_Offset. Everything else is
|
|---|
| 674 | an error.
|
|---|
| 675 |
|
|---|
| 676 | The values of the hash can be any PDF-primitive, including PDF-arrays
|
|---|
| 677 | and other dictionaries.
|
|---|
| 678 |
|
|---|
| 679 | This is the most common value returned by GetObject. If the key
|
|---|
| 680 | Stream_Offset exists, the dictionary is followed by stream data,
|
|---|
| 681 | starting at the file offeset indicated by this value.
|
|---|
| 682 |
|
|---|
| 683 | =item B<Array Reference>
|
|---|
| 684 |
|
|---|
| 685 | If (UNIVERSAL::isa ($retval, "ARRAY") is true, the object is a
|
|---|
| 686 | PDF-array. Each element may be of a different type, and may contain
|
|---|
| 687 | further references to arrays or any other PDF-primitive.
|
|---|
| 688 |
|
|---|
| 689 | =item B<String matching /^\d+ \d+ R$/>
|
|---|
| 690 |
|
|---|
| 691 | This is a reference to another PDF-Object. This value can be passed to
|
|---|
| 692 | GetObject. This kind of value may appear instead of most other types.
|
|---|
| 693 | Some PDF-writing programs seem to have special fun writing references
|
|---|
| 694 | when a simple number is expected. If the final number is need, use
|
|---|
| 695 | code like this to resolve references:
|
|---|
| 696 |
|
|---|
| 697 | while ($len =~ m/^\d+ \d+ R$/) {$len = $self->GetObject ($len); }
|
|---|
| 698 |
|
|---|
| 699 | Example: 22 0 R
|
|---|
| 700 |
|
|---|
| 701 | =item B<String matching /^\//>
|
|---|
| 702 |
|
|---|
| 703 | This is a Name in a PDF dictionary. This string is already processed
|
|---|
| 704 | by B<UnQuotName> and may differ from the value in the PDF-file. In
|
|---|
| 705 | some very old andstrange non-standard PDF-files, this may lead to
|
|---|
| 706 | confusion.
|
|---|
| 707 |
|
|---|
| 708 | Example: /MediaBox
|
|---|
| 709 |
|
|---|
| 710 | =item B<String matching /^\(.*\)$/>
|
|---|
| 711 |
|
|---|
| 712 | This is a string. It may contain newlines, quoted characters und other
|
|---|
| 713 | strange stuff. Use PDF::UnQuoteString to extract the text.
|
|---|
| 714 |
|
|---|
| 715 | Example: (This is\na string with two \(2\) lines.)
|
|---|
| 716 |
|
|---|
| 717 | =item B<String matching /^E<lt>.*E<gt>$/>
|
|---|
| 718 |
|
|---|
| 719 | This is a hex encoded string. Use PDF::UnQuoteString to extract the text.
|
|---|
| 720 |
|
|---|
| 721 | Example: E<lt>48 45 4c4C4 F1cE<gt>
|
|---|
| 722 |
|
|---|
| 723 | =item B<String matching /^[\d.\+\-]+$/>
|
|---|
| 724 |
|
|---|
| 725 | This is probably a number.
|
|---|
| 726 |
|
|---|
| 727 | Example: 611
|
|---|
| 728 |
|
|---|
| 729 | =item B<String matching none of the above>
|
|---|
| 730 |
|
|---|
| 731 | this is either a PDF bareword (eg. true, false, ...) or a value
|
|---|
| 732 | generated by this method like Stream_Offset.
|
|---|
| 733 |
|
|---|
| 734 | Example: true
|
|---|
| 735 |
|
|---|
| 736 | =back
|
|---|
| 737 |
|
|---|
| 738 | To improve performance GetObject uses an internal cache for objects.
|
|---|
| 739 | Repeated requests for the same objects are not read form the file but
|
|---|
| 740 | satisfied from the cache. With the Variable B<$PDF::Core::UseObjectCache>,
|
|---|
| 741 | the caching mechanism can be turned off.
|
|---|
| 742 |
|
|---|
| 743 | B<WARNING>
|
|---|
| 744 |
|
|---|
| 745 | Special care must be taken, when returned objects are modified. If the
|
|---|
| 746 | object contains sub-objects, the sub-objects are not duplicated and
|
|---|
| 747 | all changes affect all other copies of this object. Use your own copy,
|
|---|
| 748 | if you need to modify those values.
|
|---|
| 749 |
|
|---|
| 750 | =cut
|
|---|
| 751 |
|
|---|
| 752 | sub GetObject (\*$;$)
|
|---|
| 753 | {
|
|---|
| 754 | my $self = shift;
|
|---|
| 755 | my $ref = shift;
|
|---|
| 756 | my $force = shift;
|
|---|
| 757 |
|
|---|
| 758 | #
|
|---|
| 759 | # Is PDF file open?
|
|---|
| 760 | #
|
|---|
| 761 | croak "PDF-file not open." unless ($self->{"File_Handler"});
|
|---|
| 762 |
|
|---|
| 763 | #
|
|---|
| 764 | # Check reference
|
|---|
| 765 | #
|
|---|
| 766 | my ($ind, $gen);
|
|---|
| 767 | unless (($ind,$gen) = $ref =~ m/^(\d+) (\d+) R$/)
|
|---|
| 768 | {
|
|---|
| 769 | carp "Bad object reference '", $_, "'";
|
|---|
| 770 | return undef;
|
|---|
| 771 | }
|
|---|
| 772 | if ($ind > $#{$self->{"Gen_Num"}} || $self->{"Gen_Num"}[$ind] != $gen)
|
|---|
| 773 | {
|
|---|
| 774 | #
|
|---|
| 775 | # The page does not exist. According to the PDF specification,
|
|---|
| 776 | # this is not an error.
|
|---|
| 777 | #
|
|---|
| 778 | return undef;
|
|---|
| 779 | }
|
|---|
| 780 |
|
|---|
| 781 | # Remove leading zero for cache key.
|
|---|
| 782 | $ind += 0;
|
|---|
| 783 | # Check cache
|
|---|
| 784 | if ($UseObjectCache && ! $force
|
|---|
| 785 | && defined($self->{"Object_Cache"}{$ind}))
|
|---|
| 786 | {
|
|---|
| 787 | return $self->{"Object_Cache"}{$ind};
|
|---|
| 788 | }
|
|---|
| 789 |
|
|---|
| 790 | my $offset = $self->{"Objects"}[$ind];
|
|---|
| 791 | my @data = PDFGetPrimitive ($self->{"File_Handler"}, $offset);
|
|---|
| 792 |
|
|---|
| 793 | unless ($#data == 4 && $data[0] == $ind
|
|---|
| 794 | && $data[1] == $gen && $data[2] eq "obj")
|
|---|
| 795 | {
|
|---|
| 796 | carp "Object mismatch: Got '", join (" ", @data[0..2]),
|
|---|
| 797 | "' instead of '", join (" ", $ind, $gen, "obj"), "'";
|
|---|
| 798 | return;
|
|---|
| 799 | }
|
|---|
| 800 |
|
|---|
| 801 | #
|
|---|
| 802 | # An object is not always a dictionary. In such cases,
|
|---|
| 803 | # adding additional keys breaks the content.
|
|---|
| 804 | #
|
|---|
| 805 | if (UNIVERSAL::isa ($data[3], "HASH"))
|
|---|
| 806 | {
|
|---|
| 807 | if ($data[4] eq "stream")
|
|---|
| 808 | {
|
|---|
| 809 | #
|
|---|
| 810 | # Find end of a stream object
|
|---|
| 811 | #
|
|---|
| 812 | $data[3]{"Stream_Offset"} = $offset;
|
|---|
| 813 | my $len = $data[3]{"/Length"};
|
|---|
| 814 |
|
|---|
| 815 | # Length can be a reference to another object.
|
|---|
| 816 | # Resolve references in this case till something else appears.
|
|---|
| 817 | while ($len =~ m/^\d+ \d+ R$/)
|
|---|
| 818 | {
|
|---|
| 819 | $len = $self->GetObject ($len);
|
|---|
| 820 | }
|
|---|
| 821 |
|
|---|
| 822 | # Skip stream
|
|---|
| 823 | if ($len =~ m/^\d+$/)
|
|---|
| 824 | {
|
|---|
| 825 | $offset += $len;
|
|---|
| 826 | }
|
|---|
| 827 | else
|
|---|
| 828 | {
|
|---|
| 829 | carp "Strange: /Length resolves to '", $len, "' in object ",
|
|---|
| 830 | join (" ", @data[0..2]);
|
|---|
| 831 | }
|
|---|
| 832 |
|
|---|
| 833 | my @enddata = PDFGetPrimitive ($self->{"File_Handler"}, $offset);
|
|---|
| 834 | $data[4] = $enddata[$#enddata];
|
|---|
| 835 | }
|
|---|
| 836 | }
|
|---|
| 837 |
|
|---|
| 838 | #
|
|---|
| 839 | # Save length of object.
|
|---|
| 840 | #
|
|---|
| 841 | $self->{"Object_Length"}[$ind] = $offset - $self->{"Objects"}[$ind];
|
|---|
| 842 |
|
|---|
| 843 | carp "Bad object termination '", $data[4], "' in object ",
|
|---|
| 844 | join (" ", @data[0..2]) if ($data[4] ne "endobj");
|
|---|
| 845 |
|
|---|
| 846 |
|
|---|
| 847 | # Update cache
|
|---|
| 848 | $self->{"Object_Cache"}{$ind} = $data[3] if ($UseObjectCache);
|
|---|
| 849 |
|
|---|
| 850 | return $data[3];
|
|---|
| 851 | }
|
|---|
| 852 |
|
|---|
| 853 | #
|
|---|
| 854 | # End of Modification by johi: 18.12.1999
|
|---|
| 855 | #
|
|---|
| 856 | #################################################################
|
|---|
| 857 |
|
|---|
| 858 |
|
|---|
| 859 | 1;
|
|---|
| 860 | __END__
|
|---|
| 861 |
|
|---|
| 862 | =pod
|
|---|
| 863 |
|
|---|
| 864 | =head1 Variables
|
|---|
| 865 |
|
|---|
| 866 | Available variables are:
|
|---|
| 867 |
|
|---|
| 868 | =over 4
|
|---|
| 869 |
|
|---|
| 870 | =item B<$PDF::Core::VERSION>
|
|---|
| 871 |
|
|---|
| 872 | Contains the version of the library installed
|
|---|
| 873 |
|
|---|
| 874 | =item B<$PDF::Core::UseObjectCache>
|
|---|
| 875 |
|
|---|
| 876 | If this variable is true, all processed objects will be added to the
|
|---|
| 877 | object cache. If only header information of a PDF are read or very big
|
|---|
| 878 | PDF are processed, turning off the cache reduces the memory usage.
|
|---|
| 879 |
|
|---|
| 880 | =back 4
|
|---|
| 881 |
|
|---|
| 882 | =head1 Copyright
|
|---|
| 883 |
|
|---|
| 884 | Copyright (c) 1998 - 2000 Antonio Rosella Italy [email protected], Johannes Blach [email protected]
|
|---|
| 885 |
|
|---|
| 886 | This library is free software; you can redistribute it and/or
|
|---|
| 887 | modify it under the same terms as Perl itself.
|
|---|
| 888 |
|
|---|
| 889 | =head1 Availability
|
|---|
| 890 |
|
|---|
| 891 | The latest version of this library is likely to be available from:
|
|---|
| 892 |
|
|---|
| 893 | http://www.geocities.com/CapeCanaveral/Hangar/4794/
|
|---|
| 894 |
|
|---|
| 895 | =cut
|
|---|
