To visit RAZip at sourceforge, click here.
The RAZip bitstream format was designed to provide a faster
random access to compressed data than what is currently
possible using the GZIP format. During the desing phase,
some other features were added. Below is a list with the
main features of RAZip:

- provides fast random access to the uncompressed version of
compressed data (Example: you can compress an
ext2fs-formatted file and mount it as a read-only file
system under GNU-Linux and still have a performance
comparable to, or better than, an uncompressed file system);

- is not covered by patents;

- data can be compressed or decompressed in a single pass,
without seeking backwards, without a priori knowledge of the
number of bytes to be compressed or the number of bytes
available on the output media, using only an a priori
bounded amount of intermediate storage, so that it can be
used in Unix filters and similar structures;

- the number of bytes to be compressed and the number of
bytes the compressed stream uses is limited only by
available storage space;

- the exact number of uncompressed bytes can be derived from
the bitstream without decompressing any bytes;

- many compression algorithms can be used (including no
compression). ( If the algorithm cannot determine the end of
compressed data from the data itself, the ability to
decompress without seeking backwards is lost);

- many encryption algorithms can be used (including no

- error checking (you can check the integrity of your file);

- error recovery (the user can choose the maximum number of
bytes each single bit error in the compressed stream will be
able to affect);

- Creation / modification dates span more than 584 million
years with 1 millisecond precision (So you won't have a
similar Y2K problem too soon);

- the original file name can be stored (the size of the file
name is unbounded);

- file comments can be stored (the size of the comments is

- Macintosh files can be compressed with both data fork and
resource fork;

- Macintosh files can be compressed with its type/creator

- Macintosh files can be compressed with all its metadata
(Finder flags, icon position, etc...);

- Unix files can be compressed with all its metadata;

- Storing Unix metadata does not stop you from storing MacOS
metadata at the same time (or AmigaOS, BeOS, ...)

- Additional metadata can be stored in a variety of formats
(XML, for example). The size of the metadata is unbounded.

Below is another example:

Using the "properties" field, you can store the following

author=Elifarley Callado Coelho genre=rythm&blues lyrics=Oh
this is a song, just a song. Sing with me my song, oh
yeah... volume=75%


cartridge name=Zero Wing game category=Alien invasion game
subcategory=green-skinned arrow-eared bomb-eating Mars
invaders tips=Hit the alien with a stove in his forehead to
go to the secret level


. . . 

- text data can be represented in UTF-8;

- the RAZip header is compressed along with the data to be
compressed (but can be stored without compression too);

- almost everything is optional, so you don't waste bytes
with unnecessary information;

If you have any suggestions / questions , please let me


Elifarley C. Coelho
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