#!/bin/sh
# This is a shell archive (produced by GNU sharutils 4.15.2).
# To extract the files from this archive, save it to some FILE, remove
# everything before the '#!/bin/sh' line above, then type 'sh FILE'.
#
lock_dir=_sh30632
# Made on 2019-04-19 10:26 CDT by <dwjones@fastx03.divms.uiowa.edu>.
# Source directory was '/mnt/nfs/clasnetappvm/fs3/dwjones/mp5'.
#
# Existing files will *not* be overwritten, unless '-c' is specified.
#
# This shar contains:
# length mode       name
# ------ ---------- ------------------------------------------
#    835 -rw------- README
#   1434 -rwx------ tests
#    157 -rw------- classes
#   1222 -rw------- Errors.java
#   4689 -rw------- Gate.java
#   2370 -rw------- InputCountGate.java
#   2101 -rw------- InputGate.java
#   3007 -rw------- MP5.java
#   1105 -rw------- OutputGate.java
#   3555 -rw------- ScanSupport.java
#   1748 -rw------- Simulation.java
#   1131 -rw------- ThresholdGate.java
#   3033 -rw------- Wire.java
#    949 -rw------- XorGate.java
#
MD5SUM=${MD5SUM-md5sum}
f=`${MD5SUM} --version | egrep '^md5sum .*(core|text)utils'`
test -n "${f}" && md5check=true || md5check=false
${md5check} || \
  echo 'Note: not verifying md5sums.  Consider installing GNU coreutils.'
if test "X$1" = "X-c"
then keep_file=''
else keep_file=true
fi
echo=echo
save_IFS="${IFS}"
IFS="${IFS}:"
gettext_dir=
locale_dir=
set_echo=false

for dir in $PATH
do
  if test -f $dir/gettext \
     && ($dir/gettext --version >/dev/null 2>&1)
  then
    case `$dir/gettext --version 2>&1 | sed 1q` in
      *GNU*) gettext_dir=$dir
      set_echo=true
      break ;;
    esac
  fi
done

if ${set_echo}
then
  set_echo=false
  for dir in $PATH
  do
    if test -f $dir/shar \
       && ($dir/shar --print-text-domain-dir >/dev/null 2>&1)
    then
      locale_dir=`$dir/shar --print-text-domain-dir`
      set_echo=true
      break
    fi
  done

  if ${set_echo}
  then
    TEXTDOMAINDIR=$locale_dir
    export TEXTDOMAINDIR
    TEXTDOMAIN=sharutils
    export TEXTDOMAIN
    echo="$gettext_dir/gettext -s"
  fi
fi
IFS="$save_IFS"
if (echo "testing\c"; echo 1,2,3) | grep c >/dev/null
then if (echo -n test; echo 1,2,3) | grep n >/dev/null
     then shar_n= shar_c='
'
     else shar_n=-n shar_c= ; fi
else shar_n= shar_c='\c' ; fi
f=shar-touch.$$
st1=200112312359.59
st2=123123592001.59
st2tr=123123592001.5 # old SysV 14-char limit
st3=1231235901

if   touch -am -t ${st1} ${f} >/dev/null 2>&1 && \
     test ! -f ${st1} && test -f ${f}; then
  shar_touch='touch -am -t $1$2$3$4$5$6.$7 "$8"'

elif touch -am ${st2} ${f} >/dev/null 2>&1 && \
     test ! -f ${st2} && test ! -f ${st2tr} && test -f ${f}; then
  shar_touch='touch -am $3$4$5$6$1$2.$7 "$8"'

elif touch -am ${st3} ${f} >/dev/null 2>&1 && \
     test ! -f ${st3} && test -f ${f}; then
  shar_touch='touch -am $3$4$5$6$2 "$8"'

else
  shar_touch=:
  echo
  ${echo} 'WARNING: not restoring timestamps.  Consider getting and
installing GNU '\''touch'\'', distributed in GNU coreutils...'
  echo
fi
rm -f ${st1} ${st2} ${st2tr} ${st3} ${f}
#
if test ! -d ${lock_dir} ; then :
else ${echo} "lock directory ${lock_dir} exists"
     exit 1
fi
if mkdir ${lock_dir}
then ${echo} "x - created lock directory ${lock_dir}."
else ${echo} "x - failed to create lock directory ${lock_dir}."
     exit 1
fi
# ============= README ==============
if test -n "${keep_file}" && test -f 'README'
then
${echo} "x - SKIPPING README (file already exists)"

else
${echo} "x - extracting README (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'README' &&
README
version 2019-04-19
author  Douglas W. Jones
X
Posted solution to MP5 consisting of the following files.
These files make up a digital logic simulator.
X
README			-- this file
X
classes			-- the @ file for the javac command
X
Errors.java		-- utility package
ScanSupport.java	-- utility package
Simulation.java		-- utility package
X
Wire.java		-- wires that connect gates
Gate.java		-- gates are connected by wires
InputCountGate.java	-- a subclass of Gate
ThresholdGate.java	-- a subclass of InputCountGate
XXorGate.java		-- a subclass of InputCountGate
InputGate.java		-- a subclass of Gate
OutputGate.java		-- a subclass of Gate
X
MP5.java		-- the main program
X
tests			-- an executable test script
X
To build the simulator, use the shell command javac @classes
To run the tests, make the file tests executable and then run the script
SHAR_EOF
  (set 20 19 04 19 10 26 30 'README'
   eval "${shar_touch}") && \
  chmod 0600 'README'
if test $? -ne 0
then ${echo} "restore of README failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'README': 'MD5 check failed'
       ) << \SHAR_EOF
2e86fae00c2369724c677d30e95a01d2  README
SHAR_EOF

else
test `LC_ALL=C wc -c < 'README'` -ne 835 && \
  ${echo} "restoration warning:  size of 'README' is not 835"
  fi
fi
# ============= tests ==============
if test -n "${keep_file}" && test -f 'tests'
then
${echo} "x - SKIPPING tests (file already exists)"

else
${echo} "x - extracting tests (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'tests' &&
#!/bin/sh
# tests -- test shell script for testing mp5 (must be executable)
# Author: Douglas Jones
# Version: 2019-04-14
X
echo
echo "test xor gate example with suppressed short output pulse"
cat > testdata << EOF
gate a input 0 1.0 1
gate b xor 0.1
wire a 1.0 b 1.09 b
EOF
java MP5 testdata
rm -f testdata
read -p "Press Enter to continue"
X
echo
echo "test xor gate example with unsuppressed output pulse"
cat > testdata << EOF
gate a input 0 1.0 1
gate b xor 0.1
wire a 1.0 b 1.11 b
EOF
java MP5 testdata
rm -f testdata
read -p "Press Enter to continue"
X
echo
echo "test threshold gate 2 suppressed transitions"
cat > testdata << EOF
gate a input 0 0.1 2
gate b threshold 1 0.11
wire a 1.0 b
EOF
java MP5 testdata
rm -f testdata
read -p "Press Enter to continue"
X
echo
echo "test threshold gate 3 transitions (one from 0->1 gets through)"
cat > testdata << EOF
gate a input 0 0.05 3
gate b threshold 1 0.11
wire a 1.0 b
EOF
java MP5 testdata
rm -f testdata
read -p "Press Enter to continue"
X
echo
echo "test threshold gate 4 suppressed transitions"
cat > testdata << EOF
gate a input 0 0.0333 4
gate b threshold 1 0.11
wire a 1.0 b
EOF
java MP5 testdata
rm -f testdata
read -p "Press Enter to continue"
X
echo
echo "test threshold gate 5 transitions (one from 0-> gets through)"
cat > testdata << EOF
gate a input 0 0.025 5
gate b threshold 1 0.11
wire a 1.0 b
EOF
java MP5 testdata
rm -f testdata
read -p "Press Enter to continue"
X
SHAR_EOF
  (set 20 19 04 14 18 26 49 'tests'
   eval "${shar_touch}") && \
  chmod 0700 'tests'
if test $? -ne 0
then ${echo} "restore of tests failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'tests': 'MD5 check failed'
       ) << \SHAR_EOF
7356d2b0e955a063ebd64cef3474b944  tests
SHAR_EOF

else
test `LC_ALL=C wc -c < 'tests'` -ne 1434 && \
  ${echo} "restoration warning:  size of 'tests' is not 1434"
  fi
fi
# ============= classes ==============
if test -n "${keep_file}" && test -f 'classes'
then
${echo} "x - SKIPPING classes (file already exists)"

else
${echo} "x - extracting classes (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'classes' &&
Errors.java
ScanSupport.java
Simulation.java
Gate.java
InputCountGate.java
XXorGate.java
ThresholdGate.java
InputGate.java
OutputGate.java
Wire.java
MP5.java
SHAR_EOF
  (set 20 19 04 14 18 12 58 'classes'
   eval "${shar_touch}") && \
  chmod 0600 'classes'
if test $? -ne 0
then ${echo} "restore of classes failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'classes': 'MD5 check failed'
       ) << \SHAR_EOF
7cea55cc88e56af9e50438b8f20a7a23  classes
SHAR_EOF

else
test `LC_ALL=C wc -c < 'classes'` -ne 157 && \
  ${echo} "restoration warning:  size of 'classes' is not 157"
  fi
fi
# ============= Errors.java ==============
if test -n "${keep_file}" && test -f 'Errors.java'
then
${echo} "x - SKIPPING Errors.java (file already exists)"

else
${echo} "x - extracting Errors.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'Errors.java' &&
// errors.java
X
/** Error reporting package
X *  Provide a standard prefix and behavior for error reporting
X *  @author Douglas W. Jones
X *  @version 2019-03-03
X *  Lifted from RoadNetwork.java version 2019-03-01
X *  augmented to count errors
X */
public class Errors {
X    // prefix string for all error messages
X    private static String prefix = "??: ";
X
X    // how many warnings have been issued (see warnings() method)
X    private static int warnCount = 0;
X
X    /** Set prefix on error reports, should be done before any error reports
X     *  @arg p the prefix on any error messages
X     */
X    public static void setPrefix( String p ) {
X	prefix = p;
X    }
X
X    /** Report nonfatal errors, output a message and return
X     *  @arg m the message to output
X     */
X    public static void warn( String m ) {
X	System.err.println( prefix + ": " + m );
X	warnCount = warnCount + 1;
X    }
X
X    /** Report the number of warnings that have been issued
X     *  @returns the count
X     */
X    public static int warnings() {
X	return warnCount;
X    }
X
X    /** Report fatal errors, output a message and die
X     *  @arg m the message to output
X     */
X    public static void fatal( String m ) {
X	warn( m );
X	System.exit( 1 );
X    }
}
SHAR_EOF
  (set 20 19 04 12 10 02 22 'Errors.java'
   eval "${shar_touch}") && \
  chmod 0600 'Errors.java'
if test $? -ne 0
then ${echo} "restore of Errors.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'Errors.java': 'MD5 check failed'
       ) << \SHAR_EOF
edeeeecf3d1efed70626316955d2be78  Errors.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'Errors.java'` -ne 1222 && \
  ${echo} "restoration warning:  size of 'Errors.java' is not 1222"
  fi
fi
# ============= Gate.java ==============
if test -n "${keep_file}" && test -f 'Gate.java'
then
${echo} "x - SKIPPING Gate.java (file already exists)"

else
${echo} "x - extracting Gate.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'Gate.java' &&
// Gate.java
X
import java.util.Iterator;
import java.util.Scanner;
import java.util.List;
import java.util.LinkedList;
X
/** Subclasses of Gates are joined by Wires
X *  @author Douglas Jones
X *  @version 2019-04-03
X *  Lightly edited from RoadNetwork.java class Intersection version 2019-02-15
X *  then altered to become an abstract class with subclasses and a factory
X *  @see Wire
X *  @see InputCountGate
X *  @see InputGate
X *  @see OutputGate
X */
public abstract class Gate {
X
X    // a list of all of the gates in the universe
X    private static final List <Gate> allGates = new LinkedList <Gate> ();
X
X    /** Allow outsiders to iterate over all the gates
X     *  @returns an Iterator allowing access to gates
X     */
X    public static Iterator <Gate> iterator() {
X	return allGates.iterator();
X    }
X
X    /** look up a gate by name
X     *  @param n the name of the gate, possibly null (matches nothing)
X     *  @returns the Gate with that name, or null if no match
X     */
X    public static Gate findGate( String n ) {
X	// stupid code, a linear search, but does it matter?
X	for (Gate g: allGates) {
X	    if (g.name.equals( n )) return g;
X	}
X	return null;
X    }
X
X    // attributes of individual gates
X
X    /** The name of this gate
X      */
X    public final String name; // the gate's name or null if broken
X
X    // where the outputs from this gate go
X    protected final LinkedList <Wire> outgoing = new LinkedList <Wire> ();
X
X    // where the inputs to this gate come from
X    protected int inCount = 0; // we only seem to need a count of inputs
X
X    /** constructor, used only from within subclasses
X     *  @param n the name of the new gate
X     *  this is needed in order to make the name final
X     */
X    protected Gate( String n ) {
X	name = n;
X    }
X
X    /** build a new Gate and add it to the list of gates
X     *  @param sc the scanner used to get the attributes of this gate
X     *  @returns a new gate or null if it cannot be constructed
X     *  When called, the keyword "gate" has already been scanned,
X     *  so we are ready to scan the additional attributes, if any.
X     */
X    public static void make( Scanner sc ) {
X	// first worry about the gate name
X	final String name
X	    = ScanSupport.scanName( sc, () -> "Gate has missing name" );
X	if (name == null) {
X	    ScanSupport.finishLine(
X	        sc, () -> "gate: followed by"
X	    );
X	    return; // no gate added to allGates
X	}
X	if (findGate( name ) != null) {
X	    Errors.warn( "gate " + name + ": name reused" );
X	    ScanSupport.finishLine(
X	        sc, () -> "gate " + name + ": followed by"
X	    );
X	    return; // no gate added to allGates
X	}
X
X	// get the gate kind
X	final String kind = ScanSupport.scanName(
X	    sc, () -> "Gate " + name + ": kind missing"
X	);
X	if (kind == null) {
X	    ScanSupport.finishLine(
X		sc, () -> "gate " + name + ": followed by"
X	    );
X	    return; // no gate added to allGates
X	}
X	
X	// construct the right kind of gate
X	if ("xor".equals( kind )) {
X	    allGates.add( new XorGate( sc, name ) );
X	} else if ("threshold".equals( kind )) {
X	    allGates.add( new ThresholdGate( sc, name ) );
X	} else if ("input".equals( kind )) {
X	    allGates.add( new InputGate( sc, name ) );
X	} else if ("output".equals( kind )) {
X	    allGates.add( new OutputGate( sc, name ) );
X	} else {
X	    Errors.warn( "gate " + name + " " + kind + ": kind unknown" );
X	    ScanSupport.finishLine(
X	        sc, () -> "gate " + name + " " + kind + ": followed by"
X	    );
X	}
X    }
X
X    /** Every subclass of gate offers a sanity check
X     *  It should call Errors.warn() for each failure it detects
X     */
X    public abstract void sanityCheck();
X
X    /** connect a wire as an input to this gate
X     *  @arg w the wire
X     */
X    public void connectTo( Wire w ) {
X	inCount = inCount + 1; // it seems that all we need to do is count them
X    }
X
X    /** connect a wire as an output from this gate
X     *  @arg w the wire
X     */
X    public void connectFrom( Wire w ) {
X	outgoing.add( w );
X    }
X
X    public String toString() {
X	// note, we have a guarantee that name is not null, so
X	return "Gate " + name;
X    }
X
X    // Simulation methods
X
X    /** tell the gate that one of its inputs has changed
X     *  @param now the time at which the change occurs
X     *  @param value the new value of that input
X     *  each subclass must implement this method
X     */
X    public abstract void inputChange( float now, int value );
X
X    // actually change the output
X    protected void outputChange( float now, int value ) {
X	final int comp = 1 - value; // logical complement of the value
X	System.out.println( "time "+ now +" "+ comp +"->"+ value +" "+ this );
X	for (Wire w: outgoing) w.inputChange( now, value );
X    }
}
SHAR_EOF
  (set 20 19 04 12 10 02 32 'Gate.java'
   eval "${shar_touch}") && \
  chmod 0600 'Gate.java'
if test $? -ne 0
then ${echo} "restore of Gate.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'Gate.java': 'MD5 check failed'
       ) << \SHAR_EOF
a48188b8bc09f48d9c65fa330ac645a8  Gate.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'Gate.java'` -ne 4689 && \
  ${echo} "restoration warning:  size of 'Gate.java' is not 4689"
  fi
fi
# ============= InputCountGate.java ==============
if test -n "${keep_file}" && test -f 'InputCountGate.java'
then
${echo} "x - SKIPPING InputCountGate.java (file already exists)"

else
${echo} "x - extracting InputCountGate.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'InputCountGate.java' &&
// InputCountGate.java
X
import java.util.Scanner;
X
/** Any kind of gate that needs to track its input count
X *  @author Douglas Jones
X *  @version 2019-04-03
X *  @see Gate
X *  @see XorGate
X *  @see ThresholdGate
X */
public abstract class InputCountGate extends Gate {
X
X    private int inputCount = 0; // number of inputs that are currently one
X    private int oldOutput = 0;  // the previous output (set by input changes)
X    private int newOutput = 0;  // the previous output (set at output change)
X    protected float delay = Float.NaN; // default value allows this in err msgs
X
X    /** constructor, used only from within subclasses
X     *  @param n the name of the new gate
X     *  this is a pass-through to Gate
X     */
X    protected InputCountGate( String n ) {
X	super( n );
X    }
X
X    /** tell the gate that one of its inputs has changed
X     *  @param now the time at which the change occurs
X     *  @param value the new value of that input
X     *  each subclass must implement this method
X     */
X    public void inputChange( float now, int value ) {
X	if (value == 1) { // it change to 1
X	    inputCount = inputCount + 1;
X	} else { // it changed to 0
X	    inputCount = inputCount - 1;
X	}
X
X	// the following code suppresses changes from 1 to 1 or 0 to 0
X	// by gate input changes; eg (0 or 0) to (0 or 1) leaves output 0
X	int myOutput = logicRule( inputCount );
X	if (myOutput != oldOutput) { // the output changes
X            Simulation.schedule(
X                now + delay, (float t) -> this.outputChange( t, myOutput )
X	    );
X	    oldOutput = myOutput;
X        }
X    }
X
X    // override the default output change event, needed to suppress short pulses
X    protected void outputChange( float now, int value ) {
X
X	// first, suppress changes away from the value most recently set
X	// set by the input.  This prevents short pulses from getting through.
X	if (value != oldOutput) return;
X
X	// second, suppress changes from 1 to 1 or 0 to 0
X	// caused, eg, by events that return the value to the approved value.
X	if (value == newOutput) return;
X
X	// finally, we know that this output change should occur
X	super.outputChange( now, value );
X	newOutput = value;
X    }
X
X    /** compute the gate's logical value
X     *  @param count the number of ones on the input
X     *  each subclass must implement this method
X     */
X    public abstract int logicRule( int count );
}
SHAR_EOF
  (set 20 19 04 14 17 05 29 'InputCountGate.java'
   eval "${shar_touch}") && \
  chmod 0600 'InputCountGate.java'
if test $? -ne 0
then ${echo} "restore of InputCountGate.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'InputCountGate.java': 'MD5 check failed'
       ) << \SHAR_EOF
62422b3c3e023f64b95bcce91090725b  InputCountGate.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'InputCountGate.java'` -ne 2370 && \
  ${echo} "restoration warning:  size of 'InputCountGate.java' is not 2370"
  fi
fi
# ============= InputGate.java ==============
if test -n "${keep_file}" && test -f 'InputGate.java'
then
${echo} "x - SKIPPING InputGate.java (file already exists)"

else
${echo} "x - extracting InputGate.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'InputGate.java' &&
// InputGate.java
X
import java.util.Scanner;
X
/** input gates will provide input to the simulation
X *  @author Douglas Jones
X *  @version 2019-04-03
X *  @see Gate
X */
public class InputGate extends Gate {
X    private float delay = Float.NaN; // default values allow this in err msgs
X    private int initial = 0;
X    private int changeCount = 0;
X
X    public InputGate( Scanner sc, String name ){
X	super( name );
X	initial = ScanSupport.scanPositiveInt( sc, () -> this.toString() );
X	delay = ScanSupport.scanPositiveFloat( sc, () -> this.toString() );
X	changeCount = ScanSupport.scanPositiveInt( sc, () -> this.toString() );
X	if (initial > 1) Errors.warn( this + ": initial value > 1" );
X	ScanSupport.finishLine( sc, () -> this + " is followed by" );
X    }
X
X    /** Every subclass of gate offers a sanity check
X     *  Calls Errors.warn() for any gates where input count > 0
X     */
X    public void sanityCheck() {
X	if (inCount != 0) {
X	    Errors.warn( this.toString() + ": has unexpected input wires" );
X        }
X
X	// launch the simulation!
X	if (initial == 1) this.outputChange( 0.0F, 1 );
X	if (changeCount > 0) Simulation.schedule(
X            delay, (float t) -> this.nextChange( t, 1 - initial )
X	);
X    }
X
X    public String toString() {
X	return super.toString() + " input "
X	    + initial + " " + delay + " " + changeCount;
X    }
X
X    // Simulation methods
X
X    /** tell this input gate that one of its inputs has changed
X     *  @param now the time at which the change occurs
X     *  @param value the new value of that input
X     *  The sanity check guarantees that this will never be called
X     */
X    public void inputChange( float now, int value ) {
X	Errors.warn( this.toString() + ": Impossible input change" );
X    }
X    
X    // Output change process for sequence of inputs
X    private void nextChange( float now, int value ) {
X	// first change the output
X	this.outputChange( now, value );
X
X	// then schedule the next change, if any
X	changeCount = changeCount - 1;
X	if (changeCount > 0) Simulation.schedule(
X            now + delay, (float t) -> this.nextChange( t, 1 - value )
X	);
X    }
}
SHAR_EOF
  (set 20 19 04 12 10 02 50 'InputGate.java'
   eval "${shar_touch}") && \
  chmod 0600 'InputGate.java'
if test $? -ne 0
then ${echo} "restore of InputGate.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'InputGate.java': 'MD5 check failed'
       ) << \SHAR_EOF
447962fc015f2954e4fb0cf48ad1ab40  InputGate.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'InputGate.java'` -ne 2101 && \
  ${echo} "restoration warning:  size of 'InputGate.java' is not 2101"
  fi
fi
# ============= MP5.java ==============
if test -n "${keep_file}" && test -f 'MP5.java'
then
${echo} "x - SKIPPING MP5.java (file already exists)"

else
${echo} "x - extracting MP5.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'MP5.java' &&
// MP4.java
X
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.util.Iterator;
import java.util.List;
import java.util.LinkedList;
import java.util.Scanner;
X
/** Main program
X *  @author Douglas Jones
X *  @version 2019-04-03
X *  Originated as RoadNetwork.java class RoadNetwork version 2019-02-13,
X *  With buildLogic code heavily edited from buildNetwork,
X *  and with the lists of gates and wires moved into those classes.
X *  @see Gate
X *  @see Wire
X */
public class MP5 {
X
X    // build the logic circuit by scanning a source file
X    private static void buildLogic( Scanner sc ) {
X
X	while (sc.hasNext()) {
X	    // pick off the next part of the logic circuit description
X	    String command = sc.next();
X	    if ("--".equals( command )) {
X		sc.nextLine(); // discard remainder of comment line
X		// BUG: bad way to skip comments, requires whitespace post --
X	    } else if ("gate".equals( command )) {
X		Gate.make( sc );
X	    } else if ("wire".equals( command )) {
X		// because of multiple destinations, must get the source here
X		final String srcName
X		    = ScanSupport.scanName( sc, () -> "Wire: has no source" );
X		if (srcName != null) {
X		    final Gate source = Gate.findGate( srcName );
X		    if (source != null) {
X			// now build at least one wire and possibly more
X			Wire.make( sc, source ); 
X			while (sc.hasNextFloat()) {
X			    Wire.make( sc, source ); 
X			}
X			ScanSupport.finishLine(
X			    sc, () -> "Wire " + srcName + ": followed by"
X			);
X		    } else {
X			Errors.warn( "Wire " + srcName + ": undefined source" );
X			ScanSupport.finishLine(
X			    sc, () -> "Wire " + srcName + ": followed by"
X			);
X		    }
X		} else {
X		    // error message already done, but
X		    ScanSupport.finishLine( sc, () -> "Wire: followed by" );
X		}
X	    } else {
X		Errors.warn( "invalid command " + command );
X		ScanSupport.finishLine( sc, () -> command + ": followed by" );
X	    }
X	}
X    }
X
X    // perform sanity checks on all gates
X    private static void sanityChecks() {
X	for (Iterator <Gate> i = Gate.iterator(); i.hasNext();) {
X	    i.next().sanityCheck();
X	}
X    }
X
X    // print out the entire logic circuit
X    private static void printLogic() {
X	for (Iterator <Gate> i = Gate.iterator(); i.hasNext();) {
X	    System.out.println( i.next() );
X	}
X	for (Iterator <Wire> i = Wire.iterator(); i.hasNext();) {
X	    System.out.println( i.next() );
X	}
X    }
X
X    public static void main( String[] args ) {
X	Errors.setPrefix( "MP3" );
X	if (args.length < 1) {
X	    Errors.fatal( "missing argument" );
X	}
X	if (args.length > 1) {
X	    Errors.warn( "extra arguments" );
X	}
X	try {
X	    // args[0] is the text file holding the logic circuit description
X	    buildLogic( new Scanner( new FileInputStream( args[0] ) ) );
X	    sanityChecks();
X	    printLogic(); // something testable!
X	    if (Errors.warnings() == 0) Simulation.run();
X	} catch( FileNotFoundException e ) {
X	    Errors.fatal( "can't open file" );
X	}
X	if (Errors.warnings() > 0) System.exit( 1 ); // exit failure
X    }
}
SHAR_EOF
  (set 20 19 04 14 18 13 34 'MP5.java'
   eval "${shar_touch}") && \
  chmod 0600 'MP5.java'
if test $? -ne 0
then ${echo} "restore of MP5.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'MP5.java': 'MD5 check failed'
       ) << \SHAR_EOF
e074308eb3469c03df35264c6054ab1e  MP5.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'MP5.java'` -ne 3007 && \
  ${echo} "restoration warning:  size of 'MP5.java' is not 3007"
  fi
fi
# ============= OutputGate.java ==============
if test -n "${keep_file}" && test -f 'OutputGate.java'
then
${echo} "x - SKIPPING OutputGate.java (file already exists)"

else
${echo} "x - extracting OutputGate.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'OutputGate.java' &&
// OutputGate.java
X
import java.util.Scanner;
X
/** output gates will provide output from the simulation
X *  @author Douglas Jones
X *  @version 2019-04-03
X *  @see Gate
X */
public class OutputGate extends Gate {
X
X    public OutputGate( Scanner sc, String name ){
X	super( name );
X	
X	ScanSupport.finishLine( sc, () -> this + " is followed by" );
X    }
X
X    /** Every subclass of gate offers a sanity check
X     *  Calls Errors.warn() for any gates where input count > 0
X     */
X    public void sanityCheck() {
X	if (this.outgoing.peek() != null) { // something in the outgoing list
X	    Errors.warn( this.toString() + ": has outgoing wires" );
X	}
X    }
X
X    public String toString() {
X	return super.toString() + " output";
X    }
X
X    // Simulation methods
X
X    /** tell this output gate that one of its inputs has changed
X     *  @param now the time at which the change occurs
X     *  @param value the new value of that input
X     */
X    public void inputChange( float now, int value ) {
X	// due to the specs for MP4, nothing needs to be done here
X	// later spec changes might put all the output here
X    }
}
SHAR_EOF
  (set 20 19 04 12 10 03 10 'OutputGate.java'
   eval "${shar_touch}") && \
  chmod 0600 'OutputGate.java'
if test $? -ne 0
then ${echo} "restore of OutputGate.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'OutputGate.java': 'MD5 check failed'
       ) << \SHAR_EOF
20eca3e95869d4d0300ef3ec89839605  OutputGate.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'OutputGate.java'` -ne 1105 && \
  ${echo} "restoration warning:  size of 'OutputGate.java' is not 1105"
  fi
fi
# ============= ScanSupport.java ==============
if test -n "${keep_file}" && test -f 'ScanSupport.java'
then
${echo} "x - SKIPPING ScanSupport.java (file already exists)"

else
${echo} "x - extracting ScanSupport.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'ScanSupport.java' &&
// ScanSupport.java
X
import java.util.regex.Pattern;
import java.util.Scanner;
X
/** Support package for application dependent extensions to class Scanner
X *  @author Douglas Jones
X *  @version 2019-03-04
X *  Based on RoadNetwork.java version 2019-03-01
X *  augmented to use lambda expressions for error messages
X *  and to scan floating point numbers
X *  @see Errors
X *  If class Scanner wasn't final, this could be a subclass
X */
public class ScanSupport {
X
X    // patterns used in methods below
X    private static final Pattern name =         // match one legal name
X        Pattern.compile( "[A-Za-z]*[A-Za-z0-9]" );
X    private static final Pattern blanks =       // match any number of blanks
X        Pattern.compile( "[ \t]*" );
X    private static final Pattern theRest =      // match text up to newline
X        Pattern.compile( "[^\n]*" );
X
X    /** Support interface for passing deferred computation of message text
X     *  set up so that lambda notation can be used
X     */
X    public static interface MessageCarrier {
X	String content();
X    }
X
X    /** Scan and return one name, if available
X     *  @arg sc the scanner to read from
X     *  @arg msg the message to output if there is no name
X     *  @returns the name, or null if there is no name
X     *  Typically called as ScanSupport.scanName( sc, () -> string + expr )
X     */
X    public static String scanName( Scanner sc, MessageCarrier msg ) {
X	if (sc.hasNext( name )) return sc.next(name);
X	Errors.warn( msg.content() );
X	return null;
X    }
X
X    /** Scan and return one nonnegative int, if available
X     *  @arg sc the scanner to read from
X     *  @arg msg the message prefix to output if there is no int
X     *  @returns the value, or 0 if there is no number
X     *  Typically called as ...scanPositiveInt( sc, () -> string + expr )
X     */
X    public static int scanPositiveInt( Scanner sc, MessageCarrier msg ) {
X	if (sc.hasNextInt()) {
X	    int value = sc.nextInt();
X	    if (value >= 0) return value;
X	    Errors.warn( msg.content() + " " + value + ": must be positive" );
X        }
X	Errors.warn( msg.content() + ": integer value expected" );
X	return 0;
X    }
X
X    /** Scan and return one nonnegative float, if available
X     *  @arg sc the scanner to read from
X     *  @arg msg the message prefix to output if there is no float
X     *  @returns the value, or NaN if there is no number
X     *  Typically called as ...scanPositiveFloat( sc, () -> string + expr )
X     */
X    public static float scanPositiveFloat( Scanner sc, MessageCarrier msg ) {
X	if (sc.hasNextFloat()) {
X	    float value = sc.nextFloat();
X	    if (value >= 0.0F) return value;
X	    Errors.warn( msg.content() + " " + value + ": must be positive" );
X        }
X	Errors.warn( msg.content() + ": float value expected" );
X	return Float.NaN;
X    }
X
X    /** Skip the rest of this line, and complain if it's nonblank noncomment
X     *  @arg sc the scanner to read from
X     *  @arg msg the object that computes the message to output if needed
X     *  Typically called as ScanSupport.finishLine( sc, () -> string + expr )
X     *  This code improves on the posted solution for homework 6, problem 2
X     */
X    public static void finishLine( Scanner sc, MessageCarrier msg ) {
X	// first skip trailing blanks
X	sc.skip( blanks );
X
X	// then get everything that remains on this line
X	sc.skip( theRest );
X	final String remainder = sc.match().group( 0 );
X
X	// then see if it all makes sense
X	if ("".equals( remainder )) return;
X	if (remainder.startsWith ("--")) return;
X	Errors.warn( msg.content() + ": " + remainder );
X    }
}
SHAR_EOF
  (set 20 19 04 12 10 03 22 'ScanSupport.java'
   eval "${shar_touch}") && \
  chmod 0600 'ScanSupport.java'
if test $? -ne 0
then ${echo} "restore of ScanSupport.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'ScanSupport.java': 'MD5 check failed'
       ) << \SHAR_EOF
301237e5016a1eb8828af3be94444114  ScanSupport.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'ScanSupport.java'` -ne 3555 && \
  ${echo} "restoration warning:  size of 'ScanSupport.java' is not 3555"
  fi
fi
# ============= Simulation.java ==============
if test -n "${keep_file}" && test -f 'Simulation.java'
then
${echo} "x - SKIPPING Simulation.java (file already exists)"

else
${echo} "x - extracting Simulation.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'Simulation.java' &&
// Simulation.java
X
import java.util.PriorityQueue;
X
/** Simulation framework
X *  @author Douglas W. Jones
X *  @version 2019-03-08
X */
public class Simulation {
X
X    // this interface is so we can schedule events with lambda expressions
X    public interface Action {
X	void trigger( float time );
X    }
X
X    // Events are scheduled on the event set
X    private static class Event {
X	final float time; // the simulated time of the event
X	final Action act; // the action to trigger at that time
X
X	Event( float t, Action a ) {
X	    time = t;
X	    act = a;
X	}
X    }
X
X    // the central organizing data structure of the simulation
X    private static final PriorityQueue <Event> eventSet
X	= new PriorityQueue <Event> (
X	    ( Event e1, Event e2 ) -> Float.compare( e1.time, e2.time )
X    );
X
X    /** schedule a new event
X     *  @param t the time at which the event should occur
X     *  @param a the Action that should occur at that time
X     *  A typical call will look like this
X     *  Simulation.schedule( someTime, (float t)->codeToRunAt( t ) );
X     *  That is, the Action will be constructed by a lambda expression
X     */
X    public static void schedule( float t, Action a ) {
X	eventSet.add( new Event( t, a ) );
X    }
X
X    /** run a simulation
X     *  Call this after scheduling at least one event.
X     *  The simulation will run until either there are no more events or
X     *  some event terminates the program.
X     *  From this point on, a typical simulation program will be event driven
X     *  with the ordering of computations determined by chronological ordering
X     *  of scheduled events.
X     */
X    public static void run() {
X	while (!eventSet.isEmpty()) {
X	    Event e = eventSet.remove();
X	    e.act.trigger( e.time );
X	}
X    }
}
SHAR_EOF
  (set 20 19 04 12 10 03 30 'Simulation.java'
   eval "${shar_touch}") && \
  chmod 0600 'Simulation.java'
if test $? -ne 0
then ${echo} "restore of Simulation.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'Simulation.java': 'MD5 check failed'
       ) << \SHAR_EOF
73eaa412aab75e6a9fb7f8e7eadfbdb0  Simulation.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'Simulation.java'` -ne 1748 && \
  ${echo} "restoration warning:  size of 'Simulation.java' is not 1748"
  fi
fi
# ============= ThresholdGate.java ==============
if test -n "${keep_file}" && test -f 'ThresholdGate.java'
then
${echo} "x - SKIPPING ThresholdGate.java (file already exists)"

else
${echo} "x - extracting ThresholdGate.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'ThresholdGate.java' &&
// ThresholdGate.java
X
import java.util.Scanner;
X
/** threshold logic gates
X *  @author Douglas Jones
X *  @version 2019-04-03
X *  @see Gate
X */
public class ThresholdGate extends InputCountGate {
X    private int threshold = 0;
X
X    public ThresholdGate( Scanner sc, String name ){
X	super( name );
X	threshold = ScanSupport.scanPositiveInt( sc, () -> this.toString() );
X	delay = ScanSupport.scanPositiveFloat( sc, () -> this.toString() );
X	ScanSupport.finishLine( sc, () -> this + " is followed by" );
X    }
X
X    /** Every subclass of gate offers a sanity check
X     *  Calls Errors.warn() for any gate where threshold > input count
X     */
X    public void sanityCheck() {
X	if (threshold > inCount) {
X	    Errors.warn( this.toString() + ": has threshold > input wires" );
X	}
X    }
X
X    public String toString() {
X	return super.toString() + " threshold " + threshold + " " + delay;
X    }
X
X    /** compute the gate's logical value
X     *  @param count the number of ones on the input
X     *  each subclass must implement this method
X     */
X    public int logicRule( int count ) {
X	if (count >= threshold) return 1;
X	return 0;
X    }
}
SHAR_EOF
  (set 20 19 04 12 10 03 40 'ThresholdGate.java'
   eval "${shar_touch}") && \
  chmod 0600 'ThresholdGate.java'
if test $? -ne 0
then ${echo} "restore of ThresholdGate.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'ThresholdGate.java': 'MD5 check failed'
       ) << \SHAR_EOF
a771cd2c3b78cc24bb16a896e2f57f83  ThresholdGate.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'ThresholdGate.java'` -ne 1131 && \
  ${echo} "restoration warning:  size of 'ThresholdGate.java' is not 1131"
  fi
fi
# ============= Wire.java ==============
if test -n "${keep_file}" && test -f 'Wire.java'
then
${echo} "x - SKIPPING Wire.java (file already exists)"

else
${echo} "x - extracting Wire.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'Wire.java' &&
// Wire.java
X
import java.util.Iterator;
import java.util.List;
import java.util.LinkedList;
import java.util.Scanner;
X
/** Wires connect Gates
X *  @author Douglas Jones
X *  @version 2019-03-04
X *  Lightly edited from RoadNetwork.java class Road version 2019-02-15,
X *  except for the constructor, which is heavily edited
X *  @see Gate
X */
public class Wire {
X
X    // a list of all of the wires in the universe
X    private static final List <Wire> allWires = new LinkedList <Wire> ();
X
X    /** Allow outsiders to iterate over all the wires
X     *  @returns an Iterator allowing access to wires
X     */
X    public static Iterator <Wire> iterator() {
X	return allWires.iterator();
X    }
X
X    // attributes of each Wire
X    private final Gate source;		// where does this wire come from
X    private final Gate destination;	// where does it go
X    private final float delay;		// how long a signal takes to far end
X
X    // construct a new Wire
X    private Wire( Gate src, Gate dst, Float del ) {
X	source = src;
X	destination = dst;
X	delay = del;
X    }
X
X    /** build a new Gate and add it to the list of gates
X     *  @param sc the scanner used to get the attributes of this wire
X     *  @param src the source gate, guaranteed non null
X     *  When called, the keyword "wire" and the name of the source gate
X     *  have already been scanned, so we are ready to scan the delay and
X     *  destination.
X     */
X    public static void make( Scanner sc, Gate src ) {
X	// wire's delay and destination, until constructor call
X	final Float delay
X	     = ScanSupport.scanPositiveFloat( sc, () -> "wire " + src.name );
X	final String dstName = ScanSupport.scanName(
X	    sc, () -> "Wire " + src.name + " " + delay + ": destination missing"
X	);
X
X	// all scanning is done now, may return at any time to avoid making wire
X	if (dstName == null) return;
X	
X	Gate dst = Gate.findGate( dstName );
X	if (dst == null) {
X	    Errors.warn(
X		"Wire " + src.name + " " + delay + " " + dstName
X		+ ": undefined destination"
X	    );
X	    return;
X	}
X
X	// make the wire, after which w.toString is legal
X	Wire w = new Wire( src, dst, delay );
X
X	// now, we can actually wire the source and destination gates
X	src.connectFrom( w );
X	dst.connectTo( w );
X
X	// finally, add wire to allWires
X	allWires.add( w );
X    }
X
X    public String toString() {
X	// note that source and destination are never null
X        return "Wire " + source.name + ' ' + delay + ' ' + destination.name;
X    }
X
X    // Simulation methods
X
X    /** tell the wire that its input has changed
X     *  @param now the time at which the change occurs
X     *  @param value the new value of that input
X     */
X    public void inputChange( float now, int value ) {
X        Simulation.schedule(
X            now + delay, (float t) -> this.outputChange( t, value )
X	);
X    }
X
X    private void outputChange( float now, int value ) {
X	final int comp = 1 - value; // logical complement of the value
X	System.out.println( "time "+ now +" "+ comp +"->"+ value +" "+ this );
X	destination.inputChange( now, value );
X    }
}
SHAR_EOF
  (set 20 19 04 12 10 03 47 'Wire.java'
   eval "${shar_touch}") && \
  chmod 0600 'Wire.java'
if test $? -ne 0
then ${echo} "restore of Wire.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'Wire.java': 'MD5 check failed'
       ) << \SHAR_EOF
34bf6cbb854bc605baedcece8b14ffc8  Wire.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'Wire.java'` -ne 3033 && \
  ${echo} "restoration warning:  size of 'Wire.java' is not 3033"
  fi
fi
# ============= XorGate.java ==============
if test -n "${keep_file}" && test -f 'XorGate.java'
then
${echo} "x - SKIPPING XorGate.java (file already exists)"

else
${echo} "x - extracting XorGate.java (text)"
  sed 's/^X//' << 'SHAR_EOF' > 'XorGate.java' &&
// XorGate.java
X
import java.util.Scanner;
X
/** Exclusive Or gates
X *  @author Douglas Jones
X *  @version 2019-04-03
X *  @see Gate
X */
public class XorGate extends InputCountGate {
X
X    public XorGate( Scanner sc, String name ){
X	super( name );
X	delay = ScanSupport.scanPositiveFloat( sc, () -> this.toString() );
X	ScanSupport.finishLine( sc, () -> this + " is followed by" );
X    }
X
X    /** Every subclass of gate offers a sanity check
X     *  Calls Errors.warn() for any gate that has not got two inputs
X     */
X    public void sanityCheck() {
X	if (inCount != 2) {
X	    Errors.warn( this.toString() + ": input wire count must be two" );
X	}
X    }
X
X    public String toString() {
X	return super.toString() + " xor " + delay;
X    }
X
X    /** compute the gate's logical value
X     *  @param count the number of ones on the input
X     *  each subclass must implement this method
X     */
X    public int logicRule( int count ) {
X	return count % 2;
X    }
}
SHAR_EOF
  (set 20 19 04 12 10 03 59 'XorGate.java'
   eval "${shar_touch}") && \
  chmod 0600 'XorGate.java'
if test $? -ne 0
then ${echo} "restore of XorGate.java failed"
fi
  if ${md5check}
  then (
       ${MD5SUM} -c >/dev/null 2>&1 || ${echo} 'XorGate.java': 'MD5 check failed'
       ) << \SHAR_EOF
b22c46f4beaf0eb91fe30abe9bf964bd  XorGate.java
SHAR_EOF

else
test `LC_ALL=C wc -c < 'XorGate.java'` -ne 949 && \
  ${echo} "restoration warning:  size of 'XorGate.java' is not 949"
  fi
fi
if rm -fr ${lock_dir}
then ${echo} "x - removed lock directory ${lock_dir}."
else ${echo} "x - failed to remove lock directory ${lock_dir}."
     exit 1
fi
exit 0