/**************************************************************************
 *
 * mg_text_estimate.c -- Program to estimate the compressed text size
 * Copyright (C) 1994  Neil Sharman
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 *
 **************************************************************************/

#include "sysfuncs.h"

#include "memlib.h"
#include "messages.h"
#include "local_strings.h"
#include "bitio_gen.h"
#include "bitio_m.h"
#include "bitio_m_stdio.h"
#include "timing.h"
#include "mgheap.h"
#include "netorder.h"  /* [RPAP - Jan 97: Endian Ordering] */

#include "mg_files.h"
#include "locallib.h"
#include "invf.h"
#include "text.h"
#include "words.h"
#include "mg.h"
#include "comp_dict.h"
#include "hash.h"





/*
   $Log$
   Revision 1.1  2003/02/20 21:18:24  mdewsnip
   Addition of MG package for search and retrieval

   Revision 1.1  1999/08/10 21:18:14  sjboddie
   renamed mg-1.3d directory mg

   Revision 1.4  1999/01/15 03:05:51  rjmcnab

   Renamed lib/heap to be lib/mgheap (it was causing some problems with
   some versions of the STL libraries which contained a heap.h)

   Revision 1.3  1998/12/17 09:12:53  rjmcnab

   Altered mg to process utf-8 encoded Unicode. The main changes
   are in the parsing of the input, the casefolding, and the stemming.

   Revision 1.2  1998/11/25 07:55:48  rjmcnab

   Modified mg to that you can specify the stemmer you want
   to use via a command line option. You specify it to
   mg_passes during the build process. The number of the
   stemmer that you used is stored within the inverted
   dictionary header and the stemmed dictionary header so
   the correct stemmer is used in later stages of building
   and querying.

   Revision 1.1  1998/11/17 09:35:19  rjmcnab
   *** empty log message ***

   * Revision 1.3  1994/10/20  03:56:59  tes
   * I have rewritten the boolean query optimiser and abstracted out the
   * components of the boolean query.
   *
   * Revision 1.2  1994/09/20  04:41:54  tes
   * For version 1.1
   *
 */

static char *RCSID = "$Id$";

typedef struct stats_t
  {
    mg_u_long freq, occur;
    mg_u_long len;
  }
stats_t;

static mg_u_long huff_count = 0;
static mg_u_long escape_count = 0;


char mode = 'H';

/* [RJM 07/97: 4G limit] */
static double ReadInWordsStandard (char *name, double *num_bytes);
static double ReadInWordsSpecial (char *name, double *num_bytes,
				  double *num_extra_bytes,
				  mg_u_long *aux_compressed);




int main (int argc, char **argv)
{
  char *stats_dict = NULL, *comp_dict = NULL;
  ProgTime StartTime;
  double num_bytes, num_extra_bytes = 0; /* [RJM 07/97: 4G limit] */
  mg_u_long aux_compressed;
  int ch;
  double bytes;
  opterr = 0;
  msg_prefix = argv[0];
  while ((ch = getopt (argc, argv, "BMDYHh")) != -1)
    switch (ch)
      {
      case 'B':
	Message ("The compressed text size for this method cannot be\n"
		 "estimated exactly, so an upper bound will be calculated.");
	mode = ch;
	break;
      case 'M':
	Message ("The compressed text size for this method cannot be\n"
		 "estimated exactly, so an upper bound will be calculated.");
	mode = 'Y';
	break;
      case 'D':
      case 'Y':
      case 'H':
	mode = ch;
	break;
      case 'h':
      case '?':
	fprintf (stderr, "usage: %s [-h] [B|M|D|Y|H] stats_dict comp_dict\n",
		 argv[0]);
	exit (1);
      }

  if (optind < argc)
    stats_dict = argv[optind++];
  else
    stats_dict = NULL;
  if (optind < argc)
    comp_dict = argv[optind++];
  else
    {
      fprintf (stderr, "usage: %s [-h] [B|M|D|Y|H] stats_dict comp_dict\n",
	       argv[0]);
      exit (1);
    }



  GetTime (&StartTime);

  if (LoadCompressionDictionary (comp_dict) == COMPERROR)
    exit (1);

  if (mode == 'H')
    bytes = ReadInWordsStandard (stats_dict, &num_bytes);
  else
    bytes = ReadInWordsSpecial (stats_dict, &num_bytes, &num_extra_bytes,
				&aux_compressed);


  Message ("Compressed Text %.2f Mb ( %.0f bytes   %0.3f %%)",
	   bytes / 1024.0 / 1024, bytes, bytes * 100 / num_bytes);
  Message ("Words portion of the dictionary %.2f Mb ( %.0f bytes   %0.3f %%)",
	   Words_disk / 1024.0 / 1024, Words_disk * 1.0,
	   (Words_disk * 100.0) / num_bytes);
  if (mode == 'H')
    Message ("Huffman info for chars in dictionary %.2f Mb ( %.0f bytes   %0.3f %%)",
	     Chars_disk / 1024.0 / 1024, Chars_disk * 1.0,
	     (Chars_disk * 100.0) / num_bytes);
  else
    {
      Message ("Aux dictionary (Uncompressed) %.2f Mb ( %.0f bytes   %0.3f %%)",
	       num_extra_bytes / 1024.0 / 1024, num_extra_bytes * 1.0,
	       (num_extra_bytes * 100.0) / num_bytes);
      Message ("Aux dictionary (Compressed)   %.2f Mb ( %.0f bytes   %0.3f %%)",
	       aux_compressed / 1024.0 / 1024, aux_compressed * 1.0,
	       (aux_compressed * 100.0) / num_bytes);
    }
  Message ("Words and non-words in the text %u", huff_count + escape_count);
  Message ("Words and non-words coded by escapes %u ( %0.3f %%)", escape_count,
	   escape_count * 100.0 / huff_count);
  Message ("%s", ElapsedTime (&StartTime, NULL));
  return 0;
}





static double 
ReadInWordsStandard (char *name, double *num_bytes)
{
  compression_stats_header csh;
  FILE *f;
  mg_u_long which;
  double bytes, bits = 0;

  f = open_named_file (name, "rb", MAGIC_STATS_DICT, MG_ABORT);  /* [RPAP - Feb 97: WIN32 Port] */

  fread (&csh, sizeof (csh), 1, f);

  /* [RPAP - Jan 97: Endian Ordering] */
  NTOHUL(csh.num_docs);
  NTOHD(csh.num_bytes); /* [RJM 07/97: 4G limit] */

  for (which = 0; which < 2; which++)
    {
      frags_stats_header fsh;
      int j;
      fread (&fsh, sizeof (fsh), 1, f);

      /* [RPAP - Jan 97: Endian Ordering] */
      NTOHUL(fsh.num_frags);
      NTOHUL(fsh.mem_for_frags);

      for (j = 0; j < fsh.num_frags; j++)
	{
	  int len, freq, res, occur_num;
	  u_char Word[16];
	  fread (&freq, sizeof (freq), 1, f);
	  fread (&occur_num, sizeof (occur_num), 1, f);
	  len = fgetc (f);

	  /* [RPAP - Jan 97: Endian Ordering] */
	  NTOHSI(freq);
	  NTOHSI(occur_num);

	  Word[0] = len;
	  fread (Word + 1, len, 1, f);

	  /* Search the hash table for Word */
	  if (ht[which])
	    {
	      register mg_u_long hashval, step;
	      register int tsize = ht[which]->size;
	      register u_char **wptr;
	      HASH (hashval, step, Word, tsize);
	      for (;;)
		{
		  register u_char *s1;
		  register u_char *s2;
		  register int len;
		  wptr = ht[which]->table[hashval];
		  if (wptr == NULL)
		    {
		      res = COMPERROR;
		      break;
		    }

		  /* Compare the words */
		  s1 = Word;
		  s2 = *wptr;
		  len = *s1 + 1;
		  for (; len; len--)
		    if (*s1++ != *s2++)
		      break;

		  if (len)
		    {
		      hashval += step;
		      if (hashval >= tsize)
			hashval -= tsize;
		    }
		  else
		    {
		      res = ht[which]->table[hashval] - ht[which]->words;
		      break;
		    }
		}
	    }
	  else
	    res = COMPERROR;

	  /* Check that the word was found in the dictionary */
	  if (res == COMPERROR)
	    {
	      escape_count += freq;
	      if (cdh.dict_type == MG_COMPLETE_DICTIONARY)
		Message ("Unknown word \"%.*s\"\n", *Word, Word + 1);
	      if (cdh.dict_type == MG_PARTIAL_DICTIONARY)
		{
		  unsigned i;
		  if (ht[which])
		    {
		      res = ht[which]->hd->num_codes - 1;
		      bits += ht[which]->hd->clens[res] * freq;
		    }
		  bits += lens_huff[which].clens[Word[0]] * freq;
		  for (i = 0; i < Word[0]; i++)
		    bits += char_huff[which].clens[Word[i + 1]] * freq;
		}
	      if (cdh.dict_type == MG_SEED_DICTIONARY)
		{
		  unsigned i;
		  if (ht[which])
		    {
		      res = ht[which]->hd->num_codes - 1;
		      bits += ht[which]->hd->clens[res] * freq;
		    }
		  bits += lens_huff[which].clens[Word[0]] * freq;
		  for (i = 0; i < Word[0]; i++)
		    bits += char_huff[which].clens[Word[i + 1]] * freq;
		}
	    }
	  else
	    {
	      bits += ht[which]->hd->clens[res] * freq;
	      huff_count += freq;
	    }
	}
    }
  fclose (f);


  /*
   * The 5.5 bits added on per document consist of
   *   1 bit for the word/non-word flag at the start of the document.
   *   1 bit on average for document termination.
   *   3.5 bits on average for padding to a byte boundary.
   */
  bits += 5.5 * csh.num_docs;

  bytes = bits / 8 + sizeof (compressed_text_header) + sizeof (mg_u_long);

  *num_bytes = csh.num_bytes;

  return bytes;
}


static int 
stats_comp (const void *a, const void *b)
{
  return ((stats_t *) a)->occur - ((stats_t *) b)->occur;
}





static double 
ReadInWordsSpecial (char *name, double *num_bytes,
		    double *num_extra_bytes,
		    mg_u_long *aux_compressed)
{
  compression_stats_header csh;
  FILE *f;
  mg_u_long magic, which;
  double bytes, bits = 0;
  double size[2];

  if (!(f = fopen (name, "rb")))  /* [RPAP - Feb 97: WIN32 Port] */
    FatalError (1, "Unable to open file \"%s\"\n", name);

  if (fread (&magic, sizeof (magic), 1, f) != 1)
    FatalError (1, "Unable to read magic number");

  NTOHUL(magic);  /* [RPAP - Jan 97: Endian Ordering] */

  if (magic != MAGIC_STATS_DICT)
    FatalError (1, "Bad magic number");

  fread (&csh, sizeof (csh), 1, f);

  /* [RPAP - Jan 97: Endian Ordering] */
  NTOHUL(csh.num_docs);
  NTOHD(csh.num_bytes); /* [RJM 07/97: 4G limit] */

  for (which = 0; which < 2; which++)
    {
      stats_t *stats;
      frags_stats_header fsh;
      int j, num = 0;
      mg_s_long lens[16], chars[256];

      bzero ((char *) lens, sizeof (lens));
      bzero ((char *) chars, sizeof (chars));

      fread (&fsh, sizeof (fsh), 1, f);

      /* [RPAP - Jan 97: Endian Ordering] */
      NTOHUL(fsh.num_frags);
      NTOHUL(fsh.mem_for_frags);

      stats = Xmalloc (fsh.num_frags * sizeof (*stats));
      if (!stats)
	FatalError (1, "Unable to allocate memory for stats");
      for (j = 0; j < fsh.num_frags; j++)
	{
	  int len, res;
	  u_char Word[16];
	  fread (&stats[num].freq, sizeof (stats[num].freq), 1, f);
	  fread (&stats[num].occur, sizeof (stats[num].occur), 1, f);
	  len = fgetc (f);

	  /* [RPAP - Jan 97: Endian Ordering] */
	  NTOHSI(stats[num].freq);
	  NTOHSI(stats[num].occur);

	  stats[num].len = len + 1;

	  Word[0] = len;
	  fread (Word + 1, len, 1, f);

	  /* Search the hash table for Word */
	  if (ht[which])
	    {
	      register mg_u_long hashval, step;
	      register int tsize = ht[which]->size;
	      register u_char **wptr;
	      HASH (hashval, step, Word, tsize);
	      for (;;)
		{
		  register u_char *s1;
		  register u_char *s2;
		  register int len;
		  wptr = ht[which]->table[hashval];
		  if (wptr == NULL)
		    {
		      res = COMPERROR;
		      break;
		    }

		  /* Compare the words */
		  s1 = Word;
		  s2 = *wptr;
		  len = *s1 + 1;
		  for (; len; len--)
		    if (*s1++ != *s2++)
		      break;

		  if (len)
		    {
		      hashval += step;
		      if (hashval >= tsize)
			hashval -= tsize;
		    }
		  else
		    {
		      res = ht[which]->table[hashval] - ht[which]->words;
		      break;
		    }
		}
	    }
	  else
	    res = COMPERROR;

	  assert (stats[num].freq > 0);

	  /* Check that the word was found in the dictionary */
	  if (res == COMPERROR)
	    {
	      if (cdh.dict_type == MG_COMPLETE_DICTIONARY)
		Message ("Unknown word \"%.*s\"\n", *Word, Word + 1);
	      if ((cdh.dict_type == MG_PARTIAL_DICTIONARY ||
		   cdh.dict_type == MG_SEED_DICTIONARY) &&
		  ht[which])
		{
		  int k;
		  res = ht[which]->hd->num_codes - 1;
		  bits += ht[which]->hd->clens[res] * stats[num].freq;
		  lens[Word[0]]++;
		  for (k = 0; k < (int) Word[0]; k++)
		    chars[Word[k + 1]]++;
		}
	      num++;
	    }
	  else
	    {
	      bits += ht[which]->hd->clens[res] * stats[num].freq;
	    }
	}

      {
	int j, num_buckets = 0;
	int start[10], end[10];
	mg_u_long flens[16], fchars[256];

	for (j = 0; j < 256; j++)
	  if (!chars[j] && PESINAWORD (j) == which)
	    fchars[j] = 1;
	  else
	    fchars[j] = chars[j];
	for (j = 0; j < 16; j++)
	  if (!lens[j])
	    flens[j] = 1;
	  else
	    flens[j] = lens[j];

	size[which] = Calculate_Huffman_Size (16, flens, lens) +
	  Calculate_Huffman_Size (256, fchars, chars);


	qsort (stats, num, sizeof (*stats), stats_comp);


	if (mode == 'Y')
	  {
	    int k;
	    num_buckets = 1;
	    start[0] = 0;
	    end[0] = cdh.num_words[which] - 1;
	    Message ("There are %d novel %swords", num, which ? "" : "non-");
	    while (end[num_buckets - 1] < num)
	      {
		start[num_buckets] = end[num_buckets - 1] + 1;
		end[num_buckets] = start[num_buckets] +
		  (end[num_buckets - 1] - start[num_buckets - 1]) * 2;
		num_buckets++;
	      }
	    for (k = 0; k < num_buckets; k++)
	      Message ("Bucket %d   %d <= x <= %d\n", k + 1, start[k], end[k]);
	  }

	for (j = 0; j < num; j++)
	  {
	    (*num_extra_bytes) += stats[j].len;
	    switch (mode)
	      {
	      case 'D':
		bits += BIO_Delta_Length (j + 1) * stats[j].freq;
		break;
	      case 'B':
		bits += BIO_Binary_Length (j + 1, num) * stats[j].freq;
		break;
	      case 'Y':
		{
		  int k = 0;
		  while (j > end[k])
		    k++;
		  if (!(j - start[k] + 1 >= 1 &&
			j - start[k] + 1 <= end[k] - start[k] + 1))
		    {
		      Message ("k = %d, j = %d", k, j);
		      assert (j - start[k] + 1 >= 1 &&
			      j - start[k] + 1 <= end[k] - start[k] + 1);
		    }
		  else
		    {
		      bits += (BIO_Gamma_Length (k + 1) +
			       BIO_Binary_Length (j - start[k] + 1,
						  end[k] - start[k] + 1)) *
			stats[j].freq;
		    }
		}
	      }
	  }
	if (mode == 'B' && num)
	  bits += BIO_Delta_Length (num) * csh.num_docs;
      }
      Xfree (stats);
    }
  fclose (f);

  *aux_compressed = (size[0] + size[1]) / 8;

  /*
   * The 5.5 bits added on per document consist of
   *   1 bit for the word/non-word flag at the start of the document.
   *   1 bit on average for document termination.
   *   3.5 bits on average for padding to a byte boundary.
   */
  bits += 5.5 * csh.num_docs;

  bytes = bits / 8 + sizeof (compressed_text_header) + sizeof (mg_u_long);

  *num_bytes = csh.num_bytes;

  return bytes;
}