Class LittleEndianDataInputStream
- java.lang.Object
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- java.io.InputStream
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- java.io.FilterInputStream
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- com.google.common.io.LittleEndianDataInputStream
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- All Implemented Interfaces:
Closeable,DataInput,AutoCloseable
@Beta @GwtIncompatible public final class LittleEndianDataInputStream extends FilterInputStream implements DataInput
An implementation ofDataInputthat uses little-endian byte ordering for readingshort,int,float,double, andlongvalues.Note: This class intentionally violates the specification of its supertype
DataInput, which explicitly requires big-endian byte order.- Since:
- 8.0
- Author:
- Chris Nokleberg, Keith Bottner
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Field Summary
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Fields inherited from class java.io.FilterInputStream
in
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Constructor Summary
Constructors Constructor Description LittleEndianDataInputStream(InputStream in)Creates aLittleEndianDataInputStreamthat wraps the given stream.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description booleanreadBoolean()Reads one input byte and returnstrueif that byte is nonzero,falseif that byte is zero.bytereadByte()Reads and returns one input byte.charreadChar()Reads a char as specified byDataInputStream.readChar(), except using little-endian byte order.doublereadDouble()Reads adoubleas specified byDataInputStream.readDouble(), except using little-endian byte order.floatreadFloat()Reads afloatas specified byDataInputStream.readFloat(), except using little-endian byte order.voidreadFully(byte[] b)Reads some bytes from an input stream and stores them into the buffer arrayb.voidreadFully(byte[] b, int off, int len)Readslenbytes from an input stream.intreadInt()Reads an integer as specified byDataInputStream.readInt(), except using little-endian byte order.StringreadLine()This method will throw anUnsupportedOperationException.longreadLong()Reads alongas specified byDataInputStream.readLong(), except using little-endian byte order.shortreadShort()Reads ashortas specified byDataInputStream.readShort(), except using little-endian byte order.intreadUnsignedByte()Reads one input byte, zero-extends it to typeint, and returns the result, which is therefore in the range0through255.intreadUnsignedShort()Reads an unsignedshortas specified byDataInputStream.readUnsignedShort(), except using little-endian byte order.StringreadUTF()Reads in a string that has been encoded using a modified UTF-8 format.intskipBytes(int n)Makes an attempt to skip overnbytes of data from the input stream, discarding the skipped bytes.-
Methods inherited from class java.io.FilterInputStream
available, close, mark, markSupported, read, read, read, reset, skip
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Methods inherited from class java.io.InputStream
nullInputStream, readAllBytes, readNBytes, readNBytes, transferTo
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Constructor Detail
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LittleEndianDataInputStream
public LittleEndianDataInputStream(InputStream in)
Creates aLittleEndianDataInputStreamthat wraps the given stream.- Parameters:
in- the stream to delegate to
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Method Detail
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readLine
@CanIgnoreReturnValue public String readLine()
This method will throw anUnsupportedOperationException.
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readFully
public void readFully(byte[] b) throws IOException
Description copied from interface:java.io.DataInputReads some bytes from an input stream and stores them into the buffer arrayb. The number of bytes read is equal to the length ofb.This method blocks until one of the following conditions occurs:
b.lengthbytes of input data are available, in which case a normal return is made.- End of
file is detected, in which case an
EOFExceptionis thrown. - An I/O error occurs, in
which case an
IOExceptionother thanEOFExceptionis thrown.
If
bisnull, aNullPointerExceptionis thrown. Ifb.lengthis zero, then no bytes are read. Otherwise, the first byte read is stored into elementb[0], the next one intob[1], and so on. If an exception is thrown from this method, then it may be that some but not all bytes ofbhave been updated with data from the input stream.- Specified by:
readFullyin interfaceDataInput- Parameters:
b- the buffer into which the data is read.- Throws:
EOFException- if this stream reaches the end before reading all the bytes.IOException- if an I/O error occurs.
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readFully
public void readFully(byte[] b, int off, int len) throws IOException
Description copied from interface:java.io.DataInputReadslenbytes from an input stream.This method blocks until one of the following conditions occurs:
lenbytes of input data are available, in which case a normal return is made.- End of file
is detected, in which case an
EOFExceptionis thrown. - An I/O error occurs, in
which case an
IOExceptionother thanEOFExceptionis thrown.
If
bisnull, aNullPointerExceptionis thrown. Ifoffis negative, orlenis negative, oroff+lenis greater than the length of the arrayb, then anIndexOutOfBoundsExceptionis thrown. Iflenis zero, then no bytes are read. Otherwise, the first byte read is stored into elementb[off], the next one intob[off+1], and so on. The number of bytes read is, at most, equal tolen.- Specified by:
readFullyin interfaceDataInput- Parameters:
b- the buffer into which the data is read.off- an int specifying the offset in the data arrayb.len- an int specifying the number of bytes to read.- Throws:
EOFException- if this stream reaches the end before reading all the bytes.IOException- if an I/O error occurs.
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skipBytes
public int skipBytes(int n) throws IOException
Description copied from interface:java.io.DataInputMakes an attempt to skip overnbytes of data from the input stream, discarding the skipped bytes. However, it may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file beforenbytes have been skipped is only one possibility. This method never throws anEOFException. The actual number of bytes skipped is returned.- Specified by:
skipBytesin interfaceDataInput- Parameters:
n- the number of bytes to be skipped.- Returns:
- the number of bytes actually skipped.
- Throws:
IOException- if an I/O error occurs.
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readUnsignedByte
@CanIgnoreReturnValue public int readUnsignedByte() throws IOException
Description copied from interface:java.io.DataInputReads one input byte, zero-extends it to typeint, and returns the result, which is therefore in the range0through255. This method is suitable for reading the byte written by thewriteBytemethod of interfaceDataOutputif the argument towriteBytewas intended to be a value in the range0through255.- Specified by:
readUnsignedBytein interfaceDataInput- Returns:
- the unsigned 8-bit value read.
- Throws:
EOFException- if this stream reaches the end before reading all the bytes.IOException- if an I/O error occurs.
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readUnsignedShort
@CanIgnoreReturnValue public int readUnsignedShort() throws IOException
Reads an unsignedshortas specified byDataInputStream.readUnsignedShort(), except using little-endian byte order.- Specified by:
readUnsignedShortin interfaceDataInput- Returns:
- the next two bytes of the input stream, interpreted as an unsigned 16-bit integer in little-endian byte order
- Throws:
IOException- if an I/O error occurs
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readInt
@CanIgnoreReturnValue public int readInt() throws IOException
Reads an integer as specified byDataInputStream.readInt(), except using little-endian byte order.- Specified by:
readIntin interfaceDataInput- Returns:
- the next four bytes of the input stream, interpreted as an
intin little-endian byte order - Throws:
IOException- if an I/O error occurs
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readLong
@CanIgnoreReturnValue public long readLong() throws IOException
Reads alongas specified byDataInputStream.readLong(), except using little-endian byte order.- Specified by:
readLongin interfaceDataInput- Returns:
- the next eight bytes of the input stream, interpreted as a
longin little-endian byte order - Throws:
IOException- if an I/O error occurs
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readFloat
@CanIgnoreReturnValue public float readFloat() throws IOException
Reads afloatas specified byDataInputStream.readFloat(), except using little-endian byte order.- Specified by:
readFloatin interfaceDataInput- Returns:
- the next four bytes of the input stream, interpreted as a
floatin little-endian byte order - Throws:
IOException- if an I/O error occurs
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readDouble
@CanIgnoreReturnValue public double readDouble() throws IOException
Reads adoubleas specified byDataInputStream.readDouble(), except using little-endian byte order.- Specified by:
readDoublein interfaceDataInput- Returns:
- the next eight bytes of the input stream, interpreted as a
doublein little-endian byte order - Throws:
IOException- if an I/O error occurs
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readUTF
@CanIgnoreReturnValue public String readUTF() throws IOException
Description copied from interface:java.io.DataInputReads in a string that has been encoded using a modified UTF-8 format. The general contract ofreadUTFis that it reads a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as aString.First, two bytes are read and used to construct an unsigned 16-bit integer in exactly the manner of the
readUnsignedShortmethod . This integer value is called the UTF length and specifies the number of additional bytes to be read. These bytes are then converted to characters by considering them in groups. The length of each group is computed from the value of the first byte of the group. The byte following a group, if any, is the first byte of the next group.If the first byte of a group matches the bit pattern
0xxxxxxx(wherexmeans "may be0or1"), then the group consists of just that byte. The byte is zero-extended to form a character.If the first byte of a group matches the bit pattern
110xxxxx, then the group consists of that byteaand a second byteb. If there is no byteb(because byteawas the last of the bytes to be read), or if bytebdoes not match the bit pattern10xxxxxx, then aUTFDataFormatExceptionis thrown. Otherwise, the group is converted to the character:
If the first byte of a group matches the bit pattern(char)(((a & 0x1F) << 6) | (b & 0x3F))1110xxxx, then the group consists of that byteaand two more bytesbandc. If there is no bytec(because byteawas one of the last two of the bytes to be read), or either bytebor bytecdoes not match the bit pattern10xxxxxx, then aUTFDataFormatExceptionis thrown. Otherwise, the group is converted to the character:
If the first byte of a group matches the pattern(char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))1111xxxxor the pattern10xxxxxx, then aUTFDataFormatExceptionis thrown.If end of file is encountered at any time during this entire process, then an
EOFExceptionis thrown.After every group has been converted to a character by this process, the characters are gathered, in the same order in which their corresponding groups were read from the input stream, to form a
String, which is returned.The
writeUTFmethod of interfaceDataOutputmay be used to write data that is suitable for reading by this method.- Specified by:
readUTFin interfaceDataInput- Returns:
- a Unicode string.
- Throws:
EOFException- if this stream reaches the end before reading all the bytes.IOException- if an I/O error occurs.UTFDataFormatException- if the bytes do not represent a valid modified UTF-8 encoding of a string.
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readShort
@CanIgnoreReturnValue public short readShort() throws IOException
Reads ashortas specified byDataInputStream.readShort(), except using little-endian byte order.- Specified by:
readShortin interfaceDataInput- Returns:
- the next two bytes of the input stream, interpreted as a
shortin little-endian byte order. - Throws:
IOException- if an I/O error occurs.
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readChar
@CanIgnoreReturnValue public char readChar() throws IOException
Reads a char as specified byDataInputStream.readChar(), except using little-endian byte order.- Specified by:
readCharin interfaceDataInput- Returns:
- the next two bytes of the input stream, interpreted as a
charin little-endian byte order - Throws:
IOException- if an I/O error occurs
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readByte
@CanIgnoreReturnValue public byte readByte() throws IOException
Description copied from interface:java.io.DataInputReads and returns one input byte. The byte is treated as a signed value in the range-128through127, inclusive. This method is suitable for reading the byte written by thewriteBytemethod of interfaceDataOutput.- Specified by:
readBytein interfaceDataInput- Returns:
- the 8-bit value read.
- Throws:
EOFException- if this stream reaches the end before reading all the bytes.IOException- if an I/O error occurs.
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readBoolean
@CanIgnoreReturnValue public boolean readBoolean() throws IOException
Description copied from interface:java.io.DataInputReads one input byte and returnstrueif that byte is nonzero,falseif that byte is zero. This method is suitable for reading the byte written by thewriteBooleanmethod of interfaceDataOutput.- Specified by:
readBooleanin interfaceDataInput- Returns:
- the
booleanvalue read. - Throws:
EOFException- if this stream reaches the end before reading all the bytes.IOException- if an I/O error occurs.
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