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General clean-up in LittleEndian util class. (Some optimization, some obsolete code removal)

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git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@707585 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Josh Micich 2008-10-24 08:58:00 +00:00
parent f175e62e37
commit 70f4ca4e9c
2 changed files with 132 additions and 296 deletions
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310
src/java/org/apache/poi/util/LittleEndian.java
View File

@ -28,13 +28,12 @@ import java.io.InputStream;
*@author Marc Johnson (mjohnson at apache dot org)
*@author Andrew Oliver (acoliver at apache dot org)
*/
public final class LittleEndian implements LittleEndianConsts {
public class LittleEndian implements LittleEndianConsts {
private LittleEndian() {
// no instances of this class
}
/**
* get a short value from a byte array
*
@ -42,9 +41,10 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@return the short (16-bit) value
*/
public static short getShort(final byte[] data, final int offset) {
return (short) getNumber(data, offset, SHORT_SIZE);
public static short getShort(byte[] data, int offset) {
int b0 = data[offset] & 0xFF;
int b1 = data[offset+1] & 0xFF;
return (short) ((b1 << 8) + (b0 << 0));
}
@ -55,49 +55,11 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@return the unsigned short (16-bit) value in an integer
*/
public static int getUShort(final byte[] data, final int offset) {
short num = (short) getNumber(data, offset, SHORT_SIZE);
int retNum;
if (num < 0) {
retNum = (Short.MAX_VALUE + 1) * 2 + num;
} else {
retNum = num;
public static int getUShort(byte[] data, int offset) {
int b0 = data[offset] & 0xFF;
int b1 = data[offset+1] & 0xFF;
return (b1 << 8) + (b0 << 0);
}
return retNum;
}
/**
* 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
*/
public static short[] getSimpleShortArray(final byte[] data, final int offset, final int size) {
short[] results = new short[size];
for (int i = 0; i < size; i++) {
results[i] = getShort(data, offset + 2 + (i * 2));
}
return results;
}
/**
* 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
*/
public static short[] getShortArray(final byte[] data, final int offset) {
int size = (int) getNumber(data, offset, SHORT_SIZE);
short[] results = getSimpleShortArray(data, offset, size);
return results;
}
/**
* get a short value from the beginning of a byte array
@ -105,23 +67,20 @@ public final class LittleEndian implements LittleEndianConsts {
*@param data the byte array
*@return the short (16-bit) value
*/
public static short getShort(final byte[] data) {
public static short getShort(byte[] data) {
return getShort(data, 0);
}
/**
* 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
*/
public static int getUShort(final byte[] data) {
public static int getUShort(byte[] data) {
return getUShort(data, 0);
}
/**
* get an int value from a byte array
*
@ -129,9 +88,13 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@return the int (32-bit) value
*/
public static int getInt(final byte[] data, final int offset) {
return (int) getNumber(data, offset, INT_SIZE);
public static int getInt(byte[] data, int offset) {
int i=offset;
int b0 = data[i++] & 0xFF;
int b1 = data[i++] & 0xFF;
int b2 = data[i++] & 0xFF;
int b3 = data[i++] & 0xFF;
return (b3 << 24) + (b2 << 16) + (b1 << 8) + (b0 << 0);
}
@ -141,8 +104,7 @@ public final class LittleEndian implements LittleEndianConsts {
*@param data the byte array
*@return the int (32-bit) value
*/
public static int getInt(final byte[] data) {
public static int getInt(byte[] data) {
return getInt(data, 0);
}
@ -154,15 +116,9 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@return the unsigned int (32-bit) value in a long
*/
public static long getUInt(final byte[] data, final int offset) {
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, int offset) {
long retNum = getInt(data, offset);
return retNum & 0x00FFFFFFFF;
}
/**
@ -171,7 +127,7 @@ public final class LittleEndian implements LittleEndianConsts {
*@param data the byte array
*@return the unsigned int (32-bit) value in a long
*/
public static long getUInt(final byte[] data) {
public static long getUInt(byte[] data) {
return getUInt(data,0);
}
@ -182,24 +138,16 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@return the long (64-bit) value
*/
public static long getLong(byte[] data, int offset) {
long result = 0;
public static long getLong(final byte[] data, final int offset) {
return getNumber(data, offset, LONG_SIZE);
for (int j = offset + LONG_SIZE - 1; j >= offset; j--) {
result <<= 8;
result |= 0xff & data[j];
}
/**
* get a long value from the beginning of a byte array
*
*@param data the byte array
*@return the long (64-bit) value
*/
public static long getLong(final byte[] data) {
return getLong(data, 0);
return result;
}
/**
* get a double value from a byte array, reads it in little endian format
* then converts the resulting revolting IEEE 754 (curse them) floating
@ -209,24 +157,10 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@return the double (64-bit) value
*/
public static double getDouble(final byte[] data, final int offset) {
return Double.longBitsToDouble(getNumber(data, offset, DOUBLE_SIZE));
public static double getDouble(byte[] data, int offset) {
return Double.longBitsToDouble(getLong(data, offset));
}
/**
* get a double value from the beginning of a byte array
*
*@param data the byte array
*@return the double (64-bit) value
*/
public static double getDouble(final byte[] data) {
return getDouble(data, 0);
}
/**
* put a short value into a byte array
*
@ -234,9 +168,10 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@param value the short (16-bit) value
*/
public static void putShort(final byte[] data, final int offset,
final short value) {
putNumber(data, offset, value, SHORT_SIZE);
public static void putShort(byte[] data, int offset, short value) {
int i = offset;
data[i++] = (byte)((value >>> 0) & 0xFF);
data[i++] = (byte)((value >>> 8) & 0xFF);
}
/**
@ -247,7 +182,7 @@ public final class LittleEndian implements LittleEndianConsts {
* Added for consistency with other put~() methods
*/
public static void putByte(byte[] data, int offset, int value) {
putNumber(data, offset, value, LittleEndianConsts.BYTE_SIZE);
data[offset] = (byte) value;
}
/**
@ -259,10 +194,10 @@ public final class LittleEndian implements LittleEndianConsts {
*
* @exception ArrayIndexOutOfBoundsException may be thrown
*/
public static void putUShort(final byte[] data, final int offset,
final int value)
{
putNumber(data, offset, value, SHORT_SIZE);
public static void putUShort(byte[] data, int offset, int value) {
int i = offset;
data[i++] = (byte)((value >>> 0) & 0xFF);
data[i++] = (byte)((value >>> 8) & 0xFF);
}
/**
@ -271,8 +206,7 @@ public final class LittleEndian implements LittleEndianConsts {
*@param data the byte array
*@param value the short (16-bit) value
*/
public static void putShort(final byte[] data, final short value) {
public static void putShort(byte[] data, short value) {
putShort(data, 0, value);
}
@ -284,10 +218,12 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@param value the int (32-bit) value
*/
public static void putInt(final byte[] data, final int offset,
final int value) {
putNumber(data, offset, value, INT_SIZE);
public static void putInt(byte[] data, int offset, int value) {
int i = offset;
data[i++] = (byte)((value >>> 0) & 0xFF);
data[i++] = (byte)((value >>> 8) & 0xFF);
data[i++] = (byte)((value >>> 16) & 0xFF);
data[i++] = (byte)((value >>> 24) & 0xFF);
}
@ -297,8 +233,7 @@ public final class LittleEndian implements LittleEndianConsts {
*@param data the byte array
*@param value the int (32-bit) value
*/
public static void putInt(final byte[] data, final int value) {
public static void putInt(byte[] data, int value) {
putInt(data, 0, value);
}
@ -310,22 +245,14 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@param value the long (64-bit) value
*/
public static void putLong(byte[] data, int offset, long value) {
int limit = LONG_SIZE + offset;
long v = value;
public static void putLong(final byte[] data, final int offset,
final long value) {
putNumber(data, offset, value, LONG_SIZE);
for (int j = offset; j < limit; j++) {
data[j] = (byte) (v & 0xFF);
v >>= 8;
}
/**
* put a long value into beginning of a byte array
*
*@param data the byte array
*@param value the long (64-bit) value
*/
public static void putLong(final byte[] data, final long value) {
putLong(data, 0, value);
}
@ -336,26 +263,13 @@ public final class LittleEndian implements LittleEndianConsts {
*@param offset a starting offset into the byte array
*@param value the double (64-bit) value
*/
public static void putDouble(final byte[] data, final int offset,
final double value) {
public static void putDouble(byte[] data, int offset, double 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);
if (Double.isNaN(value)) {
putLong(data, offset, -276939487313920L);
} else {
putLong(data, offset, Double.doubleToLongBits(value));
}
/**
* put a double value into beginning of a byte array
*
*@param data the byte array
*@param value the double (64-bit) value
*/
public static void putDouble(final byte[] data, final double value) {
putDouble(data, 0, value);
}
@ -364,7 +278,6 @@ public final class LittleEndian implements LittleEndianConsts {
*
*@author Marc Johnson (mjohnson at apache dot org)
*/
public static final class BufferUnderrunException extends IOException {
BufferUnderrunException() {
@ -376,12 +289,10 @@ public final class LittleEndian implements LittleEndianConsts {
/**
* get a short value from an InputStream
*
*@param stream the InputStream from which the short
* is to be read
*@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
*@exception BufferUnderrunException if the stream cannot provide enough bytes
*/
public static short readShort(InputStream stream) throws IOException, BufferUnderrunException {
@ -395,21 +306,19 @@ public final class LittleEndian implements LittleEndianConsts {
if ((ch1 | ch2) < 0) {
throw new BufferUnderrunException();
}
return ((ch2 << 8) + (ch1 << 0));
return (ch2 << 8) + (ch1 << 0);
}
/**
* get an int value from an InputStream
*
*@param stream the InputStream from which the int is
* to be read
*@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
* @exception BufferUnderrunException if the stream cannot provide enough bytes
*/
public static int readInt(final InputStream stream)
public static int readInt(InputStream stream)
throws IOException, BufferUnderrunException {
int ch1 = stream.read();
int ch2 = stream.read();
@ -418,22 +327,19 @@ public final class LittleEndian implements LittleEndianConsts {
if ((ch1 | ch2 | ch3 | ch4) < 0) {
throw new BufferUnderrunException();
}
return ((ch4 << 24) + (ch3<<16) + (ch2 << 8) + (ch1 << 0));
return (ch4 << 24) + (ch3<<16) + (ch2 << 8) + (ch1 << 0);
}
/**
* get a long value from an InputStream
*
*@param stream the InputStream from which the long
* is to be read
* @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
* @exception BufferUnderrunException if the stream cannot provide enough bytes
*/
public static long readLong(final InputStream stream)
public static long readLong(InputStream stream)
throws IOException, BufferUnderrunException {
int ch1 = stream.read();
int ch2 = stream.read();
@ -458,46 +364,6 @@ public final class LittleEndian implements LittleEndianConsts {
(ch1 << 0);
}
/**
* 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
*/
private static long getNumber(final byte[] data, final int offset,
final int size) {
long result = 0;
for (int j = offset + size - 1; j >= offset; j--) {
result <<= 8;
result |= 0xff & data[j];
}
return result;
}
/**
* 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
*/
private static void putNumber(final byte[] data, final int offset,
final long value, final int size) {
int limit = size + offset;
long v = value;
for (int j = offset; j < limit; j++) {
data[j] = (byte) (v & 0xFF);
v >>= 8;
}
}
/**
* Convert an 'unsigned' byte to an integer. ie, don't carry across the
* sign.
@ -506,7 +372,7 @@ public final class LittleEndian implements LittleEndianConsts {
* @return Description of the Return Value
*/
public static int ubyteToInt(byte b) {
return ((b & 0x80) == 0 ? (int) b : (b & (byte) 0x7f) + 0x80);
return b & 0xFF;
}
@ -517,19 +383,8 @@ public final class LittleEndian implements LittleEndianConsts {
* @param offset a starting offset into the byte array.
* @return the unsigned value of the byte as a 32 bit integer
*/
public static int getUnsignedByte(final byte[] data, final int offset) {
return (int) getNumber(data, offset, BYTE_SIZE);
}
/**
* get the unsigned value of a byte.
*
*@param data the byte array
*@return the unsigned value of the byte as a 32 bit integer
*/
public static int getUnsignedByte(final byte[] data) {
return getUnsignedByte(data, 0);
public static int getUnsignedByte(byte[] data, int offset) {
return data[offset] & 0xFF;
}
@ -543,29 +398,10 @@ public final class LittleEndian implements LittleEndianConsts {
* @throws IndexOutOfBoundsException - if copying would cause access of
* data outside array bounds.
*/
public static byte[] getByteArray(final byte[] data, int offset, int size) {
public static byte[] getByteArray(byte[] data, int offset, int size) {
byte[] copy = new byte[size];
System.arraycopy(data, offset, copy, 0, size);
return copy;
}
/**
* <p>Gets an unsigned int value (8 bytes) from a byte array.</p>
*
* @param data the byte array
* @param offset a starting offset into the byte array
* @return the unsigned int (32-bit) value in a long
*/
public static long getULong(final byte[] data, final int offset)
{
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;
}
}

14
src/testcases/org/apache/poi/util/TestLittleEndian.java
View File

@ -97,13 +97,13 @@ public final class TestLittleEndian extends TestCase {
* test the getDouble() method
*/
public void testGetDouble() {
assertEquals(_doubles[0], LittleEndian.getDouble(_double_array), 0.000001 );
assertEquals(_doubles[0], LittleEndian.getDouble(_double_array, 0), 0.000001 );
assertEquals(_doubles[1], LittleEndian.getDouble( _double_array, LittleEndian.DOUBLE_SIZE), 0.000001);
assertTrue(Double.isNaN(LittleEndian.getDouble(_nan_double_array)));
assertTrue(Double.isNaN(LittleEndian.getDouble(_nan_double_array, 0)));
double nan = LittleEndian.getDouble(_nan_double_array);
double nan = LittleEndian.getDouble(_nan_double_array, 0);
byte[] data = new byte[8];
LittleEndian.putDouble(data, nan);
LittleEndian.putDouble(data, 0, nan);
for ( int i = 0; i < data.length; i++ ) {
assertEquals(data[i], _nan_double_array[i]);
}
@ -144,7 +144,7 @@ public final class TestLittleEndian extends TestCase {
(byte) 0x02,
};
assertEquals(0xFFFFFFFFFFFFFF01L, LittleEndian.getLong(testdata));
assertEquals(0xFFFFFFFFFFFFFF01L, LittleEndian.getLong(testdata, 0));
assertEquals(0x02FFFFFFFFFFFFFFL, LittleEndian.getLong(testdata, 1));
}
@ -194,7 +194,7 @@ public final class TestLittleEndian extends TestCase {
public void testPutDouble() {
byte[] received = new byte[ LittleEndian.DOUBLE_SIZE + 1 ];
LittleEndian.putDouble(received, _doubles[0]);
LittleEndian.putDouble(received, 0, _doubles[0]);
assertTrue(compareByteArrays(received, _double_array, 0, LittleEndian.DOUBLE_SIZE));
LittleEndian.putDouble(received, 1, _doubles[1]);
byte[] expected = new byte[ LittleEndian.DOUBLE_SIZE + 1 ];
@ -224,7 +224,7 @@ public final class TestLittleEndian extends TestCase {
long testdata0 = 0xFFFFFFFFFFFFFF01L;
long testdata1 = 0x02FFFFFFFFFFFFFFL;
LittleEndian.putLong(received, testdata0);
LittleEndian.putLong(received, 0, testdata0);
assertTrue(compareByteArrays(received, expected, 0, LittleEndian.LONG_SIZE));
LittleEndian.putLong(received, 1, testdata1);
assertTrue(compareByteArrays(received, expected, 1, LittleEndian.LONG_SIZE));