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+\documentclass{book}
+\usepackage{html}
+\usepackage{fancyheadings}
+\usepackage{graphicx}
+
+\begin{document}
+
+\vspace*{\stretch{2}}
+
+\begin{center}
+\par
+Copyright \copyright\ 2001, 2002 Fabio Fiorina\\
+\setlength{\parskip}{4mm}
+\par
+Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License,
+Version 1.1 or any later version published by the Free Software
+Foundation; with no Invariant Sections, no Front-Cover Texts and
+no Back-Cover Texts.  A copy of the license is included in the
+chapter entitled "GNU Free Documentation License".
+\end{center}
+
+\setlength{\parindent}{2mm}
+
+\setlength{\parskip}{1mm}
+
+
+\chapter{ASN.1 structures handling}
+
+\section{Introduction}
+ This file describes the forth version of ASN.1 parser I
+developed.
+The main difference from the first version is the use of pointers and the
+possibility to save/get ASN1 definitions in/from a C vector.
+Other differences are:
+\begin{itemize}
+\item write\_value function for type ANY
+\item the introduction of ENUMERATED type,
+\item negative integer are allowed in ASN.1 syntax files,
+\item PKIX1Implicit88.txt instead of Certificate.txt for the Certificate description
+\item functions naming 
+\item an easier way to set INTEGER and get OBJECT IDENTFIER  
+\end{itemize}
+
+
+\section{ASN.1 syntax}
+The parser is case sensitive. The comments begin with "-- " and end at the end of line.
+An example is in "Certificate.txt" file.
+The ASN.1 declarations must have this form:
+      
+\begin{verbatim}
+      object_name {<object definition>}
+
+      DEFINITIONS <EXPLICIT or IMPLICIT> TAGS ::=
+
+      BEGIN 
+
+      <type and constants definitions>
+
+      END
+\end{verbatim}
+
+\par
+The token "::=" must be separate from others elements, so this is a wrong declaration:
+      Version ::=INTEGER 
+the correct one is :   Version ::= INTEGER
+Here is the list of types that the parser can manage:
+\begin{itemize}
+
+\item      INTEGER
+\item      ENUMERATED
+\item      BOOLEAN
+\item      OBJECT IDENTIFIER
+\item      NULL
+\item      BIT STRING
+\item      OCTET STRING
+\item      UTCTime
+\item      GeneralizedTime
+\item      SEQUENCE
+\item      SEQUENCE OF
+\item      SET 
+\item      SET OF
+\item      CHOICE
+\item      ANY
+\item      ANY DEFINED BY
+\end{itemize}
+
+This version doesn't manage REAL type. It also not allow the use of 
+"EXPORT" and "IMPORT" sections.
+
+The SIZE constraints are allowed but no check is done on them.
+
+
+
+\section{Naming}
+If you have this definitions:
+
+\begin{verbatim}
+      Example { 1 2 3 4 }
+
+      DEFINITIONS EXPLICIT TAGS ::=
+
+      BEGIN 
+
+      Group ::= SEQUENCE {
+         id   OBJECT IDENTIFIER,
+         value  Value
+      }
+
+      Value ::= SEQUENCE {
+         value1  INTEGER,
+         value2  BOOLEAN 
+      }
+
+      END
+\end{verbatim}
+
+to identify the type 'Group' you have to use the null terminated string "Example.Group".
+Others examples:
+Field 'id' in 'Group' type :  "Example.Group.id"
+Field 'value1' in filed 'value' in type 'Group':   "Example.Group.value.value1" 
+These strings are used in functions that are described below.
+Elements of structured types that don't have a name, receve the name "?1","?2", and so on. 
+The name "?LAST" indicates the last element of a SET\_OF or SEQUENCE\_OF.
+
+\section{Future developments}
+\begin{enumerate}
+\item type REAL 
+\item improve the error signaling with strings that give you more details. 
+   Examples: in case of ASN1 syntax error you will have the line number where the error is,  
+             if creating a der encoding the result is ASN\_VALUE\_NOT\_FOUND you will have the
+             name of the element without the value.
+\item improve the 'visit\_tree' function and change the output from stdout to a null terminated 
+   string.  
+
+\end{enumerate}
+
+\input{asn1-api}
+
+\input{fdl.tex}
+
+\end{document}