Improve math lib argument type checking.

src/core/org/luaj/lib/MathLib.java

@@ -88,37 +88,64 @@ public class MathLib extends LFunction {
 		vm.pushlvalue( value );
 	}
 	
+	private static void setResult( LuaState vm, double d ) {
+		vm.resettop();
+		vm.pushlvalue( LDouble.valueOf(d) );
+	}
+	
+	private static void setResult( LuaState vm, int i ) {
+		vm.resettop();
+		vm.pushlvalue( LInteger.valueOf(i) );
+	}
+	
 	public boolean luaStackCall( LuaState vm ) {
+		double x;
 		switch ( id ) {
 		case INSTALL:
 			install( vm._G );
 			break;
 		case ABS:
-			setResult( vm, abs( vm.topointer( 2 ) ) );
+			setResult( vm, Math.abs (  vm.checkdouble(2) ) );
 			break;
 		case COS:
-			setResult( vm, new LDouble( Math.cos ( vm.tonumber(2) ) ) );
+			setResult( vm, Math.cos ( vm.checkdouble(2) ) );
 			break;
-		case MAX:
+		case MAX: {
-			setResult( vm, max( vm.topointer(2), vm.topointer(3) ) );
+			int n = vm.gettop();
+			x = vm.checkdouble(2);
+			for ( int i=3; i<=n; i++ )
+				x = Math.max(x, vm.checkdouble(i));
+			setResult( vm, x );
 			break;
-		case MIN:
+		}
-			setResult( vm, min( vm.topointer(2), vm.topointer(3) ) );
+		case MIN: {
+			int n = vm.gettop();
+			x = vm.checkdouble(2);
+			for ( int i=3; i<=n; i++ )
+				x = Math.min(x, vm.checkdouble(i));
+			setResult(vm,x);
 			break;
-		case MODF:
+		}
-			modf( vm );
+		case MODF: {
+			double v = vm.checkdouble(2);
+			double intPart = ( v > 0 ) ? Math.floor( v ) : Math.ceil( v );
+			double fracPart = v - intPart;
+			vm.resettop();
+			vm.pushnumber( intPart );
+			vm.pushnumber( fracPart );
 			break;
+		}
 		case SIN:
-			setResult( vm, new LDouble( Math.sin( vm.tonumber(2) ) ) );
+			setResult( vm, Math.sin( vm.checkdouble(2) ) );
 			break;
 		case SQRT:
-			setResult( vm, new LDouble( Math.sqrt( vm.tonumber(2) ) ) );
+			setResult( vm, Math.sqrt( vm.checkdouble(2) ) );
 			break;
 		case CEIL:
-			setResult( vm, LInteger.valueOf( (int) Math.ceil( vm.tonumber(2) ) ) );
+			setResult( vm, (int) Math.ceil( vm.checkdouble(2) ) );
 			break;
 		case FLOOR:
-			setResult( vm, LInteger.valueOf( (int) Math.floor( vm.tonumber(2) ) ) );
+			setResult( vm, (int) Math.floor( vm.checkdouble(2) ) );
 			break;
 		case RANDOM: {
 			if ( random == null )
@@ -129,14 +156,16 @@ public class MathLib extends LFunction {
 				vm.pushnumber(random.nextDouble());
 				break;
 			case 2: {
-				int m = vm.tointeger(2);
+				int m = vm.checkint(2);
+				vm.argcheck(1<=m, 1, "interval is empty");
 				vm.resettop();
 				vm.pushinteger(1+random.nextInt(m));
 				break;
 			}
 			default: {
-				int m = vm.tointeger(2);
+				int m = vm.checkint(2);
-				int n = vm.tointeger(3);
+				int n = vm.checkint(3);
+				vm.argcheck(m<=n, 2, "interval is empty");
 				vm.resettop();
 				vm.pushinteger(m+random.nextInt(n+1-m));
 				break;
@@ -145,7 +174,7 @@ public class MathLib extends LFunction {
 			break;
 		}
 		case RANDOMSEED:
-			random = new Random( vm.tointeger(2) );
+			random = new Random( vm.checkint(2) );
 			vm.resettop();
 			break;
 		default:
@@ -153,27 +182,5 @@ public class MathLib extends LFunction {
 		}
 		return false;
 	}
-	private LValue abs( final LValue v ) {
-		LValue nv = v.luaUnaryMinus();
-		return max( v, nv );
-	}
-	
-	private LValue max( LValue lhs, LValue rhs ) {
-		return rhs.luaBinCmpUnknown( Lua.OP_LT, lhs ) ? rhs: lhs;
-	}
-	
-	private LValue min( LValue lhs, LValue rhs ) {
-		return rhs.luaBinCmpUnknown( Lua.OP_LT, lhs ) ? lhs: rhs;
-	}
-	
-	private void modf( LuaState vm ) {
-		LValue arg = vm.topointer(2);
-		double v = arg.toJavaDouble();
-		double intPart = ( v > 0 ) ? Math.floor( v ) : Math.ceil( v );
-		double fracPart = v - intPart;
-		vm.resettop();
-		vm.pushnumber( intPart );
-		vm.pushnumber( fracPart );
-	}
 	
 }

src/core/org/luaj/vm/LuaState.java

@@ -2617,23 +2617,30 @@ public class LuaState extends Lua {
 	/**
 	 * Report an error with an argument.
 	 * 
-	 * @param narg
+	 * @param narg Stack index of the bad argument
-	 *            Stack index of the bad argument
+	 * @param extramsg String to include in error message
-	 * @param extramsg
-	 *            String to include in error message
 	 */
     public void argerror(int narg, String extramsg) {
-        // TODO: port ldebug.c and provide mode useful error messages.
         error("bad argument #" + (narg - 1) + " (" + extramsg + ")");
     }
 
+	/**
+	 * Conditionally report an error with an argument.
+	 * 
+	 * @param cond boolean condition that generates an error when false
+	 * @param narg Stack index of the bad argument
+	 * @param extramsg String to include in error message
+	 */
+	public void argcheck(boolean cond, int narg, String extramsg) {
+		if ( ! cond )
+			argerror(narg,extramsg);		
+	}
+	
 	/**
      * Report a type error.
      * 
-     * @param narg
+     * @param narg Stack index of the bad argument
-     *            Stack index of the bad argument
+     * @param typename Name of the type that was expected, such as "string"
-     * @param typename
-     *            Name of the type that was expected
      */
     public void typerror(int narg, String typename) {
         argerror(narg, typename + " expected, got " + typename(narg));
@@ -2642,11 +2649,8 @@ public class LuaState extends Lua {
     /**
      * Report a type error.
      * 
-     * @param narg
+     * @param narg Stack index of the bad argument
-     *            Stack index of the bad argument
+     * @param typenum Constant value specifying the type of argument that was expected (i.e. LUA_TSTRING).
-     * @param typenum
-     *            Constant value specifying the type of argument that was
-     *            expected (i.e. LUA_TSTRING).
      */
     public void typerror(int narg, int typenum) {
         typerror(narg, TYPE_NAMES[typenum]);
@@ -2713,6 +2717,17 @@ public class LuaState extends Lua {
 		return checknumber(narg).toJavaLong();
 	}
 	
+	/**
+	 * Checks whether the function argument <code>narg</code> is a number and
+	 * returns this number cast to a <code>double</code>.
+	 * @param narg the argument number
+	 * @throws LuaErrorException if the value cannot be converted to a double
+	 * @return long value if the argument is a number or can be converted to double
+	 */
+	public double checkdouble(int narg) {
+		return checknumber(narg).toJavaDouble();
+	}
+	
 	/**
 	 * Checks whether the function argument <code>narg</code> is a number and
 	 * returns this number.