public abstract Class ImageInputStreamImpl

Implements javax.imageio.stream.ImageInputStream.close.

Doc from javax.imageio.stream.ImageInputStream.close.

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.

Exceptions

IOException:

if an I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.flush.

Doc from javax.imageio.stream.ImageInputStream.flush.

Discards the initial position of the stream prior to the current stream position. Equivalent to flushBefore(getStreamPosition()).

Exceptions

IOException:

if an I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.flushBefore.

Doc from javax.imageio.stream.ImageInputStream.flushBefore.

Discards the initial portion of the stream prior to the indicated position. 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.

Exceptions

IOException:

if an I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.getBitOffset.

Doc from javax.imageio.stream.ImageInputStream.getBitOffset.

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.

Exceptions

IOException:

if an I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.getByteOrder.

Doc from javax.imageio.stream.ImageInputStream.getByteOrder.

Returns the byte order with which data values will be read from this stream as an instance of the java.nio.ByteOrder enumeration.

Implements javax.imageio.stream.ImageInputStream.getFlushedPosition.

Doc from javax.imageio.stream.ImageInputStream.getFlushedPosition.

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.

Implements javax.imageio.stream.ImageInputStream.getStreamPosition.

Doc from javax.imageio.stream.ImageInputStream.getStreamPosition.

Returns the current byte position of the stream. The next read will take place starting at this offset.

Exceptions

IOException:

if an I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.isCached.

Default implementation returns false. Subclasses should override this if they cache data.

Implements javax.imageio.stream.ImageInputStream.isCachedFile.

Default implementation returns false. Subclasses should override this if they cache data in a temporary file.

Implements javax.imageio.stream.ImageInputStream.isCachedMemory.

Default implementation returns false. Subclasses should override this if they cache data in main memory.

Implements javax.imageio.stream.ImageInputStream.length.

Returns -1L to indicate that the stream has unknown length. Subclasses must override this method to provide actual length information.

Returns:long

-1L to indicate unknown length.

Implements javax.imageio.stream.ImageInputStream.mark.

Pushes the current stream position onto a stack of marked positions.

Redeclares javax.imageio.stream.ImageInputStream.read.

Reads a single byte from the stream and returns it as an int between 0 and 255. If EOF is reached, -1 is returned.

Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.

The bit offset within the stream must be reset to zero before the read occurs.

Returns:int

the value of the next byte in the stream, or -1 if EOF is reached.

Exceptions

IOException:

if the stream has been closed.

Implements javax.imageio.stream.ImageInputStream.read.

A convenience method that calls read(b, 0, b.length).

The bit offset within the stream is reset to zero before the read occurs.

Returns:int

the number of bytes actually read, or -1 to indicate EOF.

Exceptions

IOException:

if an I/O error occurs.

NullPointerException:

if b is null.

Redeclares javax.imageio.stream.ImageInputStream.read.

Reads up to len bytes from the stream, and stores them into b starting at index off. If no bytes can be read because the end of the stream has been reached, -1 is returned.

The bit offset within the stream must be reset to zero before the read occurs.

Subclasses must provide an implementation for this method. The subclass implementation should update the stream position before exiting.

Parameters

b:byte[]

an array of bytes to be written to.

off:int

the starting position within b to write to.

len:int

the maximum number of bytes to read.

Returns:int

the number of bytes actually read, or -1 to indicate EOF.

Exceptions

IOException:

if an I/O error occurs.

IndexOutOfBoundsException:

if off is negative, len is negative, or off + len is greater than b.length.

NullPointerException:

if b is null.

Implements javax.imageio.stream.ImageInputStream.readBit.

Doc from javax.imageio.stream.ImageInputStream.readBit.

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.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bits.

Implements javax.imageio.stream.ImageInputStream.readBits.

Doc from javax.imageio.stream.ImageInputStream.readBits.

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();
}

If the end of the stream is encountered before all the bits have been read, a java.io.EOFException is thrown.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bits.

Implements javax.imageio.stream.ImageInputStream.readBoolean.

Doc from javax.imageio.stream.ImageInputStream.readBoolean.

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.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the end of the stream is reached.

Implements javax.imageio.stream.ImageInputStream.readByte.

Doc from javax.imageio.stream.ImageInputStream.readByte.

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.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the end of the stream is reached.

Implements javax.imageio.stream.ImageInputStream.readBytes.

Doc from javax.imageio.stream.ImageInputStream.readBytes.

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.

Exceptions

IOException:

if an I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.readChar.

Doc from javax.imageio.stream.ImageInputStream.readChar.

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.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readDouble.

Doc from javax.imageio.stream.ImageInputStream.readDouble.

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.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readFloat.

Doc from javax.imageio.stream.ImageInputStream.readFloat.

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.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readFully.

Doc from javax.imageio.stream.ImageInputStream.readFully.

Reads len bytes from the stream, and stores them into b starting at index off. If the end of the stream is reached, a java.io.EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readFully.

Doc from javax.imageio.stream.ImageInputStream.readFully.

Reads b.length bytes from the stream, and stores them into b starting at index 0. If the end of the stream is reached, a java.io.EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readFully.

Doc from javax.imageio.stream.ImageInputStream.readFully.

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, a java.io.EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readFully.

Doc from javax.imageio.stream.ImageInputStream.readFully.

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, a java.io.EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readFully.

Doc from javax.imageio.stream.ImageInputStream.readFully.

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, a java.io.EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readFully.

Doc from javax.imageio.stream.ImageInputStream.readFully.

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, a java.io.EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readFully.

Doc from javax.imageio.stream.ImageInputStream.readFully.

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, a java.io.EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readFully.

Doc from javax.imageio.stream.ImageInputStream.readFully.

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, a java.io.EOFException will be thrown.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readInt.

Doc from javax.imageio.stream.ImageInputStream.readInt.

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.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readLine.

Doc from javax.imageio.stream.ImageInputStream.readLine.

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.

Exceptions

IOException:

if an I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.readLong.

Doc from javax.imageio.stream.ImageInputStream.readLong.

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.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readShort.

Doc from javax.imageio.stream.ImageInputStream.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.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readUnsignedByte.

Doc from javax.imageio.stream.ImageInputStream.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. Values between 0x80 and 0xff, which normally represent negative byte values, will be mapped into positive integers between 128 and 255.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the end of the stream is reached.

Implements javax.imageio.stream.ImageInputStream.readUnsignedInt.

Doc from javax.imageio.stream.ImageInputStream.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.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readUnsignedShort.

Doc from javax.imageio.stream.ImageInputStream.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.

The bit offset within the stream is reset to zero before the read occurs.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if the stream reaches the end before reading all the bytes.

Implements javax.imageio.stream.ImageInputStream.readUTF.

Doc from javax.imageio.stream.ImageInputStream.readUTF.

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))

(char)(((a & 0x0F) << 12) | ((b & 0x3F) << 6) | (c & 0x3F))

If end of file is encountered at any time during this entire process, then a java.io.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.

Exceptions

IOException:

if an I/O error occurs.

EOFException:

if this stream reaches the end before reading all the bytes.

UTFDataFormatException:

if the bytes do not represent a valid modified UTF-8 encoding of a string.

Implements javax.imageio.stream.ImageInputStream.reset.

Resets the current stream byte and bit positions from the stack of marked positions.

An IOException will be thrown if the previous marked position lies in the discarded portion of the stream.

Exceptions

IOException:

if an I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.seek.

Doc from javax.imageio.stream.ImageInputStream.seek.

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; a java.io.EOFException will be thrown only if a read is performed.

Exceptions

IOException:

if any other I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.setBitOffset.

Doc from javax.imageio.stream.ImageInputStream.setBitOffset.

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.

Exceptions

IOException:

if an I/O error occurs.

Implements javax.imageio.stream.ImageInputStream.setByteOrder.

Doc from javax.imageio.stream.ImageInputStream.setByteOrder.

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).

Implements javax.imageio.stream.ImageInputStream.skipBytes.

Advances the current stream position by calling seek(getStreamPosition() + n).

The bit offset is reset to zero.

Parameters

n:int

the number of bytes to seek forward.

Returns:int

an int representing the number of bytes skipped.

Exceptions

IOException:

if getStreamPosition throws an IOException when computing either the starting or ending position.

Implements javax.imageio.stream.ImageInputStream.skipBytes.

Advances the current stream position by calling seek(getStreamPosition() + n).

The bit offset is reset to zero.

Parameters

n:long

the number of bytes to seek forward.

Returns:long

a long representing the number of bytes skipped.

Exceptions

IOException:

if getStreamPosition throws an IOException when computing either the starting or ending position.