huffman_encode.m

EZW implementation which will use wavelet transforms and do the compression decompression using EZW

function [h,sortindex]=huffman_encode(f)
% HUFFMAN 哈夫曼码生成器。
%         h=huffman(f),哈夫曼码生成器
%         返回哈夫曼码矩阵h

simbols=find(f~=0);
f=f(simbols);
[f,sortindex]=sort(f);  %排序
simbols=simbols(sortindex);

n=length(f);
m=zeros(n-1,n);
for i=1:n-1
    [f,l]=sort(f);
    m(i,:)=[l(1:n-i+1),zeros(1,i-1)];
    f=[f(1)+f(2),f(3:n),1];
end
for i=1:n-1
    c(i,:)=blanks(n*n);
end
c(n-1,n)='0';
c(n-1,2*n)='1';
for i=2:n-1
    c(n-i,1:n-1)=c(n-i+1,n*(find(m(n-i+1,:)==1))-(n-2):n*(find(m(n-i+1,:)==1)));
    c(n-i,n)='0';
    c(n-i,n+1:2*n-1)=c(n-i,1:n-1);
    c(n-i,2*n)='1';
    for j=1:i-1
        c(n-i,(j+1)*n+1:(j+2)*n)=c(n-i+1,...
        n*(find(m(n-i+1,:)==j+1)-1)+1:n*find(m(n-i+1,:)==j+1));
    end
end
for i=1:n
    h(i,1:n)=c(1,n*(find(m(1,:)==i)-1)+1:find(m(1,:)==i)*n);
end