feat(objectionary#376): add a few puzzles

src/main/java/org/eolang/opeo/decompilation/DecompilerState.java

@@ -24,15 +24,12 @@
 package org.eolang.opeo.decompilation;
 
 import java.util.Deque;
-import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.Optional;
-import javax.swing.text.html.Option;
 import lombok.EqualsAndHashCode;
 import lombok.ToString;
 import org.eolang.opeo.ast.AstNode;
 import org.eolang.opeo.ast.Opcode;
-import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.Type;
 
 /**
@@ -44,6 +41,11 @@
 @EqualsAndHashCode
 public final class DecompilerState {
 
+    /**
+     * Remaining opcodes.
+     * Each method has an original list of opcodes which we decompile.
+     * When some agent decompiles an instruction, it removes it from this list.
+     */
     private final Deque<Opcode> opcodes;
 
     /**
@@ -74,6 +76,12 @@ public DecompilerState(final OperandStack operands, final LocalVariables vars) {
         this(new LinkedList<>(), operands, vars);
     }
 
+    /**
+     * Constructor.
+     * @param opcodes Remaining opcodes.
+     * @param stack Operand stack.
+     * @param vars Method local variables.
+     */
     public DecompilerState(
         final Deque<Opcode> opcodes,
         final OperandStack stack,
@@ -84,52 +92,39 @@ public DecompilerState(
         this.vars = vars;
     }
 
+    /**
+     * Retrieve current bytecode instruction.
+     * @return Current bytecode instruction.
+     */
+    public Opcode instruction() {
+        return Optional.ofNullable(this.opcodes.peek()).orElse(new Opcode(-1));
+    }
+
+    /**
+     * Check if there are any instructions left.
+     * @return True if there are instructions left.
+     */
     public boolean hasInstructions() {
         return !this.opcodes.isEmpty();
     }
 
-    public void move() {
+    /**
+     * Remove current instruction from the list.
+     * This is used when we decompile an instruction.
+     */
+    public void decompileInstruction() {
         if (!this.opcodes.isEmpty()) {
             this.opcodes.pop();
         }
     }
 
-    /**
-     * Retrieve current bytecode instruction.
-     * @return Current bytecode instruction.
-     */
-    public Opcode instruction() {
-        return Optional.ofNullable(this.opcodes.peek()).orElse(new Opcode(-100));
-//        final Iterator<AstNode> iterator = this.stack().iterator();
-//        while (iterator.hasNext()) {
-//            final AstNode next = iterator.next();
-//            if (next instanceof Opcode) {
-//                return (Opcode) next;
-//            }
-//        }
-//        throw new IllegalStateException(
-//            "No opcode found in the stack"
-//        );
-//        return (Opcode) this.stack().peek();
-    }
-
     /**
      * Instruction operand.
      * @param index Operand index.
      * @return Instruction operand.
      */
     public Object operand(final int index) {
         return this.instruction().operand(index);
-//        if (this.current.operands().size() <= index) {
-//            throw new IllegalStateException(
-//                String.format(
-//                    "Instruction '%s' doesn't have operand at index '%d'",
-//                    this.current,
-//                    index
-//                )
-//            );
-//        }
-//        return this.current.operand(index);
     }
 
     /**

src/main/java/org/eolang/opeo/decompilation/agents/AddAgent.java

@@ -54,7 +54,7 @@ public void handle(final DecompilerState state) {
             final AstNode right = state.stack().pop();
             final AstNode left = state.stack().pop();
             state.stack().push(new Addition(left, right));
-            state.move();
+            state.decompileInstruction();
         }
     }
 

src/main/java/org/eolang/opeo/decompilation/agents/AllAgents.java

@@ -32,12 +32,22 @@
 import org.eolang.opeo.decompilation.DecompilerState;
 import org.eolang.opeo.decompilation.DecompilationAgent;
 import org.objectweb.asm.Opcodes;
-import org.objectweb.asm.Type;
 
 /**
  * All agents that try to decompile incoming instructions.
  * @since 0.2
  * @checkstyle ClassFanOutComplexityCheck (500 lines)
+ * @todo #376:90min Decompilation Finish Condition.
+ *  Currently we decompile until we out of instructions.
+ *  But this might be incorrect when we start decompile high-level constructs.
+ *  We should check decompilation stack instead.
+ *  If it changes, we should continue. Otherwise, we should stop.
+ *  The current implementation you can find here {@link #handle(DecompilerState)}.
+ * @todo #376:90min Unsupported Opcodes.
+ *  Currently we have the ugly map {@link #agents} that contains instructions we can handle.
+ *  We should refactor it to a more elegant solution.
+ *  For example, each agent might provide a list of instructions it can decompile.
+ *  By doing this we can infer the entire list of supported and unsupported instructions.
  */
 public final class AllAgents implements DecompilationAgent {
 
@@ -142,15 +152,9 @@ private AllAgents(final Map<Integer, DecompilationAgent> agents) {
 
     @Override
     public void handle(final DecompilerState state) {
-        //todo: until?
         while (state.hasInstructions()) {
             this.agents.values().forEach(agent -> agent.handle(state));
-//            state.move();
         }
-//        do {
-//            hash = state.hashCode();
-//        } while (hash != state.hashCode());
-//        this.agent(state.instruction().opcode()).handle(state);
     }
 
     /**
@@ -165,15 +169,6 @@ public String[] supportedOpcodes() {
             .toArray(String[]::new);
     }
 
-    /**
-     * Get instruction handler.
-     * @param opcode Instruction opcode.
-     * @return Instruction handler.
-     */
-//    private DecompilationAgent agent(final int opcode) {
-//        return this.agents.getOrDefault(opcode, this.agents.get(AllAgents.UNIMPLEMENTED));
-//    }
-
     /**
      * Unimplemented instruction handler.
      * @since 0.1
@@ -203,8 +198,7 @@ public void handle(final DecompilerState state) {
                         this.counting
                     )
                 );
-                state.move();
-
+                state.decompileInstruction();
             }
         }
     }

src/main/java/org/eolang/opeo/decompilation/agents/BipushAgent.java

@@ -47,7 +47,7 @@ public final class BipushAgent implements DecompilationAgent {
     public void handle(final DecompilerState state) {
         if (BipushAgent.SUPPORTED.contains(state.instruction().opcode())) {
             state.stack().push(new Literal(state.operand(0)));
-            state.move();
+            state.decompileInstruction();
         }
     }
 

src/main/java/org/eolang/opeo/decompilation/agents/CastAgent.java

@@ -27,8 +27,8 @@
 import java.util.HashSet;
 import java.util.Set;
 import org.eolang.opeo.ast.Cast;
-import org.eolang.opeo.decompilation.DecompilerState;
 import org.eolang.opeo.decompilation.DecompilationAgent;
+import org.eolang.opeo.decompilation.DecompilerState;
 import org.objectweb.asm.Type;
 
 /**
@@ -37,6 +37,9 @@
  */
 public final class CastAgent implements DecompilationAgent {
 
+    /**
+     * Supported opcodes.
+     */
     private static final Set<Integer> SUPPROTED = new HashSet<>(
         Arrays.asList(
             org.objectweb.asm.Opcodes.I2B,
@@ -67,34 +70,47 @@ public void handle(final DecompilerState state) {
                     state.stack().pop()
                 )
             );
-            state.move();
+            state.decompileInstruction();
         }
     }
 
+    /**
+     * Target type.
+     * @param opcode Opcode to handle.
+     * @return Target type.
+     */
     private static Type target(final int opcode) {
+        final Type result;
         switch (opcode) {
             case org.objectweb.asm.Opcodes.I2B:
-                return Type.BYTE_TYPE;
+                result = Type.BYTE_TYPE;
+                break;
             case org.objectweb.asm.Opcodes.I2C:
-                return Type.CHAR_TYPE;
+                result = Type.CHAR_TYPE;
+                break;
             case org.objectweb.asm.Opcodes.I2S:
-                return Type.SHORT_TYPE;
+                result = Type.SHORT_TYPE;
+                break;
             case org.objectweb.asm.Opcodes.I2L:
             case org.objectweb.asm.Opcodes.F2L:
             case org.objectweb.asm.Opcodes.D2L:
-                return Type.LONG_TYPE;
+                result = Type.LONG_TYPE;
+                break;
             case org.objectweb.asm.Opcodes.I2F:
             case org.objectweb.asm.Opcodes.L2F:
             case org.objectweb.asm.Opcodes.D2F:
-                return Type.FLOAT_TYPE;
+                result = Type.FLOAT_TYPE;
+                break;
             case org.objectweb.asm.Opcodes.I2D:
             case org.objectweb.asm.Opcodes.L2D:
             case org.objectweb.asm.Opcodes.F2D:
-                return Type.DOUBLE_TYPE;
+                result = Type.DOUBLE_TYPE;
+                break;
             case org.objectweb.asm.Opcodes.L2I:
             case org.objectweb.asm.Opcodes.F2I:
             case org.objectweb.asm.Opcodes.D2I:
-                return Type.INT_TYPE;
+                result = Type.INT_TYPE;
+                break;
             default:
                 throw new IllegalArgumentException(
                     String.format(
@@ -103,5 +119,6 @@ private static Type target(final int opcode) {
                     )
                 );
         }
+        return result;
     }
 }

src/main/java/org/eolang/opeo/decompilation/agents/CheckCastAgent.java

@@ -52,7 +52,7 @@ public void handle(final DecompilerState state) {
             final AstNode value = state.stack().pop();
             final Object type = state.operand(0);
             state.stack().push(new CheckCast(Type.getObjectType((String) type), value));
-            state.move();
+            state.decompileInstruction();
         }
     }
 }

src/main/java/org/eolang/opeo/decompilation/agents/ConstAgent.java

@@ -26,13 +26,11 @@
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
-import org.eolang.opeo.SelectiveDecompiler;
 import org.eolang.opeo.ast.AstNode;
 import org.eolang.opeo.ast.Literal;
 import org.eolang.opeo.decompilation.DecompilerState;
 import org.eolang.opeo.decompilation.DecompilationAgent;
 import org.objectweb.asm.Opcodes;
-import org.objectweb.asm.Type;
 
 /**
  * Iconst instruction handler.
@@ -92,7 +90,7 @@ public void handle(final DecompilerState state) {
                     state.stack().push(res);
                     break;
             }
-            state.move();
+            state.decompileInstruction();
         }
 
     }

src/main/java/org/eolang/opeo/decompilation/agents/DupAgent.java

@@ -49,7 +49,7 @@ public void handle(final DecompilerState state) {
         if (DupAgent.SUPPORTED.contains(state.instruction().opcode())) {
             final OperandStack stack = state.stack();
             stack.push(new Duplicate(stack.pop()));
-            state.move();
+            state.decompileInstruction();
         }
     }
 

src/main/java/org/eolang/opeo/decompilation/agents/GetFieldAgent.java

@@ -51,7 +51,7 @@ public void handle(final DecompilerState state) {
                         .type("field")
                 )
             );
-            state.move();
+            state.decompileInstruction();
         }
     }
 

src/main/java/org/eolang/opeo/decompilation/agents/GetStaticAgent.java

@@ -40,7 +40,7 @@ public void handle(final DecompilerState state) {
             final String method = (String) state.operand(1);
             final String descriptor = (String) state.operand(2);
             state.stack().push(new ClassField(klass, method, descriptor));
-            state.move();
+            state.decompileInstruction();
         }
     }
 }

src/main/java/org/eolang/opeo/decompilation/agents/IfAgent.java

@@ -57,7 +57,7 @@ public void handle(final DecompilerState state) {
             final AstNode first = stack.pop();
             final Label operand = (Label) state.operand(0);
             stack.push(new If(first, second, operand));
-            state.move();
+            state.decompileInstruction();
         }
     }
 }

src/main/java/org/eolang/opeo/decompilation/agents/InvokedynamicAgent.java

@@ -54,7 +54,7 @@ public void handle(final DecompilerState state) {
                 args
             );
             state.stack().push(node);
-            state.move();
+            state.decompileInstruction();
         }
     }
 

src/main/java/org/eolang/opeo/decompilation/agents/InvokeinterfaceAgent.java

@@ -73,7 +73,7 @@ public void handle(final DecompilerState state) {
                     args
                 )
             );
-            state.move();
+            state.decompileInstruction();
         }
     }
 }

src/main/java/org/eolang/opeo/decompilation/agents/InvokespecialAgent.java

@@ -103,7 +103,7 @@ public void handle(final DecompilerState state) {
                     new Super(target, args, descriptor, type, name)
                 );
             }
-            state.move();
+            state.decompileInstruction();
         }
     }
 

src/main/java/org/eolang/opeo/decompilation/agents/InvokestaticAgent.java

@@ -60,7 +60,7 @@ public void handle(final DecompilerState state) {
                     args
                 )
             );
-            state.move();
+            state.decompileInstruction();
         }
     }
 }

src/main/java/org/eolang/opeo/decompilation/agents/InvokevirtualAgent.java

@@ -73,7 +73,7 @@ public void handle(final DecompilerState state) {
                     args
                 )
             );
-            state.move();
+            state.decompileInstruction();
         }
     }
 }

src/main/java/org/eolang/opeo/decompilation/agents/LabelAgent.java

@@ -43,7 +43,7 @@ public void handle(final DecompilerState state) {
                 new Label(String.class.cast(state.operand(0)))
             );
             state.stack().push(node);
-            state.move();
+            state.decompileInstruction();
         }
     }
 }