multipartstream.java

apache commons-fileupload-1.2.jar

     * Searches for the <code>boundary</code> in the <code>buffer</code>
     * region delimited by <code>head</code> and <code>tail</code>.
     *
     * @return The position of the boundary found, counting from the
     *         beginning of the <code>buffer</code>, or <code>-1</code> if
     *         not found.
     */
    protected int findSeparator() {
        int first;
        int match = 0;
        int maxpos = tail - boundaryLength;
        for (first = head;
        (first <= maxpos) && (match != boundaryLength);
        first++) {
            first = findByte(boundary[0], first);
            if (first == -1 || (first > maxpos)) {
                return -1;
            }
            for (match = 1; match < boundaryLength; match++) {
                if (buffer[first + match] != boundary[match]) {
                    break;
                }
            }
        }
        if (match == boundaryLength) {
            return first - 1;
        }
        return -1;
    }

    /**
     * Thrown to indicate that the input stream fails to follow the
     * required syntax.
     */
    public static class MalformedStreamException
    extends IOException {
        /**
         * Constructs a <code>MalformedStreamException</code> with no
         * detail message.
         */
        public MalformedStreamException() {
            super();
        }

        /**
         * Constructs an <code>MalformedStreamException</code> with
         * the specified detail message.
         *
         * @param message The detail message.
         */
        public MalformedStreamException(String message) {
            super(message);
        }
    }


    /**
     * Thrown upon attempt of setting an invalid boundary token.
     */
    public static class IllegalBoundaryException
            extends IOException {
        /**
         * Constructs an <code>IllegalBoundaryException</code> with no
         * detail message.
         */
        public IllegalBoundaryException() {
            super();
        }

        /**
         * Constructs an <code>IllegalBoundaryException</code> with
         * the specified detail message.
         *
         * @param message The detail message.
         */
        public IllegalBoundaryException(String message) {
            super(message);
        }
    }

    /**
     * An {@link InputStream} for reading an items contents.
     */
    public class ItemInputStream extends InputStream implements Closeable {
        /** The number of bytes, which have been read so far.
         */
        private long total;
        /** The number of bytes, which must be hold, because
         * they might be a part of the boundary.
         */
        private int pad;
        /** The current offset in the buffer.
         */
        private int pos;
        /** Whether the stream is already closed.
         */
        private boolean closed;

        /**
         * Creates a new instance.
         */
        ItemInputStream() {
            findSeparator();
        }

        /**
         * Called for finding the separator.
         */
        private void findSeparator() {
            pos = MultipartStream.this.findSeparator();
            if (pos == -1) {
                if (tail - head > keepRegion) {
                    pad = keepRegion;
                } else {
                    pad = tail - head;
                }
            }
        }

        /**
         * Returns the number of bytes, which have been read
         * by the stream.
         * @return Number of bytes, which have been read so far.
         */
        public long getBytesRead() {
            return total;
        }

        /**
         * Returns the number of bytes, which are currently
         * available, without blocking.
         * @throws IOException An I/O error occurs.
         * @return Number of bytes in the buffer.
         */
        public int available() throws IOException {
            if (pos == -1) {
                return tail - head - pad;
            }
            return pos - head;
        }

        /** Offset when converting negative bytes to integers.
         */
        private static final int BYTE_POSITIVE_OFFSET = 256;

        /**
         * Returns the next byte in the stream.
         * @return The next byte in the stream, as a non-negative
         *   integer, or -1 for EOF.
         * @throws IOException An I/O error occurred.
         */
        public int read() throws IOException {
            if (closed) {
                throw new FileItemStream.ItemSkippedException();
            }
            if (available() == 0) {
                if (makeAvailable() == 0) {
                    return -1;
                }
            }
            ++total;
            int b = buffer[head++];
            if (b >= 0) {
                return b;
            }
            return b + BYTE_POSITIVE_OFFSET;
        }

        /**
         * Reads bytes into the given buffer.
         * @param b The destination buffer, where to write to.
         * @param off Offset of the first byte in the buffer.
         * @param len Maximum number of bytes to read.
         * @return Number of bytes, which have been actually read,
         *   or -1 for EOF.
         * @throws IOException An I/O error occurred.
         */
        public int read(byte[] b, int off, int len) throws IOException {
            if (closed) {
                throw new FileItemStream.ItemSkippedException();
            }
            if (len == 0) {
                return 0;
            }
            int res = available();
            if (res == 0) {
                res = makeAvailable();
                if (res == 0) {
                    return -1;
                }
            }
            res = Math.min(res, len);
            System.arraycopy(buffer, head, b, off, res);
            head += res;
            total += res;
            return res;
        }

        /**
         * Closes the input stream.
         * @throws IOException An I/O error occurred.
         */
        public void close() throws IOException {
            if (closed) {
                return;
            }
            for (;;) {
                int av = available();
                if (av == 0) {
                    av = makeAvailable();
                    if (av == 0) {
                        break;
                    }
                }
                skip(av);
            }
            closed = true;
        }

        /**
         * Skips the given number of bytes.
         * @param bytes Number of bytes to skip.
         * @return The number of bytes, which have actually been
         *   skipped.
         * @throws IOException An I/O error occurred.
         */
        public long skip(long bytes) throws IOException {
            if (closed) {
                throw new FileItemStream.ItemSkippedException();
            }
            int av = available();
            if (av == 0) {
                av = makeAvailable();
                if (av == 0) {
                    return 0;
                }
            }
            long res = Math.min(av, bytes);
            head += res;
            return res;
        }

        /**
         * Attempts to read more data.
         * @return Number of available bytes
         * @throws IOException An I/O error occurred.
         */
        private int makeAvailable() throws IOException {
            if (pos != -1) {
                return 0;
            }

            // Move the data to the beginning of the buffer.
            total += tail - head - pad;
            System.arraycopy(buffer, tail - pad, buffer, 0, pad);

            // Refill buffer with new data.
            head = 0;
            int bytesRead = input.read(buffer, pad, bufSize - pad);
            if (bytesRead == -1) {
                // The last pad amount is left in the buffer.
                // Boundary can't be in there so signal an error
                // condition.
                throw new MalformedStreamException(
                "Stream ended unexpectedly");
            }
            notifier.noteBytesRead(bytesRead);
            tail = pad + bytesRead;
            findSeparator();
            return available();
        }

        /**
         * Returns, whether the stream is closed.
         * @return True, if the stream is closed, otherwise false.
         */
        public boolean isClosed() {
            return closed;
        }
    }

    // ------------------------------------------------------ Debugging methods


    // These are the methods that were used to debug this stuff.
    /*

    // Dump data.
    protected void dump()
    {
        System.out.println("01234567890");
        byte[] temp = new byte[buffer.length];
        for(int i=0; i<buffer.length; i++)
        {
            if (buffer[i] == 0x0D || buffer[i] == 0x0A)
            {
                temp[i] = 0x21;
            }
            else
            {
                temp[i] = buffer[i];
            }
        }
        System.out.println(new String(temp));
        int i;
        for (i=0; i<head; i++)
            System.out.print(" ");
        System.out.println("h");
        for (i=0; i<tail; i++)
            System.out.print(" ");
        System.out.println("t");
        System.out.flush();
    }

    // Main routine, for testing purposes only.
    //
    // @param args A String[] with the command line arguments.
    // @throws Exception, a generic exception.
    public static void main( String[] args )
        throws Exception
    {
        File boundaryFile = new File("boundary.dat");
        int boundarySize = (int)boundaryFile.length();
        byte[] boundary = new byte[boundarySize];
        FileInputStream input = new FileInputStream(boundaryFile);
        input.read(boundary,0,boundarySize);

        input = new FileInputStream("multipart.dat");
        MultipartStream chunks = new MultipartStream(input, boundary);

        int i = 0;
        String header;
        OutputStream output;
        boolean nextChunk = chunks.skipPreamble();
        while (nextChunk)
        {
            header = chunks.readHeaders();
            System.out.println("!"+header+"!");
            System.out.println("wrote part"+i+".dat");
            output = new FileOutputStream("part"+(i++)+".dat");
            chunks.readBodyData(output);
            nextChunk = chunks.readBoundary();
        }
    }

     */
}