DigestImpl.java

/*
 * Demoiselle Framework
 * Copyright (C) 2010 SERPRO
 * ----------------------------------------------------------------------------
 * This file is part of Demoiselle Framework.
 *
 * Demoiselle Framework is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License version 3
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License version 3
 * along with this program; if not,  see <http://www.gnu.org/licenses/>
 * or write to the Free Software Foundation, Inc., 51 Franklin Street,
 * Fifth Floor, Boston, MA  02110-1301, USA.
 * ----------------------------------------------------------------------------
 * Este arquivo é parte do Framework Demoiselle.
 *
 * O Framework Demoiselle é um software livre; você pode redistribuí-lo e/ou
 * modificá-lo dentro dos termos da GNU LGPL versão 3 como publicada pela Fundação
 * do Software Livre (FSF).
 *
 * Este programa é distribuído na esperança que possa ser útil, mas SEM NENHUMA
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 * APLICAÇÃO EM PARTICULAR. Veja a Licença Pública Geral GNU/LGPL em português
 * para maiores detalhes.
 *
 * Você deve ter recebido uma cópia da GNU LGPL versão 3, sob o título
 * "LICENCA.txt", junto com esse programa. Se não, acesse <http://www.gnu.org/licenses/>
 * ou escreva para a Fundação do Software Livre (FSF) Inc.,
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package br.gov.frameworkdemoiselle.certificate.criptography.implementation;

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import br.gov.frameworkdemoiselle.certificate.criptography.CriptographyException;
import br.gov.frameworkdemoiselle.certificate.criptography.Digest;
import br.gov.frameworkdemoiselle.certificate.criptography.DigestAlgorithmEnum;

public class DigestImpl implements Digest {

    private String algorithm = DigestAlgorithmEnum.DEFAULT.getAlgorithm();
    private final int BUFSIZE = 128;

    @Override
    public void setAlgorithm(String algorithm) {
        this.algorithm = algorithm;
    }

    /**
     * Método responsável por gerar um resumo dos bytes passados como parâmetro.
     * Utiliza o algoritmo MD5 como default.
     *
     * @param content
     * @return
     */
    @Override
    public byte[] digest(byte[] content) {
        byte[] result = null;

        if (this.algorithm == null) {
            this.algorithm = DigestAlgorithmEnum.DEFAULT.getAlgorithm();
        }

        if (content == null) {
            throw new CriptographyException("The content can not be null");
        }

        try {
            MessageDigest digest = MessageDigest.getInstance(this.algorithm);
            digest.update(content);
            result = digest.digest();
        } catch (NoSuchAlgorithmException ex) {
            throw new CriptographyException("Error on digest content", ex);
        }
        return result;
    }

    @Override
    public byte[] digestFile(File file) {
        try {
            MessageDigest md = MessageDigest.getInstance(this.algorithm);
            FileInputStream fileIS = new FileInputStream(file);
            BufferedInputStream bis = new BufferedInputStream(fileIS);
            DataInputStream dis = new DataInputStream(bis);
            DigestInputStream digin = new DigestInputStream(dis, md);
            byte[] buffer = new byte[BUFSIZE];
            while (digin.read(buffer, 0, BUFSIZE) != -1)
				;
            digin.close();
            return md.digest();
        } catch (NoSuchAlgorithmException e) {
            throw new CriptographyException("Failed to set algorithm", e);
        } catch (FileNotFoundException e) {
            throw new CriptographyException("File [" + file + "] not found", e);
        } catch (IOException e) {
            throw new CriptographyException("Error reading file [" + file + "]", e);
        }
    }

    @Override
    public String digestFileHex(File file) {
        byte[] bytes = this.digestFile(file);
        String hex = this.convertToHex(bytes);
        return hex;
    }

    @Override
    public String digestHex(byte[] content) {
        byte[] bytes = this.digest(content);
        String hex = this.convertToHex(bytes);
        return hex;
    }

    private String convertToHex(byte[] data) {
        StringBuffer buf = new StringBuffer();
        for (int i = 0; i < data.length; i++) {
            int halfbyte = (data[i] >>> 4) & 0x0F;
            int two_halfs = 0;
            do {
                if ((0 <= halfbyte) && (halfbyte <= 9)) {
                    buf.append((char) ('0' + halfbyte));
                } else {
                    buf.append((char) ('a' + (halfbyte - 10)));
                }
                halfbyte = data[i] & 0x0F;
            } while (two_halfs++ < 1);
        }
        return buf.toString();

    }

    @Override
    public void setAlgorithm(DigestAlgorithmEnum algorithm) {
        this.setAlgorithm(algorithm.getAlgorithm());
    }

}