/*
   Copyright (c) 2000, 2011, Oracle and/or its affiliates.
   Copyright (c) 2009, 2013, Monty Program Ab.

   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; version 2 of the License.

   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

/*
  Functions to create a unireg form-file from a FIELD and a fieldname-fieldinfo
  struct.
  In the following functions FIELD * is an ordinary field-structure with
  the following exeptions:
    sc_length,typepos,row,kol,dtype,regnr and field need not to be set.
    str is a (long) to record position where 0 is the first position.
*/

#include <my_global.h>
#include "sql_priv.h"
#include "unireg.h"
#include "sql_partition.h"                      // struct partition_info
#include "sql_class.h"                  // THD, Internal_error_handler
#include "create_options.h"
#include "discover.h"
#include <m_ctype.h>

#define FCOMP			17		/* Bytes for a packed field */

/* threshold for safe_alloca */
#define ALLOCA_THRESHOLD       2048

static uint pack_keys(uchar *,uint, KEY *, ulong);
static bool pack_header(THD *, uchar *, List<Create_field> &, uint, ulong, handler *);
static uint get_interval_id(uint *,List<Create_field> &, Create_field *);
static bool pack_fields(uchar *, List<Create_field> &, ulong);
static size_t packed_fields_length(List<Create_field> &);
static bool make_empty_rec(THD *, uchar *, uint, List<Create_field> &, uint, ulong);

/*
  write the length as
  if (  0 < length <= 255)      one byte
  if (256 < length <= 65535)    zero byte, then two bytes, low-endian
*/
static uchar *extra2_write_len(uchar *pos, size_t len)
{
  if (len <= 255)
    *pos++= len;
  else
  {
    /*
      At the moment we support options_len up to 64K.
      We can easily extend it in the future, if the need arises.
    */
    DBUG_ASSERT(len <= 65535);
    int2store(pos + 1, len);
    pos+= 3;
  }
  return pos;
}

static uchar *extra2_write(uchar *pos, enum extra2_frm_value_type type,
                           LEX_STRING *str)
{
  *pos++ = type;
  pos= extra2_write_len(pos, str->length);
  memcpy(pos, str->str, str->length);
  return pos + str->length;
}

static uchar *extra2_write(uchar *pos, enum extra2_frm_value_type type,
                           LEX_CUSTRING *str)
{
  return extra2_write(pos, type, reinterpret_cast<LEX_STRING *>(str));
}

/**
  Create a frm (table definition) file

  @param thd                    Thread handler
  @param table                  Name of table
  @param create_info            create info parameters
  @param create_fields          Fields to create
  @param keys                   number of keys to create
  @param key_info               Keys to create
  @param db_file                Handler to use.

  @return the generated frm image as a LEX_CUSTRING,
  or null LEX_CUSTRING (str==0) in case of an error.
*/

LEX_CUSTRING build_frm_image(THD *thd, const char *table,
                              HA_CREATE_INFO *create_info,
                              List<Create_field> &create_fields,
                              uint keys, KEY *key_info, handler *db_file)
{
  LEX_STRING str_db_type;
  uint reclength, key_info_length, i;
  ulong key_buff_length;
  ulong filepos, data_offset;
  uint options_len;
  uint gis_extra2_len= 0;
  uchar fileinfo[FRM_HEADER_SIZE],forminfo[FRM_FORMINFO_SIZE];
  const partition_info *part_info= IF_PARTITIONING(thd->work_part_info, 0);
  int error;
  uchar *frm_ptr, *pos;
  LEX_CUSTRING frm= {0,0};
  DBUG_ENTER("build_frm_image");

 /* If fixed row records, we need one bit to check for deleted rows */
  if (!(create_info->table_options & HA_OPTION_PACK_RECORD))
    create_info->null_bits++;
  data_offset= (create_info->null_bits + 7) / 8;

  error= pack_header(thd, forminfo, create_fields, create_info->table_options,
                     data_offset, db_file);

  if (error)
    DBUG_RETURN(frm);

  reclength=uint2korr(forminfo+266);

  /* Calculate extra data segment length */
  str_db_type= *hton_name(create_info->db_type);
  /* str_db_type */
  create_info->extra_size= (2 + str_db_type.length +
                            2 + create_info->connect_string.length);
  /*
    Partition:
      Length of partition info = 4 byte
      Potential NULL byte at end of partition info string = 1 byte
      Indicator if auto-partitioned table = 1 byte
      => Total 6 byte
  */
  create_info->extra_size+= 6;
  if (part_info)
    create_info->extra_size+= part_info->part_info_len;

  for (i= 0; i < keys; i++)
  {
    if (key_info[i].parser_name)
      create_info->extra_size+= key_info[i].parser_name->length + 1;
  }

  options_len= engine_table_options_frm_length(create_info->option_list,
                                               create_fields,
                                               keys, key_info);
#ifdef HAVE_SPATIAL
  gis_extra2_len= gis_field_options_image(NULL, create_fields);
#endif /*HAVE_SPATIAL*/
  DBUG_PRINT("info", ("Options length: %u", options_len));

  if (validate_comment_length(thd, &create_info->comment, TABLE_COMMENT_MAXLEN,
                              ER_TOO_LONG_TABLE_COMMENT, table))
     DBUG_RETURN(frm);
  /*
    If table comment is longer than TABLE_COMMENT_INLINE_MAXLEN bytes,
    store the comment in an extra segment (up to TABLE_COMMENT_MAXLEN bytes).
    Pre 5.5, the limit was 60 characters, with no extra segment-handling.
  */
  if (create_info->comment.length > TABLE_COMMENT_INLINE_MAXLEN)
  {
    forminfo[46]=255;
    create_info->extra_size+= 2 + create_info->comment.length;
  }
  else
  {
    strmake((char*) forminfo+47, create_info->comment.str ?
            create_info->comment.str : "", create_info->comment.length);
    forminfo[46]=(uchar) create_info->comment.length;
  }

  if (!create_info->tabledef_version.str)
  {
    uchar *to= (uchar*) thd->alloc(MY_UUID_SIZE);
    if (unlikely(!to))
      DBUG_RETURN(frm);
    my_uuid(to);
    create_info->tabledef_version.str= to;
    create_info->tabledef_version.length= MY_UUID_SIZE;
  }
  DBUG_ASSERT(create_info->tabledef_version.length > 0);
  DBUG_ASSERT(create_info->tabledef_version.length <= 255);

  prepare_frm_header(thd, reclength, fileinfo, create_info, keys, key_info);

  /* one byte for a type, one or three for a length */
  uint extra2_size= 1 + 1 + create_info->tabledef_version.length;
  if (options_len)
    extra2_size+= 1 + (options_len > 255 ? 3 : 1) + options_len;

  if (part_info)
    extra2_size+= 1 + 1 + hton_name(part_info->default_engine_type)->length;

  if (gis_extra2_len)
    extra2_size+= 1 + (gis_extra2_len > 255 ? 3 : 1) + gis_extra2_len;


  key_buff_length= uint4korr(fileinfo+47);

  frm.length= FRM_HEADER_SIZE;                  // fileinfo;
  frm.length+= extra2_size + 4;                 // mariadb extra2 frm segment

  int2store(fileinfo+4, extra2_size);
  int2store(fileinfo+6, frm.length);            // Position to key information
  frm.length+= key_buff_length;
  frm.length+= reclength;                       // row with default values
  frm.length+= create_info->extra_size;

  filepos= frm.length;
  frm.length+= FRM_FORMINFO_SIZE;               // forminfo
  frm.length+= packed_fields_length(create_fields);

  if (frm.length > FRM_MAX_SIZE)
  {
    my_error(ER_TABLE_DEFINITION_TOO_BIG, MYF(0), table);
    DBUG_RETURN(frm);
  }

  frm_ptr= (uchar*) my_malloc(frm.length, MYF(MY_WME | MY_ZEROFILL |
                                              MY_THREAD_SPECIFIC));
  if (!frm_ptr)
    DBUG_RETURN(frm);

  /* write the extra2 segment */
  pos = frm_ptr + 64;
  compile_time_assert(EXTRA2_TABLEDEF_VERSION != '/');
  pos= extra2_write(pos, EXTRA2_TABLEDEF_VERSION,
                    &create_info->tabledef_version);

  if (part_info)
    pos= extra2_write(pos, EXTRA2_DEFAULT_PART_ENGINE,
                      hton_name(part_info->default_engine_type));

  if (options_len)
  {
    *pos++= EXTRA2_ENGINE_TABLEOPTS;
    pos= extra2_write_len(pos, options_len);
    pos= engine_table_options_frm_image(pos, create_info->option_list,
                                        create_fields, keys, key_info);
  }

#ifdef HAVE_SPATIAL
  if (gis_extra2_len)
  {
    *pos= EXTRA2_GIS;
    pos= extra2_write_len(pos+1, gis_extra2_len);
    pos+= gis_field_options_image(pos, create_fields);
  }
#endif /*HAVE_SPATIAL*/

  int4store(pos, filepos); // end of the extra2 segment
  pos+= 4;

  DBUG_ASSERT(pos == frm_ptr + uint2korr(fileinfo+6));
  key_info_length= pack_keys(pos, keys, key_info, data_offset);

  int2store(forminfo+2, frm.length - filepos);
  int4store(fileinfo+10, frm.length);
  fileinfo[26]= (uchar) MY_TEST((create_info->max_rows == 1) &&
                                (create_info->min_rows == 1) && (keys == 0));
  int2store(fileinfo+28,key_info_length);

  if (part_info)
  {
    fileinfo[61]= (uchar) ha_legacy_type(part_info->default_engine_type);
    DBUG_PRINT("info", ("part_db_type = %d", fileinfo[61]));
  }

  int2store(fileinfo+59,db_file->extra_rec_buf_length());

  memcpy(frm_ptr, fileinfo, FRM_HEADER_SIZE);

  pos+= key_buff_length;
  if (make_empty_rec(thd, pos, create_info->table_options, create_fields,
                     reclength, data_offset))
    goto err;

  pos+= reclength;
  int2store(pos, create_info->connect_string.length);
  pos+= 2;
  memcpy(pos, create_info->connect_string.str, create_info->connect_string.length);
  pos+= create_info->connect_string.length;
  int2store(pos, str_db_type.length);
  pos+= 2;
  memcpy(pos, str_db_type.str, str_db_type.length);
  pos+= str_db_type.length;

  if (part_info)
  {
    char auto_partitioned= part_info->is_auto_partitioned ? 1 : 0;
    int4store(pos, part_info->part_info_len);
    pos+= 4;
    memcpy(pos, part_info->part_info_string, part_info->part_info_len + 1);
    pos+= part_info->part_info_len + 1;
    *pos++= auto_partitioned;
  }
  else
  {
    pos+= 6;
  }

  for (i= 0; i < keys; i++)
  {
    if (key_info[i].parser_name)
    {
      memcpy(pos, key_info[i].parser_name->str, key_info[i].parser_name->length + 1);
      pos+= key_info[i].parser_name->length + 1;
    }
  }
  if (forminfo[46] == (uchar)255)       // New style MySQL 5.5 table comment
  {
    int2store(pos, create_info->comment.length);
    pos+=2;
    memcpy(pos, create_info->comment.str, create_info->comment.length);
    pos+= create_info->comment.length;
  }

  memcpy(frm_ptr + filepos, forminfo, 288);
  if (pack_fields(frm_ptr + filepos + 288, create_fields, data_offset))
    goto err;

  {
    /* 
      Restore all UCS2 intervals.
      HEX representation of them is not needed anymore.
    */
    List_iterator<Create_field> it(create_fields);
    Create_field *field;
    while ((field=it++))
    {
      if (field->save_interval)
      {
        field->interval= field->save_interval;
        field->save_interval= 0;
      }
    }
  }

  frm.str= frm_ptr;
  DBUG_RETURN(frm);

err:
  my_free(frm_ptr);
  DBUG_RETURN(frm);
}


/**
  Create a frm (table definition) file and the tables

  @param thd           Thread handler
  @param frm           Binary frm image of the table to create
  @param path          Name of file (including database, without .frm)
  @param db            Data base name
  @param table_name    Table name
  @param create_info   create info parameters
  @param file          Handler to use or NULL if only frm needs to be created

  @retval 0   ok
  @retval 1   error
*/

int rea_create_table(THD *thd, LEX_CUSTRING *frm,
                     const char *path, const char *db, const char *table_name,
                     HA_CREATE_INFO *create_info, handler *file,
                     bool no_ha_create_table)
{
  DBUG_ENTER("rea_create_table");

  if (no_ha_create_table)
  {
    if (writefrm(path, db, table_name, true, frm->str, frm->length))
      goto err_frm;
  }

  if (thd->variables.keep_files_on_create)
    create_info->options|= HA_CREATE_KEEP_FILES;

  if (file->ha_create_partitioning_metadata(path, NULL, CHF_CREATE_FLAG))
    goto err_part;

  if (!no_ha_create_table)
  {
    if (ha_create_table(thd, path, db, table_name, create_info, frm))
      goto err_part;
  }

  DBUG_RETURN(0);

err_part:
  file->ha_create_partitioning_metadata(path, NULL, CHF_DELETE_FLAG);
err_frm:
  deletefrm(path);
  DBUG_RETURN(1);
} /* rea_create_table */


/* Pack keyinfo and keynames to keybuff for save in form-file. */

static uint pack_keys(uchar *keybuff, uint key_count, KEY *keyinfo,
                      ulong data_offset)
{
  uint key_parts,length;
  uchar *pos, *keyname_pos;
  KEY *key,*end;
  KEY_PART_INFO *key_part,*key_part_end;
  DBUG_ENTER("pack_keys");

  pos=keybuff+6;
  key_parts=0;
  for (key=keyinfo,end=keyinfo+key_count ; key != end ; key++)
  {
    int2store(pos, (key->flags ^ HA_NOSAME));
    int2store(pos+2,key->key_length);
    pos[4]= (uchar) key->user_defined_key_parts;
    pos[5]= (uchar) key->algorithm;
    int2store(pos+6, key->block_size);
    pos+=8;
    key_parts+=key->user_defined_key_parts;
    DBUG_PRINT("loop", ("flags: %lu  key_parts: %d  key_part: 0x%lx",
                        key->flags, key->user_defined_key_parts,
                        (long) key->key_part));
    for (key_part=key->key_part,key_part_end=key_part+key->user_defined_key_parts ;
	 key_part != key_part_end ;
	 key_part++)

    {
      uint offset;
      DBUG_PRINT("loop",("field: %d  startpos: %lu  length: %d",
			 key_part->fieldnr, key_part->offset + data_offset,
                         key_part->length));
      int2store(pos,key_part->fieldnr+1+FIELD_NAME_USED);
      offset= (uint) (key_part->offset+data_offset+1);
      int2store(pos+2, offset);
      pos[4]=0;					// Sort order
      int2store(pos+5,key_part->key_type);
      int2store(pos+7,key_part->length);
      pos+=9;
    }
  }
	/* Save keynames */
  keyname_pos=pos;
  *pos++=(uchar) NAMES_SEP_CHAR;
  for (key=keyinfo ; key != end ; key++)
  {
    uchar *tmp=(uchar*) strmov((char*) pos,key->name);
    *tmp++= (uchar) NAMES_SEP_CHAR;
    *tmp=0;
    pos=tmp;
  }
  *(pos++)=0;
  for (key=keyinfo,end=keyinfo+key_count ; key != end ; key++)
  {
    if (key->flags & HA_USES_COMMENT)
    {
      int2store(pos, key->comment.length);
      uchar *tmp= (uchar*)strnmov((char*) pos+2,key->comment.str,
                                  key->comment.length);
      pos= tmp;
    }
  }

  if (key_count > 127 || key_parts > 127)
  {
    keybuff[0]= (key_count & 0x7f) | 0x80;
    keybuff[1]= key_count >> 7;
    int2store(keybuff+2,key_parts);
  }
  else
  {
    keybuff[0]=(uchar) key_count;
    keybuff[1]=(uchar) key_parts;
    keybuff[2]= keybuff[3]= 0;
  }
  length=(uint) (pos-keyname_pos);
  int2store(keybuff+4,length);
  DBUG_RETURN((uint) (pos-keybuff));
} /* pack_keys */


/* Make formheader */

static bool pack_header(THD *thd, uchar *forminfo,
                        List<Create_field> &create_fields,
                        uint table_options, ulong data_offset, handler *file)
{
  uint length,int_count,int_length,no_empty, int_parts;
  uint time_stamp_pos,null_fields;
  ulong reclength, totlength, n_length, com_length, vcol_info_length;
  DBUG_ENTER("pack_header");

  if (create_fields.elements > MAX_FIELDS)
  {
    my_message(ER_TOO_MANY_FIELDS, ER_THD(thd, ER_TOO_MANY_FIELDS), MYF(0));
    DBUG_RETURN(1);
  }

  totlength= 0L;
  reclength= data_offset;
  no_empty=int_count=int_parts=int_length=time_stamp_pos=null_fields=0;
  com_length=vcol_info_length=0;
  n_length=2L;

  /* Check fields */
  List_iterator<Create_field> it(create_fields);
  Create_field *field;
  while ((field=it++))
  {
    if (validate_comment_length(thd, &field->comment, COLUMN_COMMENT_MAXLEN,
                                ER_TOO_LONG_FIELD_COMMENT, field->field_name))
       DBUG_RETURN(1);

    if (field->vcol_info)
    {
      uint col_expr_maxlen= field->virtual_col_expr_maxlen();
      uint tmp_len= my_charpos(system_charset_info,
                               field->vcol_info->expr_str.str,
                               field->vcol_info->expr_str.str +
                               field->vcol_info->expr_str.length,
                               col_expr_maxlen);

      if (tmp_len < field->vcol_info->expr_str.length)
      {
        my_error(ER_WRONG_STRING_LENGTH, MYF(0),
                 field->vcol_info->expr_str.str,"VIRTUAL COLUMN EXPRESSION",
                 col_expr_maxlen);
        DBUG_RETURN(1);
      }
      /*
        Sum up the length of the expression string and the length of the
        mandatory header to the total length of info on the defining 
        expressions saved in the frm file for virtual columns.
      */
      vcol_info_length+= field->vcol_info->expr_str.length+
	                 FRM_VCOL_HEADER_SIZE(field->interval);
    }

    totlength+= field->length;
    com_length+= field->comment.length;
    if (MTYP_TYPENR(field->unireg_check) == Field::NOEMPTY ||
	field->unireg_check & MTYP_NOEMPTY_BIT)
    {
      field->unireg_check= (Field::utype) ((uint) field->unireg_check |
					   MTYP_NOEMPTY_BIT);
      no_empty++;
    }
    /* 
      We mark first TIMESTAMP field with NOW() in DEFAULT or ON UPDATE 
      as auto-update field.
    */
    if (field->sql_type == MYSQL_TYPE_TIMESTAMP &&
        MTYP_TYPENR(field->unireg_check) != Field::NONE &&
	!time_stamp_pos)
      time_stamp_pos= (uint) field->offset+ (uint) data_offset + 1;
    length=field->pack_length;
    if ((uint) field->offset+ (uint) data_offset+ length > reclength)
      reclength=(uint) (field->offset+ data_offset + length);
    n_length+= (ulong) strlen(field->field_name)+1;
    field->interval_id=0;
    field->save_interval= 0;
    if (field->interval)
    {
      uint old_int_count=int_count;

      if (field->charset->mbminlen > 1)
      {
        /* 
          Escape UCS2 intervals using HEX notation to avoid
          problems with delimiters between enum elements.
          As the original representation is still needed in 
          the function make_empty_rec to create a record of
          filled with default values it is saved in save_interval
          The HEX representation is created from this copy.
        */
        field->save_interval= field->interval;
        field->interval= (TYPELIB*) thd->alloc(sizeof(TYPELIB));
        *field->interval= *field->save_interval; 
        field->interval->type_names= 
          (const char **) thd->alloc(sizeof(char*) * 
                                     (field->interval->count+1));
        field->interval->type_names[field->interval->count]= 0;
        field->interval->type_lengths=
          (uint *) thd->alloc(sizeof(uint) * field->interval->count);
 
        for (uint pos= 0; pos < field->interval->count; pos++)
        {
          char *dst;
          const char *src= field->save_interval->type_names[pos];
          uint hex_length;
          length= field->save_interval->type_lengths[pos];
          hex_length= length * 2;
          field->interval->type_lengths[pos]= hex_length;
          field->interval->type_names[pos]= dst=
            (char*) thd->alloc(hex_length + 1);
          octet2hex(dst, src, length);
        }
      }

      field->interval_id=get_interval_id(&int_count,create_fields,field);
      if (old_int_count != int_count)
      {
	for (const char **pos=field->interval->type_names ; *pos ; pos++)
	  int_length+=(uint) strlen(*pos)+1;	// field + suffix prefix
	int_parts+=field->interval->count+1;
      }
    }
    if (f_maybe_null(field->pack_flag))
      null_fields++;
  }
  int_length+=int_count*2;			// 255 prefix + 0 suffix

  /* Save values in forminfo */
  if (reclength > (ulong) file->max_record_length())
  {
    my_error(ER_TOO_BIG_ROWSIZE, MYF(0), static_cast<long>(file->max_record_length()));
    DBUG_RETURN(1);
  }
  /* Hack to avoid bugs with small static rows in MySQL */
  reclength=MY_MAX(file->min_record_length(table_options),reclength);
  if ((ulong) create_fields.elements*FCOMP+FRM_FORMINFO_SIZE+
      n_length+int_length+com_length+vcol_info_length > 65535L || 
      int_count > 255)
  {
    my_message(ER_TOO_MANY_FIELDS, ER_THD(thd, ER_TOO_MANY_FIELDS), MYF(0));
    DBUG_RETURN(1);
  }

  bzero((char*)forminfo,FRM_FORMINFO_SIZE);
  length=(create_fields.elements*FCOMP+FRM_FORMINFO_SIZE+n_length+int_length+
	  com_length+vcol_info_length);
  int2store(forminfo,length);
  forminfo[256] = 0;
  int2store(forminfo+258,create_fields.elements);
  int2store(forminfo+260,0);
  int2store(forminfo+262,totlength);
  int2store(forminfo+264,no_empty);
  int2store(forminfo+266,reclength);
  int2store(forminfo+268,n_length);
  int2store(forminfo+270,int_count);
  int2store(forminfo+272,int_parts);
  int2store(forminfo+274,int_length);
  int2store(forminfo+276,time_stamp_pos);
  int2store(forminfo+278,80);			/* Columns needed */
  int2store(forminfo+280,22);			/* Rows needed */
  int2store(forminfo+282,null_fields);
  int2store(forminfo+284,com_length);
  int2store(forminfo+286,vcol_info_length);
  DBUG_RETURN(0);
} /* pack_header */


/* get each unique interval each own id */
static uint get_interval_id(uint *int_count,List<Create_field> &create_fields,
			    Create_field *last_field)
{
  List_iterator<Create_field> it(create_fields);
  Create_field *field;
  TYPELIB *interval=last_field->interval;

  while ((field=it++) != last_field)
  {
    if (field->interval_id && field->interval->count == interval->count)
    {
      const char **a,**b;
      for (a=field->interval->type_names, b=interval->type_names ;
	   *a && !strcmp(*a,*b);
	   a++,b++) ;

      if (! *a)
      {
	return field->interval_id;		// Re-use last interval
      }
    }
  }
  return ++*int_count;				// New unique interval
}


static size_t packed_fields_length(List<Create_field> &create_fields)
{
  Create_field *field;
  size_t length= 0;
  DBUG_ENTER("packed_fields_length");

  List_iterator<Create_field> it(create_fields);
  uint int_count=0;
  while ((field=it++))
  {
    if (field->interval_id > int_count)
    {
      int_count= field->interval_id;
      length++;
      for (int i=0; field->interval->type_names[i]; i++)
      {
        length+= field->interval->type_lengths[i];
        length++;
      }
      length++;
    }
    if (field->vcol_info)
    {
      length+= field->vcol_info->expr_str.length +
               FRM_VCOL_HEADER_SIZE(field->interval);
    }
    length+= FCOMP;
    length+= strlen(field->field_name)+1;
    length+= field->comment.length;
  }
  length++;
  length++;
  DBUG_RETURN(length);
}

/* Save fields, fieldnames and intervals */

static bool pack_fields(uchar *buff, List<Create_field> &create_fields,
                        ulong data_offset)
{
  uint int_count, comment_length= 0, vcol_info_length=0;
  Create_field *field;
  DBUG_ENTER("pack_fields");

  /* Write field info */
  List_iterator<Create_field> it(create_fields);
  int_count=0;
  while ((field=it++))
  {
    uint recpos;
    uint cur_vcol_expr_len= 0;
    int2store(buff+3, field->length);
    /* The +1 is here becasue the col offset in .frm file have offset 1 */
    recpos= field->offset+1 + (uint) data_offset;
    int3store(buff+5,recpos);
    int2store(buff+8,field->pack_flag);
    DBUG_ASSERT(field->unireg_check < 256);
    buff[10]= (uchar) field->unireg_check;
    buff[12]= (uchar) field->interval_id;
    buff[13]= (uchar) field->sql_type; 
    if (field->sql_type == MYSQL_TYPE_GEOMETRY)
    {
      buff[11]= 0;
      buff[14]= (uchar) field->geom_type;
#ifndef HAVE_SPATIAL
      DBUG_ASSERT(0);                           // Should newer happen
#endif
    }
    else if (field->charset) 
    {
      buff[11]= (uchar) (field->charset->number >> 8);
      buff[14]= (uchar) field->charset->number;
    }
    else
    {
      buff[11]= buff[14]= 0;			// Numerical
    }
    if (field->vcol_info)
    {
      /* 
        Use the interval_id place in the .frm file to store the length of
        the additional data saved for the virtual field
      */
      buff[12]= cur_vcol_expr_len= field->vcol_info->expr_str.length +
	                           FRM_VCOL_HEADER_SIZE(field->interval);
      vcol_info_length+= cur_vcol_expr_len;
      buff[13]= (uchar) MYSQL_TYPE_VIRTUAL;
    }
    int2store(buff+15, field->comment.length);
    comment_length+= field->comment.length;
    set_if_bigger(int_count,field->interval_id);
    buff+= FCOMP;
  }

  /* Write fieldnames */
  *buff++= NAMES_SEP_CHAR;
  it.rewind();
  while ((field=it++))
  {
    buff= (uchar*)strmov((char*) buff, field->field_name);
    *buff++=NAMES_SEP_CHAR;
  }
  *buff++= 0;

  /* Write intervals */
  if (int_count)
  {
    it.rewind();
    int_count=0;
    while ((field=it++))
    {
      if (field->interval_id > int_count)
      {
        unsigned char  sep= 0;
        unsigned char  occ[256];
        uint           i;
        unsigned char *val= NULL;

        bzero(occ, sizeof(occ));

        for (i=0; (val= (unsigned char*) field->interval->type_names[i]); i++)
          for (uint j = 0; j < field->interval->type_lengths[i]; j++)
            occ[(unsigned int) (val[j])]= 1;

        if (!occ[(unsigned char)NAMES_SEP_CHAR])
          sep= (unsigned char) NAMES_SEP_CHAR;
        else if (!occ[(unsigned int)','])
          sep= ',';
        else
        {
          for (uint i=1; i<256; i++)
          {
            if(!occ[i])
            {
              sep= i;
              break;
            }
          }

          if (!sep)
          {
            /* disaster, enum uses all characters, none left as separator */
            my_message(ER_WRONG_FIELD_TERMINATORS,
                       ER(ER_WRONG_FIELD_TERMINATORS),
                       MYF(0));
            DBUG_RETURN(1);
          }
        }

        int_count= field->interval_id;
        *buff++= sep;
        for (int i=0; field->interval->type_names[i]; i++)
        {
          memcpy(buff, field->interval->type_names[i], field->interval->type_lengths[i]);
          buff+= field->interval->type_lengths[i];
          *buff++= sep;
        }
        *buff++= 0;
        
      }
    }
  }
  if (comment_length)
  {
    it.rewind();
    while ((field=it++))
    {
      memcpy(buff, field->comment.str, field->comment.length);
      buff+= field->comment.length;
    }
  }
  if (vcol_info_length)
  {
    it.rewind();
    while ((field=it++))
    {
      /*
        Pack each virtual field as follows:
        byte 1      = interval_id == 0 ? 1 : 2 
        byte 2      = sql_type
        byte 3      = flags (as of now, 0 - no flags, 1 - field is physically stored)
        [byte 4]    = possible interval_id for sql_type
        next byte ...  = virtual column expression (text data)
      */
      if (field->vcol_info && field->vcol_info->expr_str.length)
      {
        *buff++= (uchar) (1 + MY_TEST(field->interval));
        *buff++= (uchar) field->sql_type;
        *buff++= (uchar) field->vcol_info->stored_in_db;
        if (field->interval)
          *buff++= (uchar) field->interval_id;
        memcpy(buff, field->vcol_info->expr_str.str, field->vcol_info->expr_str.length);
        buff+= field->vcol_info->expr_str.length;
      }
    }
  }
  DBUG_RETURN(0);
}


/* save an empty record on start of formfile */

static bool make_empty_rec(THD *thd, uchar *buff, uint table_options,
			   List<Create_field> &create_fields,
			   uint reclength, ulong data_offset)
{
  int error= 0;
  Field::utype type;
  uint null_count;
  uchar *null_pos;
  TABLE table;
  TABLE_SHARE share;
  Create_field *field;
  enum_check_fields old_count_cuted_fields= thd->count_cuted_fields;
  DBUG_ENTER("make_empty_rec");

  /* We need a table to generate columns for default values */
  bzero((char*) &table, sizeof(table));
  bzero((char*) &share, sizeof(share));
  table.s= &share;

  table.in_use= thd;

  null_count=0;
  if (!(table_options & HA_OPTION_PACK_RECORD))
  {
    null_count++;			// Need one bit for delete mark
    *buff|= 1;
  }
  null_pos= buff;

  List_iterator<Create_field> it(create_fields);
  thd->count_cuted_fields= CHECK_FIELD_WARN;    // To find wrong default values
  while ((field=it++))
  {
    /* regfield don't have to be deleted as it's allocated on THD::mem_root */
    Field *regfield= make_field(&share, thd->mem_root,
                                buff+field->offset + data_offset,
                                field->length,
                                null_pos + null_count / 8,
                                null_count & 7,
                                field->pack_flag,
                                field->sql_type,
                                field->charset,
                                field->geom_type, field->srid,
                                field->unireg_check,
                                field->save_interval ? field->save_interval :
                                field->interval, 
                                field->field_name);
    if (!regfield)
    {
      error= 1;
      goto err;                                 // End of memory
    }

    /* save_in_field() will access regfield->table->in_use */
    regfield->init(&table);

    if (!(field->flags & NOT_NULL_FLAG))
    {
      *regfield->null_ptr|= regfield->null_bit;
      null_count++;
    }

    if (field->sql_type == MYSQL_TYPE_BIT && !f_bit_as_char(field->pack_flag))
      null_count+= field->length & 7;

    type= (Field::utype) MTYP_TYPENR(field->unireg_check);

    if (field->def)
    {
      int res= field->def->save_in_field(regfield, 1);
      /* If not ok or warning of level 'note' */
      if (res != 0 && res != 3)
      {
        my_error(ER_INVALID_DEFAULT, MYF(0), regfield->field_name);
        error= 1;
        delete regfield; //To avoid memory leak
        goto err;
      }
    }
    else if (regfield->real_type() == MYSQL_TYPE_ENUM &&
	     (field->flags & NOT_NULL_FLAG))
    {
      regfield->set_notnull();
      regfield->store((longlong) 1, TRUE);
    }
    else if (type == Field::YES)		// Old unireg type
      regfield->store(ER_THD(thd, ER_YES),(uint) strlen(ER_THD(thd, ER_YES)),
                      system_charset_info);
    else if (type == Field::NO)			// Old unireg type
      regfield->store(ER_THD(thd, ER_NO), (uint) strlen(ER_THD(thd, ER_NO)),
                      system_charset_info);
    else
      regfield->reset();
  }
  DBUG_ASSERT(data_offset == ((null_count + 7) / 8));

  /*
    We need to set the unused bits to 1. If the number of bits is a multiple
    of 8 there are no unused bits.
  */
  if (null_count & 7)
    *(null_pos + null_count / 8)|= ~(((uchar) 1 << (null_count & 7)) - 1);

err:
  thd->count_cuted_fields= old_count_cuted_fields;
  DBUG_RETURN(error);
} /* make_empty_rec */