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ntriples_parse.c

/* -*- Mode: c; c-basic-offset: 2 -*-
 *
 * ntriples_parse.c - Raptor N-Triples Parser implementation
 *
 * N-Triples
 * http://www.w3.org/TR/rdf-testcases/#ntriples
 *
 * Copyright (C) 2001-2010, David Beckett http://www.dajobe.org/
 * Copyright (C) 2001-2005, 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 <raptor_config.h>
#endif

#ifdef WIN32
#include <win32_raptor_config.h>
#endif

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdarg.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif

/* Raptor includes */
#include "raptor.h"
#include "raptor_internal.h"

/* Set RAPTOR_DEBUG to > 1 to get lots of buffer related debugging */
/*
#undef RAPTOR_DEBUG
#define RAPTOR_DEBUG 2
*/


/* Prototypes for local functions */
static void raptor_ntriples_generate_statement(raptor_parser* parser, const unsigned char *subject, const raptor_term_type subject_type, const unsigned char *predicate, const raptor_term_type predicate_type, const void *object, const raptor_term_type object_type, const unsigned char *object_literal_language, const unsigned char *object_literal_datatype, const void *graph, const raptor_term_type graph_type);

/*
 * NTriples parser object
 */
00065 struct raptor_ntriples_parser_context_s {
  /* current line */
  unsigned char *line;
  /* current line length */
  int line_length;
  /* current char in line buffer */
  int offset;

  char last_char;
  
  /* static statement for use in passing to user code */
  raptor_statement statement;

  /* Non-0 if N-Quads */
  int is_nquads;

  int literal_graph_warning;
};


typedef struct raptor_ntriples_parser_context_s raptor_ntriples_parser_context;



/**
 * raptor_ntriples_parse_init:
 *
 * Initialise the Raptor NTriples parser.
 *
 * Return value: non 0 on failure
 **/

static int
raptor_ntriples_parse_init(raptor_parser* rdf_parser, const char *name)
{
  raptor_ntriples_parser_context *ntriples_parser;
  ntriples_parser = (raptor_ntriples_parser_context*)rdf_parser->context;

  raptor_statement_init(&ntriples_parser->statement, rdf_parser->world);

  if(!strcmp(name, "nquads"))
    ntriples_parser->is_nquads = 1;
  
  return 0;
}


/* PUBLIC FUNCTIONS */


/*
 * raptor_ntriples_parse_terminate - Free the Raptor NTriples parser
 * @rdf_parser: parser object
 * 
 **/
static void
raptor_ntriples_parse_terminate(raptor_parser* rdf_parser)
{
  raptor_ntriples_parser_context *ntriples_parser;
  ntriples_parser = (raptor_ntriples_parser_context*)rdf_parser->context;
  if(ntriples_parser->line_length)
    RAPTOR_FREE(cdata, ntriples_parser->line);
}


static void
raptor_ntriples_generate_statement(raptor_parser* parser, 
                                   const unsigned char *subject,
                                   const raptor_term_type subject_type,
                                   const unsigned char *predicate,
                                   const raptor_term_type predicate_type,
                                   const void *object,
                                   const raptor_term_type object_type,
                                   const unsigned char *object_literal_language,
                                   const unsigned char *object_literal_datatype,
                                   const void *graph,
                                   const raptor_term_type graph_type)
{
  /* raptor_ntriples_parser_context *ntriples_parser = (raptor_ntriples_parser_context*)parser->context; */
  raptor_statement *statement = &parser->statement;
  raptor_uri *predicate_uri = NULL;
  raptor_uri *datatype_uri = NULL;

  if(!parser->emitted_default_graph) {
    raptor_parser_start_graph(parser, NULL, 0);
    parser->emitted_default_graph++;
  }

  /* If there is no statement handler - there is nothing else to do */
  if(!parser->statement_handler)
    goto cleanup;

  /* Two choices for subject from N-Triples */
  if(subject_type == RAPTOR_TERM_TYPE_BLANK) {
    statement->subject = raptor_new_term_from_blank(parser->world, subject);
  } else {
    raptor_uri *subject_uri;

    /* must be RAPTOR_TERM_TYPE_URI */
    subject_uri = raptor_new_uri(parser->world, subject);
    if(!subject_uri) {
      raptor_parser_error(parser, "Could not create subject uri '%s', skipping", subject);
      goto cleanup;
    }
    statement->subject = raptor_new_term_from_uri(parser->world, subject_uri);
    raptor_free_uri(subject_uri);
  }

  if(object_literal_datatype) {
    datatype_uri = raptor_new_uri(parser->world, object_literal_datatype);
    if(!datatype_uri) {
      raptor_parser_error(parser, "Could not create object literal datatype uri '%s', skipping", object_literal_datatype);
      goto cleanup;
    }
    object_literal_language = NULL;
  }

  /* Predicates in N-Triples are URIs but check for bad ordinals */
  if(!strncmp((const char*)predicate, "http://www.w3.org/1999/02/22-rdf-syntax-ns#_", 44)) {
    int predicate_ordinal = raptor_check_ordinal(predicate+44);
    if(predicate_ordinal <= 0)
      raptor_parser_error(parser, "Illegal ordinal value %d in property '%s'.", predicate_ordinal, predicate);
  }
  
  predicate_uri = raptor_new_uri(parser->world, predicate);
  if(!predicate_uri) {
    raptor_parser_error(parser, "Could not create predicate uri '%s', skipping", predicate);
    goto cleanup;
  }
  statement->predicate = raptor_new_term_from_uri(parser->world, predicate_uri);
  raptor_free_uri(predicate_uri);
  predicate_uri = NULL;
  
  /* Three choices for object from N-Triples */
  if(object_type == RAPTOR_TERM_TYPE_URI) {
    raptor_uri *object_uri;

    object_uri = raptor_new_uri(parser->world, (const unsigned char*)object);
    if(!object_uri) {
      raptor_parser_error(parser, "Could not create object uri '%s', skipping", (const char *)object);
      goto cleanup;
    }
    statement->object = raptor_new_term_from_uri(parser->world, object_uri);
    raptor_free_uri(object_uri);
    object_uri = NULL;
  } else if(object_type == RAPTOR_TERM_TYPE_BLANK) {
    statement->object = raptor_new_term_from_blank(parser->world, 
                                                   (const unsigned char*)object);
  } else { 
    /*  RAPTOR_TERM_TYPE_LITERAL */
    statement->object = raptor_new_term_from_literal(parser->world,
                                                     (const unsigned char*)object,
                                                     datatype_uri,
                                                     (const unsigned char*)object_literal_language);
  }


  if(graph) {
    /* Three choices for graph/context from N-Quads according to
     * http://sw.deri.org/2008/07/n-quads/ but I am IGNORING Literal
     */
    if(graph_type == RAPTOR_TERM_TYPE_URI) {
      raptor_uri *graph_uri;

      graph_uri = raptor_new_uri(parser->world, (const unsigned char*)graph);
      if(!graph_uri) {
        raptor_parser_error(parser,
                            "Could not create object uri '%s', skipping", 
                            (const char *)graph);
        goto cleanup;
      }
      statement->graph = raptor_new_term_from_uri(parser->world, graph_uri);
      raptor_free_uri(graph_uri);
      graph_uri = NULL;
    } else if(graph_type == RAPTOR_TERM_TYPE_BLANK) {
      statement->graph = raptor_new_term_from_blank(parser->world, 
                                                    (const unsigned char*)graph);
    } else { 
      /* Warning about literal graphs is handled below */
      statement->graph = NULL;
    }
  }

  /* Generate the statement */
  (*parser->statement_handler)(parser->user_data, statement);

  cleanup:
  raptor_free_statement(statement);

  if(predicate_uri)
    raptor_free_uri(predicate_uri);
  if(datatype_uri)
    raptor_free_uri(datatype_uri);
}


/* These are for 7-bit ASCII and not locale-specific */
#define IS_ASCII_ALPHA(c) (((c) > 0x40 && (c) < 0x5B) || ((c) > 0x60 && (c) < 0x7B))
#define IS_ASCII_UPPER(c) ((c) > 0x40 && (c) < 0x5B)
#define IS_ASCII_DIGIT(c) ((c) > 0x2F && (c) < 0x3A)
#define IS_ASCII_PRINT(c) ((c) > 0x1F && (c) < 0x7F)
#define TO_ASCII_LOWER(c) ((c)+0x20)

typedef enum {
  RAPTOR_TERM_CLASS_URI,      /* ends on > */
  RAPTOR_TERM_CLASS_BNODEID,  /* ends on first non [A-Za-z][A-Za-z0-9]* */
  RAPTOR_TERM_CLASS_STRING,   /* ends on non-escaped " */
  RAPTOR_TERM_CLASS_LANGUAGE, /* ends on first non [a-z0-9]+ ('-' [a-z0-9]+ )? */
  RAPTOR_TERM_CLASS_FULL      /* the entire string is used */
} raptor_ntriples_term_class;


static int 
raptor_ntriples_term_valid(unsigned char c, int position, 
                           raptor_ntriples_term_class term_class) 
{
  int result = 0;

  switch(term_class) {
    case RAPTOR_TERM_CLASS_URI:
      /* ends on > */
      result = (c != '>');
      break;
      
    case RAPTOR_TERM_CLASS_BNODEID:  
      /* ends on first non [A-Za-z][A-Za-z0-9]* */
      result = IS_ASCII_ALPHA(c);
      if(position)
        result = (result || IS_ASCII_DIGIT(c));
      break;
      
    case RAPTOR_TERM_CLASS_STRING:
      /* ends on " */
      result = (c != '"');
      break;

    case RAPTOR_TERM_CLASS_LANGUAGE:
      /* ends on first non [a-z0-9]+ ('-' [a-z0-9]+ )? */
      result = (IS_ASCII_ALPHA(c) || IS_ASCII_DIGIT(c));
      if(position)
        result = (result || c == '-');
      break;
      
    case RAPTOR_TERM_CLASS_FULL:
      result = 1;
      break;
      
    default:
      RAPTOR_FATAL2("Unknown ntriples term %d", term_class);
  }

  return result;
}


/*
 * raptor_ntriples_term:
 * @parser: NTriples parser
 * @start: pointer to starting character of string (in)
 * @dest: destination of string (in)
 * @lenp: pointer to length of string (in/out)
 * @dest_lenp: pointer to length of destination string (out)
 * @end_char: string ending character
 * @class: string class
 * @allow_utf8: Non-0 if UTF-8 chars are allowed in the term
 *
 * Parse an N-Triples term with escapes.
 *
 * Relies that @dest is long enough; it need only be as large as the
 * input string @start since when UTF-8 encoding, the escapes are
 * removed and the result is always less than or equal to length of
 * input.
 *
 * N-Triples strings/URIs are written in ASCII at present; characters
 * outside the printable ASCII range are discarded with a warning.
 * See the grammar for full details of the allowed ranges.
 *
 * If the class is RAPTOR_TERM_CLASS_FULL, the end_char is ignored.
 *
 * UTF-8 is only allowed if allow_utf8 is non-0, otherwise the
 * string is US-ASCII and only the \u and \U esapes are allowed.
 * If enabled, both are allowed.
 *
 * Return value: Non 0 on failure
 **/
static int
raptor_ntriples_term(raptor_parser* rdf_parser, 
                     const unsigned char **start, unsigned char *dest, 
                     size_t *lenp, size_t *dest_lenp,
                     char end_char,
                     raptor_ntriples_term_class term_class,
                     int allow_utf8)
{
  const unsigned char *p = *start;
  unsigned char c = '\0';
  size_t ulen = 0;
  unsigned long unichar = 0;
  unsigned int position = 0;
  int end_char_seen = 0;

  if(term_class == RAPTOR_TERM_CLASS_FULL)
    end_char = '\0';
  
  /* find end of string, fixing backslashed characters on the way */
  while(*lenp > 0) {
    c = *p;

    p++;
    (*lenp)--;
    rdf_parser->locator.column++;
    rdf_parser->locator.byte++;

    if(allow_utf8) {
      if(c > 0x7f) {
        /* just copy the UTF-8 bytes through */
        size_t unichar_len;
        unichar_len = raptor_unicode_utf8_string_get_char(p - 1, 1 + *lenp, NULL);
        if(unichar_len > *lenp) {
          raptor_parser_error(rdf_parser, "UTF-8 encoding error at character %d (0x%02X) found.", c, c);
          /* UTF-8 encoding had an error or ended in the middle of a string */
          return 1;
        }
        memcpy(dest, p-1, unichar_len);
        dest += unichar_len;

        unichar_len--; /* p, *lenp were moved on by 1 earlier */
        
        p += unichar_len;
        (*lenp) -= unichar_len;
        rdf_parser->locator.column += unichar_len;
        rdf_parser->locator.byte += unichar_len;
        continue;
      }
    } else if(!IS_ASCII_PRINT(c)) {
      /* This is an ASCII check, not a printable character check 
       * so isprint() is not appropriate, since that is a locale check.
       */
      raptor_parser_error(rdf_parser, "Non-printable ASCII character %d (0x%02X) found.", c, c);
      continue;
    }
    
    if(c != '\\') {
      /* finish at non-backslashed end_char */
      if(end_char && c == end_char) {
        end_char_seen = 1;
        break;
      }

      if(!raptor_ntriples_term_valid(c, position, term_class)) {
        if(end_char) {
          /* end char was expected, so finding an invalid thing is an error */
          raptor_parser_error(rdf_parser, "Missing terminating '%c' (found '%c')", end_char, c);
          return 0;
        } else {
          /* it's the end - so rewind 1 to save next char */
          p--;
          (*lenp)++;
          rdf_parser->locator.column--;
          rdf_parser->locator.byte--;
          break;
        }
      }
      
      /* otherwise store and move on */
      *dest++ = c;
      position++;
      continue;
    }

    if(!*lenp) {
      if(term_class != RAPTOR_TERM_CLASS_FULL)
        raptor_parser_error(rdf_parser, "\\ at end of line");
      return 0;
    }

    c = *p;

    p++;
    (*lenp)--;
    rdf_parser->locator.column++;
    rdf_parser->locator.byte++;

    switch(c) {
      case '"':
      case '\\':
        *dest++ = c;
        break;
      case 'n':
        *dest++ = '\n';
        break;
      case 'r':
        *dest++ = '\r';
        break;
      case 't':
        *dest++ = '\t';
        break;
      case 'u':
      case 'U':
        ulen = (c == 'u') ? 4 : 8;
        
        if(*lenp < ulen) {
          raptor_parser_error(rdf_parser, "%c over end of line", c);
          return 0;
        }

        if(1) {
          int n;

          n = sscanf((const char*)p, ((ulen == 4) ? "%04lx" : "%08lx"), &unichar);
          if(n != 1) {
            raptor_parser_error(rdf_parser, "Illegal Uncode escape '%c%s...'", c, p);
            break;
          }
        }

        p += ulen;
        (*lenp) -= ulen;
        rdf_parser->locator.column += ulen;
        rdf_parser->locator.byte += ulen;
        
        if(unichar > raptor_unicode_max_codepoint) {
          raptor_parser_error(rdf_parser,
                              "Illegal Unicode character with code point #x%lX (max #x%lX).",
                              unichar, raptor_unicode_max_codepoint);
          break;
        }

        /* The destination length is set here to 4 since we know that in 
         * all cases, the UTF-8 encoded output sequence is always shorter
         * than the input sequence, and the buffer is edited in place.
         *   \uXXXX: 6 bytes input - UTF-8 max 3 bytes output
         *   \uXXXXXXXX: 10 bytes input - UTF-8 max 4 bytes output
         */
        dest += raptor_unicode_utf8_string_put_char(unichar, dest, 4);
        break;

      default:
        raptor_parser_error(rdf_parser,
                            "Illegal string escape \\%c in \"%s\"", c, 
                            (char*)start);
        return 0;
    }

    position++;
  } /* end while */

  
  if(end_char && !end_char_seen) {
    raptor_parser_error(rdf_parser, "Missing terminating '%c' before end of line.", end_char);
    return 1;
  }

  /* terminate dest, can be shorter than source */
  *dest = '\0';

  if(dest_lenp)
    *dest_lenp = p - *start;

  *start = p;

  return 0;
}


static int
raptor_ntriples_parse_line(raptor_parser* rdf_parser,
                           unsigned char *buffer, size_t len,
                           int max_terms)
{
  raptor_ntriples_parser_context *ntriples_parser = (raptor_ntriples_parser_context*)rdf_parser->context;
  int i;
  unsigned char *p;
  unsigned char *dest;
  unsigned char *terms[4];
  size_t term_lengths[4];
  raptor_term_type term_types[4];
  size_t term_length = 0;
  unsigned char *object_literal_language = NULL;
  unsigned char *object_literal_datatype = NULL;
  int rc = 0;
  
  /* ASSERTION:
   * p always points to first char we are considering
   * p[len-1] always points to last char
   */
  
  /* Handle empty  lines */
  if(!len)
    return 0;

#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
  RAPTOR_DEBUG3("handling line '%s' (%d bytes)\n", buffer, (unsigned int)len);
#endif
  
  p = buffer;

  while(len > 0 && isspace((int)*p)) {
    p++;
    rdf_parser->locator.column++;
    rdf_parser->locator.byte++;
    len--;
  }

  /* Handle empty - all whitespace lines */
  if(!len)
    return 0;
  
  /* Handle comment lines */
  if(*p == '#')
    return 0;
  
  /* Remove trailing spaces */
  while(len > 0 && isspace((int)p[len-1])) {
    p[len-1] = '\0';
    len--;
  }

  /* can't be empty now - that would have been caught above */
  
  /* Check for terminating '.' */
  if(p[len-1] != '.') {
    /* Move current location to point to problem */
    rdf_parser->locator.column += len-2;
    rdf_parser->locator.byte += len-2;
    raptor_parser_error(rdf_parser, "Missing . at end of line");
    return 0;
  }

  p[len-1] = '\0';
  len--;


  /* Must be triple */

  for(i = 0; i < max_terms; i++) {
    if(!len) {
      raptor_parser_error(rdf_parser, "Unexpected end of line");
      goto cleanup;
    }
    

    if(i == 2) {
      /* object term (2): expect either <URI> or _:name or literal */
      if(*p != '<' && *p != '_' && *p != '"' && *p != 'x') {
        raptor_parser_error(rdf_parser, "Saw '%c', expected <URIref>, _:bnodeID or \"literal\"", *p);
        goto cleanup;
      }
    } else if(i == 1) {
      /* predicate term (1): expect URI only */
      if(*p != '<') {
        raptor_parser_error(rdf_parser, "Saw '%c', expected <URIref>", *p);
        goto cleanup;
      }
    } else {
      /* subject (0) or graph (3) terms: expect <URI> or _:name */
      if(*p != '<' && *p != '_') {
        raptor_parser_error(rdf_parser, "Saw '%c', expected <URIref> or _:bnodeID", *p);
        goto cleanup;
      }
    }


    switch(*p) {
      case '<':
        term_types[i] = RAPTOR_TERM_TYPE_URI;
        
        dest = p;

        p++;
        len--;
        rdf_parser->locator.column++;
        rdf_parser->locator.byte++;

        if(raptor_ntriples_term(rdf_parser,
                                (const unsigned char**)&p, 
                                dest, &len, &term_length, 
                                '>', RAPTOR_TERM_CLASS_URI, 0)) {
          rc = 1;
          goto cleanup;
        }
        break;

      case '"':
        term_types[i] = RAPTOR_TERM_TYPE_LITERAL;
        
        dest = p;

        p++;
        len--;
        rdf_parser->locator.column++;
        rdf_parser->locator.byte++;

        if(raptor_ntriples_term(rdf_parser,
                                (const unsigned char**)&p,
                                dest, &len, &term_length,
                                '"', RAPTOR_TERM_CLASS_STRING, 0)) {
          rc = 1;
          goto cleanup;
        }
        
        if(len && (*p == '-' || *p == '@')) {
          if(*p == '-')
            raptor_parser_error(rdf_parser, "Old N-Triples language syntax using \"string\"-lang rather than \"string\"@lang.");

          object_literal_language = p;

          /* Skip - */
          p++;
          len--;
          rdf_parser->locator.column++;
          rdf_parser->locator.byte++;

          if(!len) {
            raptor_parser_error(rdf_parser, "Missing language after \"string\"-");
            goto cleanup;
          }
          

          if(raptor_ntriples_term(rdf_parser,
                                  (const unsigned char**)&p,
                                  object_literal_language, &len, NULL,
                                  '\0', RAPTOR_TERM_CLASS_LANGUAGE, 0)) {
            rc = 1;
            goto cleanup;
          }
        }

        if(len >1 && *p == '^' && p[1] == '^') {

          object_literal_datatype = p;

          /* Skip ^^ */
          p += 2;
          len -= 2;
          rdf_parser->locator.column += 2;
          rdf_parser->locator.byte += 2;

          if(!len || (len && *p != '<')) {
            raptor_parser_error(rdf_parser, "Missing datatype URI-ref in\"string\"^^<URI-ref> after ^^");
            goto cleanup;
          }

          p++;
          len--;
          rdf_parser->locator.column++;
          rdf_parser->locator.byte++;

          if(raptor_ntriples_term(rdf_parser,
                                  (const unsigned char**)&p,
                                  object_literal_datatype, &len, NULL,
                                  '>', RAPTOR_TERM_CLASS_URI, 0)) {
            rc = 1;
            goto cleanup;
          }
          
        }

        if(object_literal_datatype && object_literal_language) {
          raptor_parser_warning(rdf_parser, "Typed literal used with a language - ignoring the language");
          object_literal_language = NULL;
        }

        break;


      case '_':
        term_types[i] = RAPTOR_TERM_TYPE_BLANK;

        /* store where _ was */
        dest = p;

        p++;
        len--;
        rdf_parser->locator.column++;
        rdf_parser->locator.byte++;

        if(!len || (len > 0 && *p != ':')) {
          raptor_parser_error(rdf_parser, "Illegal bNodeID - _ not followed by :");
          goto cleanup;
        }

        /* Found ':' - move on */

        p++;
        len--;
        rdf_parser->locator.column++;
        rdf_parser->locator.byte++;

        if(raptor_ntriples_term(rdf_parser,
                                (const unsigned char**)&p,
                                dest, &len, &term_length,
                                '\0', RAPTOR_TERM_CLASS_BNODEID, 0)) {
          rc = 1;
          goto cleanup;
        }

        if(!term_length) {
          raptor_parser_error(rdf_parser, "Bad or missing bNodeID after _:");
          goto cleanup;
        }

        break;

      default:
        raptor_parser_fatal_error(rdf_parser, "Unknown term type");
        rc = 1;
        goto cleanup;
    }


    /* Store term */
    terms[i] = dest; term_lengths[i] = term_length;

    /* Whitespace must separate the terms */
    if(i < 2 && !isspace((int)*p)) {
      raptor_parser_error(rdf_parser, "Missing whitespace after term '%s'", terms[i]);
      rc = 1;
      goto cleanup;
    }

    /* Skip whitespace after terms */
    while(len > 0 && isspace((int)*p)) {
      p++;
      len--;
      rdf_parser->locator.column++;
      rdf_parser->locator.byte++;
    }

#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
    fprintf(stderr, "item %d: term '%s' len %d type %d\n",
            i, terms[i], (unsigned int)term_lengths[i], term_types[i]);
#endif    
  }

  if(len) {
    raptor_parser_error(rdf_parser, "Junk before terminating \".\"");
    return 0;
  }
  

  if(object_literal_language) {
    unsigned char *q;
    /* Normalize language to lowercase
     * http://www.w3.org/TR/rdf-concepts/#dfn-language-identifier
     */
    for(q = object_literal_language; *q; q++) {
      if(IS_ASCII_UPPER(*q))
        *q = TO_ASCII_LOWER(*q);
    }
  }


  /* Just to be sure */
  if(!ntriples_parser->is_nquads)
    terms[3] = NULL;

  if(terms[3] && term_types[3] == RAPTOR_TERM_TYPE_LITERAL) {
    if(!ntriples_parser->literal_graph_warning++)
      raptor_parser_warning(rdf_parser, "Ignoring N-Quad literal contexts");

    terms[3] = NULL;
  }

  raptor_ntriples_generate_statement(rdf_parser, 
                                     terms[0], term_types[0],
                                     terms[1], term_types[1],
                                     terms[2], term_types[2],
                                     object_literal_language,
                                     object_literal_datatype,
                                     terms[3], term_types[3]);

  rdf_parser->locator.byte += len;

 cleanup:

  return rc;
}


static int
raptor_ntriples_parse_chunk(raptor_parser* rdf_parser, 
                            const unsigned char *s, size_t len,
                            int is_end)
{
  unsigned char *buffer;
  unsigned char *ptr;
  unsigned char *start;
  raptor_ntriples_parser_context *ntriples_parser = (raptor_ntriples_parser_context*)rdf_parser->context;
  int max_terms = ntriples_parser->is_nquads ? 4 : 3;
  
#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
  RAPTOR_DEBUG2("adding %d bytes to buffer\n", (unsigned int)len);
#endif

  /* No data?  It's the end */
  if(!len)
    return 0;

  buffer = (unsigned char*)RAPTOR_MALLOC(cstring, ntriples_parser->line_length + len + 1);
  if(!buffer) {
    raptor_parser_fatal_error(rdf_parser, "Out of memory");
    return 1;
  }

  if(ntriples_parser->line_length) {
    memcpy(buffer, ntriples_parser->line, ntriples_parser->line_length);
    RAPTOR_FREE(cstring, ntriples_parser->line);
  }

  ntriples_parser->line = buffer;

  /* move pointer to end of cdata buffer */
  ptr = buffer+ntriples_parser->line_length;

  /* adjust stored length */
  ntriples_parser->line_length += len;

  /* now write new stuff at end of cdata buffer */
  memcpy(ptr, s, len);
  ptr += len;
  *ptr = '\0';

#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
  RAPTOR_DEBUG2("buffer now %d bytes\n", ntriples_parser->line_length);
#endif

  ptr = buffer+ntriples_parser->offset;
  while(*(start = ptr)) {
    unsigned char *line_start = ptr;
    
#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
  RAPTOR_DEBUG3("line buffer now '%s' (offset %d)\n", ptr, ptr-(buffer+ntriples_parser->offset));
#endif

    /* skip \n when just seen \r - i.e. \r\n or CR LF */
    if(ntriples_parser->last_char == '\r' && *ptr == '\n') {
#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
      RAPTOR_DEBUG1("skipping a \\n\n");
#endif
      ptr++;
      rdf_parser->locator.byte++;
      rdf_parser->locator.column = 0;
      start = line_start = ptr;
    }

    while(*ptr && *ptr != '\n' && *ptr != '\r')
      ptr++;

    if(!*ptr)
      break;

#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
    RAPTOR_DEBUG3("found newline \\x%02x at offset %d\n", *ptr,
                  ptr-line_start);
#endif
    ntriples_parser->last_char = *ptr;

    len = ptr-line_start;
    rdf_parser->locator.column = 0;

    *ptr = '\0';
    if(raptor_ntriples_parse_line(rdf_parser, line_start, len, max_terms))
      return 1;
    
    rdf_parser->locator.line++;

    /* go past newline */
    ptr++;
    rdf_parser->locator.byte++;

#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
    /* Do not peek if too far */
    if(ptr-buffer < ntriples_parser->line_length)
      RAPTOR_DEBUG2("next char is \\x%02x\n", *ptr);
    else
      RAPTOR_DEBUG1("next char unknown - end of buffer\n");
#endif
  }

  ntriples_parser->offset = start-buffer;

  len = ntriples_parser->line_length - ntriples_parser->offset;
    
  if(len) {
    /* collapse buffer */

#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
    RAPTOR_DEBUG3("collapsing buffer from %d to %d bytes\n", ntriples_parser->line_length, (unsigned int)len);
#endif
    buffer = (unsigned char*)RAPTOR_MALLOC(cstring, len + 1);
    if(!buffer) {
      raptor_parser_fatal_error(rdf_parser, "Out of memory");
      return 1;
    }

    memcpy(buffer, 
           ntriples_parser->line + ntriples_parser->line_length - len,
           len);
    buffer[len] = '\0';

    RAPTOR_FREE(cstring, ntriples_parser->line);

    ntriples_parser->line = buffer;
    ntriples_parser->line_length -= ntriples_parser->offset;
    ntriples_parser->offset = 0;

#if defined(RAPTOR_DEBUG) && RAPTOR_DEBUG > 1
    RAPTOR_DEBUG3("buffer now '%s' (%d bytes)\n", ntriples_parser->line, ntriples_parser->line_length);
#endif    
  }
  
  /* exit now, no more input */
  if(is_end) {
    if(ntriples_parser->offset != ntriples_parser->line_length) {
       raptor_parser_error(rdf_parser, "Junk at end of input.\"");
       return 1;
    }
    
    if(rdf_parser->emitted_default_graph) {
      raptor_parser_end_graph(rdf_parser, NULL, 0);
      rdf_parser->emitted_default_graph--;
    }

    return 0;
  }
    
  return 0;
}


static int
raptor_ntriples_parse_start(raptor_parser* rdf_parser) 
{
  raptor_locator *locator = &rdf_parser->locator;
  raptor_ntriples_parser_context *ntriples_parser = (raptor_ntriples_parser_context*)rdf_parser->context;

  locator->line = 1;
  locator->column = 0;
  locator->byte = 0;

  ntriples_parser->last_char = '\0';

  return 0;
}


#ifdef RAPTOR_PARSER_NTRIPLES
static int
raptor_ntriples_parse_recognise_syntax(raptor_parser_factory* factory, 
                                       const unsigned char *buffer, size_t len,
                                       const unsigned char *identifier, 
                                       const unsigned char *suffix, 
                                       const char *mime_type)
{
  int score = 0;
  
  if(suffix) {
    if(!strcmp((const char*)suffix, "nt"))
      score = 8;

    /* Explicitly refuse to do anything with Turtle or N3 named content */
    if(!strcmp((const char*)suffix, "ttl") ||
       !strcmp((const char*)suffix, "n3")) {
      return 0;
    }
  }
  
  if(mime_type) {
    if(strstr((const char*)mime_type, "ntriples"))
      score += 6;
  }
  
  if(buffer && len) {
    int has_ntriples_3;

    /* recognizing N-Triples is tricky but rely that it is line based
     * and that all URLs are absolute, and there are a lot of http:
     * URLs
     */
#define  HAS_AT_PREFIX (raptor_memstr((const char*)buffer, len, "@prefix ") != NULL)

#define  HAS_NTRIPLES_START_1_LEN 8
#define  HAS_NTRIPLES_START_1 (!memcmp((const char*)buffer, "<http://", HAS_NTRIPLES_START_1_LEN))
#define  HAS_NTRIPLES_START_2_LEN 2
#define  HAS_NTRIPLES_START_2 (!memcmp((const char*)buffer, "_:", HAS_NTRIPLES_START_2_LEN))

#define  HAS_NTRIPLES_1 (raptor_memstr((const char*)buffer, len, "\n<http://") != NULL)
#define  HAS_NTRIPLES_2 (raptor_memstr((const char*)buffer, len, "\r<http://") != NULL)
#define  HAS_NTRIPLES_3 (raptor_memstr((const char*)buffer, len, "> <http://") != NULL)
#define  HAS_NTRIPLES_4 (raptor_memstr((const char*)buffer, len, "> <") != NULL)
#define  HAS_NTRIPLES_5 (raptor_memstr((const char*)buffer, len, "> \"") != NULL)
    if(HAS_AT_PREFIX)
      /* Turtle */
      return 0;

    has_ntriples_3 = HAS_NTRIPLES_3;

    /* Bonus if the first bytes look N-Triples-like */
    if(len >= HAS_NTRIPLES_START_1_LEN && HAS_NTRIPLES_START_1)
      score++;
    if(len >= HAS_NTRIPLES_START_2_LEN && HAS_NTRIPLES_START_2)
      score++;

    if(HAS_NTRIPLES_1 || HAS_NTRIPLES_2) {
      /* N-Triples file with newlines and HTTP subjects */
      score += 6;
      if(has_ntriples_3)
        score++;
    } else if(has_ntriples_3) {
      /* an HTTP URL predicate or object but no HTTP subject */
      score += 3;
    } else if(HAS_NTRIPLES_4) {
      /* non HTTP urls - weak check */
      score += 2;
      if(HAS_NTRIPLES_5)
        /* bonus for a literal object */
        score++;
    }
  }

  return score;
}


static const char* const ntriples_names[2] = { "ntriples", NULL };

static const char* const ntriples_uri_strings[2] = {
  "http://www.w3.org/TR/rdf-testcases/#ntriples",
  NULL
};
  
#define NTRIPLES_TYPES_COUNT 1
static const raptor_type_q ntriples_types[NTRIPLES_TYPES_COUNT + 1] = {
  { "text/plain", 10, 1}, 
  { NULL, 0, 0}
};

static int
raptor_ntriples_parser_register_factory(raptor_parser_factory *factory) 
{
  int rc = 0;

  factory->desc.names = ntriples_names;

  factory->desc.mime_types = ntriples_types;

  factory->desc.label = "N-Triples";
  factory->desc.uri_strings = ntriples_uri_strings;

  factory->desc.flags = 0;
  
  factory->context_length     = sizeof(raptor_ntriples_parser_context);

  factory->init      = raptor_ntriples_parse_init;
  factory->terminate = raptor_ntriples_parse_terminate;
  factory->start     = raptor_ntriples_parse_start;
  factory->chunk     = raptor_ntriples_parse_chunk;
  factory->recognise_syntax = raptor_ntriples_parse_recognise_syntax;

  return rc;
}


int
raptor_init_parser_ntriples(raptor_world* world)
{
  return !raptor_world_register_parser_factory(world,
                                               &raptor_ntriples_parser_register_factory);
}

#endif


#ifdef RAPTOR_PARSER_NQUADS
static int
raptor_nquads_parse_recognise_syntax(raptor_parser_factory* factory, 
                                     const unsigned char *buffer, size_t len,
                                     const unsigned char *identifier, 
                                     const unsigned char *suffix, 
                                     const char *mime_type)
{
  int score = 0;
  
  if(suffix) {
    if(!strcmp((const char*)suffix, "nq"))
      score = 2;

    /* Explicitly refuse to do anything with N-Triples, Turtle or N3
     * named content 
     */
    if(!strcmp((const char*)suffix, "nt") ||
       !strcmp((const char*)suffix, "ttl") ||
       !strcmp((const char*)suffix, "n3")) {
      return 0;
    }
  }
  
  if(mime_type) {
    if(strstr((const char*)mime_type, "nquads"))
      score += 2;
  }
  
  /* Do not guess using content since it looks so similar to N-Triples */

  return score;
}


static const char* const nquads_names[2] = { "nquads", NULL };

static const char* const nquads_uri_strings[2] = {
  "http://sw.deri.org/2008/07/n-quads/",
  NULL
};
  
#define NQUADS_TYPES_COUNT 0
static const raptor_type_q nquads_types[NQUADS_TYPES_COUNT + 1] = {
  { NULL, 0, 0}
};

static int
raptor_nquads_parser_register_factory(raptor_parser_factory *factory) 
{
  int rc = 0;

  factory->desc.names = nquads_names;

  factory->desc.mime_types = nquads_types;

  factory->desc.label = "N-Quads";
  factory->desc.uri_strings = nquads_uri_strings;

  factory->desc.flags = 0;
  
  factory->context_length     = sizeof(raptor_ntriples_parser_context);

  factory->init      = raptor_ntriples_parse_init;
  factory->terminate = raptor_ntriples_parse_terminate;
  factory->start     = raptor_ntriples_parse_start;
  factory->chunk     = raptor_ntriples_parse_chunk;
  factory->recognise_syntax = raptor_nquads_parse_recognise_syntax;

  return rc;
}


int
raptor_init_parser_nquads(raptor_world* world)
{
  return !raptor_world_register_parser_factory(world,
                                               &raptor_nquads_parser_register_factory);
}
#endif

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