ben/brouter
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions 1

initial commit of BRouter Version 0.98

Browse source
This commit is contained in:
Arndt Brenschede 2014-01-18 15:29:05 +01:00
parent e4ae2b37d3
commit 91e62f1164
120 changed files with 15382 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

173
brouter-expressions/src/main/java/btools/expressions/BExpression.java Normal file
View file

@ -0,0 +1,173 @@
package btools.expressions;
final class BExpression
{
private static final int OR_EXP = 10;
private static final int AND_EXP = 11;
private static final int NOT_EXP = 12;
private static final int ADD_EXP = 20;
private static final int MULTIPLY_EXP = 21;
private static final int MAX_EXP = 22;
private static final int SWITCH_EXP = 30;
private static final int ASSIGN_EXP = 31;
private static final int LOOKUP_EXP = 32;
private static final int NUMBER_EXP = 33;
private static final int VARIABLE_EXP = 34;
private static final int DUMPPOS_EXP = 40;
private int typ;
private BExpression op1;
private BExpression op2;
private BExpression op3;
private float numberValue;
private int variableIdx;
private int lookupNameIdx;
private int lookupValueIdx;
// Parse the expression and all subexpression
public static BExpression parse( BExpressionContext ctx, int level ) throws Exception
{
String operator = ctx.parseToken();
if ( operator == null )
{
if ( level == 0 ) return null;
else throw new IllegalArgumentException( "unexpected end of file" );
}
if ( level == 0 )
{
if ( !"assign".equals( operator ) )
{
throw new IllegalArgumentException( "operator " + operator + " is invalid on toplevel (only 'assign' allowed)" );
}
}
BExpression exp = new BExpression();
int nops = 3;
if ( "switch".equals( operator ) )
{
exp.typ = SWITCH_EXP;
}
else
{
nops = 2; // check binary expressions
if ( "or".equals( operator ) )
{
exp.typ = OR_EXP;
}
else if ( "and".equals( operator ) )
{
exp.typ = AND_EXP;
}
else if ( "multiply".equals( operator ) )
{
exp.typ = MULTIPLY_EXP;
}
else if ( "add".equals( operator ) )
{
exp.typ = ADD_EXP;
}
else if ( "max".equals( operator ) )
{
exp.typ = MAX_EXP;
}
else
{
nops = 1; // check unary expressions
if ( "assign".equals( operator ) )
{
if ( level > 0 ) throw new IllegalArgumentException( "assign operator within expression" );
exp.typ = ASSIGN_EXP;
String variable = ctx.parseToken();
if ( variable == null ) throw new IllegalArgumentException( "unexpected end of file" );
exp.variableIdx = ctx.getVariableIdx( variable, true );
if ( exp.variableIdx < ctx.getMinWriteIdx() ) throw new IllegalArgumentException( "cannot assign to readonly variable " + variable );
}
else if ( "not".equals( operator ) )
{
exp.typ = NOT_EXP;
}
else if ( "dumppos".equals( operator ) )
{
exp.typ = DUMPPOS_EXP;
}
else
{
nops = 0; // check elemantary expressions
int idx = operator.indexOf( '=' );
if ( idx >= 0 )
{
exp.typ = LOOKUP_EXP;
String name = operator.substring( 0, idx );
String value = operator.substring( idx+1 );
exp.lookupNameIdx = ctx.getLookupNameIdx( name );
if ( exp.lookupNameIdx < 0 )
{
throw new IllegalArgumentException( "unknown lookup name: " + name );
}
exp.lookupValueIdx = ctx.getLookupValueIdx( exp.lookupNameIdx, value );
if ( exp.lookupValueIdx < 0 )
{
throw new IllegalArgumentException( "unknown lookup value: " + value );
}
}
else if ( (idx = ctx.getVariableIdx( operator, false )) >= 0 )
{
exp.typ = VARIABLE_EXP;
exp.variableIdx = idx;
}
else
{
try
{
exp.numberValue = Float.parseFloat( operator );
exp.typ = NUMBER_EXP;
}
catch( NumberFormatException nfe )
{
throw new IllegalArgumentException( "unknown expression: " + operator );
}
}
}
}
}
// parse operands
if ( nops > 0 ) exp.op1 = BExpression.parse( ctx, level+1 );
if ( nops > 1 ) exp.op2 = BExpression.parse( ctx, level+1 );
if ( nops > 2 ) exp.op3 = BExpression.parse( ctx, level+1 );
return exp;
}
// Evaluate the expression
public float evaluate( BExpressionContext ctx )
{
switch( typ )
{
case OR_EXP: return op1.evaluate(ctx) != 0.f ? 1.f : ( op2.evaluate(ctx) != 0.f ? 1.f : 0.f );
case AND_EXP: return op1.evaluate(ctx) != 0.f ? ( op2.evaluate(ctx) != 0.f ? 1.f : 0.f ) : 0.f;
case ADD_EXP: return op1.evaluate(ctx) + op2.evaluate(ctx);
case MULTIPLY_EXP: return op1.evaluate(ctx) * op2.evaluate(ctx);
case MAX_EXP: return max( op1.evaluate(ctx), op2.evaluate(ctx) );
case SWITCH_EXP: return op1.evaluate(ctx) != 0.f ? op2.evaluate(ctx) : op3.evaluate(ctx);
case ASSIGN_EXP: return ctx.assign( variableIdx, op1.evaluate(ctx) );
case LOOKUP_EXP: return ctx.getLookupMatch( lookupNameIdx, lookupValueIdx );
case NUMBER_EXP: return numberValue;
case VARIABLE_EXP: return ctx.getVariableValue( variableIdx );
case NOT_EXP: return op1.evaluate(ctx) == 0.f ? 1.f : 0.f;
case DUMPPOS_EXP: ctx.expressionWarning( "INFO" ); return op1.evaluate(ctx);
default: throw new IllegalArgumentException( "unknown op-code: " + typ );
}
}
private float max( float v1, float v2 )
{
return v1 > v2 ? v1 : v2;
}
}