EhViewer/app/src/main/java/com/hippo/ehviewer/gallery/A7ZipArchive.java

/*
 * Copyright 2019 Hippo Seven
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hippo.ehviewer.gallery;

import androidx.annotation.NonNull;

import com.hippo.a7zip.ArchiveException;
import com.hippo.a7zip.InArchive;
import com.hippo.a7zip.PropID;
import com.hippo.a7zip.PropType;
import com.hippo.a7zip.SeekableInputStream;
import com.hippo.unifile.UniRandomAccessFile;

import java.io.Closeable;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;

class A7ZipArchive implements Closeable {

    private final InArchive archive;

    private A7ZipArchive(InArchive archive) {
        this.archive = archive;
    }

    private static boolean isSupportedFilename(String name) {
        for (String extension : GalleryProvider2.SUPPORT_IMAGE_EXTENSIONS) {
            if (name.endsWith(extension)) {
                return true;
            }
        }
        return false;
    }

    static A7ZipArchive create(UniRandomAccessFile file) throws ArchiveException {
        SeekableInputStream store = new UniRandomAccessFileInStream(file);
        InArchive archive = InArchive.open(store);
        if ((archive.getArchivePropertyType(PropID.ENCRYPTED) == PropType.BOOL && archive.getArchiveBooleanProperty(PropID.ENCRYPTED))
                || (archive.getArchivePropertyType(PropID.SOLID) == PropType.BOOL && archive.getArchiveBooleanProperty(PropID.SOLID))
                || (archive.getArchivePropertyType(PropID.IS_VOLUME) == PropType.BOOL && archive.getArchiveBooleanProperty(PropID.IS_VOLUME))) {
            throw new ArchiveException("Unsupported archive");
        }
        return new A7ZipArchive(archive);
    }

    @Override
    public void close() {
        archive.close();
    }

    List<A7ZipArchiveEntry> getArchiveEntries() {
        List<A7ZipArchiveEntry> entries = new ArrayList<>();

        for (int i = 0, n = archive.getNumberOfEntries(); i < n; i++) {
            if (!archive.getEntryBooleanProperty(i, PropID.ENCRYPTED)
                    && !archive.getEntryBooleanProperty(i, PropID.IS_DIR)
                    && !archive.getEntryBooleanProperty(i, PropID.IS_VOLUME)
                    && !archive.getEntryBooleanProperty(i, PropID.SOLID)) {
                String path = archive.getEntryPath(i);
                if (isSupportedFilename(path.toLowerCase())) {
                    entries.add(new A7ZipArchiveEntry(archive, i, path));
                }
            }
        }

        return entries;
    }

    static class A7ZipArchiveEntry {

        private final InArchive archive;
        private final int index;
        private final String path;

        private A7ZipArchiveEntry(InArchive archive, int index, String path) {
            this.archive = archive;
            this.index = index;
            this.path = path;
        }

        String getPath() {
            return path;
        }

        void extract(OutputStream os) throws ArchiveException {
            archive.extractEntry(index, new OutputStreamSequentialOutStream(os));
        }
    }

    private static class UniRandomAccessFileInStream extends SeekableInputStream {

        private final byte[] scratch = new byte[8];
        private final UniRandomAccessFile file;

        public UniRandomAccessFileInStream(UniRandomAccessFile file) {
            this.file = file;
        }

        @Override
        public void seek(long pos) throws IOException {
            file.seek(pos);
        }

        @Override
        public long tell() throws IOException {
            return file.getFilePointer();
        }

        @Override
        public long size() throws IOException {
            return file.length();
        }

        @Override
        public int read() throws IOException {
            return (file.read(scratch, 0, 1) != -1) ? scratch[0] & 0xff : -1;
        }

        @Override
        public int read(@NonNull byte[] b) throws IOException {
            return file.read(b, 0, b.length);
        }

        @Override
        public int read(byte[] b, int off, int len) throws IOException {
            return file.read(b, off, len);
        }

        @Override
        public void close() throws IOException {
            file.close();
        }
    }

    private static class OutputStreamSequentialOutStream extends OutputStream {

        private final OutputStream stream;

        public OutputStreamSequentialOutStream(OutputStream stream) {
            this.stream = stream;
        }

        @Override
        public void write(int b) throws IOException {
            stream.write(b);
        }

        @Override
        public void write(byte[] b, int off, int len) throws IOException {
            stream.write(b, off, len);
        }

        @Override
        public void close() throws IOException {
            stream.close();
        }
    }
}