~repos /gdx-studio

/*
 * 01/11/2010
 *
 * Copyright (C) 2011 Robert Futrell
 * robert_futrell at users.sourceforge.net
 * http://fifesoft.com/rsyntaxtextarea
 *
 * This library is distributed under a modified BSD license.  See the included
 * RSTALanguageSupport.License.txt file for details.
 */
package org.fife.rsta.ac.common;

import java.util.ArrayList;
import java.util.List;


/**
 * A block of code.  This can be used to implement <em>very</em> simple
 * parsing for languages that have some concept of code blocks, such as C,
 * Perl, Java, etc.  Currently, using <code>CodeBlock</code>s provides a
 * means of remembering where variables are defined, as well as their scopes.
 *
 * @author Robert Futrell
 * @version 1.0
 * @see VariableDeclaration
 */
public class CodeBlock {

  private int start;
  private int end;
  private CodeBlock parent;
  private List children;
  private List varDecs;


  /**
   * Constructor.
   *
   * @param start The starting offset of the code block.
   */
  public CodeBlock(int start) {
    this.start = start;
    end = Integer.MAX_VALUE;
  }


  /**
   * Creates and returns a child (nested) code block.
   *
   * @param start The starting offset of the nested code block.
   * @return The code block.
   */
  public CodeBlock addChildCodeBlock(int start) {
    CodeBlock child = new CodeBlock(start);
    child.parent = this;
    if (children==null) {
      children = new ArrayList();
    }
    children.add(child);
    return child;
  }


  /**
   * Adds a variable declaration.
   *
   * @param varDec The variable declaration.
   */
  public void addVariable(VariableDeclaration varDec) {
    if (varDecs==null) {
      varDecs = new ArrayList();
    }
    varDecs.add(varDec);
  }


  /**
   * Returns whether this code block contains a given offset.
   *
   * @param offset The offset.
   * @return Whether this code block contains that offset.
   */
  public boolean contains(int offset) {
    return offset>=start && offset<end;
  }


  /**
   * Returns a child code block.
   *
   * @param index The index of the child code block.
   * @return The child code block.
   * @see #getChildCodeBlockCount()
   */
  public CodeBlock getChildCodeBlock(int index) {
    return (CodeBlock)children.get(index);
  }


  /**
   * Returns the number of child code blocks.
   *
   * @return The child code block count.
   * @see #getChildCodeBlock(int)
   */
  public int getChildCodeBlockCount() {
    return children==null ? 0 : children.size();
  }


  /**
   * Returns the deepest code block nested under this one (or this one
   * itself) containing a given offset.
   *
   * @param offs The offset to look for.
   * @return The deepest-nested code block containing the offset, or
   *         <code>null</code> if this code block and none of its children
   *         contain the offset.
   */
  public CodeBlock getDeepestCodeBlockContaining(int offs) {
    if (!contains(offs)) {
      return null;
    }
    for (int i=0; i<getChildCodeBlockCount(); i++) {
      CodeBlock child = getChildCodeBlock(i);
      if (child.contains(offs)) {
        return child.getDeepestCodeBlockContaining(offs);
      }
    }
    return this;
  }


  /**
   * Returns the end offset of this code block.
   *
   * @return The end offset.
   * @see #getStartOffset()
   * @see #setEndOffset(int)
   */
  public int getEndOffset() {
    return end;
  }


  /**
   * Returns the parent code block.
   *
   * @return The parent code block, or <code>null</code> if there isn't one.
   */
  public CodeBlock getParent() {
    return parent;
  }


  /**
   * Returns the start offset of this code block.
   *
   * @return The start offset.
   * @see #getEndOffset()
   */
  public int getStartOffset() {
    return start;
  }


  /**
   * Returns a variable declaration.
   *
   * @param index The index of the declaration.
   * @return The declaration.
   * @see #getVariableDeclarationCount()
   */
  public VariableDeclaration getVariableDeclaration(int index) {
    return (VariableDeclaration)varDecs.get(index);
  }


  /**
   * Returns the number of variable declarations in this code block.
   *
   * @return The number of variable declarations.
   * @see #getVariableDeclaration(int)
   */
  public int getVariableDeclarationCount() {
    return varDecs==null ? 0 : varDecs.size();
  }


  /**
   * Returns all local variables declared before a given offset, both in
   * this code block and in all parent blocks.
   *
   * @param offs The offset.
   * @return The {@link VariableDeclaration}s, or an empty list of none were
   *         declared before the offset.
   */
  public List getVariableDeclarationsBefore(int offs) {

    List vars = new ArrayList();

    int varCount = getVariableDeclarationCount();
    for (int i=0; i<varCount; i++) {
      VariableDeclaration localVar = getVariableDeclaration(i);
      if (localVar.getOffset()<offs) {
        vars.add(localVar);
      }
      else {
        break;
      }
    }

    if (parent!=null) {
      vars.addAll(parent.getVariableDeclarationsBefore(offs));
    }

    return vars;

  }


  /**
   * Sets the end offset of this code block.
   *
   * @param end The end offset.
   * @see #getEndOffset()
   */
  public void setEndOffset(int end) {
    this.end = end;
  }


}