CodeTrawler by scideas software
scideas@iol.ie
Contents
What is CodeTrawler ?
Why ?
Using CodeTrawler
1 Setting the preferences
2 Loading text
3 Dictionary Menu
4 Search phrase
5 Search
6 The results
What is CodeTrawler ?
CodeTrawler is a skip code search tool. A skip code is a very simple way of
embedding encoded information into text; words are constructed by skipping a
number of characters in the text between encoded characters. In principal the
skip code might be variable (and there are an infinite number of other codes
that might be used) but CodeTrawler is limited to simple, fixed skip code searches.
For example, the line of text below contains the word elvis using a skip code
of -5:
she
had no desire to spurn Jimmy,
never-the-less the
way ahead led to ...
Why ?
In the middle ages a tradition of searching for coded messages in the Torah,
the Jewish Bible, was founded by a group of rabis who became known as the Kaballists.
Ever since people have searched texts for hidden meaning encoded using the skip
code method.
you can download plain text, single-file versions of the Old
Testament and New
Testament in English from the http://web.ukonline.co.uk/mr.hill/ site
Using CodeTrawler
The concept
Using specified text preparation and search parameters, CodeTrawler will find
any instances of a phrase you have provided and for each occurence will find
any possible messages encoded nearby in the text.
1 Setting
the preferences
text Preparation
A copy of the text to be searched is prepared to remove unwanted characters.
The original text file is NOT changed.
Set these before you load your text as the text is automatically processed
upon loading
Letters only removes all characters from
the text that are not in your current alphabet.
You might choose Remove spaces and Remove
punctuation instead if you wished to retain numerical characters.
Augment dictionary with text box allows the user dictionary to be updated with any new words from the loaded text (could take some time for a large document).
check Re-prepare text on close if you have
already loaded text and want it configured using parameters you have just entered.
Searching
use letters only in search phrase - checking
this will strip away any spaces you put in the search phrase. For example given
John Wayne CodeTrawler would actually search for JohnWayne.
Maximum skip code value - CodeTrawler will
try all skip codes up to and including this value, for both the search phrase
and any messages. This greatly affects speed so use a small value when testing.
Multi-word messages only - checking this
prevents single words from being reported as possible messages.
Message search area factor - this defines how big an area of text around
each occurence of the search phrase is trawled for possible messages. A value
of 0 will restrict the search to within the search phrase itself. A value of
1 will look within the search phrase and a search phrase length on either side.
A value of 2 will look in 2 search phrase lengths either side. When searching
for messages the search area is indicated with gray text ; use this to get a
feel for this parameter.
Minimum word length - discards any words
in any possible messages that have fewer letters than this value. For instance
setting this to 4 will reject pronouns.
2 Loading text
use the Load text button to navigate to your text file. you may load any kind
of file but text from a file that is not actually a text file will not be prepared
as well. The original text will appear in the text view on the left of the window;
the text view on the right will display any results using the prepared version
of the text.
A user dictionary may be used to supplement the Apple Spellchecker dictionary. This is accessed via the Dictionary menu.
Load Dictionary - load any text file, any words not in the Apple dictionary and not already in the user dictionary will be added to it.
Augment with Text - scans the loaded text for any new words and adds them to the user dictionary. This may take some time for a large document but will be particularly useful if names are of interest or for text written before the eighteenth century when no standard spelling existed.
Display Dictionary - opens a window from which the user dictionary may be viewed within a scrolling menu. Included only for verification.
Clear Dictionary - removes all items from
the user dictionary.
4 Search phrase
Type it into the box near the top of the window. CodeTrawler is case-insensitive.
Any spaces in your phrase will not be included in the search if you have checked
this box in the preferences.
5 Search
Hit the button and wait. CodeTrawler first finds all occurances of the search
phrase. An Abort buton appears at the bottom
of the controls section. Depending on the search parameters set, the search
may take a few seconds to abort. The application will respond during the search
but certain functions are unavailable: you cannot load text, start another search,
change the text size of the prepared text view or change preferences (but you
can look at them).
As soon as all occurances of the search phrase have been located, CodeTrawler
starts to examine each one for any possible messages nearby. Depending on the
parameters set, the number of occurances and the speed of your machine the complete
search might take a very long time.
6 The results
Here you can access details of the search results
The number of instances of the search phrase is shown and below this you can
select any one of them. this will provide the following:
view of that occurance in the prepared text view, with the phrase highlighted
in yellow
the skip code used to decode that instance of the search phrase
all possible messages found in the vicinity of that instance
Selecting one of the messages will highlight it in the prepared text in red
Please note that message searching relies on the Apple Spellchecker and this is flawed; for instance in the British English version vvv, vvvvv, vvvvvvvv etc are all valid words !
The Find in original button will attempt to find the location in the original text. This is approximate as the search phrase is not encoded in the original text. If successful, the area containing the search phrase is denoted by grey text. If un-successful an alert appears.
The Select/Highlight button (just above the Load button) toggles between allowing the selection and editting of either text view and allowing individual characters to be highlighted. With the button showing HL simply click on any character to highlight in cyan. Click again to remove the highlight.
Text size sliders allow the text size of
both the original and the prepared text views to be changed.