/*
 * $Id: RandomAccessFileOrArray.java 4882 2011-05-24 16:33:21Z blowagie $
 *
 * This file is part of the iText (R) project.
 * Copyright (c) 1998-2011 1T3XT BVBA
 * Authors: Bruno Lowagie, Paulo Soares, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY 1T3XT,
 * 1T3XT DISCLAIMS THE WARRANTY OF NON INFRINGEMENT OF THIRD PARTY RIGHTS.
 *
 * 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 Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * 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, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * a covered work must retain the producer line in every PDF that is created
 * or manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
 *
 * For more information, please contact iText Software Corp. at this
 * address: sales@itextpdf.com
 */
package com.itextpdf.text.pdf;

import com.itextpdf.text.Document;
import java.io.ByteArrayOutputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.URL;
import java.nio.channels.FileChannel;
import com.itextpdf.text.error_messages.MessageLocalization;
/** An implementation of a RandomAccessFile for input only
 * that accepts a file or a byte array as data source.
 *
 * @author Paulo Soares
 */
public class RandomAccessFileOrArray implements DataInput {
        
    MappedRandomAccessFile rf;
    RandomAccessFile trf;
    boolean plainRandomAccess;
    String filename;
    byte arrayIn[];
    int arrayInPtr;
    byte back;
    boolean isBack = false;
    
    /** Holds value of property startOffset. */
    private int startOffset = 0;

    public RandomAccessFileOrArray(String filename) throws IOException {
        this(filename, false, Document.plainRandomAccess);
    }
    
    /**
     * Constructs a new RandomAccessFileOrArrayObject
     * @param filename the file to open (can be a file system file or one of hte following url strings: file://, http://, https://, jar:, wsjar:
     * @param forceRead if true, the entire file will be read into memory
     * @param plainRandomAccess if true, a regular RandomAccessFile is used to access the file contents.  If false, a memory mapped file will be used, unless the file cannot be mapped into memory, in which case regular RandomAccessFile will be used
     * @throws IOException if there is a failure opening or reading the file
     */
    public RandomAccessFileOrArray(String filename, boolean forceRead, boolean plainRandomAccess) throws IOException {
        this.plainRandomAccess = plainRandomAccess;
        File file = new File(filename);
        if (!file.canRead()) {
            if (filename.startsWith("file:/") || filename.startsWith("http://") 
                    || filename.startsWith("https://") || filename.startsWith("jar:") || filename.startsWith("wsjar:")) {
                InputStream is = new URL(filename).openStream();
                try {
                    this.arrayIn = InputStreamToArray(is);
                    return;
                }
                finally {
                    try {is.close();}catch(IOException ioe){}
                }
            }
            else {
                InputStream is = BaseFont.getResourceStream(filename);
                if (is == null)
                    throw new IOException(MessageLocalization.getComposedMessage("1.not.found.as.file.or.resource", filename));
                try {
                    this.arrayIn = InputStreamToArray(is);
                    return;
                }
                finally {
                    try {is.close();}catch(IOException ioe){}
                }
            }
        }
        else if (forceRead) {
            InputStream s = null;
            try {
                s = new FileInputStream(file);
                this.arrayIn = InputStreamToArray(s);
            }
            finally {
                try {if (s != null) {s.close();}}catch(Exception e){}
            }
                return;
        }
        this.filename = filename;
        if (plainRandomAccess){
            trf = new RandomAccessFile(filename, "r");
        }else{
            try{
                rf = new MappedRandomAccessFile(filename, "r");
            } catch (IOException e){
                if (exceptionIsMapFailureException(e)){
                    this.plainRandomAccess = true;
                    trf = new RandomAccessFile(filename, "r");
                } else {
                    throw e;
                }
            }
        }
    }

    /**
     * Utility method that determines whether a given IOException is the result
     * of a failure to map a memory mapped file.  It would be better if the runtime
     * provided a special exception for this case, but it doesn't, so we have to rely
     * on parsing the exception message.
     * @param e the exception to check
     * @return true if the exception was the result of a failure to map a memory mapped file
     * @since 5.0.3
     */
    private static boolean exceptionIsMapFailureException(IOException e){
        if (e.getMessage().indexOf("Map failed") >= 0)
            return true;

        return false;
    }
    
    public RandomAccessFileOrArray(URL url) throws IOException {
        InputStream is = url.openStream();
        try {
            this.arrayIn = InputStreamToArray(is);
        }
        finally {
            try {is.close();}catch(IOException ioe){}
        }
    }

    public RandomAccessFileOrArray(InputStream is) throws IOException {
        this.arrayIn = InputStreamToArray(is);
    }
    
    public static byte[] InputStreamToArray(InputStream is) throws IOException {
        byte b[] = new byte[8192];
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        while (true) {
            int read = is.read(b);
            if (read < 1)
                break;
            out.write(b, 0, read);
        }
        out.close();
        return out.toByteArray();
    }

    public RandomAccessFileOrArray(byte arrayIn[]) {
        this.arrayIn = arrayIn;
    }
    
    public RandomAccessFileOrArray(RandomAccessFileOrArray file) {
        filename = file.filename;
        arrayIn = file.arrayIn;
        startOffset = file.startOffset;
        plainRandomAccess = file.plainRandomAccess;
    }
    
    public void pushBack(byte b) {
        back = b;
        isBack = true;
    }
    
    public int read() throws IOException {
        if(isBack) {
            isBack = false;
            return back & 0xff;
        }
        if (arrayIn == null)
            return plainRandomAccess ? trf.read() : rf.read();
        else {
            if (arrayInPtr >= arrayIn.length)
                return -1;
            return arrayIn[arrayInPtr++] & 0xff;
        }
    }
    
    public int read(byte[] b, int off, int len) throws IOException {
        if (len == 0)
            return 0;
        int n = 0;
        if (isBack) {
            isBack = false;
            if (len == 1) {
                b[off] = back;
                return 1;
            }
            else {
                n = 1;
                b[off++] = back;
                --len;
            }
        }
        if (arrayIn == null) {
            return (plainRandomAccess ? trf.read(b, off, len) : rf.read(b, off, len)) + n;
        }
        else {
            if (arrayInPtr >= arrayIn.length)
                return -1;
            if (arrayInPtr + len > arrayIn.length)
                len = arrayIn.length - arrayInPtr;
            System.arraycopy(arrayIn, arrayInPtr, b, off, len);
            arrayInPtr += len;
            return len + n;
        }
    }
    
    public int read(byte b[]) throws IOException {
        return read(b, 0, b.length);
    }
    
    public void readFully(byte b[]) throws IOException {
        readFully(b, 0, b.length);
    }
    
    public void readFully(byte b[], int off, int len) throws IOException {
        int n = 0;
        do {
            int count = read(b, off + n, len - n);
            if (count < 0)
                throw new EOFException();
            n += count;
        } while (n < len);
    }
    
    public long skip(long n) throws IOException {
        return skipBytes((int)n);
    }
    
    public int skipBytes(int n) throws IOException {
        if (n <= 0) {
            return 0;
        }
        int adj = 0;
        if (isBack) {
            isBack = false;
            if (n == 1) {
                return 1;
            }
            else {
                --n;
                adj = 1;
            }
        }
        int pos;
        int len;
        int newpos;
        
        pos = getFilePointer();
        len = length();
        newpos = pos + n;
        if (newpos > len) {
            newpos = len;
        }
        seek(newpos);
        
        /* return the actual number of bytes skipped */
        return newpos - pos + adj;
    }
    
    public void reOpen() throws IOException {
        if (filename != null && rf == null && trf == null) {
            if (plainRandomAccess)
                trf = new RandomAccessFile(filename, "r");
            else
                rf = new MappedRandomAccessFile(filename, "r");
        }
        seek(0);
    }
    
    protected void insureOpen() throws IOException {
        if (filename != null && rf == null && trf == null) {
            reOpen();
        }
    }
    
    public boolean isOpen() {
        return (filename == null || rf != null || trf != null);
    }
    
    public void close() throws IOException {
        isBack = false;
        if (rf != null) {
            rf.close();
            rf = null;
            // it's very expensive to open a memory mapped file and for the usage pattern of this class
            // in iText it's faster the next re-openings to be done as a plain random access
            // file
            plainRandomAccess = true;
        }
        else if (trf != null) {
            trf.close();
            trf = null;
        }
    }
    
    public int length() throws IOException {
        if (arrayIn == null) {
            insureOpen();
            return (int)(plainRandomAccess ? trf.length() : rf.length()) - startOffset;
        }
        else
            return arrayIn.length - startOffset;
    }
    
    public void seek(int pos) throws IOException {
        pos += startOffset;
        isBack = false;
        if (arrayIn == null) {
            insureOpen();
            if (plainRandomAccess)
                trf.seek(pos);
            else
                rf.seek(pos);
        }
        else
            arrayInPtr = pos;
    }
    
    public void seek(long pos) throws IOException {
        seek((int)pos);
    }
    
    public int getFilePointer() throws IOException {
        insureOpen();
        int n = isBack ? 1 : 0;
        if (arrayIn == null) {
            return (int)(plainRandomAccess ? trf.getFilePointer() : rf.getFilePointer()) - n - startOffset;
        }
        else
            return arrayInPtr - n - startOffset;
    }
    
    public boolean readBoolean() throws IOException {
        int ch = this.read();
        if (ch < 0)
            throw new EOFException();
        return (ch != 0);
    }
    
    public byte readByte() throws IOException {
        int ch = this.read();
        if (ch < 0)
            throw new EOFException();
        return (byte)(ch);
    }
    
    public int readUnsignedByte() throws IOException {
        int ch = this.read();
        if (ch < 0)
            throw new EOFException();
        return ch;
    }
    
    public short readShort() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0)
            throw new EOFException();
        return (short)((ch1 << 8) + ch2);
    }
    
    /**
     * Reads a signed 16-bit number from this stream in little-endian order.
     * The method reads two
     * bytes from this stream, starting at the current stream pointer.
     * If the two bytes read, in order, are
     * <code>b1</code> and <code>b2</code>, where each of the two values is
     * between <code>0</code> and <code>255</code>, inclusive, then the
     * result is equal to:
     * <blockquote><pre>
     *     (short)((b2 &lt;&lt; 8) | b1)
     * </pre></blockquote>
     * <p>
     * This method blocks until the two bytes are read, the end of the
     * stream is detected, or an exception is thrown.
     *
     * @return     the next two bytes of this stream, interpreted as a signed
     *             16-bit number.
     * @exception  EOFException  if this stream reaches the end before reading
     *               two bytes.
     * @exception  IOException   if an I/O error occurs.
     */
    public final short readShortLE() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0)
            throw new EOFException();
        return (short)((ch2 << 8) + (ch1 << 0));
    }
    
    public int readUnsignedShort() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0)
            throw new EOFException();
        return (ch1 << 8) + ch2;
    }
    
    /**
     * Reads an unsigned 16-bit number from this stream in little-endian order.
     * This method reads
     * two bytes from the stream, starting at the current stream pointer.
     * If the bytes read, in order, are
     * <code>b1</code> and <code>b2</code>, where
     * <code>0&nbsp;&lt;=&nbsp;b1, b2&nbsp;&lt;=&nbsp;255</code>,
     * then the result is equal to:
     * <blockquote><pre>
     *     (b2 &lt;&lt; 8) | b1
     * </pre></blockquote>
     * <p>
     * This method blocks until the two bytes are read, the end of the
     * stream is detected, or an exception is thrown.
     *
     * @return     the next two bytes of this stream, interpreted as an
     *             unsigned 16-bit integer.
     * @exception  EOFException  if this stream reaches the end before reading
     *               two bytes.
     * @exception  IOException   if an I/O error occurs.
     */
    public final int readUnsignedShortLE() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0)
            throw new EOFException();
        return (ch2 << 8) + (ch1 << 0);
    }
    
    public char readChar() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0)
            throw new EOFException();
        return (char)((ch1 << 8) + ch2);
    }
    
    /**
     * Reads a Unicode character from this stream in little-endian order.
     * This method reads two
     * bytes from the stream, starting at the current stream pointer.
     * If the bytes read, in order, are
     * <code>b1</code> and <code>b2</code>, where
     * <code>0&nbsp;&lt;=&nbsp;b1,&nbsp;b2&nbsp;&lt;=&nbsp;255</code>,
     * then the result is equal to:
     * <blockquote><pre>
     *     (char)((b2 &lt;&lt; 8) | b1)
     * </pre></blockquote>
     * <p>
     * This method blocks until the two bytes are read, the end of the
     * stream is detected, or an exception is thrown.
     *
     * @return     the next two bytes of this stream as a Unicode character.
     * @exception  EOFException  if this stream reaches the end before reading
     *               two bytes.
     * @exception  IOException   if an I/O error occurs.
     */
    public final char readCharLE() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        if ((ch1 | ch2) < 0)
            throw new EOFException();
        return (char)((ch2 << 8) + (ch1 << 0));
    }
    
    public int readInt() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        int ch3 = this.read();
        int ch4 = this.read();
        if ((ch1 | ch2 | ch3 | ch4) < 0)
            throw new EOFException();
        return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + ch4);
    }
    
    /**
     * Reads a signed 32-bit integer from this stream in little-endian order.
     * This method reads 4
     * bytes from the stream, starting at the current stream pointer.
     * If the bytes read, in order, are <code>b1</code>,
     * <code>b2</code>, <code>b3</code>, and <code>b4</code>, where
     * <code>0&nbsp;&lt;=&nbsp;b1, b2, b3, b4&nbsp;&lt;=&nbsp;255</code>,
     * then the result is equal to:
     * <blockquote><pre>
     *     (b4 &lt;&lt; 24) | (b3 &lt;&lt; 16) + (b2 &lt;&lt; 8) + b1
     * </pre></blockquote>
     * <p>
     * This method blocks until the four bytes are read, the end of the
     * stream is detected, or an exception is thrown.
     *
     * @return     the next four bytes of this stream, interpreted as an
     *             <code>int</code>.
     * @exception  EOFException  if this stream reaches the end before reading
     *               four bytes.
     * @exception  IOException   if an I/O error occurs.
     */
    public final int readIntLE() throws IOException {
        int ch1 = this.read();
        int ch2 = this.read();
        int ch3 = this.read();
        int ch4 = this.read();
        if ((ch1 | ch2 | ch3 | ch4) < 0)
            throw new EOFException();
        return ((ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0));
    }
    
    /**
     * Reads an unsigned 32-bit integer from this stream. This method reads 4
     * bytes from the stream, starting at the current stream pointer.
     * If the bytes read, in order, are <code>b1</code>,
     * <code>b2</code>, <code>b3</code>, and <code>b4</code>, where
     * <code>0&nbsp;&lt;=&nbsp;b1, b2, b3, b4&nbsp;&lt;=&nbsp;255</code>,
     * then the result is equal to:
     * <blockquote><pre>
     *     (b1 &lt;&lt; 24) | (b2 &lt;&lt; 16) + (b3 &lt;&lt; 8) + b4
     * </pre></blockquote>
     * <p>
     * This method blocks until the four bytes are read, the end of the
     * stream is detected, or an exception is thrown.
     *
     * @return     the next four bytes of this stream, interpreted as a
     *             <code>long</code>.
     * @exception  EOFException  if this stream reaches the end before reading
     *               four bytes.
     * @exception  IOException   if an I/O error occurs.
     */
    public final long readUnsignedInt() throws IOException {
        long ch1 = this.read();
        long ch2 = this.read();
        long ch3 = this.read();
        long ch4 = this.read();
        if ((ch1 | ch2 | ch3 | ch4) < 0)
            throw new EOFException();
        return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + (ch4 << 0));
    }
    
    public final long readUnsignedIntLE() throws IOException {
        long ch1 = this.read();
        long ch2 = this.read();
        long ch3 = this.read();
        long ch4 = this.read();
        if ((ch1 | ch2 | ch3 | ch4) < 0)
            throw new EOFException();
        return ((ch4 << 24) + (ch3 << 16) + (ch2 << 8) + (ch1 << 0));
    }
    
    public long readLong() throws IOException {
        return ((long)(readInt()) << 32) + (readInt() & 0xFFFFFFFFL);
    }
    
    public final long readLongLE() throws IOException {
        int i1 = readIntLE();
        int i2 = readIntLE();
        return ((long)i2 << 32) + (i1 & 0xFFFFFFFFL);
    }
    
    public float readFloat() throws IOException {
        return Float.intBitsToFloat(readInt());
    }
    
    public final float readFloatLE() throws IOException {
        return Float.intBitsToFloat(readIntLE());
    }
    
    public double readDouble() throws IOException {
        return Double.longBitsToDouble(readLong());
    }
    
    public final double readDoubleLE() throws IOException {
        return Double.longBitsToDouble(readLongLE());
    }
    
    public String readLine() throws IOException {
        StringBuffer input = new StringBuffer();
        int c = -1;
        boolean eol = false;
        
        while (!eol) {
            switch (c = read()) {
                case -1:
                case '\n':
                    eol = true;
                    break;
                case '\r':
                    eol = true;
                    int cur = getFilePointer();
                    if ((read()) != '\n') {
                        seek(cur);
                    }
                    break;
                default:
                    input.append((char)c);
                    break;
            }
        }
        
        if ((c == -1) && (input.length() == 0)) {
            return null;
        }
        return input.toString();
    }
    
    public String readUTF() throws IOException {
        return DataInputStream.readUTF(this);
    }
    
    /** Getter for property startOffset.
     * @return Value of property startOffset.
     *
     */
    public int getStartOffset() {
        return this.startOffset;
    }
    
    /** Setter for property startOffset.
     * @param startOffset New value of property startOffset.
     *
     */
    public void setStartOffset(int startOffset) {
        this.startOffset = startOffset;
    }

    /**
     * @since 2.0.8
     */
    public java.nio.ByteBuffer getNioByteBuffer() throws IOException {
        if (filename != null) {
                FileChannel channel;
            if (plainRandomAccess)
                channel = trf.getChannel();
            else
                channel = rf.getChannel();
            return channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
        }
        return java.nio.ByteBuffer.wrap(arrayIn);
    }
}