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:
- This interface allows you to call finish() on a stream, which will write any end-of-stream marker.
- 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.
- Keeps track of the strings one is printing and prints them only on the first occasion. Allows you to filter error messages for instance.
Standard Encoding Streams
- 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".
- 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.
- 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.