gcc/libjava/classpath/gnu/CORBA/GIOP/CodeSetServiceContext.java

/* CodeSet_sctx.java --
   Copyright (C) 2005 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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permission to link this library with independent modules to produce an
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package gnu.CORBA.GIOP;

import gnu.CORBA.CDR.AbstractCdrInput;
import gnu.CORBA.CDR.AbstractCdrOutput;
import gnu.CORBA.IOR;
import gnu.CORBA.IOR.CodeSets_profile;

import java.io.IOException;

/**
 * The code set service context. This context must be included in all
 * messages that use wide characters.
 *
 * @author Audrius Meskauskas (AudriusA@Bioinformatics.org)
 */
public class CodeSetServiceContext
  extends ServiceContext
{
  /**
   * The context code sets id.
   */
  public static final int ID = 1;

  /**
   * The standard component to include in the messages.
   */
  public static final CodeSetServiceContext STANDARD = new CodeSetServiceContext();

  /**
   * The encoding, used to transfer the narrow (1 byte) character data.
   * The default value is taken from {@link CharSets_OSF#NATIVE_CHARACTER}.
   */
  public int char_data = CharSets_OSF.NATIVE_CHARACTER;

  /**
   * The encoding, used to transfer the wide character data.
   * The default value is taken from
   * {@link CharSets_OSF#NATIVE_WIDE_CHARACTER}.
   */
  public int wide_char_data = CharSets_OSF.NATIVE_WIDE_CHARACTER;

  /**
   * Find and return the code set service context in the give
   * contexts array. Returns {@link #STANDARD} if no code set
   * context is present.
   *
   * @param contexts the array of contexts, can be null.
   */
  public static CodeSetServiceContext find(ServiceContext[] contexts)
  {
    if (contexts != null)
      for (int i = 0; i < contexts.length; i++)
        {
          if (contexts [ i ] instanceof CodeSetServiceContext)
            return (CodeSetServiceContext) contexts [ i ];
        }
    return STANDARD;
  }

  /**
   * Select the suitable encoding that is defined in the provided profile.
   *
   * TODO character encoding. Now the encoding can be set, but it is ignored.
   * If you take this task, scan 'TODO character encoding' for
   * relevant places.
   */
  public static CodeSetServiceContext negotiate(IOR.CodeSets_profile profile)
  {
    if (profile.negotiated != null)
      return profile.negotiated;

    CodeSetServiceContext use = new CodeSetServiceContext();

    use.char_data =
      negotiate(profile.narrow, STANDARD.char_data, CharSets_OSF.ISO8859_1);

    use.wide_char_data =
      negotiate(profile.wide, STANDARD.wide_char_data, CharSets_OSF.UTF16);

    profile.negotiated = use;

    return use;
  }

  /**
   * Read the context from the given stream. Does not read the
   * code sets id.
   */
  public void readContext(AbstractCdrInput input)
  {
    AbstractCdrInput encap = input.read_encapsulation();

    char_data = encap.read_ulong();
    wide_char_data = encap.read_ulong();
  }

  /**
   * Return a string representation.
   */
  public String toString()
  {
    return " Encoding: narrow " + name(char_data) + ", wide " +
           name(wide_char_data) + ". ";
  }

  /**
   * Write the context to the given stream, including the code
   * sets id.
   */
  public void write(AbstractCdrOutput output)
  {
    output.write_ulong(ID);

    AbstractCdrOutput enout = output.createEncapsulation();

    enout.write_long(char_data);
    enout.write_ulong(wide_char_data);

    try
      {
        enout.close();
      }
    catch (IOException ex)
      {
        InternalError t = new InternalError();
        t.initCause(ex);
        throw t;
      }
  }

  /**
   * Negotiate about the character encoding. Prefer our native encoding,
   * if no, prefer IORs native encoding, if no, find any encoding,
   * supported by both sides, if no, return the specified final decission.
   *
   * @param profile the component profile in IOR.
   * @param our_native our native encoding
   * @param final_decission the encoding that must be returned if no
   * compromise is found.
   *
   * @return the resulted encoding.
   */
  protected static int negotiate(IOR.CodeSets_profile.CodeSet_component profile,
                                 int our_native, int final_decission
                                )
  {
    // If our and IORs native sets match, use the native set.
    if (profile.native_set == our_native)
      return our_native;

    // If the native sets do not match, but the IOR says it
    // supports our native set, use our native set.
    if (profile.conversion != null)
      for (int i = 0; i < profile.conversion.length; i++)
        {
          if (our_native == profile.conversion [ i ])
            return our_native;
        }

    // At this point, we suggest to use the IORs native set.
    int[] allSupported = CharSets_OSF.getSupportedCharSets();

    for (int s = 0; s < allSupported.length; s++)
      if (allSupported [ s ] == profile.native_set)
        return profile.native_set;

    // Any compromise left?
    if (profile.conversion != null)
      for (int s = 0; s < allSupported.length; s++)
        for (int i = 0; i < profile.conversion.length; i++)
          if (allSupported [ s ] == profile.conversion [ i ])
            return allSupported [ s ];

    // Return the CORBA default char encoding.
    return final_decission;
  }

  /**
   * Conveniency method, used in toString()
   */
  private String name(int set)
  {
    return "0x" + Integer.toHexString(set) + " (" + CharSets_OSF.getName(set) +
           ") ";
  }
}