IGBheader.cc

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// ----------------------------------------------------------------------------
// openCARP is an open cardiac electrophysiology simulator.
//
// Copyright (C) 2020 openCARP project
//
// 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 3 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, see <https://www.gnu.org/licenses/>.
// ----------------------------------------------------------------------------


#include<cstdlib>
#include<cstdio>
#include<iostream>
#include "IGBheader.h"
#include <cassert>
#include <cmath>
#include <cfloat>

using namespace std;

// -------------- Bits de statut pour Header_Read et Header_Write ------ */
#define     MOT_CLEF_INV    2
#define     GRANDEUR_INV    4

/*
 * Types de trames
 */
#define MIN_TRAME 0
#define C8    0
#define C4    1
#define HEX   2
#define HEXEDGES  3
#define HEXBRIDGES  4
#define HEXLINES  5
#define HEX2    6
#define MAX_TRAME 6
#define NTRAMES   7

#define LF  0x0A
#define FF  0x0C
#define CR  0x0D

/*---------------------------------------------------------------------------*\

        y  x->   1 2 3 4 5
        |
        v
          X|X|X|X|X|X
        1 -o-o-o-o-o-
          X|X|X|X|X|X
        2 -o-o-o-o-o-
  \|/       X|X|X|X|X|X
C8: -o-     3 -o-o-o-o-o-
  /|\       X|X|X|X|X|X
        4 -o-o-o-o-o-
          X|X|X|X|X|X
        5 -o-o-o-o-o-
          X|X|X|X|X|X

\*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*\

        y  x->   1 2 3 4 5
        |
        v
           | | | | |
        1 -o-o-o-o-o-
           | | | | |
        2 -o-o-o-o-o-
   |         | | | | |
C4: -o-     3 -o-o-o-o-o-
   |         | | | | |
        4 -o-o-o-o-o-
           | | | | |
        5 -o-o-o-o-o-
           | | | | |

\*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*\

        y  x->   1 2 3 4 5   1   2   3   4   5
        |
        v        1   2   3   4   5

          \|\|\|\|\|  \ / \ / \ / \ / \ /
        1 -o-o-o-o-o- -o---o---o---o---o---
      \|    /|/|/|/|/|/ / \ / \ / \ / \ / \ /
  y impair  -o- 2 -o-o-o-o-o- ---o---o---o---o---o-
      /|    \|\|\|\|\|\ \ / \ / \ / \ / \ / \
HEX:        3 -o-o-o-o-o- -o---o---o---o---o---
       |/   /|/|/|/|/|/ / \ / \ / \ / \ / \ /
  y pair    -o- 4 -o-o-o-o-o- ---o---o---o---o---o-
       |\   \|\|\|\|\|\ \ / \ / \ / \ / \ / \
        5 -o-o-o-o-o- -o---o---o---o---o---
          /|/|/|/|/|  / \ / \ / \ / \ / \

\*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*\

           x  x->  1 2 3 4 5   1   2   3   4   5   6

    impair  pair           1   2   3   4   5

        y          1   2   3   4   5
        |
    \|    v        1   2   3   4   5
  y%4==1  -o- -o-
    /|      \|  \|  \|  \ /  .  \ /  .  \ /  .
        1 -o-o-o-o-o- -o---o---o---o---o---o
     |    /   /|  /|  /|  / \  .  / \  .  / \  .
  y%4==2   o   o  2  o o o o o     o   o   o   o   o
     |  /    |/  |/  |/  .  \ /  .  \ /  .  \
HEXEDGES:     3 -o-o-o-o-o- -o---o---o---o---o---o
     |/      |\  |\  |\  .  / \  .  / \  .  /
  y%4==3  -o- -o- 4  o o o o o     o   o   o   o   o
     |\     \|  \|  \|  \ /  .  \ /  .  \ /  .
        5 -o-o-o-o-o- -o---o---o---o---o---o
     |  \   /|  /|  /|  / \  .  / \  .  / \  .
  y%4==0   o   o  6  o o o o o     o   o   o   o   o
     |    \    |/  |/  |   .  \ /  .  \ /  .  \

\*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*\

           x  x->  1  2  3  4  5   1   2   3   4   5   6


    impair  pair           1   2   3   4   5


        y          1   2   3   4   5
        |
        v
  y%4==1   o  -o-          1   2   3   4   5
                   .       .       .
        1  o -o- o -o- o   o  -o-  o  -o-  o  -o
                   .       .       .
     |    /    |   / |   / |    \ . . / \ . . / \ .
  y%4==2   o   o  2  o  o  o  o  o     o   o   o   o   o
     |  /    | /   | /   |    . \ / . . \ / . . \
               .       .       .
HEXBRIDGES:     3  o -o- o -o- o  -o-  o  -o-  o  -o-  o
               .       .       .
           | \   | \   |    . / \ . . / \ . . /
  y%4==3   o  -o- 4  o  o  o  o  o     o   o   o   o   o
           |   \ |   \ |    / . . \ / . . \ / .
                   .       .       .
        5  o -o- o -o- o   o  -o-  o  -o-  o  -o
                   .       .       .
     |  \    |   / |   / |    \ . . / \ . . / \ .
  y%4==0   o   o  6  o  o  o  o  o     o   o   o   o   o
     |    \    | /   | /   |  . \ / . . \ / . . \

\*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*\

           x  x->  1  2  3  4  5   1   2   3   4   5   6

    impair  pair           1   2   3   4   5

        y          1   2   3   4   5
        |
      \|  v        1   2   3   4   5
  y%4==1   o   o
      /|      \|  \|      \./     \./     \./
        1  o o o o o   o   o   o   o   o   o
      /  |      /|  /|  /     /.\     /.\     /.\
  y%4==2  -o-   -o- 2 -o-o-o-o-o- ---o---o---o---o---o---
    /  |    /  |/  |/ \./     \./     \./
HEXLINES:     3  o o o o o   o   o   o   o   o   o
       |/      |\  |\ /.\     /.\     /.\
  y%4==3   o   o  4 -o-o-o-o-o- ---o---o---o---o---o---
       |\     \|  \|      \./     \./     \./
        5  o o o o oo  o   o   o   o   o   o
    \  |      /|  /|  /     /.\     /.\     /.\
  y%4==0  -o- -o- 6 -o-o-o-o-o- ---o---o---o---o---o---
      \  |    /  |/  |/   /     \./     \./

\*---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------*\

        x->  1 2 3 4 5   1   2   3   4   5   6

        y        1   2   3   4   5
        |
        v          1   2   3   4   5

      \|           1   2   3   4   5
  y%4==1    -o-
      /|    \|\|\|\|\|  \ / \ / \ / \ / \ /
        1 -o-o-o-o-o- -o---o---o---o---o---o
       |/   /|/|/|/|/|  / \ / \ / \ / \ / \ /
  y%4==2    -o- 2 -o-o-o-o-o- ---o---o---o---o---o-
      /|    /|/|/|/|/|/ \ / \ / \ / \ / \ / \
HEX2:       3 -o-o-o-o-o- -o---o---o---o---o---o
       |/   \|\|\|\|\|  / \ / \ / \ / \ / \ /
  y%4==3    -o- 4 -o-o-o-o-o- ---o---o---o---o---o-
       |\   \|\|\|\|\|  \ / \ / \ / \ / \ / \
        5 -o-o-o-o-o- -o---o---o---o---o---o
      \|    /|/|/|/|/|  / \ / \ / \ / \ / \ /
  y%4==0    -o- 6 -o-o-o-o-o- ---o---o---o---o---o-
       |\   /|/|/|/|/|    / \ / \ / \ / \ / \

\*---------------------------------------------------------------------------*/

// -------------- Definitions pour conv_date --------------------------- */

#define FRANCAIS  0
#define ANGLAIS   1
#define NUMERIQUE 2
#define IGB_DATE    0

// -------------- Constantes diverses ---------------------------------- */

#define     MAXL      80  //  Longueur maximale d'une ligne d'entete */
#define     N_MAX_ITEMS     30  //  Nombre maximal d'items optionnels */
#define     L_MAX_ITEM      49  //  Longueur maximale pour un item
#ifndef     VRAI
#define     VRAI      1
#endif
#ifndef     FAUX
#define     FAUX      0
#endif


int my_fputs( FILE *, char * );

bool Header_Quiet = false;
char Header_Message[256];

const char *Header_Type[] =
  {
    "", "byte", "char", "short", "long", "float", "double", "complex",
    "double_complex", "rgba", "structure", "pointer", "list","int","uint",
    "ushort",
  "vec3f","vec3d","vec4f","vec4d","hfloat","vec9f","vec9d"
  };


const char *deprecated[] = {
    "fac_x", "fac_y", "fac_z", "fac_t"
  };

//* size of the stored data, not the variable type
const size_t Data_Size[] =
  {
    0, sizeof(Byte), sizeof(char), sizeof(short), sizeof(long), sizeof(float),
    sizeof(double), 0, 0, 0, 0, sizeof(void *), 0, sizeof(int), sizeof(UInt),
    sizeof(unsigned short),
    3*sizeof(float), 3*sizeof(double), 4*sizeof(float), 4*sizeof(double),
    sizeof(short_float), 9*sizeof(float), 9*sizeof(double)
  };


const unsigned short Num_Components[] =
  {
    0, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 3, 3, 4, 4, 1, 9, 9
  };


const unsigned long
Header_Systeme_No[] =
  {
    IGB_BIG_ENDIAN,
    IGB_LITTLE_ENDIAN
  };

const char
*Header_Systeme[] =
  {
    "big_endian",
    "little_endian"
  };


static bool
is_deprecated( char *s ) {
  for( size_t i=0; i<sizeof(deprecated)/sizeof(deprecated[0]); i++ )
    if( !strcmp( s, deprecated[i] ) )
      return true;
  return false;
}

#define MAKE_CONSISTENT( D ) \
  if( bool_dim_##D && bool_inc_##D && bool_##D ) \
    if(  !almost_equal(v_dim_##D, v_inc_##D * (v_##D-1) ) ) { \
      fprintf( stderr, "Adjusting dim_%s to make dimensions consistent\n", #D ); \
      v_dim_##D = v_inc_##D * (v_##D-1);\
    }


IGBheader::IGBheader( FILE *f, bool _read, bool quiet )
{
  fileptr(f);
  if( _read )
    if( read( quiet ) )
      throw 1;
}


IGBheader::IGBheader( gzFile f, bool _read, bool quiet )
{
  fileptr(f);
  if( _read )
    if( read( quiet ) )
      throw 1;
}


IGBheader::~IGBheader()
{}


// set output for gzipped output
void IGBheader::fileptr( gzFile fp )
{
  file = fp;
  gzipping = true;
}

// set output for normal unziped output
void IGBheader::fileptr( FILE* fp )
{
  file = fp;
  gzipping = false;
}


int IGBheader::write()
{
  int statut = 1;

  if (getenv("HEADER_QUIET")) Header_Quiet = VRAI;

  if (file==NULL) {
    if (!Header_Quiet)
      cerr<< "\nERREUR: descripteur de fichier nul\n";
    snprintf(Header_Message, sizeof Header_Message, "\nERREUR: descripteur de fichier nul\n");
    return(0) ;
  }

  if (v_type<IGB_MIN_TYPE || v_type>IGB_MAX_TYPE) {
    if (!Header_Quiet)
      cerr<< "\nHeader_Write: type inconnu: "<< v_type;
    snprintf(Header_Message, sizeof Header_Message, "\nHeader_Write: type inconnu: %d\n",
            v_type);
    return (0);
  }
  const char *type = Header_Type[v_type];

  if (v_type==IGB_STRUCTURE && v_taille<1) {
    if (!Header_Quiet)
      cerr << "\nHeader_Write: taille invalide:" << v_taille << endl;
    snprintf(Header_Message, sizeof Header_Message, "\nHeader_Write: taille invalide: %d\n",
            v_taille);
    return (0);
  }

  if (v_trame<MIN_TRAME || v_trame>MAX_TRAME) {
    if (!Header_Quiet)
      fprintf(stderr, "\nHeader_Write: trame inconnue: %d\n", v_trame);
    snprintf(Header_Message, sizeof Header_Message, "\nHeader_Write: trame inconnue: %d\n",
            v_trame);
    return (0);
  }

  MAKE_CONSISTENT( x );
  MAKE_CONSISTENT( y );
  MAKE_CONSISTENT( z );
  MAKE_CONSISTENT( t );

  char ligne[1024];
  if (bool_t) {
    if (bool_z) {
      snprintf(ligne, sizeof ligne, "x:%zu y:%zu z:%zu t:%zu type:%s systeme:%s ",
              v_x, v_y, v_z, v_t, type, systemestr());
    } else {
      snprintf(ligne, sizeof ligne, "x:%zu y:%zu t:%zu type:%s systeme:%s ",
              v_x, v_y, v_t, type, systemestr());
    }
  } else {
    if (bool_z) {
      snprintf(ligne, sizeof ligne, "x:%zu y:%zu z:%zu type:%s systeme:%s ",
              v_x, v_y, v_z, type, systemestr());
    } else {
      snprintf(ligne, sizeof ligne, "x:%zu y:%zu type:%s systeme:%s ",
              v_x, v_y, type, systemestr());
    }
  }
  int n_car = strlen(ligne);

  int n_lignes = 1;
  int n_items = 0;
  int l_item[N_MAX_ITEMS+1];
  char items[N_MAX_ITEMS+1][L_MAX_ITEM];
  /*
     Le mot-clef "taille" n'est ecrit que pour le type STRUCTURE mais il est
     obligatoire pour ce cas.
   */
  if (v_type==IGB_STRUCTURE) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "taille:%d ", v_taille);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_org_x) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "org_x:%g ", v_org_x);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_org_y) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "org_y:%g ", v_org_y);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_org_z) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "org_z:%g ", v_org_z);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_org_t) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "org_t:%g ", v_org_t);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_dim_x) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "dim_x:%g ", v_dim_x);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_inc_x) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "dim_x:%g ", v_inc_x);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_dim_y) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "dim_y:%g ", v_dim_y);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_inc_y) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "dim_y:%g ", v_inc_y);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_dim_z) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "dim_z:%g ", v_dim_z);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_inc_z) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "dim_z:%g ", v_inc_z);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_dim_t) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "dim_t:%g ", v_dim_t);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_inc_t) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "inc_t:%g ", v_inc_t);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_vect_z) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "vect_z:1 ");
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_unites_x) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "unites_x:%.40s ", v_unites_x);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_unites_y) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "unites_y:%.40s ", v_unites_y);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_unites_z) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "unites_z:%.40s ", v_unites_z);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_unites_t) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "unites_t:%.40s ", v_unites_t);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_num) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "num:%d ", v_num);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_bin) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "bin:%d ", v_bin);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_trame) {
    switch (v_trame) {
      case C8:
        snprintf(&items[n_items][0], L_MAX_ITEM, "trame:c8 ");
        break;
      case C4:
        snprintf(&items[n_items][0], L_MAX_ITEM, "trame:c4 ");
        break;
      case HEX:
        snprintf(&items[n_items][0], L_MAX_ITEM, "trame:hex ");
        break;
      case HEXEDGES:
        snprintf(&items[n_items][0], L_MAX_ITEM, "trame:hexedges ");
        break;
      case HEXBRIDGES:
        snprintf(&items[n_items][0], L_MAX_ITEM, "trame:hexbridges ");
        break;
      case HEXLINES:
        snprintf(&items[n_items][0], L_MAX_ITEM, "trame:hexlines ");
        break;
      case HEX2:
        snprintf(&items[n_items][0], L_MAX_ITEM, "trame:hex2 ");
        break;
    }
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_lut) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "lut:%d ", v_lut);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_comp) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "comp:%d ", v_comp);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_epais) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "epais:%g ", v_epais);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_unites) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "unites:%.40s ", v_unites);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_facteur) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "facteur:%g ", v_facteur);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_zero) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "zero:%g ", v_zero);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if ( v_transparent != NULL ) {
    char *p=(char *)v_transparent, value[MAXL];
    int a;
    for ( a=0; a<Data_Size[v_type]; a++ )
      snprintf( value+a*2, MAXL, "%0.2x", *(p++) );
    value[2*Data_Size[v_type]] = '\0';
    snprintf(&items[n_items][0], L_MAX_ITEM, "transparent:%s ", value );
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_struct_desc) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "struct:%.40s ", v_struct_desc);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  if (bool_aut_name) {
    snprintf(&items[n_items][0], L_MAX_ITEM, "aut:%.40s ", v_aut_name);
    l_item[n_items] = strlen(&items[n_items][0]);
    n_items++;
  }
  int n_car_total = 0;
  int n_comment = 0;
  char **comment;
  if (bool_comment) {
    comment = v_comment;
    while (*comment != NULL) {
      n_comment++;
      n_car_total += strlen(*comment++) + 3;
    }
  }

  /*
     Ecrit tous les items, sauf les commentaires
   */
  for (int i=0;i<n_items;i++) {
    if (n_car+l_item[i]<71) {   /*  Ajoute a la ligne courante s'il reste de la place */
      strcat(ligne, &items[i][0]);
      n_car += l_item[i];
    } else {        /*  Sinon, ecrit cette ligne et commence-en une autre */
      ligne[n_car++] = '\r';
      ligne[n_car++] = '\n';
      ligne[n_car]   = '\000';
      n_car_total += n_car;
      if (puts_fcn( ligne)==-1) {
        if (!Header_Quiet) {
          fprintf(stderr, "\nHeader_Write: Erreur a l'ecriture \n");
          perror("\n *** ");
          fprintf(stderr,  "\n");
        }
        snprintf(Header_Message, sizeof Header_Message, "\nHeader_Write: Erreur a l'ecriture \n");
        return (0);
      }
      strcpy(ligne, &items[i][0]);
      n_car = l_item[i];
      n_lignes++;
    }
  }

  /*
     Termine la derniere ligne
   */
  ligne[n_car++] = '\r';
  ligne[n_car++] = '\n';
  ligne[n_car]   = '\000';
  n_car_total += n_car;
  if (puts_fcn( ligne )==-1) {
    if (!Header_Quiet) {
      fprintf(stderr, "\nHeader_Write: Erreur a l'ecriture \n");
      perror("\n *** ");
      fprintf(stderr,  "\n");
    }
    snprintf(Header_Message, sizeof Header_Message, "\nHeader_Write: Erreur a l'ecriture \n");
    return (0);
  }
  n_lignes++;

  /*
     Determine le nombre de caracteres et de lignes supplementaires
     necessaires
   */
  int n_blocs   = 1 + (n_car_total-1)/1024;
  int n_car_sup = n_blocs*1024 - n_car_total;
  int n_lig_sup;
  if (n_car_sup>0) {
    n_lig_sup = 1 + (n_car_sup-1)/72;
  } else {
    n_lig_sup = 0;
  }
  int n_car_dl  = 1 + (n_car_sup-1)%72;

  /*
     Ecrit les commentaires
   */
  if (bool_comment) {
    comment = v_comment;
    while (*comment != NULL) {
      if( gzipping )
        n_car = gzprintf((gzFile)file, "#%.80s\r\n", *comment++);
      else
        n_car = fprintf((FILE*)file, "#%.80s\r\n", *comment++);
      if (n_car==0) {
        if (!Header_Quiet) {
          fprintf(stderr, "\nHeader_Write: Erreur a l'ecriture \n");
          perror("\n *** ");
          fprintf(stderr,  "\n");
        }
        snprintf(Header_Message, sizeof Header_Message, "\nHeader_Write: Erreur a l'ecriture \n");
        return (0);
      }
    }
  }

  /*
     Complete l'entete a un multiple de 1024 caracteres
   */
  for (int i=0;i<70;i++) ligne[i] = ' ';
  ligne[70] = '\r';
  ligne[71] = '\n';
  ligne[72] = '\000';
  for (int i=0;i<n_lig_sup-1;i++) {
    if (puts_fcn( ligne)==-1) {
      if (!Header_Quiet) {
        fprintf(stderr, "\nHeader_Write: Erreur a l'ecriture \n");
        perror("\n *** ");
        fprintf(stderr,  "\n");
      }
      snprintf(Header_Message, sizeof Header_Message, "\nHeader_Write: Erreur a l'ecriture \n");
      return 0;
    }
  }

  /*
     La derniere ligne se termine par un saut de page (FF)
   */
  for (int i=0;i<n_car_dl-2;i++) ligne[i] = ' ';
  if (n_car_dl>2) ligne[n_car_dl-3] = '\r';
  if (n_car_dl>1) ligne[n_car_dl-2] = '\n';
  ligne[n_car_dl-1] = FF;
  ligne[n_car_dl] = '\000';
  if (puts_fcn( ligne )==-1) {
    if (!Header_Quiet) {
      fprintf(stderr, "\nHeader_Write: Erreur a l'ecriture \n");
      perror("\n *** ");
      fprintf(stderr,  "\n");
    }
    snprintf(Header_Message, sizeof Header_Message, "\nHeader_Write: Erreur a l'ecriture \n");
    return (0);
  }

  if (n_car_total>1024) {
    if (!Header_Quiet)
      fprintf(stderr,
              "\nHeader_Write ATTENTION: etiquette de grandeur non-standard \n");
    snprintf(Header_Message, sizeof Header_Message,
            "\nHeader_Write ATTENTION: etiquette de grandeur non-standard \n");
    statut |= GRANDEUR_INV;
  } else {
    snprintf(Header_Message, sizeof Header_Message,
            "\nHeader_Write: Entete transcrite sans problemes\n");
  }

  /*
  if (bool_vect_z) {
    if (v_vect_z==NULL) {
      if (!Header_Quiet)
        fprintf(stderr,"\nERREUR: vect_z nul\n");
      snprintf(Header_Message, sizeof Header_Message, "\nERREUR: vect_z nul\n");
      return(0) ;
    }
    gzwrite(file, v_vect_z, sizeof(float)*v_z);
  }
  */

  return (statut);

}


int IGBheader::read( bool quiet )
{
  int   go=VRAI, nosup=VRAI;
  int   in, com=0;
  char  str[MAXL+1];
  int   statut=0;
  float v_fac_t;
  bool  bool_fac_t = false;

  Header_Quiet = quiet;

  /* --- pour toutes les lignes de l'entete (def=8) ou jusqu'a un <FF> -- */
  for ( int s=8; (s>0 || nosup) && go; s-- ) {

    /* --- lit la ligne dans le fichier --- */
    int i = 0 ;
    if( tell()<0 ) return 2;

    while (1) {

      /* --- (ligne trop longue) --> erreur --- */
      if ( i >= 80 ) {
        if (!Header_Quiet)
          fprintf(stderr,
                  "\nERREUR ligne trop longue (>80) dans l'entete !\n" ) ;
        snprintf(Header_Message, sizeof Header_Message,
                "\nERREUR ligne trop longue (>80) dans l'entete !\n" ) ;
        return ERR_LINE_TOO_LONG;
      }

      /* --- lit le caractere suivant --- */
      in = get_character() ;

      /* --- (EOF dans l'entete) --> erreur --- */
      if ( in == -1 ) {
        if (!Header_Quiet)
          fprintf(stderr,
                  "\nERREUR Fin de fichier dans l'entete !\n" ) ;
        snprintf(Header_Message, sizeof Header_Message,
                "\nERREUR Fin de fichier dans l'entete !\n" ) ;
        return ERR_EOF_IN_HEADER;
      }

      /* --- FF --> termine le header --- */
      else if ( in == FF ) {
        str[i] = '\000' ;
        go = FAUX ;
        break ;
      }

      /* --- CR et LF --> termine la ligne --- */
      else if ( in == CR ) {
        str[i] = '\000' ;
      } else if ( in == LF ) {
        str[i] = '\000' ;
        break ;
      }

      /* --- (0x20 < caractere > 0x7E) si non --> erreur --- */
      else if ( in && ! isprint(in) ) {
        if (!Header_Quiet)
          fprintf(stderr,
                  "\nERREUR caract. non imprim. 0x%.2X dans "
                  "l'entete at byte number %ld\n", in, tell() );
        snprintf(Header_Message, sizeof Header_Message,
                "\nERREUR caract. non imprim. 0x%.2X dans l'entete !\n", in );
        return ERR_UNPRINTABLE_CHAR;
      } else {
        str[i++] = (char) in ;
      }

    }

    /* --- ----- ----- ----- sauve les commentaires ----- ----- --- */
    for ( char* pt_1=str; *pt_1; pt_1++ ) {

      /* --- '*' ou '#' = commentaires ------> dans comment --- */
      if ( *pt_1 == '*' || *pt_1 == '#') {
        if ( *(pt_1+1) ) {
          v_comment[com] = (char *)malloc( strlen(pt_1+1) + 1 ) ;
          strcpy( v_comment[com++], pt_1+1 ) ;
          if (com%NALLOC == 0)
            v_comment = (char **)
                realloc(v_comment, (com+NALLOC)*sizeof(char *));
          v_comment[com] = NULL ;
          bool_comment = VRAI;
        }
        *pt_1 = '\000' ;
        break ;
      }

      /* --- convertit majuscule un minuscules --- */
      if (isupper(*pt_1)) *pt_1 = tolower( *pt_1 ) ;

    }


    /* --- ----- ----- ----- analyse la ligne ----- ----- ----- --- */
    for ( char *pt_1=strtok(str," ,;\t"); pt_1; pt_1=strtok(NULL," ,;\t") ) {

      /* --- separe la chaine de caract. --- */
      /* --- pt_1 pointe au key_word ---- */
      /* --- pt_2 pointe a la donne  ---- */
      char *pt_2;
      for ( pt_2 = pt_1; *pt_2 != ':'; pt_2 ++ )
        if ( ! *pt_2 ) {
          if (!Header_Quiet)
            fprintf(stderr,
                    "\nERREUR de syntaxe dans l'entete (%s)\n", pt_1);
          snprintf(Header_Message, sizeof Header_Message,
                  "\nERREUR de syntaxe dans l'entete (%s)\n", pt_1);
          return ERR_IGB_SYNTAX;
        }

      *pt_2++ = '\000' ;

      /* --- recherche le mot-clef --- */
      if ( ! strcmp( pt_1, "x" ) ) {
        v_x = strtoul(pt_2, NULL, 10);
        bool_x = VRAI;

      } else if ( ! strcmp( pt_1, "y" ) ) {
        v_y = strtoul(pt_2, NULL, 10) ;
        bool_y = VRAI;

      } else if ( ! strcmp( pt_1, "z" ) ) {
        v_z = strtoul(pt_2, NULL, 10) ;
        bool_z = VRAI;

      } else if ( ! strcmp( pt_1, "t" ) ) {
        v_t = strtoul(pt_2, NULL, 10) ;
        bool_t = VRAI;

        /* Pour compatibilite avec les vielles images */
      } else if ( ! strcmp( pt_1, "sup" ) ) {
        s += atoi( pt_2 ) ;
        nosup = FAUX;

      } else if ( ! strcmp( pt_1, "type" ) ) {

        for( int htype=IGB_MIN_TYPE; htype<=IGB_MAX_TYPE; htype++ )
          if ( !strcmp( pt_2, Header_Type[htype] ) ) {
            v_type = htype;
          }
        bool_type = VRAI;

      } else if ( ! strcmp( pt_1, "taille" ) ) {
        v_taille = atoi( pt_2 ) ;
        bool_taille = VRAI;

      } else if ( ! strcmp( pt_1, "systeme" ) ) {
        v_systeme = INCONNU;
        for (i=0;i<N_SYSTEMES;i++) {
          if ( ! strcmp( pt_2, Header_Systeme[i] ) ) {
            v_systeme = Header_Systeme_No[i] ;
            break;
          }
        }

      } else if ( ! strcmp( pt_1, "bin" ) ) {
        v_bin = atoi( pt_2 ) ;
        bool_bin = VRAI;

      } else if ( ! strcmp( pt_1, "trame" ) ) {

        if ( ! strcmp( pt_2, "c8" ) ) {
          v_trame = C8 ;
        } else if ( ! strcmp( pt_2, "c4" ) ) {
          v_trame = C4 ;
        } else if ( ! strcmp( pt_2, "hex" ) ) {
          v_trame = HEX ;
        } else if ( ! strcmp( pt_2, "hexedges" ) ) {
          v_trame = HEXEDGES ;
        } else if ( ! strcmp( pt_2, "hexbridges" ) ) {
          v_trame = HEXBRIDGES ;
        } else if ( ! strcmp( pt_2, "hexlines" ) ) {
          v_trame = HEXLINES ;
        } else if ( ! strcmp( pt_2, "hex2" ) ) {
          v_trame = HEX2 ;
        }
        bool_trame = VRAI;

      } else if ( ! strcmp( pt_1, "num" ) ) {
        v_num = atoi( pt_2 ) ;
        bool_num = VRAI;

      } else if ( ! strcmp( pt_1, "comp" ) ) {
        v_comp = atoi( pt_2 ) ;
        bool_comp = VRAI;

      } else if ( ! strcmp( pt_1, "lut" ) ) {
        v_lut = atoi( pt_2 ) ;
        bool_lut = VRAI;

      } else if ( ! strcmp( pt_1, "dim_x" ) ) {
        v_dim_x = atof( pt_2 ) ;
        bool_dim_x = VRAI;

      } else if ( ! strcmp( pt_1, "dim_y" ) ) {
        v_dim_y = atof( pt_2 ) ;
        bool_dim_y = VRAI;

      } else if ( ! strcmp( pt_1, "dim_z" ) ) {
        v_dim_z = atof( pt_2 ) ;
        bool_dim_z = VRAI;

      } else if ( ! strcmp( pt_1, "dim_t" ) ) {
        v_dim_t = atof( pt_2 ) ;
        bool_dim_t = VRAI;

      } else if ( ! strcmp( pt_1, "inc_x" ) ) {
        v_inc_x = atof( pt_2 ) ;
        bool_inc_x = VRAI;

      } else if ( ! strcmp( pt_1, "inc_y" ) ) {
        v_inc_y = atof( pt_2 ) ;
        bool_inc_y = VRAI;

      } else if ( ! strcmp( pt_1, "inc_z" ) ) {
        v_inc_z = atof( pt_2 ) ;
        bool_inc_z = VRAI;

      } else if ( ! strcmp( pt_1, "inc_t" ) ) {
        v_inc_t = atof( pt_2 ) ;
        bool_inc_t = VRAI;

      } else if ( ! strcmp( pt_1, "org_x" ) ) {
        v_org_x = atof( pt_2 ) ;
        bool_org_x = VRAI;

      } else if ( ! strcmp( pt_1, "org_y" ) ) {
        v_org_y = atof( pt_2 ) ;
        bool_org_y = VRAI;

      } else if ( ! strcmp( pt_1, "org_z" ) ) {
        v_org_z = atof( pt_2 ) ;
        bool_org_z = VRAI;

      } else if ( ! strcmp( pt_1, "org_t" ) ) {
        v_org_t = atof( pt_2 ) ;
        bool_org_t = VRAI;

      } else if ( ! strcmp( pt_1, "vect_z" ) ) {
        bool_vect_z = VRAI;

      } else if ( ! strcmp( pt_1, "unites_x" ) ) {
        strncpy( v_unites_x, pt_2, 40 ) ;
        bool_unites_x = VRAI;

      } else if ( ! strcmp( pt_1, "unites_y" ) ) {
        strncpy( v_unites_y, pt_2, 40 ) ;
        bool_unites_y = VRAI;

      } else if ( ! strcmp( pt_1, "unites_z" ) ) {
        strncpy( v_unites_z, pt_2, 40 ) ;
        bool_unites_z = VRAI;

      } else if ( ! strcmp( pt_1, "unites_t" ) ) {
        strncpy( v_unites_t, pt_2, 40 ) ;
        bool_unites_t = VRAI;

      } else if ( ! strcmp( pt_1, "epais" ) ) {
        v_epais = atof( pt_2 ) ;
        bool_epais = VRAI;

      } else if ( ! strcmp( pt_1, "unites" ) ) {
        strncpy( v_unites, pt_2, 40 ) ;
        bool_unites = VRAI;

      } else if ( ! strcmp( pt_1, "facteur" ) ) {
        v_facteur = atof( pt_2 ) ;
        bool_facteur = VRAI;

      } else if ( ! strcmp( pt_1, "zero" ) ) {
        v_zero = atof( pt_2 ) ;
        bool_zero = VRAI;

      } else if ( ! strcmp( pt_1, "struct" ) ) {
        strncpy( v_struct_desc, pt_2, 40 ) ;
        bool_struct_desc = VRAI;

      } else if ( ! strcmp( pt_1, "aut" ) ) {
        strncpy( v_aut_name, pt_2, 40 ) ;
        bool_aut_name = VRAI;

      } else if ( !strcmp( pt_1, "transparent" ) ) {
        strcpy( transstr, pt_2 );
        bool_transparent = VRAI;

      } else {
        if( is_deprecated( pt_1 ) ){
          if (!Header_Quiet)
            fprintf(stderr,"\nATTENTION: mot-clef %s obsolete !\n", pt_1 ) ;
          if( !strcmp( pt_1, "fac_t" ) ){
            v_fac_t = atof( pt_2 );
            bool_fac_t = VRAI;
          }
        } else {
          if (!Header_Quiet)
            fprintf(stderr,"\nATTENTION: mot-clef %s non reconnu !\n", pt_1 );
          snprintf(Header_Message, sizeof Header_Message,
                  "\nATTENTION: mot-clef %s non reconnu !\n", pt_1 ) ;
          statut |= MOT_CLEF_INV;
        }
      }
    }
  }
  /* determine the transparent value if one was chosen */
  if ( bool_transparent ) {
    if ( strlen(transstr) != 2*Data_Size[v_type] ) {
      fprintf(stderr,"ATTENTION: ignoring invalid transparent value !\n");
    } else {
      char s[3], *p, *v;
      s[2] = '\0';
      v = (char *)(v_transparent = calloc( Data_Size[v_type], 1 ));
      for ( int i=0; i<Data_Size[v_type]; i++ ) {
        s[0] = transstr[i*2];
        s[1] = transstr[i*2+1];
        v[i] = strtol( s, &p, 16 );
      }
    }
  }

  /* --- l'info x y et type est obligatoire --- */
  if ( !bool_x || !bool_y || !bool_type ) {
    if (!Header_Quiet)
      fprintf(stderr, "\nERREUR x, y ou type non definis\n") ;
    snprintf(Header_Message, sizeof Header_Message, "\nERREUR x, y ou type non definis\n") ;
    return ERR_UNDEFINED_X_Y_TYPE ;
  }

  /* --- calcul des inc et dim --- */
  if ( bool_dim_x )
    if ( bool_inc_x ) {
      float dim_x = v_inc_x * v_x ;
      if ( !almost_equal(dim_x, v_dim_x) ) {
        if (!Header_Quiet) {
          fprintf(stderr, "\nATTENTION:\n") ;
          fprintf(stderr,
              "conflit entre x (%zu) * inc_x (%.12g) = %.12g et dim_x (%.12g)\n",
                  v_x, v_inc_x, dim_x, v_dim_x) ;
        }
        snprintf(Header_Message, sizeof Header_Message,
              "conflit entre x (%zu) * inc_x (%.12g) = %.12g et dim_x (%.12g)\n",
                v_x, v_inc_x, dim_x, v_dim_x) ;
        statut = WARN_DIM_INCONSISTENT ;
      }
    } else {
      v_inc_x = v_dim_x / v_x ;
      bool_inc_x = VRAI;
    }
    else {
      v_dim_x = v_x * v_inc_x ;
      if ( bool_inc_x ) bool_dim_x = VRAI;
    }

  if ( bool_dim_y )
    if ( bool_inc_y ) {
      float dim_y = v_inc_y * v_y ;
      if ( !almost_equal(dim_y, v_dim_y) ) {
        if (!Header_Quiet) {
          fprintf(stderr, "\nATTENTION:\n") ;
          fprintf(stderr,
              "conflit entre y (%zu) * inc_y (%.12g) = %.12g et dim_y (%.12g)\n",
                 v_y, v_inc_y, dim_y, v_dim_y) ;
        }
        snprintf(Header_Message, sizeof Header_Message,
              "conflit entre y (%zu) * inc_y (%.12g) = %.12g et dim_y (%.12g)\n",
                v_y, v_inc_y, dim_y, v_dim_y) ;
        statut = WARN_DIM_INCONSISTENT ;
      }
    } else {
      v_inc_y = v_dim_y / v_y ;
      bool_inc_y = VRAI;
    }
    else {
      v_dim_y = v_y * v_inc_y ;
      if ( bool_inc_y ) bool_dim_y = VRAI;
    }

  if ( bool_dim_z )
    if ( bool_inc_z ) {
      float dim_z = v_inc_z * v_z ;
      if ( !almost_equal(dim_z, v_dim_z) ) {
        if (!Header_Quiet) {
          fprintf(stderr, "\nATTENTION:\n") ;
          fprintf(stderr,
              "conflit entre z (%zu) * inc_z (%.12g) = %.12g et dim_z (%.12g)\n",
                 v_z, v_inc_z, dim_z, v_dim_z) ;
        }
        snprintf(Header_Message, sizeof Header_Message,
              "conflit entre z (%zu) * inc_z (%.12g) = %.12g et dim_z (%.12g)\n",
                v_z, v_inc_z, dim_z, v_dim_z) ;
        statut = WARN_DIM_INCONSISTENT ;
      }
    } else {
      v_inc_z = v_dim_z / v_z ;
      bool_inc_z = VRAI;
    }
    else {
      v_dim_z = v_z * v_inc_z ;
      if ( bool_inc_z ) bool_dim_z = VRAI;
    }

  if( !bool_inc_t && bool_fac_t ) {
    bool_inc_t = VRAI;
    v_inc_t = v_fac_t;
  }
  if ( bool_dim_t )
    if ( bool_inc_t ) {
      float dim_t = v_inc_t * (v_t-1) ;
      if ( !almost_equal(dim_t, v_dim_t) ) {
        if (!Header_Quiet) {
          fprintf(stderr, "\nATTENTION:\n") ;
          fprintf(stderr,
              "conflit entre t (%zu) * inc_t (%.12g) = %.12g et dim_t (%.12g)\n",
                  v_t, v_inc_t, dim_t, v_dim_t) ;
        }
        snprintf(Header_Message, sizeof Header_Message,
              "conflit entre t (%zu) * inc_t (%.12g) = %.12g et dim_t (%.12g)\n",
                v_t, v_inc_t, dim_t, v_dim_t) ;
        v_dim_t = dim_t;
        //statut = WARN_DIM_INCONSISTENT ;
      }
    } else {
      v_inc_t = v_dim_t / (v_t - 1) ;
      bool_inc_t = VRAI;
    }
    else {
      v_dim_t = (v_t-1) * v_inc_t ;
      if ( bool_inc_t )
        bool_dim_t = VRAI;
    }

  if ( bool_taille ) {
    if (v_type!=IGB_STRUCTURE) {
      if (!Header_Quiet)
        fprintf(stderr,
                "\nERREUR taille redefinie pour type autre que structure\n") ;
      snprintf(Header_Message, sizeof Header_Message,
              "\nERREUR taille redefinie pour type autre que structure\n") ;
      return ERR_SIZE_REDEFINED;
    }
  } else {
    if (v_type==IGB_STRUCTURE) {
      if (!Header_Quiet)
        fprintf(stderr,
                "\nERREUR taille non definie pour type structure\n") ;
      snprintf(Header_Message, sizeof Header_Message,
              "\nERREUR taille non definie pour type structure\n") ;
      return ERR_SIZE_NOT_DEFINED;
    } else {
      v_taille = Data_Size[v_type];
    }
  }

  if (tell()!=1024) {
    seek( 1024, SEEK_SET );
    if (!Header_Quiet) {
      fprintf(stderr,
              "\nATTENTION: etiquette de grandeur non-standard: %ld \n", tell());
    }
    snprintf(Header_Message, sizeof Header_Message,
            "\nATTENTION: etiquette de grandeur non-standard \n");
    statut |= GRANDEUR_INV;
  } else {
    snprintf(Header_Message, sizeof Header_Message,
            "\nHeader_Read: Etiquette lue sans problemes\n");
  }

  if (bool_vect_z) {
    v_vect_z = (float *)malloc(v_z*sizeof(float));
    read_vz(v_vect_z, sizeof(float)*v_z);
  }

  return statut;
}

/*
 * add a comment line
 * clear comments is NULL is passed
 */
void IGBheader::comment(const char *ligne)
{
  const int maxln = 78;
  int i = 0, n_lignes = 0;

  if ( ligne == NULL ) {
    while ( v_comment[n_lignes] != NULL )
      free( v_comment[n_lignes++] );
    return;
  }

  int newlines = (strlen(ligne)+maxln-1)/maxln;
  while (v_comment[i++]!=NULL) n_lignes++;
  v_comment = (char **)realloc(v_comment, (n_lignes+newlines+1)*sizeof(char *));

  for( int j=0; j<newlines; j++ ){
    v_comment[n_lignes] = (char *)malloc(maxln+2) ;
    v_comment[n_lignes][maxln] = '\0';
    strncpy(v_comment[n_lignes++], ligne+j*maxln, maxln);
  }
  v_comment[n_lignes] = NULL;
  bool_comment = true;
}

const char *IGBheader::systemestr( void )
{
  int i;

  for ( i=0; i<N_SYSTEMES; i++ )
    if ( Header_Systeme_No[i] == v_systeme )
      break;

  if ( i<N_SYSTEMES )
    return Header_Systeme[i];
  else
    return NULL;
}


void IGBheader::systeme( const char* s )
{
  int i;
  for ( i=0; i<N_SYSTEMES; i++ )
    if ( !strncmp( Header_Systeme[i], s, strlen(s) ) )
      break;

  if ( i<N_SYSTEMES )
    v_systeme = Header_Systeme_No[i];
}


void IGBheader::type( char *datatype )
{
  int tn=IGB_MIN_TYPE;
  while ( tn<=IGB_MAX_TYPE && strcmp(Header_Type[tn],datatype) )
    tn++;
  if ( tn<=IGB_MAX_TYPE )
    v_type = tn;
  else {
    cerr << "illegal data type specified for IGB header" << endl;
    exit(1);
  }
  bool_type = true;
}


// simple wrapper for ftell/gztell
long IGBheader::tell()
{
    if( gzipping )
      return gztell( (gzFile)file );
    else {
      if( file==stdin )
        return bytes_read; //tricked to think a proper sized header has been read
      else
        return ftell( (FILE*)file );
    }
}


// simple wrapper so gzputs and fputs argument order jive
int IGBheader::puts_fcn( char* s )
{
  if ( gzipping ) {
    gzFile gzf=(gzFile)file;
    return gzputs( gzf, s );
  } else {
    FILE *fptr=(FILE *)file;
    return fputs( s, fptr );
  }
}


void IGBheader :: swab( void *data, int nd )
{
  if ( data_size()==1 || v_type==IGB_RGBA )
    return;

  unsigned char *bp = (unsigned char *)data;
  int ds = data_size()/num_components();

  if ( nd<0 ) nd = v_x*v_y*v_z*v_t;

  nd *= num_components();

  switch ( ds ) {
    case 2:
      for ( int i=0; i<nd; i++ ) {
        unsigned char tmpb = bp[0];
        bp[0] = bp[1];
        bp[1] = tmpb;
        bp += data_size();
      }
      break;
    case 4:
      for ( int i=0; i<nd; i++ ) {
        unsigned char tmpb = bp[0];
        bp[0] = bp[3];
        bp[3] = tmpb;
        tmpb = bp[1];
        bp[1] = bp[2];
        bp[2] = tmpb;
        bp += data_size();
      }
      break;
    case 8:
      for ( int i=0; i<nd; i++ ) {
        unsigned char tmpb = bp[0];
        bp[0] = bp[7];
        bp[7] = tmpb;
        tmpb = bp[1];
        bp[1] = bp[6];
        bp[6] = tmpb;
        tmpb = bp[2];
        bp[2] = bp[5];
        bp[5] = tmpb;
        tmpb = bp[3];
        bp[3] = bp[4];
        bp[4] = tmpb;
        bp += data_size();
      }
      break;
  }
}


int IGBheader::endian()
{
  float val=IGB_ENDIAN_VAL;
  unsigned char   le_val[] = { IGB_LITTLE_END_REP },
                    *pval   = (unsigned char *)(&val);

  assert( sizeof(float) == 4 );

  if ( *pval == le_val[0] )
    return IGB_LITTLE_ENDIAN;
  else
    return IGB_BIG_ENDIAN;
}

int IGBheader::get_character()
{
    if( gzipping )
      return gzgetc( (gzFile)file );
    else {
      if( file==stdin ) bytes_read++;
      return fgetc( (FILE*)file );
    }
}


int IGBheader::seek(size_t offset, int whence)
{
  if( gzipping )
    return gzseek( (gzFile)file, offset, whence );
  else {
    if( file == stdin ) {
      size_t pos;
      if(whence==SEEK_SET) {
        if( offset < bytes_read ) 
          return -1;
        pos = offset - bytes_read;
      } else if(whence==SEEK_CUR)
        pos = offset;
      else
        return -1;
      for( int i=0; i<pos; i++ ) getchar();
      bytes_read += pos;
      return 0;
    } else
      return fseek( (FILE*)file, offset, whence );
  }
}

int IGBheader::read_vz( float *vz, int sz )
{
    if( gzipping )
      return gzread( (gzFile)file, vz, sz );
    else {
      bytes_read += sz;
      return fread( vz, sz, 1, (FILE*)file );
    }
}


int IGBheader:: go2slice(size_t s)
{
  s *= slice_sz() * data_size();
  s += 1024;
  return seek( s, SEEK_SET );
}