File	Doc	Category	Size	Date	Package
LittleEndian.java	API Doc	Apache Poi 3.0.1	17579	Mon Jan 01 12:39:42 GMT 2007	org.apache.poi.util

LittleEndian

• java.lang.Object

Fields Summary

Constructors Summary
private LittleEndian() Constructor for the LittleEndian object

Methods Summary
public static byte[]	getByteArray(byte[] data, int offset, int size) Copy a portion of a byte array param data the original byte array param offset Where to start copying from. param size Number of bytes to copy. return The byteArray value throws IndexOutOfBoundsException - if copying would cause access of data outside array bounds. byte[] copy = new byte[size]; System.arraycopy(data, offset, copy, 0, size); return copy;
public static double	getDouble(byte[] data, int offset) get a double value from a byte array, reads it in little endian format then converts the resulting revolting IEEE 754 (curse them) floating point number to a happy java double param data the byte array param offset a starting offset into the byte array return the double (64-bit) value return Double.longBitsToDouble(getNumber(data, offset, DOUBLE_SIZE));
public static double	getDouble(byte[] data) get a double value from the beginning of a byte array param data the byte array return the double (64-bit) value return getDouble(data, 0);
public static int	getInt(byte[] data, int offset) get an int value from a byte array param data the byte array param offset a starting offset into the byte array return the int (32-bit) value return (int) getNumber(data, offset, INT_SIZE);
public static int	getInt(byte[] data) get an int value from the beginning of a byte array param data the byte array return the int (32-bit) value return getInt(data, 0);
public static long	getLong(byte[] data, int offset) get a long value from a byte array param data the byte array param offset a starting offset into the byte array return the long (64-bit) value return getNumber(data, offset, LONG_SIZE);
public static long	getLong(byte[] data) get a long value from the beginning of a byte array param data the byte array return the long (64-bit) value return getLong(data, 0);
private static long	getNumber(byte[] data, int offset, int size) Gets the number attribute of the LittleEndian class param data Description of the Parameter param offset Description of the Parameter param size Description of the Parameter return The number value long result = 0; for (int j = offset + size - 1; j >= offset; j--) { result <<= 8; result |= 0xff & data[j]; } return result;
public static short	getShort(byte[] data, int offset) get a short value from a byte array param data the byte array param offset a starting offset into the byte array return the short (16-bit) value return (short) getNumber(data, offset, SHORT_SIZE);
public static short	getShort(byte[] data) get a short value from the beginning of a byte array param data the byte array return the short (16-bit) value return getShort(data, 0);
public static short[]	getShortArray(byte[] data, int offset) get a short array from a byte array. The short array is assumed to start with a word describing the length of the array. param data Description of the Parameter param offset Description of the Parameter return The shortArray value int size = (int) getNumber(data, offset, SHORT_SIZE); short[] results = getSimpleShortArray(data, offset, size); return results;
public static short[]	getSimpleShortArray(byte[] data, int offset, int size) get a short array from a byte array. param data Description of the Parameter param offset Description of the Parameter param size Description of the Parameter return The simpleShortArray value short[] results = new short[size]; for (int i = 0; i < size; i++) { results[i] = getShort(data, offset + 2 + (i * 2)); } return results;
public static long	getUInt(byte[] data, int offset) get an unsigned int value from a byte array param data the byte array param offset a starting offset into the byte array return the unsigned int (32-bit) value in a long int num = (int) getNumber(data, offset, INT_SIZE); long retNum; if (num < 0) { retNum = ((long) Integer.MAX_VALUE + 1) * 2 + num; } else { retNum = num; } return retNum;
public static long	getUInt(byte[] data) get an unsigned int value from a byte array param data the byte array return the unsigned int (32-bit) value in a long return getUInt(data,0);
public static long	getULong(byte[] data, int offset) Gets an unsigned int value (8 bytes) from a byte array. param data the byte array param offset a starting offset into the byte array return the unsigned int (32-bit) value in a long int num = (int) getNumber(data, offset, LONG_SIZE); long retNum; if (num < 0) retNum = ((long) Integer.MAX_VALUE + 1) * 2 + num; else retNum = num; return retNum;
public static int	getUShort(byte[] data, int offset) get an unsigned short value from a byte array param data the byte array param offset a starting offset into the byte array return the unsigned short (16-bit) value in an integer short num = (short) getNumber(data, offset, SHORT_SIZE); int retNum; if (num < 0) { retNum = (Short.MAX_VALUE + 1) * 2 + num; } else { retNum = num; } return retNum;
public static int	getUShort(byte[] data) get an unsigned short value from the beginning of a byte array param data the byte array return the unsigned short (16-bit) value in an int return getUShort(data, 0);
public static int	getUnsignedByte(byte[] data, int offset) get the unsigned value of a byte. param data the byte array. param offset a starting offset into the byte array. return the unsigned value of the byte as a 32 bit integer return (int) getNumber(data, offset, BYTE_SIZE);
public static int	getUnsignedByte(byte[] data) get the unsigned value of a byte. param data the byte array return the unsigned value of the byte as a 32 bit integer return getUnsignedByte(data, 0);
public static void	putDouble(byte[] data, int offset, double value) put a double value into a byte array param data the byte array param offset a starting offset into the byte array param value the double (64-bit) value // Excel likes NaN to be a specific value. if (Double.isNaN(value)) putNumber(data, offset, -276939487313920L, DOUBLE_SIZE); else putNumber(data, offset, Double.doubleToLongBits(value), DOUBLE_SIZE);
public static void	putDouble(byte[] data, double value) put a double value into beginning of a byte array param data the byte array param value the double (64-bit) value putDouble(data, 0, value);
public static void	putInt(byte[] data, int offset, int value) put an int value into a byte array param data the byte array param offset a starting offset into the byte array param value the int (32-bit) value putNumber(data, offset, value, INT_SIZE);
public static void	putInt(byte[] data, int value) put an int value into beginning of a byte array param data the byte array param value the int (32-bit) value putInt(data, 0, value);
public static void	putLong(byte[] data, int offset, long value) put a long value into a byte array param data the byte array param offset a starting offset into the byte array param value the long (64-bit) value putNumber(data, offset, value, LONG_SIZE);
public static void	putLong(byte[] data, long value) put a long value into beginning of a byte array param data the byte array param value the long (64-bit) value putLong(data, 0, value);
private static void	putNumber(byte[] data, int offset, long value, int size) Description of the Method param data Description of the Parameter param offset Description of the Parameter param value Description of the Parameter param size Description of the Parameter int limit = size + offset; long v = value; for (int j = offset; j < limit; j++) { data[j] = (byte) (v & 0xFF); v >>= 8; }
public static void	putShort(byte[] data, int offset, short value) put a short value into a byte array param data the byte array param offset a starting offset into the byte array param value the short (16-bit) value putNumber(data, offset, value, SHORT_SIZE);
public static void	putShort(byte[] data, short value) put a short value into beginning of a byte array param data the byte array param value the short (16-bit) value putShort(data, 0, value);
public static void	putShortArray(byte[] data, int offset, short[] value) put a array of shorts into a byte array param data the byte array param offset a starting offset into the byte array param value the short array putNumber(data, offset, value.length, SHORT_SIZE); for (int i = 0; i < value.length; i++) { putNumber(data, offset + 2 + (i * 2), value[i], SHORT_SIZE); }
public static void	putUShort(byte[] data, int offset, int value) put an unsigned short value into a byte array param data the byte array param offset a starting offset into the byte array param value the short (16-bit) value exception ArrayIndexOutOfBoundsException may be thrown putNumber(data, offset, value, SHORT_SIZE);
public static byte[]	readFromStream(java.io.InputStream stream, int size) Read the appropriate number of bytes from the stream and return them to the caller. However, for the purposes of the POI project, this risk is deemed negligible. It is, however, so noted. param stream the InputStream we're reading from param size the number of bytes to read; in 99.99% of cases, this will be SHORT_SIZE, INT_SIZE, or LONG_SIZE -- but it doesn't have to be. return the byte array containing the required number of bytes. The array will contain all zero's on end of stream exception IOException will be propagated back to the caller exception BufferUnderrunException if the stream cannot provide enough bytes byte[] buffer = new byte[size]; int count = stream.read(buffer); if (count == -1) { // return a zero-filled buffer Arrays.fill(buffer, (byte) 0); } else if (count != size) { throw new BufferUnderrunException(); } return buffer;
public static int	readInt(java.io.InputStream stream) get an int value from an InputStream param stream the InputStream from which the int is to be read return the int (32-bit) value exception IOException will be propagated back to the caller exception BufferUnderrunException if the stream cannot provide enough bytes return getInt(readFromStream(stream, INT_SIZE));
public static long	readLong(java.io.InputStream stream) get a long value from an InputStream param stream the InputStream from which the long is to be read return the long (64-bit) value exception IOException will be propagated back to the caller exception BufferUnderrunException if the stream cannot provide enough bytes return getLong(readFromStream(stream, LONG_SIZE));
public static short	readShort(java.io.InputStream stream) get a short value from an InputStream param stream the InputStream from which the short is to be read return the short (16-bit) value exception IOException will be propagated back to the caller exception BufferUnderrunException if the stream cannot provide enough bytes return getShort(readFromStream(stream, SHORT_SIZE));
public static int	ubyteToInt(byte b) Convert an 'unsigned' byte to an integer. ie, don't carry across the sign. param b Description of the Parameter return Description of the Return Value return ((b & 0x80) == 0 ? (int) b : (b & (byte) 0x7f) + 0x80);