audacity/lib-src/redland/librdf/rdf_statement.c

/* -*- Mode: c; c-basic-offset: 2 -*-
 *
 * rdf_statement.c - RDF Triple (Statement) interface
 *
 * Copyright (C) 2000-2008, David Beckett http://www.dajobe.org/
 * Copyright (C) 2000-2005, University of Bristol, UK http://www.bristol.ac.uk/
 * 
 * This package is Free Software and part of Redland http://librdf.org/
 * 
 * It is licensed under the following three licenses as alternatives:
 *   1. GNU Lesser General Public License (LGPL) V2.1 or any newer version
 *   2. GNU General Public License (GPL) V2 or any newer version
 *   3. Apache License, V2.0 or any newer version
 * 
 * You may not use this file except in compliance with at least one of
 * the above three licenses.
 * 
 * See LICENSE.html or LICENSE.txt at the top of this package for the
 * complete terms and further detail along with the license texts for
 * the licenses in COPYING.LIB, COPYING and LICENSE-2.0.txt respectively.
 * 
 * 
 */


#ifdef HAVE_CONFIG_H
#include <rdf_config.h>
#endif

#ifdef WIN32
#include <win32_rdf_config.h>
#endif

#include <stdio.h>
#include <string.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h> /* for abort() as used in errors */
#endif

#include <redland.h>


#ifndef STANDALONE

/* class methods */

/**
 * librdf_init_statement:
 * @world: redland world object
 *
 * INTERNAL - Initialise the statement module.
 *
 **/
void
librdf_init_statement(librdf_world *world) 
{
}


/**
 * librdf_finish_statement:
 * @world: redland world object
 *
 * INTERNAL - Terminate the statement module.
 *
 **/
void
librdf_finish_statement(librdf_world *world) 
{
}


/**
 * librdf_new_statement:
 * @world: redland world object
 *
 * Constructor - create a new empty #librdf_statement.
 * 
 * Return value: a new #librdf_statement or NULL on failure
 **/
librdf_statement*
librdf_new_statement(librdf_world *world) 
{
  librdf_statement* new_statement;

  librdf_world_open(world);

  new_statement=(librdf_statement*)LIBRDF_CALLOC(librdf_statement, 1, 
                                                 sizeof(librdf_statement));
  if(!new_statement)
    return NULL;

  new_statement->world=world;

  return new_statement;
}


/**
 * librdf_new_statement_from_statement:
 * @statement: #librdf_statement to copy
 *
 * Copy constructor - create a new librdf_statement from an existing librdf_statement.
 * 
 * Return value: a new #librdf_statement with copy or NULL on failure
 **/
librdf_statement*
librdf_new_statement_from_statement(librdf_statement* statement)
{
  librdf_statement* new_statement;

  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, NULL);

  if(!statement)
    return NULL;
  
  new_statement = librdf_new_statement(statement->world);
  if(!new_statement)
    return NULL;

  if(statement->subject) {
    new_statement->subject=librdf_new_node_from_node(statement->subject);
    if(!new_statement->subject) {
      librdf_free_statement(new_statement);
      return NULL;
    }
  }
  if(statement->predicate) {
    new_statement->predicate=librdf_new_node_from_node(statement->predicate);
    if(!new_statement->predicate) {
      librdf_free_statement(new_statement);
      return NULL;
    }
  }
  if(statement->object) {
    new_statement->object=librdf_new_node_from_node(statement->object);
    if(!new_statement->object) {
      librdf_free_statement(new_statement);
      return NULL;
    }
  }

  return new_statement;
}


/**
 * librdf_new_statement_from_nodes:
 * @world: redland world object
 * @subject: #librdf_node
 * @predicate: #librdf_node
 * @object: #librdf_node
 *
 * Constructor - create a new #librdf_statement from existing #librdf_node objects.
 * 
 * The node objects become owned by the new statement (or freed on error).
 *
 * Return value: a new #librdf_statement with copy or NULL on failure
 **/
librdf_statement*
librdf_new_statement_from_nodes(librdf_world *world, 
                                librdf_node* subject,
                                librdf_node* predicate,
                                librdf_node* object)
{
  librdf_statement* new_statement;

  librdf_world_open(world);

  new_statement = librdf_new_statement(world);
  if(!new_statement) {
    if(subject)
      librdf_free_node(subject);
    if(predicate)
      librdf_free_node(predicate);
    if(object)
      librdf_free_node(object);
    return NULL;
  }
  
  new_statement->subject=subject;
  new_statement->predicate=predicate;
  new_statement->object=object;

  return new_statement;
}


/**
 * librdf_statement_init:
 * @world: redland world object
 * @statement: #librdf_statement object
 *
 * Initialise a statically declared librdf_statement.
 * 
 * This MUST be called on a statically declared librdf_statement
 * to initialise it properly.  It is the responsibility of the
 * user of the statically allocated librdf_statement to deal
 * with deallocation of any statement parts (subject, predicate, object).
 **/
void
librdf_statement_init(librdf_world *world, librdf_statement *statement)
{
  librdf_world_open(world);

  LIBRDF_ASSERT_OBJECT_POINTER_RETURN(statement, librdf_statement);

  statement->world=world;
  statement->subject=NULL;
  statement->predicate=NULL;
  statement->object=NULL;
}


/**
 * librdf_statement_clear:
 * @statement: #librdf_statement object
 *
 * Empty a librdf_statement of nodes.
 * 
 **/
void
librdf_statement_clear(librdf_statement *statement)
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN(statement, librdf_statement);

  if(statement->subject) {
    librdf_free_node(statement->subject);
    statement->subject=NULL;
  }
  if(statement->predicate) {
    librdf_free_node(statement->predicate);
    statement->predicate=NULL;
  }
  if(statement->object) {
    librdf_free_node(statement->object);
    statement->object=NULL;
  }
}


/**
 * librdf_free_statement:
 * @statement: #librdf_statement object
 *
 * Destructor - destroy a #librdf_statement.
 * 
 **/
void
librdf_free_statement(librdf_statement* statement)
{
#ifdef WITH_THREADS
  librdf_world *world;
#endif

  LIBRDF_ASSERT_OBJECT_POINTER_RETURN(statement, librdf_statement);

#ifdef WITH_THREADS
  world = statement->world;
  pthread_mutex_lock(world->statements_mutex);
#endif

  librdf_statement_clear(statement);

#ifdef WITH_THREADS
  pthread_mutex_unlock(world->statements_mutex);
#endif

  LIBRDF_FREE(librdf_statement, statement);
}



/* methods */

/**
 * librdf_statement_get_subject:
 * @statement: #librdf_statement object
 *
 * Get the statement subject.
 * 
 * This method returns a SHARED pointer to the subject which must
 * be copied by the caller if needed.
 * 
 * Return value: a pointer to the #librdf_node of the statement subject - 
 **/
librdf_node*
librdf_statement_get_subject(librdf_statement *statement) 
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, NULL);

  return statement->subject;
}


/**
 * librdf_statement_set_subject:
 * @statement: #librdf_statement object
 * @node: #librdf_node of subject
 *
 * Set the statement subject.
 * 
 * The subject passed in becomes owned by
 * the statement object and must not be used by the caller after this call.
 **/
void
librdf_statement_set_subject(librdf_statement *statement, librdf_node *node)
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN(statement, librdf_statement);

  statement->subject=node;
}


/**
 * librdf_statement_get_predicate:
 * @statement: #librdf_statement object
 *
 * Get the statement predicate.
 * 
 * This method returns a SHARED pointer to the predicate which must
 * be copied by the caller if needed.
 * 
 * Return value: a pointer to the #librdf_node of the statement predicate - 
 **/
librdf_node*
librdf_statement_get_predicate(librdf_statement *statement) 
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, NULL);

  return statement->predicate;
}


/**
 * librdf_statement_set_predicate:
 * @statement: #librdf_statement object
 * @node: #librdf_node of predicate
 *
 * Set the statement predicate.
 *
 * The predicate passed in becomes owned by
 * the statement object and must not be used by the caller after this call.
 **/
void
librdf_statement_set_predicate(librdf_statement *statement, librdf_node *node)
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN(statement, librdf_statement);

  statement->predicate=node;
}


/**
 * librdf_statement_get_object:
 * @statement: #librdf_statement object
 *
 * Get the statement object.
 * 
 * This method returns a SHARED pointer to the object which must
 * be copied by the caller if needed.
 * 
 * Return value: a pointer to the #librdf_node of the statement object - 
 **/
librdf_node*
librdf_statement_get_object(librdf_statement *statement) 
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, NULL);

  return statement->object;
}


/**
 * librdf_statement_set_object:
 * @statement: #librdf_statement object
 * @node: #librdf_node of object
 *
 * Set the statement object.
 * 
 * The object passed in becomes owned by
 * the statement object and must not be used by the caller after this call.
 **/
void
librdf_statement_set_object(librdf_statement *statement, librdf_node *node)
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN(statement, librdf_statement);

  statement->object=node;
}


/**
 * librdf_statement_is_complete:
 * @statement: #librdf_statement object
 *
 * Check if statement is a complete and legal RDF triple.
 *
 * Checks that all subject, predicate, object fields are present
 * and they have the allowed node types.
 * 
 * Return value: non 0 if the statement is complete and legal
 **/
int
librdf_statement_is_complete(librdf_statement *statement)
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 0);

  if(!statement->subject ||
     (!librdf_node_is_resource(statement->subject) && 
      !librdf_node_is_blank(statement->subject)))
    return 0;

  if(!statement->predicate || !librdf_node_is_resource(statement->predicate))
     return 0;

  if(!statement->object)
    return 0;

  return 1;
}


/**
 * librdf_statement_to_string:
 * @statement: the statement
 *
 * Format the librdf_statement as a string.
 * 
 * Formats the statement as a newly allocate string that must be freed by
 * the caller.
 * 
 * Return value: the string or NULL on failure.
 **/
unsigned char *
librdf_statement_to_string(librdf_statement *statement)
{
  unsigned char *subject_string, *predicate_string, *object_string;
  unsigned char *s;
  int statement_string_len=0;
  const char *format;
#define NULL_STRING_LENGTH 6
  static const unsigned char * const null_string=(const unsigned char *)"(null)";
  size_t len;

  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, NULL);

  if(statement->subject) {
    subject_string=librdf_node_to_counted_string(statement->subject, &len);
    if(!subject_string)
      return NULL;
    statement_string_len += len;
  } else {
    subject_string=(unsigned char*)null_string;
    statement_string_len += NULL_STRING_LENGTH;
  }

  
  if(statement->predicate) {
    predicate_string=librdf_node_to_counted_string(statement->predicate, &len);
    if(!predicate_string) {
      if(subject_string != null_string)
        LIBRDF_FREE(cstring, subject_string);
      return NULL;
    }
    statement_string_len += len;
  } else {
    predicate_string=(unsigned char*)null_string;
    statement_string_len += NULL_STRING_LENGTH;
  }
  

  if(statement->object) {
    object_string=librdf_node_to_counted_string(statement->object, &len);
    if(!object_string) {
      if(subject_string != null_string)
        LIBRDF_FREE(cstring, subject_string);
      if(predicate_string != null_string)
        LIBRDF_FREE(cstring, predicate_string);
      return NULL;
    }
    statement_string_len += len;
  } else {
    object_string=(unsigned char*)null_string;
    statement_string_len += NULL_STRING_LENGTH;
  }
  


#define LIBRDF_STATEMENT_FORMAT_STRING_LITERAL "{%s, %s, \"%s\"}"
#define LIBRDF_STATEMENT_FORMAT_RESOURCE_LITERAL "{%s, %s, %s}"
  statement_string_len += + 1 + /* "{" %s */
                            2 + /* ", " %s */
                            2 + /* ", " %s */
                            1; /* "}" */
  if(statement->object &&
     librdf_node_get_type(statement->object) == LIBRDF_NODE_TYPE_LITERAL) {
    format=LIBRDF_STATEMENT_FORMAT_STRING_LITERAL;
    statement_string_len+=2; /* Extra "" around literal */
  } else {
    format=LIBRDF_STATEMENT_FORMAT_RESOURCE_LITERAL;
  }
    
  s=(unsigned char*)LIBRDF_MALLOC(cstring, statement_string_len+1);
  if(s)
    sprintf((char*)s, format, subject_string, predicate_string, object_string);

  /* always free allocated intermediate strings */
  if(subject_string != null_string)
    LIBRDF_FREE(cstring, subject_string);
  if(predicate_string != null_string)
    LIBRDF_FREE(cstring, predicate_string);
  if(object_string != null_string)
    LIBRDF_FREE(cstring, object_string);

  return s;
}

/**
 * librdf_statement_print:
 * @statement: the statement
 * @fh: file handle
 *
 * Pretty print the statement to a file descriptor.
 * 
 * This method is for debugging and the format of the output should
 * not be relied on.
 * 
 **/
void
librdf_statement_print(librdf_statement *statement, FILE *fh) 
{
  unsigned char *s;

  LIBRDF_ASSERT_OBJECT_POINTER_RETURN(statement, librdf_statement);

  if(!statement)
    return;
  
  s=librdf_statement_to_string(statement);
  if(!s)
    return;
  fputs((const char*)s, fh);
  LIBRDF_FREE(cstring, s);
}



/**
 * librdf_statement_equals:
 * @statement1: first #librdf_statement
 * @statement2: second #librdf_statement
 *
 * Check if two statements are equal.
 * 
 * Return value: non 0 if statements are equal
 **/
int
librdf_statement_equals(librdf_statement* statement1, 
                        librdf_statement* statement2)
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement1, librdf_statement, 0);
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement2, librdf_statement, 0);

  if(!statement1 || !statement2)
    return 0;
  
  if(!librdf_node_equals(statement1->subject, statement2->subject))
    return 0;
  
  if(!librdf_node_equals(statement1->predicate, statement2->predicate))
    return 0;
  
  if(!librdf_node_equals(statement1->object, statement2->object))
    return 0;

  return 1;
}


/**
 * librdf_statement_match:
 * @statement: statement
 * @partial_statement: statement with possible empty parts
 *
 * Match a statement against a 'partial' statement.
 * 
 * A partial statement is where some parts of the statement -
 * subject, predicate or object can be empty (NULL).
 * Empty parts match against any value, parts with values
 * must match exactly.  Node matching is done via librdf_node_equals()
 * 
 * Return value: non 0 on match
 **/
int
librdf_statement_match(librdf_statement* statement, 
                       librdf_statement* partial_statement)
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 0);
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(partial_statement, librdf_statement, 0);

  if(partial_statement->subject &&
     !librdf_node_equals(statement->subject, partial_statement->subject))
      return 0;

  if(partial_statement->predicate &&
     !librdf_node_equals(statement->predicate, partial_statement->predicate))
      return 0;

  if(partial_statement->object &&
     !librdf_node_equals(statement->object, partial_statement->object))
      return 0;

  return 1;
}


/**
 * librdf_statement_encode:
 * @statement: the statement to serialise
 * @buffer: the buffer to use
 * @length: buffer size
 *
 * Serialise a statement into a buffer.
 * 
 * Encodes the given statement in the buffer, which must be of sufficient
 * size.  If buffer is NULL, no work is done but the size of buffer
 * required is returned.
 * 
 * Return value: the number of bytes written or 0 on failure.
 **/
size_t
librdf_statement_encode(librdf_statement* statement, 
                        unsigned char *buffer, 
                        size_t length)
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 0);

  return librdf_statement_encode_parts(statement, NULL,
                                       buffer, length,
                                       LIBRDF_STATEMENT_ALL);
}


/**
 * librdf_statement_encode_parts:
 * @statement: statement to serialise
 * @context_node: #librdf_node context node (can be NULL)
 * @buffer: the buffer to use
 * @length: buffer size
 * @fields: fields to encode
 *
 * Serialise parts of a statement into a buffer.
 * 
 * Encodes the given statement in the buffer, which must be of sufficient
 * size.  If buffer is NULL, no work is done but the size of buffer
 * required is returned.
 *
 * The fields values are or-ed combinations of:
 * LIBRDF_STATEMENT_SUBJECT LIBRDF_STATEMENT_PREDICATE
 * LIBRDF_STATEMENT_OBJECT
 * or LIBRDF_STATEMENT_ALL for subject,prdicate,object fields
 * 
 * If context_node is given, it is encoded also
 *
 * Return value: the number of bytes written or 0 on failure.
 **/
size_t
librdf_statement_encode_parts(librdf_statement* statement, 
                              librdf_node* context_node,
                              unsigned char *buffer, size_t length,
                              librdf_statement_part fields)
{
  size_t total_length=0;
  size_t node_len;
  unsigned char *p;

  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 0);

  /* min size */
  if(buffer && length < 1)
    return 0;

  p=buffer;
  /* magic number 'x' */
  if(p) {
    *p++='x';
    length--;
  }
  total_length++;

  if((fields & LIBRDF_STATEMENT_SUBJECT) && statement->subject) {
    /* 's' + subject */
    if(p) {
      *p++='s';
      length--;
    }
    total_length++;

    node_len=librdf_node_encode(statement->subject, p, length);
    if(!node_len)
      return 0;
    if(p) {
      p += node_len;
      length -= node_len;
    }
    
    
    total_length += node_len;
  }
  
  
  if((fields & LIBRDF_STATEMENT_PREDICATE) && statement->predicate) {
    /* 'p' + predicate */
    if(p) {
      *p++='p';
      length--;
    }
    total_length++;

    node_len=librdf_node_encode(statement->predicate, p, length);
    if(!node_len)
      return 0;
    if(p) {
      p += node_len;
      length -= node_len;
    }
    
    total_length += node_len;
  }
  
  if((fields & LIBRDF_STATEMENT_OBJECT) && statement->object) {
    /* 'o' object */
    if(p) {
      *p++='o';
      length--;
    }
    total_length++;

    node_len= librdf_node_encode(statement->object, p, length);
    if(!node_len)
      return 0;
    if(p) {
      p += node_len;
      length -= node_len;
    }

    total_length += node_len;
  }

  if(context_node) {
    /* 'o' object */
    if(p) {
      *p++='c';
      length--;
    }
    total_length++;

    node_len= librdf_node_encode(context_node, p, length);
    if(!node_len)
      return 0;
    if(p) {
      p += node_len;
      length -= node_len;
    }

    total_length += node_len;
  }

  return total_length;
}


/**
 * librdf_statement_decode:
 * @statement: the statement to deserialise into
 * @buffer: the buffer to use
 * @length: buffer size
 *
 * Decodes a statement from a buffer.
 * 
 * Decodes the serialised statement (as created by librdf_statement_encode() )
 * from the given buffer.
 * 
 * Return value: number of bytes used or 0 on failure (bad encoding, allocation failure)
 **/
size_t
librdf_statement_decode(librdf_statement* statement, 
                        unsigned char *buffer, size_t length)
{
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 0);

  return librdf_statement_decode_parts(statement, NULL, buffer, length);
}


/**
 * librdf_statement_decode_parts:
 * @statement: the statement to deserialise into
 * @context_node: pointer to #librdf_node context_node to deserialise into
 * @buffer: the buffer to use
 * @length: buffer size
 *
 * Decodes a statement + context node from a buffer.
 * 
 * Decodes the serialised statement (as created by librdf_statement_encode() )
 * from the given buffer.  If a context node is found and context_node is
 * not NULL, a pointer to the new #librdf_node is stored in *context_node.
 * 
 * Return value: number of bytes used or 0 on failure (bad encoding, allocation failure)
 **/
size_t
librdf_statement_decode_parts(librdf_statement* statement, 
                              librdf_node** context_node,
                              unsigned char *buffer, size_t length)
{
  unsigned char *p;
  librdf_node* node;
  unsigned char type;
  size_t total_length=0;
  
  LIBRDF_ASSERT_OBJECT_POINTER_RETURN_VALUE(statement, librdf_statement, 0);

#if defined(LIBRDF_DEBUG) && LIBRDF_DEBUG > 1
    LIBRDF_DEBUG2("Decoding buffer of %d bytes\n", length);
#endif


  /* absolute minimum - first byte is type */
  if(length < 1)
    return 0;

  p=buffer;
  if(*p++ != 'x')
    return 0;
  length--;
  total_length++;
  
  
  while(length>0) {
    size_t node_len;
    
    type=*p++;
    length--;
    total_length++;

    if(!length)
      return 0;
    
    if(!(node=librdf_node_decode(statement->world, &node_len, p, length)))
      return 0;

    p += node_len;
    length -= node_len;
    total_length += node_len;
    
#if defined(LIBRDF_DEBUG) && LIBRDF_DEBUG > 1
    LIBRDF_DEBUG3("Found type %c (%d bytes)\n", type, node_len);
#endif
  
    switch(type) {
    case 's': /* subject */
      statement->subject=node;
      break;
      
    case 'p': /* predicate */
      statement->predicate=node;
      break;
      
    case 'o': /* object */
      statement->object=node;
      break;

    case 'c': /* context */
      if(context_node)
        *context_node=node;
      else
        librdf_free_node(node);
      break;

    default:
      librdf_log(statement->world,
                 0, LIBRDF_LOG_ERROR, LIBRDF_FROM_STATEMENT, NULL,
                 "Illegal statement encoding '%c' seen", p[-1]);
      return 0;
    }
  }

  return total_length;
}

#endif


/* TEST CODE */


#ifdef STANDALONE

/* one more prototype */
int main(int argc, char *argv[]);


int
main(int argc, char *argv[]) 
{
  librdf_statement *statement, *statement2;
  int size, size2;
  const char *program=librdf_basename((const char*)argv[0]);
  char *s, *buffer;
  librdf_world *world;
  
  world=librdf_new_world();
  librdf_world_open(world);

  fprintf(stderr, "%s: Creating statement\n", program);
  statement=librdf_new_statement(world);

  s=(char*)librdf_statement_to_string(statement);
  fprintf(stderr, "%s: Empty statement: %s\n", program, s);
  LIBRDF_FREE(cstring, s);

  librdf_statement_set_subject(statement, librdf_new_node_from_uri_string(world, (const unsigned char*)"http://purl.org/net/dajobe/"));
  librdf_statement_set_predicate(statement, librdf_new_node_from_uri_string(world, (const unsigned char*)"http://purl.org/dc/elements/1.1/#Creator"));
  librdf_statement_set_object(statement, librdf_new_node_from_literal(world, (const unsigned char*)"Dave Beckett", NULL, 0));

  s=(char*)librdf_statement_to_string(statement);
  fprintf(stderr, "%s: Resulting statement: %s\n", program, s);
  LIBRDF_FREE(cstring, s);

  size=librdf_statement_encode(statement, NULL, 0);
  fprintf(stdout, "%s: Encoding statement requires %d bytes\n", program, size);
  buffer=(char*)LIBRDF_MALLOC(cstring, size);

  fprintf(stdout, "%s: Encoding statement in buffer\n", program);
  size2=librdf_statement_encode(statement, (unsigned char*)buffer, size);
  if(size2 != size) {
    fprintf(stderr, "%s: Encoding statement used %d bytes, expected it to use %d\n", program, size2, size);
    return(1);
  }
  
    
  fprintf(stdout, "%s: Creating new statement\n", program);
  statement2=librdf_new_statement(world);

  fprintf(stdout, "%s: Decoding statement from buffer\n", program);
  if(!librdf_statement_decode(statement2, (unsigned char*)buffer, size)) {
    fprintf(stderr, "%s: Decoding statement failed\n", program);
    return(1);
  }
  LIBRDF_FREE(cstring, buffer);
   
  fprintf(stdout, "%s: New statement is: ", program);
  librdf_statement_print(statement2, stdout);
  fputs("\n", stdout);
 
  
  fprintf(stdout, "%s: Freeing statements\n", program);
  librdf_free_statement(statement2);
  librdf_free_statement(statement);


  librdf_free_world(world);
  
  /* keep gcc -Wall happy */
  return(0);
}

#endif