freehep-io - FreeHEP I/O

Introduction

The FreeHEP IO package extends the Java IO package with a number of input and output streams.

The FreeHEP IO package lives in org.freehep.util.io and is included in freehep-base.jar.

The FreeHEP IO streams are in use by the FreeHEP VectorGraphics package and the PostScript viewer. Of course all these classes are usable elsewhere.

A special part of the streams are the "Tagged" Input- and OutputStreams which allow for tagged blocks to be read and written.

Below follows a description of the different streams available:

FinishableOutputStream: This interface allows you to call finish() on a stream, which will write any end-of-stream marker.
NoCloseInputStream: This class (which is buffered by itself) allows you to call a non-active close(). If you have a stream from which you suddenly need to read in a different encoding (ASCII85, ...), wrap the stream in a NoCloseInputStream, then wrap that one in the encoding, read until the end-of-stream marker, then close that stream and keep reading from the underlying stream.
BitIn- / OutputStream: Reads or writes in bit format of any length bit streams.
ByteOrderInput- / OutputStream: Reads or writes lo- of hi-endian byte streams.
ByteCountInput- / OutputStream: Reads or writes a stream while keeping track the number of bytes read or written. Also keeps track of sub-counts if necessary.
UniquePrintStream: Keeps track of the strings one is printing and prints them only on the first occasion. Allows you to filter error messages for instance.

ASCII85In- / OutputStream: Reads or writes ASCII85 encoding, used in e-mail for instance.
ASCIIHexIn- / OutputStream: Reads or writes ASCIIHex encoding.
DCTIn- / OutputStream: Reads or writes Discrete Cosine Transform encoding, used in JPEG image for instance.
RunLengthIn- / OutputStream: Reads or writes Run Length encoding, used in PostScript sometimes.
EExecEn- / Decryption: Reads or writes EExec encoding, used in Type1 fonts.

TaggedInput- / OutputStream, Tag, UndefinedTag, TagSet, Action, Action.Unknown and ActionSet: Reads or writes tags. Tags are blocks identified by some tag-id and a tag-length. A specific TagSet can be used to handle the tags as they are read or written. UndefinedTags can be skipped automatically. For writing the tag-length is automatically calculated. Total stream length can also be calculated. Actions are handled as a special set of "Tags".

ConditionalInputStream: Reads a stream and filters parts depending on properties set and statements in the stream. Works like the conditional compilation part of a C pre-processor.
RoutedInputStream and RouteListener: Routes a stream to a listener, who can keep reading from the stream, for a certain delimited part of the stream.
PromptInputStream and PromptListener: Reads a stream until the prompt and signals the listener.

StandardFileFilter: Implements a filter with the default file filter scheme used in most Operating Systems. You can specify "*" for 0 or more "any" characters, and "?" for a single "any" character.