import java.io.*;

import java.nio.*;

import java.util.*;

import java.util.zip.*;

public class LargeZipFile {

    // If true, don't delete large ZIP file created for test.

    static final boolean debug = System.getProperty("debug") != null;

    static final int DATA_LEN = 1024 * 1024;

    static final int DATA_SIZE = 8;

    static long fileSize = 3L * 1024L * 1024L * 1024L; // 3GB

    static boolean userFile = false;

    static byte[] data;

    static File largeFile;

    static String lastEntryName;

    /* args can be empty, in which case check a 3 GB file which is created for

     * this test (and then deleted).  Or it can be a number, in which case

     * that designates the size of the file that's created for this test (and

     * then deleted).  Or it can be the name of a file to use for the test, in

     * which case it is *not* deleted.  Note that in this last case, the data

     * comparison might fail.

     */

    static void realMain (String[] args) throws Throwable {

        if (args.length > 0) {

            try {

                fileSize = Long.parseLong(args[0]);

                System.out.println("Testing with file of size " + fileSize);

            } catch (NumberFormatException ex) {

                largeFile = new File(args[0]);

                if (!largeFile.exists()) {

                    throw new Exception("Specified file " + args[0] + " does not exist");

                }

                userFile = true;

                System.out.println("Testing with user-provided file " + largeFile);

            }

        }

        File testDir = null;

        if (largeFile == null) {

            testDir = new File(System.getProperty("test.scratch", "."),

                                    "LargeZip");

            if (testDir.exists()) {

                if (!testDir.delete()) {

                    throw new Exception("Cannot delete already-existing test directory");

                }

            }

            check(!testDir.exists() && testDir.mkdirs());

            largeFile = new File(testDir, "largezip.zip");

            createLargeZip();

        }

        readLargeZip();

        if (!userFile && !debug) {

            check(largeFile.delete());

            check(testDir.delete());

        }

    }

    static void createLargeZip() throws Throwable {

        int iterations = DATA_LEN / DATA_SIZE;

        ByteBuffer bb = ByteBuffer.allocate(DATA_SIZE);

        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        for (int i = 0; i < iterations; i++) {

            bb.putDouble(0, Math.random());

            baos.write(bb.array(), 0, DATA_SIZE);

        }

        data = baos.toByteArray();

        ZipOutputStream zos = new ZipOutputStream(

            new BufferedOutputStream(new FileOutputStream(largeFile)));

        long length = 0;

        while (length < fileSize) {

            ZipEntry ze = new ZipEntry("entry-" + length);

            lastEntryName = ze.getName();

            zos.putNextEntry(ze);

            zos.write(data, 0, data.length);

            zos.closeEntry();

            length = largeFile.length();

        }

        System.out.println("Last entry written is " + lastEntryName);

        zos.close();

    }

    static void readLargeZip() throws Throwable {

        ZipFile zipFile = new ZipFile(largeFile);

        ZipEntry entry = null;

        String entryName = null;

        int count = 0;

        Enumeration<? extends ZipEntry> entries = zipFile.entries();

        while (entries.hasMoreElements()) {

            entry = entries.nextElement();

            entryName = entry.getName();

            count++;

        }

        System.out.println("Number of entries read: " + count);

        System.out.println("Last entry read is " + entryName);

        check(!entry.isDirectory());

        if (check(entryName.equals(lastEntryName))) {

            ByteArrayOutputStream baos = new ByteArrayOutputStream();

            InputStream is = zipFile.getInputStream(entry);

            byte buf[] = new byte[4096];

            int len;

            while ((len = is.read(buf)) >= 0) {

                baos.write(buf, 0, len);

            }

            baos.close();

            is.close();

            check(Arrays.equals(data, baos.toByteArray()));

        }

        try {

          zipFile.close();

        } catch (IOException ioe) {/* what can you do */ }

    }

    //--------------------- Infrastructure ---------------------------

    static volatile int passed = 0, failed = 0;

    static void pass() {passed++;}

    static void pass(String msg) {System.out.println(msg); passed++;}

    static void fail() {failed++; Thread.dumpStack();}

    static void fail(String msg) {System.out.println(msg); fail();}

    static void unexpected(Throwable t) {failed++; t.printStackTrace();}

    static void unexpected(Throwable t, String msg) {

        System.out.println(msg); failed++; t.printStackTrace();}

    static boolean check(boolean cond) {if (cond) pass(); else fail(); return cond;}

    static void equal(Object x, Object y) {

        if (x == null ? y == null : x.equals(y)) pass();

        else fail(x + " not equal to " + y);}

    public static void main(String[] args) throws Throwable {

        try {realMain(args);} catch (Throwable t) {unexpected(t);}

        System.out.println("\nPassed = " + passed + " failed = " + failed);

        if (failed > 0) throw new AssertionError("Some tests failed");}

}