# package lzw
`import "compress/lzw"`
lzw包實現了Lempel-Ziv-Welch數據壓縮格式,這是一種T. A. Welch在“A Technique for High-Performance Data Compression”一文(Computer, 17(6) (June 1984), pp 8-19)提出的一種壓縮格式。
本包實現了用于GIF、TIFF、PDF文件的lzw壓縮格式,這是一種最長達到12位的變長碼,頭兩個非字面碼為clear和EOF碼。
## Index
* [type Order](#Order)
* [func NewReader(r io.Reader, order Order, litWidth int) io.ReadCloser](#NewReader)
* [func NewWriter(w io.Writer, order Order, litWidth int) io.WriteCloser](#NewWriter)
## type [Order](https://github.com/golang/go/blob/master/src/compress/lzw/reader.go#L25 "View Source")
```
type Order int
```
Order指定一個lzw數據流的位順序。
```
const (
// LSB表示最小權重位在前,用在GIF文件格式
LSB Order = iota
// MSB表示最大權重位在前,用在TIFF和PDF文件格式
MSB
)
```
## func [NewReader](https://github.com/golang/go/blob/master/src/compress/lzw/reader.go#L225 "View Source")
```
func NewReader(r io.Reader, order Order, litWidth int) io.ReadCloser
```
創建一個io.ReadCloser,它從r讀取并解壓數據。調用者有責任在結束讀取后調用返回值的Close方法;litWidth指定字面碼的位數,必須在[2,8]范圍內,一般為8。
## func [NewWriter](https://github.com/golang/go/blob/master/src/compress/lzw/writer.go#L234 "View Source")
```
func NewWriter(w io.Writer, order Order, litWidth int) io.WriteCloser
```
創建一個io.WriteCloser,它將數據壓縮后寫入w。調用者有責任在結束寫入后調用返回值的Close方法;litWidth指定字面碼的位數,必須在[2,8]范圍內,一般為8。
- 庫
- package achive
- package tar
- package zip
- package bufio
- package builtin
- package bytes
- package compress
- package bzip2
- package flate
- package gzip
- package lzw
- package zlib
- package container
- package heap
- package list
- package ring
- package crypto
- package aes
- package cipher
- package des
- package dsa
- package ecdsa
- package elliptic
- package hmac
- package md5
- package rand
- package rc4
- package rsa
- package sha1
- package sha256
- package sha512
- package subtle
- package tls
- package x509
- package pkix
- package database
- package sql
- package driver
- package encoding
- package ascii85
- package asn1
- package base32
- package base64
- package binary
- package csv
- package gob
- package hex
- package json
- package pem
- package xml
- package errors
- package expvar
- package flag
- package fmt
- package go
- package doc
- package format
- package parser
- package printer
- package hash
- package adler32
- package crc32
- package crc64
- package fnv
- package html
- package template
- package image
- package color
- package palette
- package draw
- package gif
- package jpeg
- package png
- package index
- package suffixarray
- package io
- package ioutil
- package log
- package syslog
- package math
- package big
- package cmplx
- package rand
- package mime
- package multipart
- package net
- package http
- package cgi
- package cookiejar
- package fcgi
- package httptest
- package httputil
- package pprof
- package mail
- package rpc
- package jsonrpc
- package smtp
- package textproto
- package url
- package os
- package exec
- package signal
- package user
- package path
- package filepath
- package reflect
- package regexp
- package runtime
- package cgo
- package debug
- package pprof
- package race
- package sort
- package strconv
- package strings
- package sync
- package atomic
- package text
- package scanner
- package tabwriter
- package template
- package time
- package unicode
- package utf16
- package utf8
- package unsafe