randomaccessfileorarray.java

iText是一个能够快速产生PDF文件的java类库。iText的java类对于那些要产生包含文本

            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;
    }
    
}