Namespace: go.std.compress.lzw

v1.0

Contents

• Summary
• Index
• Constants
• Variables
• Functions, Macros, and Special Forms
• Types

Summary

Provides a low-level interface to the compress/lzw package.

Package lzw implements the Lempel-Ziv-Welch compressed data format,
described in T. A. Welch, “A Technique for High-Performance Data
Compression”, Computer, 17(6) (June 1984), pp 8-19.

In particular, it implements LZW as used by the GIF and PDF file
formats, which means variable-width codes up to 12 bits and the first
two non-literal codes are a clear code and an EOF code.

The TIFF file format uses a similar but incompatible version of the LZW
algorithm. See the golang.org/x/image/tiff/lzw package for an
implementation.

Index

• *Order
• *Reader
• *Writer
• LSB
• MSB
• NewReader
• NewWriter
• Order
• Reader
• Writer
• arrayOfOrder
• arrayOfReader
• arrayOfWriter

Legend

Constant Variable Function Macro Special form Type GoVar Receiver/Method

Constants

Constants are variables with :const true in their metadata. Joker currently does not recognize them as special; as such, it allows redefining them or their values.

(None.)

Variables

• LSB

  GoObject v1.0

  LSB means Least Significant Bits first, as used in the GIF file format.
  

• MSB

  GoObject v1.0

  MSB means Most Significant Bits first, as used in the TIFF and PDF
  file formats.
  

Functions, Macros, and Special Forms

• NewReader

  Function v1.0

  (NewReader r order litWidth)
  

  NewReader creates a new io.ReadCloser.
  Reads from the returned io.ReadCloser read and decompress data from r.
  If r does not also implement io.ByteReader,
  the decompressor may read more data than necessary from r.
  It is the caller's responsibility to call Close on the ReadCloser when
  finished reading.
  The number of bits to use for literal codes, litWidth, must be in the
  range [2,8] and is typically 8. It must equal the litWidth
  used during compression.
  
  It is guaranteed that the underlying type of the returned io.ReadCloser
  is a *Reader.
  
  Go input arguments: (r io.Reader, order Order, litWidth int)
  
  Go returns: io.ReadCloser
  
  Joker input arguments: [^go.std.io/Reader r, ^Order order, ^Int litWidth]
  
  Joker returns: ^go.std.io/ReadCloser

• NewWriter

  Function v1.0

  (NewWriter w order litWidth)
  

  NewWriter creates a new io.WriteCloser.
  Writes to the returned io.WriteCloser are compressed and written to w.
  It is the caller's responsibility to call Close on the WriteCloser when
  finished writing.
  The number of bits to use for literal codes, litWidth, must be in the
  range [2,8] and is typically 8. Input bytes must be less than 1<<litWidth.
  
  It is guaranteed that the underlying type of the returned io.WriteCloser
  is a *Writer.
  
  Go input arguments: (w io.Writer, order Order, litWidth int)
  
  Go returns: io.WriteCloser
  
  Joker input arguments: [^go.std.io/Writer w, ^Order order, ^Int litWidth]
  
  Joker returns: ^go.std.io/WriteCloser

Types

• *Order

  Concrete Type v1.0

  Order specifies the bit ordering in an LZW data stream.
  

• *Reader

  Concrete Type v1.0

  Reader is an io.Reader which can be used to read compressed data in the
  LZW format.
  

• Close

  Receiver for *Reader v1.0

  ([])
  

  Close closes the Reader and returns an error for any future read operation.
  It does not close the underlying io.Reader.
  

• Read

  Receiver for *Reader v1.0

  ([b])
  

  Read implements io.Reader, reading uncompressed bytes from its underlying Reader.
  

• Reset

  Receiver for *Reader v1.0

  ([src order litWidth])
  

  Reset clears the Reader's state and allows it to be reused again
  as a new Reader.
  

• *Writer

  Concrete Type v1.0

  Writer is an LZW compressor. It writes the compressed form of the data
  to an underlying writer (see NewWriter).
  

• Close

  Receiver for *Writer v1.0

  ([])
  

  Close closes the Writer, flushing any pending output. It does not close
  w's underlying writer.
  

• Reset

  Receiver for *Writer v1.0

  ([dst order litWidth])
  

  Reset clears the Writer's state and allows it to be reused again
  as a new Writer.
  

• Write

  Receiver for *Writer v1.0

  ([p])
  

  Write writes a compressed representation of p to w's underlying writer.
  

• Order

  Concrete Type v1.0

  Order specifies the bit ordering in an LZW data stream.
  

• Reader

  Concrete Type v1.0

  Reader is an io.Reader which can be used to read compressed data in the
  LZW format.
  

• Writer

  Concrete Type v1.0

  Writer is an LZW compressor. It writes the compressed form of the data
  to an underlying writer (see NewWriter).
  

• arrayOfOrder

  Concrete Type v1.0

  Order specifies the bit ordering in an LZW data stream.
  

• arrayOfReader

  Concrete Type v1.0

  Reader is an io.Reader which can be used to read compressed data in the
  LZW format.
  

• arrayOfWriter

  Concrete Type v1.0

  Writer is an LZW compressor. It writes the compressed form of the data
  to an underlying writer (see NewWriter).