sexp
Class SexpInputStream

java.lang.Object
  |
  +--java.io.InputStream
        |
        +--java.io.FilterInputStream
              |
              +--java.io.BufferedInputStream
                    |
                    +--sexp.SexpInputStream

public class SexpInputStream

extends BufferedInputStream

This class provides S-Expression input stream functionallity, in the same manner as Ron Rivest's reference S-Expression parser.

Version:

$Id: SexpInputStream.java,v 1.1.1.2 2002/05/08 22:48:27 tep Exp $

Author:

Per Harald Myrvang <perm@pasta.cs.uit.no>

See Also:

SexpOutputStream

Field Summary

static String	__me
private int	bits
private int	byteSize
private int	count
boolean	debug
private boolean	isEOF
private int	nBits
private int	nextByte
private int[]	saved_state

Fields inherited from class java.io.BufferedInputStream

buf, count, defaultBufferSize, marklimit, markpos, pos

Fields inherited from class java.io.FilterInputStream

in

Fields inherited from class java.io.InputStream

SKIP_BUFFER_SIZE, skipBuffer

Constructor Summary

SexpInputStream(InputStream stream)
Creates and initializes a new InputStream object.

Method Summary

void	changeByteSize(int base) Change the input byte size.
boolean	EOF() Test to see if this stream have reached end-of-file.
void	mark(int readlimit) Marks the current position and state in this input stream.
int	read() Reads the next byte of data from this buffered input stream.
void	reset() Repositions this stream to the position and state at the time the mark method was last called on this input stream.
void	scanBase64String(SimpleString ss, long length) Scan input as Base64 string of given length.
long	scanDecimal(long val) Scan input as a decimal number of some encoding.
void	scanHexString(SimpleString ss, long length) Scan input as hexadecimal string of given length.
SList	scanList() Scan input as a SList.
SExpression	scanObject() Scans input for either a SList or a Sexp.
void	scanQuotedString(SimpleString ss, long length) Scan input as quoted string of given length.
SimpleString	scanSimpleString() Scan input into a SimpleString.
Sexp	scanString() Scan input as a Sexp.
boolean	scanToken(SimpleString ss) Scan one or more characters into the given simple string as a token.
void	scanVerbatimString(SimpleString ss, long length) Scan input as verbatim string of given length.
boolean	skipChar(int c) Skip the following input character on input stream is, if it is equal to the character c.
boolean	skipWhiteSpace() Skip over any white space on the given InputStream.

Methods inherited from class java.io.BufferedInputStream

, available, close, ensureOpen, fill, markSupported, read, read1, skip

Methods inherited from class java.io.FilterInputStream

read

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait

Field Detail

__me

public static final String __me

nextByte

private int nextByte

byteSize

private int byteSize

bits

private int bits

nBits

private int nBits

count

private int count

isEOF

private boolean isEOF

saved_state

private int[] saved_state

debug

public boolean debug

Constructor Detail

SexpInputStream

public SexpInputStream(InputStream stream)

Creates and initializes a new InputStream object. Prefixes stream with one blank, and initializes stream so that it reads from the supplied InputStream.

Parameters:

stream - InputStream to attach this SexpInputStream to for input.

Method Detail

mark

public void mark(int readlimit)

Marks the current position and state in this input stream.

Overrides:

mark in class BufferedInputStream

See Also:

BufferedInputStream.mark(int), reset

reset

public void reset()
           throws IOException

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

Overrides:

reset in class BufferedInputStream

See Also:

BufferedInputStream.reset(), mark

changeByteSize

public void changeByteSize(int base)

Change the input byte size.

Parameters:

newByteSize - 4 (hexadecimal), 6 (Base64), or 8 (binary raw data).

EOF

public boolean EOF()

Test to see if this stream have reached end-of-file.

Returns:

true if this stream has reached EOF.

read

public int read()
         throws IOException,
                CharConversionException

Reads the next byte of data from this buffered input stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

Overrides:

read in class BufferedInputStream

Returns:

the next byte of data, or -1 if the end of the stream is reached.

Throws:

IOException - if an I/O Error occurs

EOFException - if end of file is reached

CharConversionException - if an error during input conversion occurs

See Also:

BufferedInputStream

skipWhiteSpace

public boolean skipWhiteSpace()
                       throws IOException

Skip over any white space on the given InputStream.

Returns:

true if there's more characters to read (not EOF).

skipChar

public boolean skipChar(int c)
                 throws IOException

Skip the following input character on input stream is, if it is equal to the character c. If it is not equal, then an error occurs.

Returns:

true if there's more characters to read (not EOF).

scanToken

public boolean scanToken(SimpleString ss)
                  throws IOException

Scan one or more characters into the given simple string as a token.

Parameters:

ss - SimpleString to scan token into

Returns:

true if there's more characters to read (not EOF).

scanDecimal

public long scanDecimal(long val)
                 throws IOException

Scan input as a decimal number of some encoding. TODO: Make BigInteger version of this method.

Parameters:

val - starer value (typically 0)

Returns:

long integer that is value of decimal number

Throws:

NumberFormatException - if some error occured during conversion (typically the string was too large to contain a decimal number)

EOFException - if input ended prematurely

scanVerbatimString

public void scanVerbatimString(SimpleString ss,
                               long length)
                        throws IOException

Scan input as verbatim string of given length.

Parameters:

ss - SimpleString to scan verbatim string into

length - length of verbatim string to scan

Throws:

EOFException - if input ended prematurely

scanQuotedString

public void scanQuotedString(SimpleString ss,
                             long length)
                      throws IOException

Scan input as quoted string of given length. Handles ordinary C escapes.

Parameters:

ss - SimpleString to scan verbatim string into

length - length of verbatim string to scan. If of indefinite length, use -1.

Throws:

EOFException - if input ended prematurely

scanHexString

public void scanHexString(SimpleString ss,
                          long length)
                   throws IOException

Scan input as hexadecimal string of given length.

Parameters:

ss - SimpleString to scan verbatim string into

length - length of verbatim string to scan. If of indefinite length, use -1.

Throws:

EOFException - if input ended prematurely

scanBase64String

public void scanBase64String(SimpleString ss,
                             long length)
                      throws IOException

Scan input as Base64 string of given length.

Parameters:

ss - SimpleString to scan verbatim string into

length - length of verbatim string to scan. If of indefinite length, use -1.

Throws:

EOFException - if input ended prematurely

scanSimpleString

public SimpleString scanSimpleString()
                              throws IOException

Scan input into a SimpleString. Determines type of simple string from the initial character, and dispatches to appropriate method based on that.

Returns:

SimpleString

Throws:

IOException - if something went wrong

EOFException - if premature end-of-file was detected

scanString

public Sexp scanString()
                throws IOException

Scan input as a Sexp. Reads and returns a string [presentationhint]string from input stream.

Returns:

Sexp

Throws:

IOException - if something went wrong

EOFException - if premature end-of-file was detected

scanList

public SList scanList()
               throws IOException

Scan input as a SList.

Returns:

SList

Throws:

IOException - if something went wrong

EOFException - if premature end-of-file was detected

scanObject

public SExpression scanObject()
                       throws IOException

Scans input for either a SList or a Sexp. This is the highest-level scanning method available.

Returns:

SExpression (either a SList or a String) or null if the scanned object couldn't be scanned properly.

Throws:

IOException - if something went wrong

EOFException - if premature end-of-file was detected

See Also:

SExpression