Make LInteger constructor private and use LInteger.valueOf() everywhere, caching common values.

src/addon/java/lua/addon/compile/FuncState.java

@@ -435,7 +435,7 @@ public class FuncState extends LuaC {
 			double d = r.luaAsDouble();
 			int i = (int) d;
 			if ( d == (double) i ) 
-				r = new LInteger(i);
+				r = LInteger.valueOf(i);
 		}
 		return this.addk(r);
 	}

src/addon/java/lua/addon/compile/LexState.java

@@ -677,7 +677,7 @@ public class LexState extends LuaC {
 				_nval = r;
 			}
 			public LNumber nval() {
-				return (_nval == null? new LInteger(s.info): _nval);
+				return (_nval == null? LInteger.valueOf(s.info): _nval);
 			}
 		};
 		final U u = new U();
@@ -1621,7 +1621,7 @@ public class LexState extends LuaC {
 		if (this.testnext(','))
 			this.exp1(); /* optional step */
 		else { /* default step = 1 */
-			fs.codeABx(Lua.OP_LOADK, fs.freereg, fs.numberK(new LInteger(1)));
+			fs.codeABx(Lua.OP_LOADK, fs.freereg, fs.numberK(LInteger.valueOf(1)));
 			fs.reserveregs(1);
 		}
 		this.forbody(base, line, 1, true);

src/addon/java/lua/addon/luacompat/LuaCompat.java

@@ -375,7 +375,7 @@ public class LuaCompat extends LFunction {
 				return;
 			}
 		} else if ( arg.luaAsString().equals( "#" ) ) {
-			vm.setResult( new LInteger( vm.getArgCount() - 1 ) );
+			vm.setResult( LInteger.valueOf( vm.getArgCount() - 1 ) );
 		}
 		vm.setResult();
 	}
@@ -516,7 +516,7 @@ public class LuaCompat extends LFunction {
 		String filename = vm.getArgAsString(0);
 		if ( loadfile( vm, filename ) ) {
 			int s = vm.lua_pcall(1, 0);
-			vm.setResult( new LInteger( s!=0? 1: 0 ) );
+			vm.setResult( LInteger.valueOf( s!=0? 1: 0 ) );
 		} else {
 			vm.lua_error("cannot open "+filename);
 		}
@@ -709,7 +709,7 @@ public class LuaCompat extends LFunction {
 	 */ 
 	private void maxn(VM vm) {
 		LTable table = (LTable) vm.getArg(0);
-		vm.setResult( new LInteger( table.luaMaxN() ) );
+		vm.setResult( LInteger.valueOf( table.luaMaxN() ) );
 	}
 
 

src/addon/java/lua/addon/luacompat/StrLib.java

@@ -36,7 +36,7 @@ public class StrLib {
 			return;
 		int n = j - i + 1;
 		for ( int k=0; k < n; k++ )
-			vm.push( new LInteger( ls.luaByte(k+i-1) ) );
+			vm.push( LInteger.valueOf( ls.luaByte(k+i-1) ) );
 	}
 
 	/** 
@@ -252,7 +252,7 @@ public class StrLib {
 		lbuf.append( src.substring( soffset, srclen ) );
 		vm.setResult();
 		vm.push( lbuf.toLuaString() );
-		vm.push( new LInteger( n ) );
+		vm.push( LInteger.valueOf( n ) );
 	}
 	
 	/** 
@@ -262,7 +262,7 @@ public class StrLib {
 	 * Embedded zeros are counted, so "a\000bc\000" has length 5. 
 	 */
 	static void len( VM vm ) {		
-		vm.setResult( new LInteger( vm.getArgAsLuaString(0).length()) );
+		vm.setResult( LInteger.valueOf( vm.getArgAsLuaString(0).length()) );
 	}
 
 	/** 
@@ -566,7 +566,7 @@ public class StrLib {
 					vm.lua_error( "unfinished capture" );
 				}
 				if ( l == CAP_POSITION ) {
-					vm.push( new LInteger( cinit[i] + 1 ) );
+					vm.push( LInteger.valueOf( cinit[i] + 1 ) );
 				} else {
 					int begin = cinit[i];
 					vm.push( s.substring( begin, begin + l ) );

src/addon/java/lua/addon/luajava/CoerceJavaToLua.java

@@ -29,7 +29,7 @@ public class CoerceJavaToLua {
 		Coercion intCoercion = new Coercion() {
 			public LValue coerce( Object javaValue ) {
 				Number n = (Number) javaValue;
-				return new LInteger( n.intValue() );
+				return LInteger.valueOf( n.intValue() );
 			} 
 		} ;
 		Coercion doubleCoercion = new Coercion() {

src/main/java/lua/io/LoadState.java

@@ -107,7 +107,7 @@ public class LoadState {
 	
 	static LNumber longBitsToLuaNumber( long bits ) {
 		if ( ( bits & ( ( 1L << 63 ) - 1 ) ) == 0L ) {
-			return new LInteger( 0 );
+			return LInteger.valueOf( 0 );
 		}
 		
 		int e = (int)((bits >> 52) & 0x7ffL) - 1023;
@@ -118,7 +118,7 @@ public class LoadState {
 			long intPrecMask = ( 1L << shift ) - 1;
 			if ( ( f & intPrecMask ) == 0 ) {
 				int intValue = (int)( f >> shift ) | ( 1 << e );
-				return new LInteger( ( ( bits >> 63 ) != 0 ) ? -intValue : intValue );
+				return LInteger.valueOf( ( ( bits >> 63 ) != 0 ) ? -intValue : intValue );
 			}
 		}
 		
@@ -129,7 +129,7 @@ public class LoadState {
 	LNumber loadNumber() throws IOException {
 		if ( this.luacIsNumberIntegral ) {
 			int value = loadInt();
-			return new LInteger( value );
+			return LInteger.valueOf( value );
 		} else {
 			return longBitsToLuaNumber( loadInt64() );
 		}

src/main/java/lua/value/LInteger.java

@@ -5,7 +5,24 @@ import lua.Lua;
 public class LInteger extends LNumber {
 	private final int m_value;
 	
-	public LInteger(int value) {
+	/* local cache of commonly used LInteger values */
+	private static final int INTS_MIN =  -16;
+	private static final int INTS_MAX  =  32;
+	private static final LInteger s_ints[] = new LInteger[1+INTS_MAX-INTS_MIN];
+	static {
+		for ( int i=INTS_MIN; i<=INTS_MAX; i++ )
+			s_ints[i-INTS_MIN] = new LInteger(i);
+	}
+	
+	/** Get an LInteger corresponding to a particular int value */
+	public static LInteger valueOf(int n) {
+		if ( n >= INTS_MIN && n <= INTS_MAX )
+			return s_ints[n-INTS_MIN];
+		return new LInteger(n);
+	}
+
+	/** use LInteger.valueOf() instead */
+	private LInteger(int value) {
 		this.m_value = value;
 	}
 	
@@ -37,12 +54,12 @@ public class LInteger extends LNumber {
 	// binary operations on integers
 	public LValue luaBinOpInteger(int opcode, int rhs) {
 		switch ( opcode ) {
-		case Lua.OP_ADD: return new LInteger( m_value + rhs );
+		case Lua.OP_ADD: return LInteger.valueOf( m_value + rhs );
-		case Lua.OP_SUB: return new LInteger( m_value - rhs );
+		case Lua.OP_SUB: return LInteger.valueOf( m_value - rhs );
-		case Lua.OP_MUL: return new LInteger( m_value * rhs );
+		case Lua.OP_MUL: return LInteger.valueOf( m_value * rhs );
-		case Lua.OP_DIV: return new LInteger( m_value / rhs );
+		case Lua.OP_DIV: return LInteger.valueOf( m_value / rhs );
-		case Lua.OP_MOD: return new LInteger( m_value - ((int) Math.floor(m_value/(double)rhs)) * rhs );
+		case Lua.OP_MOD: return LInteger.valueOf( m_value - ((int) Math.floor(m_value/(double)rhs)) * rhs );
-		case Lua.OP_POW: return new LInteger( ipow(m_value, rhs) );
+		case Lua.OP_POW: return LInteger.valueOf( ipow(m_value, rhs) );
 		}
 		return luaUnsupportedOperation();
 	}
@@ -83,8 +100,7 @@ public class LInteger extends LNumber {
 
 	/** Arithmetic negative */
 	public LValue luaUnaryMinus() {
-		return new LInteger( -m_value );
+		return LInteger.valueOf( -m_value );
 	}
 
-
 }

src/main/java/lua/value/LString.java

@@ -256,7 +256,7 @@ public class LString extends LValue {
 		if ( base >= 2 && base <= 36 ) {
 			String str = toJavaString().trim();
 			try {
-				return new LInteger( Integer.parseInt( str, base ) );
+				return LInteger.valueOf( Integer.parseInt( str, base ) );
 			} catch ( NumberFormatException nfe ) {
 				if ( base == 10 ) {
 					try {
@@ -284,7 +284,7 @@ public class LString extends LValue {
 	
 	/** Built-in opcode LEN, for Strings and Tables */
 	public LValue luaLength() {
-		return new LInteger( length() );
+		return LInteger.valueOf( length() );
 	}
 
 	public LString luaGetType() {

src/main/java/lua/value/LTable.java

@@ -163,7 +163,7 @@ public class LTable extends LValue {
 		int slot = findSlot( key );
 		if ( fillHashSlot( slot, value ) )
 			return;
-		m_hashKeys[ slot ] = new LInteger( key );
+		m_hashKeys[ slot ] = LInteger.valueOf( key );
 	}
 	
 	
@@ -241,10 +241,10 @@ public class LTable extends LValue {
 		for ( int i = Math.max( 0, m_arrayEntries-1 ); i < m_vector.length; ++i ) {
 			if ( m_vector[i] != LNil.NIL &&
 					( i+1 == m_vector.length || m_vector[i+1] == LNil.NIL ) ) {
-				return new LInteger( i+1 );
+				return LInteger.valueOf( i+1 );
 			}
 		}
-		return new LInteger( 0 );
+		return LInteger.valueOf( 0 );
 	}
 	
 	/** Valid for tables */
@@ -289,7 +289,7 @@ public class LTable extends LValue {
 			int i;
 			while ( ( i = arrayIndex++ ) < m_vector.length ) {
 				if ( m_vector[i] != LNil.NIL ) {
-					vm.push( new LInteger( arrayIndex ) );
+					vm.push( LInteger.valueOf( arrayIndex ) );
 					vm.push( m_vector[ i ] );
 					return false;
 				}
@@ -319,7 +319,7 @@ public class LTable extends LValue {
 		
 		for ( int i = 0; i < m_vector.length; ++i ) {
 			if ( m_vector[ i ] != LNil.NIL ) {
-				keys[ out++ ] = new LInteger( i + 1 );
+				keys[ out++ ] = LInteger.valueOf( i + 1 );
 			}
 		}
 		
@@ -496,7 +496,7 @@ public class LTable extends LValue {
 					if (checkLoadFactor())
 						rehash();
 					final int slot = findSlot( i+1 );
-					m_hashKeys[ slot ] = new LInteger( i+1 );
+					m_hashKeys[ slot ] = LInteger.valueOf( i+1 );
 					m_hashValues[ slot ] = v;
 					++m_hashEntries;
 				}

src/test/java/lua/io/LoadStateTest.java

@@ -55,7 +55,7 @@ public class LoadStateTest extends TestCase {
 		int valueAsInt = (int) value;
 		
 		if ( value == (double) valueAsInt ) {
-			return new LInteger( valueAsInt );
+			return LInteger.valueOf( valueAsInt );
 		} else {
 			return new LDouble( value );
 		}

src/test/java/lua/value/LTableTest.java

@@ -48,7 +48,7 @@ public class LTableTest extends TestCase {
 		for ( int i = 0; i < 10; ++i ) {
 			LString str = new LString( String.valueOf( i ) );
 			t.put( i, str );
-			t.put( str, new LInteger( i ) );
+			t.put( str, LInteger.valueOf( i ) );
 		}
 		
 		assertTrue( t.getArrayCapacity() >= 9 ); // 1, 2, ..., 9
@@ -105,7 +105,7 @@ public class LTableTest extends TestCase {
 		t.put( "test", LNil.NIL );
 		assertEquals( 0, t.size() );
 		
-		t.put( 10, new LInteger( 5 ) );
+		t.put( 10, LInteger.valueOf( 5 ) );
 		t.put( 10, LNil.NIL );
 		assertEquals( 0, t.size() );
 	}
@@ -114,7 +114,7 @@ public class LTableTest extends TestCase {
 		LTable t = new LTable(0, 1);
 		
 		t.put( "test", new LString("foo") );
-		t.put( "string", new LInteger( 10 ) );
+		t.put( "string", LInteger.valueOf( 10 ) );
 		assertEquals( 2, t.size() );
 		
 		t.put( "string", LNil.NIL );
@@ -124,7 +124,7 @@ public class LTableTest extends TestCase {
 		t.put( "test", LNil.NIL );
 		assertEquals( 1, t.size() );
 		
-		t.put( 10, new LInteger( 5 ) );
+		t.put( 10, LInteger.valueOf( 5 ) );
 		assertEquals( 2, t.size() );
 		
 		t.put( 10, LNil.NIL );