jdk.io.PushbackInputStream — clojure-interop/java.io 1.0.5

A PushbackInputStream adds functionality to another input stream, namely the ability to "push back" or "unread" one byte. This is useful in situations where it is convenient for a fragment of code to read an indefinite number of data bytes that are delimited by a particular byte value; after reading the terminating byte, the code fragment can "unread" it, so that the next read operation on the input stream will reread the byte that was pushed back. For example, bytes representing the characters constituting an identifier might be terminated by a byte representing an operator character; a method whose job is to read just an identifier can read until it sees the operator and then push the operator back to be re-read.

->pushback-input-stream clj

(->pushback-input-stream in)

(->pushback-input-stream in size)

Constructor.

Creates a PushbackInputStream with a pushback buffer of the specified size, and saves its argument, the input stream in, for later use. Initially, there is no pushed-back byte (the field pushBack is initialized to -1).

in - the input stream from which bytes will be read. - java.io.InputStream size - the size of the pushback buffer. - int

throws: java.lang.IllegalArgumentException - if size <= 0

available clj

(available this)

Returns an estimate of the number of bytes that can be read (or skipped over) from this input stream without blocking by the next invocation of a method for this input stream. The next invocation might be the same thread or another thread. A single read or skip of this many bytes will not block, but may read or skip fewer bytes.

The method returns the sum of the number of bytes that have been pushed back and the value returned by available.

returns: the number of bytes that can be read (or skipped over) from the input stream without blocking. - int

throws: java.io.IOException - if this input stream has been closed by invoking its close() method, or an I/O error occurs.

close clj

(close this)

Closes this input stream and releases any system resources associated with the stream. Once the stream has been closed, further read(), unread(), available(), reset(), or skip() invocations will throw an IOException. Closing a previously closed stream has no effect.

throws: java.io.IOException - if an I/O error occurs.

mark clj

(mark this readlimit)

Marks the current position in this input stream.

The mark method of PushbackInputStream does nothing.

readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid. - int

mark-supported clj

(mark-supported this)

Tests if this input stream supports the mark and reset methods, which it does not.

returns: false, since this class does not support the mark and reset methods. - boolean

read clj

(read this)

(read this b off len)

Reads up to len bytes of data from this input stream into an array of bytes. This method first reads any pushed-back bytes; after that, if fewer than len bytes have been read then it reads from the underlying input stream. If len is not zero, the method blocks until at least 1 byte of input is available; otherwise, no bytes are read and 0 is returned.

b - the buffer into which the data is read. - byte[] off - the start offset in the destination array b - int len - the maximum number of bytes read. - int

returns: the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached. - int

throws: java.lang.NullPointerException - If b is null.

reset clj

(reset this)

Repositions this stream to the position at the time the mark method was last called on this input stream.

The method reset for class PushbackInputStream does nothing except throw an IOException.

throws: java.io.IOException - if this method is invoked.

skip clj

(skip this n)

Skips over and discards n bytes of data from this input stream. The skip method may, for a variety of reasons, end up skipping over some smaller number of bytes, possibly zero. If n is negative, no bytes are skipped.

The skip method of PushbackInputStream first skips over the bytes in the pushback buffer, if any. It then calls the skip method of the underlying input stream if more bytes need to be skipped. The actual number of bytes skipped is returned.

n - the number of bytes to be skipped. - long

returns: the actual number of bytes skipped. - long

throws: java.io.IOException - if the stream does not support seek, or the stream has been closed by invoking its close() method, or an I/O error occurs.

unread clj

(unread this b)

(unread this b off len)

Pushes back a portion of an array of bytes by copying it to the front of the pushback buffer. After this method returns, the next byte to be read will have the value b[off], the byte after that will have the value b[off+1], and so forth.

b - the byte array to push back. - byte[] off - the start offset of the data. - int len - the number of bytes to push back. - int

throws: java.io.IOException - If there is not enough room in the pushback buffer for the specified number of bytes, or this input stream has been closed by invoking its close() method.