/*

 * Copyright (c) 1997, 2008, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package org.apidesign.bck2brwsr.emul.lang;

import java.io.FilterInputStream;

import java.io.IOException;

import java.io.InputStream;

import org.apidesign.bck2brwsr.core.Exported;

/*

 * A fast buffered input stream for parsing manifest files.

 * 

 * Taken from java.util.jar.Manifest.FastInputStream and modified to be

 * independent of other Manifest functionality.

 */

@Exported

public abstract class ManifestInputStream extends FilterInputStream {

    private byte[] buf;

    private int count = 0;

    private int pos = 0;

    protected ManifestInputStream(InputStream in) {

        this(in, 8192);

    }

    protected ManifestInputStream(InputStream in, int size) {

        super(in);

        buf = new byte[size];

    }

    public int read() throws IOException {

        if (pos >= count) {

            fill();

            if (pos >= count) {

                return -1;

            }

        }

        return buf[pos++] & 0xff;

    }

    public int read(byte[] b, int off, int len) throws IOException {

        int avail = count - pos;

        if (avail <= 0) {

            if (len >= buf.length) {

                return in.read(b, off, len);

            }

            fill();

            avail = count - pos;

            if (avail <= 0) {

                return -1;

            }

        }

        if (len > avail) {

            len = avail;

        }

        System.arraycopy(buf, pos, b, off, len);

        pos += len;

        return len;

    }

    /*

     * Reads 'len' bytes from the input stream, or until an end-of-line

     * is reached. Returns the number of bytes read.

     */

    public int readLine(byte[] b, int off, int len) throws IOException {

        byte[] tbuf = this.buf;

        int total = 0;

        while (total < len) {

            int avail = count - pos;

            if (avail <= 0) {

                fill();

                avail = count - pos;

                if (avail <= 0) {

                    return -1;

                }

            }

            int n = len - total;

            if (n > avail) {

                n = avail;

            }

            int tpos = pos;

            int maxpos = tpos + n;

            while (tpos < maxpos && tbuf[tpos++] != '\n') {

                ;

            }

            n = tpos - pos;

            System.arraycopy(tbuf, pos, b, off, n);

            off += n;

            total += n;

            pos = tpos;

            if (tbuf[tpos - 1] == '\n') {

                break;

            }

        }

        return total;

    }

    public byte peek() throws IOException {

        if (pos == count) {

            fill();

        }

        if (pos == count) {

            return -1; // nothing left in buffer

        }

        return buf[pos];

    }

    public int readLine(byte[] b) throws IOException {

        return readLine(b, 0, b.length);

    }

    public long skip(long n) throws IOException {

        if (n <= 0) {

            return 0;

        }

        long avail = count - pos;

        if (avail <= 0) {

            return in.skip(n);

        }

        if (n > avail) {

            n = avail;

        }

        pos += n;

        return n;

    }

    public int available() throws IOException {

        return (count - pos) + in.available();

    }

    public void close() throws IOException {

        if (in != null) {

            in.close();

            in = null;

            buf = null;

        }

    }

    private void fill() throws IOException {

        count = pos = 0;

        int n = in.read(buf, 0, buf.length);

        if (n > 0) {

            count = n;

        }

    }

    protected abstract String putValue(String key, String value);

    public void readAttributes(byte[] lbuf) throws IOException {

        ManifestInputStream is = this;

        String name = null;

        String value = null;

        byte[] lastline = null;

        int len;

        while ((len = is.readLine(lbuf)) != -1) {

            boolean lineContinued = false;

            if (lbuf[--len] != '\n') {

                throw new IOException("line too long");

            }

            if (len > 0 && lbuf[len - 1] == '\r') {

                --len;

            }

            if (len == 0) {

                break;

            }

            int i = 0;

            if (lbuf[0] == ' ') {

                if (name == null) {

                    throw new IOException("misplaced continuation line");

                }

                lineContinued = true;

                byte[] buf = new byte[lastline.length + len - 1];

                System.arraycopy(lastline, 0, buf, 0, lastline.length);

                System.arraycopy(lbuf, 1, buf, lastline.length, len - 1);

                if (is.peek() == ' ') {

                    lastline = buf;

                    continue;

                }

                value = new String(buf, 0, buf.length, "UTF8");

                lastline = null;

            } else {

                while (lbuf[i++] != ':') {

                    if (i >= len) {

                        throw new IOException("invalid header field");

                    }

                }

                if (lbuf[i++] != ' ') {

                    throw new IOException("invalid header field");

                }

                name = new String(lbuf, 0, 0, i - 2);

                if (is.peek() == ' ') {

                    lastline = new byte[len - i];

                    System.arraycopy(lbuf, i, lastline, 0, len - i);

                    continue;

                }

                value = new String(lbuf, i, len - i, "UTF8");

            }

            try {

                if ((putValue(name, value) != null) && (!lineContinued)) {

                    throw new IOException("Duplicate name in Manifest: " + name + ".\n" + "Ensure that the manifest does not " + "have duplicate entries, and\n" + "that blank lines separate " + "individual sections in both your\n" + "manifest and in the META-INF/MANIFEST.MF " + "entry in the jar file.");

                }

            } catch (IllegalArgumentException e) {

                throw new IOException("invalid header field name: " + name);

            }

        }

    }

}