jdd.bdd

Class BDDIO

java.lang.Object

jdd.bdd.BDDIO

public class BDDIO
extends Object

BDDIO is used to save and load binary decision diagrams independent of the BDD managers.

The format used is the following:

 MAGIC STRING: "FORMAT:JDD.BDD"
 SIZE, ID
 ID VAR LOW HIGH (repeated SIZE times)
 

where each element (besides magic) is a little-endian 32 bit number.
the first ID represents the saved BDD while the rest build the involved table entries which the top BDD depends on. To save space, the file is automatically compressed with "gzip".

Constructor Summary

Constructors

Constructor and Description
BDDIO()

Method Summary

Modifier and Type	Method and Description
static void	internal_test() testbench.
static int	load(BDD manager, String filename) Load a BDD (in the native JDD format) from a file.
static void	save(BDD manager, int bdd, String filename) Save a BDD to a file using the native JDD format.
static void	saveBuDDy(BDD manager, int bdd, String filename) Save a BDD to a file.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BDDIO

public BDDIO()

Method Detail

save

public static void save(BDD manager,
                        int bdd,
                        String filename)
                 throws IOException

Save a BDD to a file using the native JDD format.

This format is preferred over the BuDDy format since (1) you can load it back into JDD and (2) it takes less space on your harddrive since it is compressed.

Throws:

IOException

load

public static int load(BDD manager,
                       String filename)
                throws IOException

Load a BDD (in the native JDD format) from a file. The file must have been created with the BDDIO.save() function.

Important note: you must ref-count this BDD by yourself. The returned BDD will have refount 0, and may (will) be garbage collected if you don't refcount it right away!

Throws:

IOException

See Also:

save(jdd.bdd.BDD, int, java.lang.String)

saveBuDDy

public static void saveBuDDy(BDD manager,
                             int bdd,
                             String filename)
                      throws IOException

Save a BDD to a file. use the format BuDDy uses.
If you save a BDD in this format, you can not load it into JDD again. You can however load the saved BDD in BuDDy using the function
int bdd_fnload(char *, BDD *);

For the sake of clearness, we suggest that you the *.bdd extension for the JDD format and the *.buddy extension for the BuDDy format.

The BuDDy format is best bescribed by this comment from bddio.c in buddy:

 Loads a BDD from a file into the BDD pointed to by r.
 The file can either be the file ifile which must be opened
 for reading or the file named fname which will be opened
 automatically for reading.

 The input file format consists of integers arranged in the following
 manner. First the number of nodes $N$ used by the BDD and then the
 number of variables $V$ allocated and the variable ordering
 in use at the time the BDD was saved.
 If $N$ and $V$ are both zero then the BDD is either the constant
 true or false BDD, indicated by a $1$ or a $0$ as the next integer.

 In any other case the next $N$ sets of $4$ integers will describe
 the nodes used by the BDD. Each set consists of first the node
 number, then the variable number and then the low and high nodes.

 The nodes must be saved in a order such that any low or
 high node must be defined before it is mentioned.
 

NOTE: this method is completely untested!

Throws:

IOException

internal_test

public static void internal_test()

testbench. do not call