LZW 伪代码

lzw

Encode:

[.c.] = Empty;
[.c.]k = First Character in CharStream;
while ([.c.]k != EOF )
{
　　if ( [.c.]k is in the StringTable)
　　{
　　　　[.c.] = [.c.]k;
　　}
　　else
　　{
　　　　add [.c.]k to the StringTable;
　　　　Output the Index of [.c.] in the StringTable to the CodeStream;
　　　　[.c.] = k;
　　}
　　[.c.]k = Next Character in CharStream;
}
Output the Index of [.c.] in the StringTable to the CodeStream;

Decode:

[code] = First Code in the CodeStream;
Output the String for [code] to the CharStream;
[old] = [code];
[code] = Next Code in the CodeStream;
while ([code] != EOF )
{
　　if ( [code] is in the StringTable)
　　{
　　　　Output the String for [code] to the CharStream; // 输出[code]所对应的字符串
　　　　[...] = translation for [old]; // [old]所对应的字符串
　　　　k = first character of translation for [code]; // [code]所对应的字符串的第一个字符
　　　　add [...]k to the StringTable;
　　　　[old] = [code]; 
　　}
　　else
　　{
　　　　[...] = translation for [old]; 
　　　　k = first character of [...]; 
　　　　Output [...]k to CharStream;
　　　　add [...]k to the StringTable;
　　　　[old] = [code]; 
　　}
　　[code] = Next Code in the CodeStream;
}