PDFlib Text Extraction Toolkit (TET) Manual

5.2 Resource Configuration and File Searching
UPR files and resource categories. In some situations TET needs access to resources
such as encoding definitions or glyph name mapping tables. In order to make resource
handling platform-independent and customizable, a configuration file can be supplied
for describing the available resources along with the names of their corresponding disk
files. In addition to a static configuration file, dynamic configuration can be accomplished
at runtime by adding resources with TET_set_option( ). For the configuration file
a simple text format called Unix PostScript Resource (UPR) is used. The UPR file format as
used by TET will be described below. TET supports the resource categories listed in Table
5.1.
Table 5.1 Resource categories (all file names must be specified in UTF-8)
category format 1
explanation
cmap key=value Resource name and file name of a CMap
codelist key=value Resource name and file name of a code list
encoding key=value Resource name and file name of an encoding
glyphlist key=value Resource name and file name of a glyph list
glyphmapping option list An option list describing a glyph mapping method according to Table 10.4,
page 132. This resource will be evaluated in TET_open_document( ), and
the result will be appended after the mappings specified in the option
glyphmapping of TET_open_document( ).
hostfont key=value Name of a host font resource (key is the PDF font name; value is the UTF-8
encoded host font name) to be used for an unembedded font
fontoutline key=value Font and file name of a TrueType or OpenType font to be used for an unembedded
font
searchpath value Relative or absolute path name of directories containing data files
1. While the UPR syntax requires an equal character ’=’ between the name and value, this character is neither required nor allowed
when specifying resources with TET_set_option( ).
The UPR file format. UPR files are text files with a very simple structure that can easily
be written in a text editor or generated automatically. To start with, let’s take a look at
some syntactical issues:
> Lines can have a maximum of 255 characters.
> A backslash ’\’ escapes newline characters. This may be used to extend lines.
> An isolated period character ’ . ’ serves as a section terminator.
> Comment lines may be introduced with a percent ’%’ character, and terminated by
the end of the line.
> Whitespace is ignored everywhere except in resource names and file names.
UPR files consist of the following components:
> A magic line for identifying the file. It has the following form:
PS-Resources-1.0
> A section listing all resource categories described in the file. Each line describes one
resource category. The list is terminated by a line with a single period character.
5.2 Resource Configuration and File Searching 51