| javax.imageio.stream.ImageInputStream
All known Subclasses: javax.imageio.stream.ImageInputStreamImpl,
| Method Summary | |
| void | close()
Closes the stream. | | void | flush()
Discards the initial position of the stream prior to the current
stream position. | | void | flushBefore(long pos)
Discards the initial portion of the stream prior to the
indicated postion. | | int | getBitOffset()
Returns the current bit offset, as an integer between 0 and 7,
inclusive. | | ByteOrder | getByteOrder()
Returns the byte order with which data values will be read from
this stream as an instance of the
java.nio.ByteOrder enumeration. | | long | getFlushedPosition()
Returns the earliest position in the stream to which seeking
may be performed. | | long | getStreamPosition()
Returns the current byte position of the stream. | | boolean | isCached()
Returns true if this ImageInputStream
caches data itself in order to allow seeking backwards. | | boolean | isCachedFile()
Returns true if this ImageInputStream
caches data itself in order to allow seeking backwards, and
the cache is kept in a temporary file. | | boolean | isCachedMemory()
Returns true if this ImageInputStream
caches data itself in order to allow seeking backwards, and
the cache is kept in main memory. | | long | length()
Returns the total length of the stream, if known. | | void | mark()
Marks a position in the stream to be returned to by a
subsequent call to reset. | | int | read()
Reads a single byte from the stream and returns it as an
integer between 0 and 255. | | int | read(byte[] b)
Reads up to b.length bytes from the stream, and
stores them into b starting at index 0. | | int | read(byte[] b, int off, int len)
Reads up to len bytes from the stream, and stores
them into b starting at index off.
The number of bytes read is returned. | | int | readBit()
Reads a single bit from the stream and returns it as an
int with the value 0 or
1. | | long | readBits(int numBits)
Reads a bitstring from the stream and returns it as a
long, with the first bit read becoming the most
significant bit of the output. | | boolean | readBoolean()
Reads a byte from the stream and returns a boolean
value of true if it is nonzero, false
if it is zero. | | byte | readByte()
Reads a byte from the stream and returns it as a
byte value. | | void | readBytes(IIOByteBuffer buf, int len)
Reads up to len bytes from the stream, and
modifies the supplied IIOByteBuffer to indicate
the byte array, offset, and length where the data may be found. | | char | readChar()
Equivalent to readUnsignedShort, except that the
result is returned using the char datatype. | | double | readDouble()
Reads 8 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as a double. | | float | readFloat()
Reads 4 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as a float. | | void | readFully(byte[] b, int off, int len)
Reads len bytes from the stream, and stores them
into b starting at index off. | | void | readFully(byte[] b)
Reads b.length bytes from the stream, and stores them
into b starting at index 0. | | void | readFully(short[] s, int off, int len)
Reads len shorts (signed 16-bit integers) from the
stream according to the current byte order, and
stores them into s starting at index
off. | | void | readFully(char[] c, int off, int len)
Reads len chars (unsigned 16-bit integers) from the
stream according to the current byte order, and
stores them into c starting at index
off. | | void | readFully(int[] i, int off, int len)
Reads len ints (signed 32-bit integers) from the
stream according to the current byte order, and
stores them into i starting at index
off. | | void | readFully(long[] l, int off, int len)
Reads len longs (signed 64-bit integers) from the
stream according to the current byte order, and
stores them into l starting at index
off. | | void | readFully(float[] f, int off, int len)
Reads len floats (32-bit IEEE single-precision
floats) from the stream according to the current byte order,
and stores them into f starting at
index off. | | void | readFully(double[] d, int off, int len)
Reads len doubles (64-bit IEEE double-precision
floats) from the stream according to the current byte order,
and stores them into d starting at
index off. | | int | readInt()
Reads 4 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as an int. | | String | readLine()
Reads the next line of text from the input stream. | | long | readLong()
Reads 8 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as a long. | | short | readShort()
Reads two bytes from the stream, and (conceptually)
concatenates them according to the current byte order, and
returns the result as a short value. | | String | readUTF()
Reads in a string that has been encoded using a
modified
UTF-8
format. | | int | readUnsignedByte()
Reads a byte from the stream, and (conceptually) converts it to
an int, masks it with 0xff in order to strip off
any sign-extension bits, and returns it as a byte
value.
Thus, byte values between 0x00 and
0x7f are simply returned as integer values between
0 and 127. | | long | readUnsignedInt()
Reads 4 bytes from the stream, and (conceptually) concatenates
them according to the current byte order, converts the result
to a long, masks it with 0xffffffffL in order to
strip off any sign-extension bits, and returns the result as an
unsigned long value. | | int | readUnsignedShort()
Reads two bytes from the stream, and (conceptually)
concatenates them according to the current byte order, converts
the resulting value to an int, masks it with
0xffff in order to strip off any sign-extension
buts, and returns the result as an unsigned int
value. | | void | reset()
Returns the stream pointer to its previous position, including
the bit offset, at the time of the most recent unmatched call
to mark. | | void | seek(long pos)
Sets the current stream position to the desired location. | | void | setBitOffset(int bitOffset)
Sets the bit offset to an integer between 0 and 7, inclusive. | | void | setByteOrder(ByteOrder byteOrder)
Sets the desired byte order for future reads of data values
from this stream. | | int | skipBytes(int n)
Moves the stream position forward by a given number of bytes. | | long | skipBytes(long n)
Moves the stream position forward by a given number of bytes.
This method is identical to skipBytes(int) except
that it allows for a larger skip distance.
Parameters:
n - a long containing the number of bytes tobe skipped. |
| close | | void close() throws IOException(Code) | | Closes the stream. Attempts to access a stream that has been
closed may result in IOExceptions or incorrect
behavior. Calling this method may allow classes implementing
this interface to release resources associated with the stream
such as memory, disk space, or file descriptors.
exception:
IOException - if an I/O error occurs. |
| flush | | void flush() throws IOException(Code) | | Discards the initial position of the stream prior to the current
stream position. Equivalent to
flushBefore(getStreamPosition()).
exception:
IOException - if an I/O error occurs. |
| flushBefore | | void flushBefore(long pos) throws IOException(Code) | | Discards the initial portion of the stream prior to the
indicated postion. Attempting to seek to an offset within the
flushed portion of the stream will result in an
IndexOutOfBoundsException.
Calling flushBefore may allow classes
implementing this interface to free up resources such as memory
or disk space that are being used to store data from the
stream.
Parameters:
pos - a long containing the length of thestream prefix that may be flushed.
exception:
IndexOutOfBoundsException - if pos liesin the flushed portion of the stream or past the current streamposition.
exception:
IOException - if an I/O error occurs. |
| getBitOffset | | int getBitOffset() throws IOException(Code) | | Returns the current bit offset, as an integer between 0 and 7,
inclusive. The bit offset is updated implicitly by calls to
the readBits method. A value of 0 indicates the
most-significant bit, and a value of 7 indicates the least
significant bit, of the byte being read.
The bit offset is set to 0 when a stream is first
opened, and is reset to 0 by calls to seek,
skipBytes, or any read or
readFully method.
an int containing the bit offset between0 and 7, inclusive.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.setBitOffset |
| getByteOrder | | ByteOrder getByteOrder()(Code) | | Returns the byte order with which data values will be read from
this stream as an instance of the
java.nio.ByteOrder enumeration.
one of ByteOrder.BIG_ENDIAN orByteOrder.LITTLE_ENDIAN, indicating which byteorder is being used.
See Also: java.nio.ByteOrder
See Also: ImageInputStream.setByteOrder |
| getFlushedPosition | | long getFlushedPosition()(Code) | | Returns the earliest position in the stream to which seeking
may be performed. The returned value will be the maximum of
all values passed into previous calls to
flushBefore.
the earliest legal position for seeking, as along. |
| getStreamPosition | | long getStreamPosition() throws IOException(Code) | | Returns the current byte position of the stream. The next read
will take place starting at this offset.
a long containing the position of the stream.
exception:
IOException - if an I/O error occurs. |
| isCached | | boolean isCached()(Code) | | Returns true if this ImageInputStream
caches data itself in order to allow seeking backwards.
Applications may consult this in order to decide how frequently,
or whether, to flush in order to conserve cache resources.
true if this ImageInputStreamcaches data.
See Also: ImageInputStream.isCachedMemory
See Also: ImageInputStream.isCachedFile |
| isCachedFile | | boolean isCachedFile()(Code) | | Returns true if this ImageInputStream
caches data itself in order to allow seeking backwards, and
the cache is kept in a temporary file. Applications may consult
this in order to decide how frequently, or whether, to flush
in order to conserve cache resources.
true if this ImageInputStreamcaches data in a temporary file.
See Also: ImageInputStream.isCached
See Also: ImageInputStream.isCachedMemory |
| isCachedMemory | | boolean isCachedMemory()(Code) | | Returns true if this ImageInputStream
caches data itself in order to allow seeking backwards, and
the cache is kept in main memory. Applications may consult
this in order to decide how frequently, or whether, to flush
in order to conserve cache resources.
true if this ImageInputStreamcaches data in main memory.
See Also: ImageInputStream.isCached
See Also: ImageInputStream.isCachedFile |
| length | | long length() throws IOException(Code) | | Returns the total length of the stream, if known. Otherwise,
-1 is returned.
a long containing the length of thestream, if known, or else -1.
exception:
IOException - if an I/O error occurs. |
| mark | | void mark()(Code) | | Marks a position in the stream to be returned to by a
subsequent call to reset. Unlike a standard
InputStream, all ImageInputStreams
support marking. Additionally, calls to mark and
reset may be nested arbitrarily.
Unlike the mark methods declared by the
Reader and InputStream interfaces, no
readLimit parameter is used. An arbitrary amount
of data may be read following the call to mark.
The bit position used by the readBits method
is saved and restored by each pair of calls to
mark and reset.
Note that it is valid for an ImageReader to call
flushBefore as part of a read operation.
Therefore, if an application calls mark prior to
passing that stream to an ImageReader, the application
should not assume that the marked position will remain valid after
the read operation has completed.
|
| read | | int read() throws IOException(Code) | | Reads a single byte from the stream and returns it as an
integer between 0 and 255. If the end of the stream is
reached, -1 is returned.
The bit offset within the stream is reset to zero before
the read occurs.
a byte value from the stream, as an int, or -1 toindicate EOF.
exception:
IOException - if an I/O error occurs. |
| read | | int read(byte[] b) throws IOException(Code) | | Reads up to b.length bytes from the stream, and
stores them into b starting at index 0. The
number of bytes read is returned. If no bytes can be read
because the end of the stream has been reached, -1 is returned.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
b - an array of bytes to be written to. the number of bytes actually read, or -1to indicate EOF.
exception:
NullPointerException - if b isnull.
exception:
IOException - if an I/O error occurs. |
| read | | int read(byte[] b, int off, int len) throws IOException(Code) | | Reads up to len bytes from the stream, and stores
them into b starting at index off.
The number of bytes read is returned. If no bytes can be read
because the end of the stream has been reached, -1
is returned.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
b - an array of bytes to be written to.
Parameters:
off - the starting position within b to write to.
Parameters:
len - the maximum number of bytes to read. the number of bytes actually read, or -1to indicate EOF.
exception:
NullPointerException - if b isnull.
exception:
IndexOutOfBoundsException - if off isnegative, len is negative, or off +len is greater than b.length.
exception:
IOException - if an I/O error occurs. |
| readBit | | int readBit() throws IOException(Code) | | Reads a single bit from the stream and returns it as an
int with the value 0 or
1. The bit offset is advanced by one and reduced
modulo 8.
an int containing the value 0or 1.
exception:
EOFException - if the stream reaches the end beforereading all the bits.
exception:
IOException - if an I/O error occurs. |
| readBits | | long readBits(int numBits) throws IOException(Code) | | Reads a bitstring from the stream and returns it as a
long, with the first bit read becoming the most
significant bit of the output. The read starts within the byte
indicated by getStreamPosition, at the bit given
by getBitOffset. The bit offset is advanced by
numBits and reduced modulo 8.
The byte order of the stream has no effect on this
method. The return value of this method is constructed as
though the bits were read one at a time, and shifted into
the right side of the return value, as shown by the following
pseudo-code:
long accum = 0L;
for (int i = 0; i < numBits; i++) {
accum <<= 1; // Shift left one bit to make room
accum |= readBit();
}
Note that the result of readBits(32) may thus not
be equal to that of readInt() if a reverse network
byte order is being used (i.e., getByteOrder() ==
false).
If the end of the stream is encountered before all the bits
have been read, an EOFException is thrown.
Parameters:
numBits - the number of bits to read, as an intbetween 0 and 64, inclusive. the bitstring, as a long with the last bitread stored in the least significant bit.
exception:
IllegalArgumentException - if numBitsis not between 0 and 64, inclusive.
exception:
EOFException - if the stream reaches the end beforereading all the bits.
exception:
IOException - if an I/O error occurs. |
| readBoolean | | boolean readBoolean() throws IOException(Code) | | Reads a byte from the stream and returns a boolean
value of true if it is nonzero, false
if it is zero.
The bit offset within the stream is reset to zero before
the read occurs.
a boolean value from the stream.
exception:
EOFException - if the end of the stream is reached.
exception:
IOException - if an I/O error occurs. |
| readByte | | byte readByte() throws IOException(Code) | | Reads a byte from the stream and returns it as a
byte value. Byte values between 0x00
and 0x7f represent integer values between
0 and 127. Values between
0x80 and 0xff represent negative
values from -128 to /1.
The bit offset within the stream is reset to zero before
the read occurs.
a signed byte value from the stream.
exception:
EOFException - if the end of the stream is reached.
exception:
IOException - if an I/O error occurs. |
| readBytes | | void readBytes(IIOByteBuffer buf, int len) throws IOException(Code) | | Reads up to len bytes from the stream, and
modifies the supplied IIOByteBuffer to indicate
the byte array, offset, and length where the data may be found.
The caller should not attempt to modify the data found in the
IIOByteBuffer.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
buf - an IIOByteBuffer object to be modified.
Parameters:
len - the maximum number of bytes to read.
exception:
IndexOutOfBoundsException - if len isnegative.
exception:
NullPointerException - if buf isnull.
exception:
IOException - if an I/O error occurs. |
| readChar | | char readChar() throws IOException(Code) | | Equivalent to readUnsignedShort, except that the
result is returned using the char datatype.
The bit offset within the stream is reset to zero before
the read occurs.
an unsigned char value from the stream.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.readUnsignedShort |
| readDouble | | double readDouble() throws IOException(Code) | | Reads 8 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as a double.
The bit offset within the stream is reset to zero before
the read occurs.
a double value from the stream.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.getByteOrder |
| readFloat | | float readFloat() throws IOException(Code) | | Reads 4 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as a float.
The bit offset within the stream is reset to zero before
the read occurs.
a float value from the stream.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.getByteOrder |
| readFully | | void readFully(byte[] b, int off, int len) throws IOException(Code) | | Reads len bytes from the stream, and stores them
into b starting at index off.
If the end of the stream is reached, an EOFException
will be thrown.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
b - an array of bytes to be written to.
Parameters:
off - the starting position within b to write to.
Parameters:
len - the maximum number of bytes to read.
exception:
IndexOutOfBoundsException - if off isnegative, len is negative, or off +len is greater than b.length.
exception:
NullPointerException - if b isnull.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs. |
| readFully | | void readFully(byte[] b) throws IOException(Code) | | Reads b.length bytes from the stream, and stores them
into b starting at index 0.
If the end of the stream is reached, an EOFException
will be thrown.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
b - an array of bytes.
exception:
NullPointerException - if b isnull.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs. |
| readFully | | void readFully(short[] s, int off, int len) throws IOException(Code) | | Reads len shorts (signed 16-bit integers) from the
stream according to the current byte order, and
stores them into s starting at index
off. If the end of the stream is reached, an
EOFException will be thrown.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
s - an array of shorts to be written to.
Parameters:
off - the starting position withinb to write to.
Parameters:
len - the maximum number of shorts to read.
exception:
IndexOutOfBoundsException - if off isnegative, len is negative, or off +len is greater than s.length.
exception:
NullPointerException - if s isnull.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs. |
| readFully | | void readFully(char[] c, int off, int len) throws IOException(Code) | | Reads len chars (unsigned 16-bit integers) from the
stream according to the current byte order, and
stores them into c starting at index
off. If the end of the stream is reached, an
EOFException will be thrown.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
c - an array of chars to be written to.
Parameters:
off - the starting position withinb to write to.
Parameters:
len - the maximum number of chars to read.
exception:
IndexOutOfBoundsException - if off isnegative, len is negative, or off +len is greater than c.length.
exception:
NullPointerException - if c isnull.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs. |
| readFully | | void readFully(int[] i, int off, int len) throws IOException(Code) | | Reads len ints (signed 32-bit integers) from the
stream according to the current byte order, and
stores them into i starting at index
off. If the end of the stream is reached, an
EOFException will be thrown.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
i - an array of ints to be written to.
Parameters:
off - the starting position withinb to write to.
Parameters:
len - the maximum number of ints to read.
exception:
IndexOutOfBoundsException - if off isnegative, len is negative, or off +len is greater than i.length.
exception:
NullPointerException - if i isnull.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs. |
| readFully | | void readFully(long[] l, int off, int len) throws IOException(Code) | | Reads len longs (signed 64-bit integers) from the
stream according to the current byte order, and
stores them into l starting at index
off. If the end of the stream is reached, an
EOFException will be thrown.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
l - an array of longs to be written to.
Parameters:
off - the starting position withinb to write to.
Parameters:
len - the maximum number of longs to read.
exception:
IndexOutOfBoundsException - if off isnegative, len is negative, or off +len is greater than l.length.
exception:
NullPointerException - if l isnull.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs. |
| readFully | | void readFully(float[] f, int off, int len) throws IOException(Code) | | Reads len floats (32-bit IEEE single-precision
floats) from the stream according to the current byte order,
and stores them into f starting at
index off. If the end of the stream is reached,
an EOFException will be thrown.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
f - an array of floats to be written to.
Parameters:
off - the starting position withinb to write to.
Parameters:
len - the maximum number of floats to read.
exception:
IndexOutOfBoundsException - if off isnegative, len is negative, or off +len is greater than f.length.
exception:
NullPointerException - if f isnull.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs. |
| readFully | | void readFully(double[] d, int off, int len) throws IOException(Code) | | Reads len doubles (64-bit IEEE double-precision
floats) from the stream according to the current byte order,
and stores them into d starting at
index off. If the end of the stream is reached,
an EOFException will be thrown.
The bit offset within the stream is reset to zero before
the read occurs.
Parameters:
d - an array of doubles to be written to.
Parameters:
off - the starting position withinb to write to.
Parameters:
len - the maximum number of doubles to read.
exception:
IndexOutOfBoundsException - if off isnegative, len is negative, or off +len is greater than d.length.
exception:
NullPointerException - if d isnull.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs. |
| readInt | | int readInt() throws IOException(Code) | | Reads 4 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as an int.
The bit offset within the stream is ignored and treated as
though it were zero.
a signed int value from the stream.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.getByteOrder |
| readLine | | String readLine() throws IOException(Code) | | Reads the next line of text from the input stream. It reads
successive bytes, converting each byte separately into a
character, until it encounters a line terminator or end of
file; the characters read are then returned as a
String. Note that because this method processes
bytes, it does not support input of the full Unicode character
set.
If end of file is encountered before even one byte can be
read, then null is returned. Otherwise, each byte
that is read is converted to type char by
zero-extension. If the character '\n' is
encountered, it is discarded and reading ceases. If the
character '\r' is encountered, it is discarded
and, if the following byte converts to the character
'\n', then that is discarded also; reading then
ceases. If end of file is encountered before either of the
characters '\n' and '\r' is
encountered, reading ceases. Once reading has ceased, a
String is returned that contains all the
characters read and not discarded, taken in order. Note that
every character in this string will have a value less than
\u0100, that is, (char)256.
The bit offset within the stream is reset to zero before
the read occurs.
a String containing a line of text from the stream.
exception:
IOException - if an I/O error occurs. |
| readLong | | long readLong() throws IOException(Code) | | Reads 8 bytes from the stream, and (conceptually) concatenates
them according to the current byte order and returns the result
as a long.
The bit offset within the stream is reset to zero before
the read occurs.
a signed long value from the stream.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.getByteOrder |
| readShort | | short readShort() throws IOException(Code) | | Reads two bytes from the stream, and (conceptually)
concatenates them according to the current byte order, and
returns the result as a short value.
The bit offset within the stream is reset to zero before
the read occurs.
a signed short value from the stream.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.getByteOrder |
| readUTF | | String readUTF() throws IOException(Code) | | Reads in a string that has been encoded using a
modified
UTF-8
format. The general contract of readUTF is that
it reads a representation of a Unicode character string encoded
in modified UTF-8 format; this string of characters is
then returned as a String.
First, two bytes are read and used to construct an unsigned
16-bit integer in the manner of the
readUnsignedShort method, using network byte order
(regardless of the current byte order setting). 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 (where x means "may be
0 or 1"), 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 byte
a and a second byte b. If there is no
byte b (because byte a was the last
of the bytes to be read), or if byte b does not
match the bit pattern 10xxxxxx, then a
UTFDataFormatException is thrown. Otherwise, the
group is converted to the character:
(char)(((a& 0x1F) << 6) | (b & 0x3F))
If the first byte of a group matches the bit pattern
1110xxxx, then the group consists of that byte
a and two more bytes b and
c. If there is no byte c (because
byte a was one of the last two of the bytes to be
read), or either byte b or byte c
does not match the bit pattern 10xxxxxx, then a
UTFDataFormatException is thrown. Otherwise, the
group is converted to the character:
(char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))
If the first byte of a group matches the pattern
1111xxxx or the pattern 10xxxxxx,
then a UTFDataFormatException is thrown.
If end of file is encountered at any time during this
entire process, then an EOFException is 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 current byte order setting is ignored.
The bit offset within the stream is reset to zero before
the read occurs.
Note: This method should not be used in
the implementation of image formats that use standard UTF-8,
because the modified UTF-8 used here is incompatible with
standard UTF-8.
a String read from the stream.
exception:
EOFException - if this stream reaches the endbefore reading all the bytes.
exception:
UTFDataFormatException - if the bytes do not represent avalid modified UTF-8 encoding of a string.
exception:
IOException - if an I/O error occurs. |
| readUnsignedByte | | int readUnsignedByte() throws IOException(Code) | | Reads a byte from the stream, and (conceptually) converts it to
an int, masks it with 0xff in order to strip off
any sign-extension bits, and returns it as a byte
value.
Thus, byte values between 0x00 and
0x7f are simply returned as integer values between
0 and 127. Values between
0x80 and 0xff, which normally
represent negative bytevalues, will be mapped into
positive integers between 128 and
255.
The bit offset within the stream is reset to zero before
the read occurs.
an unsigned byte value from the stream.
exception:
EOFException - if the end of the stream is reached.
exception:
IOException - if an I/O error occurs. |
| readUnsignedInt | | long readUnsignedInt() throws IOException(Code) | | Reads 4 bytes from the stream, and (conceptually) concatenates
them according to the current byte order, converts the result
to a long, masks it with 0xffffffffL in order to
strip off any sign-extension bits, and returns the result as an
unsigned long value.
The bit offset within the stream is reset to zero before
the read occurs.
an unsigned int value from the stream, as a long.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.getByteOrder |
| readUnsignedShort | | int readUnsignedShort() throws IOException(Code) | | Reads two bytes from the stream, and (conceptually)
concatenates them according to the current byte order, converts
the resulting value to an int, masks it with
0xffff in order to strip off any sign-extension
buts, and returns the result as an unsigned int
value.
The bit offset within the stream is reset to zero before
the read occurs.
an unsigned short value from the stream, as an int.
exception:
EOFException - if the stream reaches the end beforereading all the bytes.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.getByteOrder |
| reset | | void reset() throws IOException(Code) | | Returns the stream pointer to its previous position, including
the bit offset, at the time of the most recent unmatched call
to mark.
Calls to reset without a corresponding call
to mark have no effect.
An IOException will be thrown if the previous
marked position lies in the discarded portion of the stream.
exception:
IOException - if an I/O error occurs. |
| seek | | void seek(long pos) throws IOException(Code) | | Sets the current stream position to the desired location. The
next read will occur at this location. The bit offset is set
to 0.
An IndexOutOfBoundsException will be thrown if
pos is smaller than the flushed position (as
returned by getflushedPosition).
It is legal to seek past the end of the file; an
EOFException will be thrown only if a read is
performed.
Parameters:
pos - a long containing the desired filepointer position.
exception:
IndexOutOfBoundsException - if pos is smallerthan the flushed position.
exception:
IOException - if any other I/O error occurs. |
| setBitOffset | | void setBitOffset(int bitOffset) throws IOException(Code) | | Sets the bit offset to an integer between 0 and 7, inclusive.
The byte offset within the stream, as returned by
getStreamPosition, is left unchanged.
A value of 0 indicates the
most-significant bit, and a value of 7 indicates the least
significant bit, of the byte being read.
Parameters:
bitOffset - the desired offset, as an intbetween 0 and 7, inclusive.
exception:
IllegalArgumentException - if bitOffsetis not between 0 and 7, inclusive.
exception:
IOException - if an I/O error occurs.
See Also: ImageInputStream.getBitOffset |
| setByteOrder | | void setByteOrder(ByteOrder byteOrder)(Code) | | Sets the desired byte order for future reads of data values
from this stream. For example, the sequence of bytes '0x01
0x02 0x03 0x04' if read as a 4-byte integer would have the
value '0x01020304' using network byte order and the value
'0x04030201' under the reverse byte order.
The enumeration class java.nio.ByteOrder is
used to specify the byte order. A value of
ByteOrder.BIG_ENDIAN specifies so-called
big-endian or network byte order, in which the high-order byte
comes first. Motorola and Sparc processors store data in this
format, while Intel processors store data in the reverse
ByteOrder.LITTLE_ENDIAN order.
The byte order has no effect on the results returned from
the readBits method (or the value written by
ImageOutputStream.writeBits).
Parameters:
byteOrder - one of ByteOrder.BIG_ENDIAN orjava.nio.ByteOrder.LITTLE_ENDIAN, indicating whethernetwork byte order or its reverse will be used for futurereads.
See Also: java.nio.ByteOrder
See Also: ImageInputStream.getByteOrder
See Also: ImageInputStream.readBits(int) |
| skipBytes | | int skipBytes(int n) throws IOException(Code) | | Moves the stream position forward by a given number of bytes. It
is possible that this method will only be able to skip forward
by a smaller number of bytes than requested, for example if the
end of the stream is reached. In all cases, the actual number
of bytes skipped is returned. The bit offset is set to zero
prior to advancing the position.
Parameters:
n - an int containing the number of bytes tobe skipped. an int representing the number of bytes skipped.
exception:
IOException - if an I/O error occurs. |
| skipBytes | | long skipBytes(long n) throws IOException(Code) | | Moves the stream position forward by a given number of bytes.
This method is identical to skipBytes(int) except
that it allows for a larger skip distance.
Parameters:
n - a long containing the number of bytes tobe skipped. a long representing the number of bytesskipped.
exception:
IOException - if an I/O error occurs. |
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