Piper's Pit BBS/FTP: ibm 0010 - 0019/ibm0010-0019/ibm0010.tar/ibm0010/CODE4-1.ZIP/SOURCE.ZIP/I4OPEN.C

C/C++ Source or Header | 1989-10-14 | 4.8 KB | 177 lines

/*  i4open.c   (c)Copyright Sequiter Software Inc., 1987, 1988, 1989.  All rights reserved.

    Opens an index file.

    Returns
       >=0 The reference (int) to the index file.
       -1  Error

*/

#include "d4base.h"
#include "u4error.h"

#include <string.h>
#ifndef UNIX
   #include <io.h>
#endif

extern BASE   *v4base ;
extern INDEX  *v4index ;

extern int     v4cur_base, v4block_max ;
extern unsigned char _osmajor;


int   i4open( index_name )
char *index_name ;
{
   int        index_ref, rc, h_size ;
   char    *result ;
   char     name[90] ;

   INDEX   *index_ptr     ;
   BASE    *base_ptr     ;

   #ifdef CLIPPER
      u4name_full( name, index_name, ".NTX" ) ;
   #else
      u4name_full( name, index_name, ".NDX" ) ;
   #endif
   if ( (rc=i4ref(name)) >= 0 )  return( rc ) ;  /* File already Open */

   base_ptr  =    v4base +  v4cur_base ;

   index_ref = base_ptr->index_ref
         = h4get((char **) &v4index, base_ptr->index_ref ) ;
   if ( index_ref < 0 )  return -1 ;

   index_ptr=  v4index + index_ref ;

   strncpy( index_ptr->name, name, 64) ;
   index_ptr->name[63] = '\0' ;
   strupr( index_ptr->name ) ;

   if ( (index_ptr->dos_file =    u4open( name, 0 ))  < 0 )
   {
      base_ptr->index_ref =  h4free ( (char **) &v4index, index_ref ) ;
      return   ( -1 ) ;
   }

   lseek( index_ptr->dos_file, (long) 0, 0) ;
   #ifdef CLIPPER
      h_size =  (int) ((char *)(v4index+1) - (char *)&v4index->sign) ;
      rc =  read( index_ptr->dos_file, (char *)&index_ptr->sign, h_size ) ;
   #else
      h_size =  (int) ((char *)(v4index+1) - (char *)&v4index->root) ;
      rc =  read( index_ptr->dos_file, (char *)&index_ptr->root, h_size ) ;
   #endif
   while (rc < 0)
   {
      /*  Wait until the database is unlocked  */
      lseek( index_ptr->dos_file, (long) 0, 0) ;
      #ifdef CLIPPER
     rc =  read( index_ptr->dos_file, (char *)&index_ptr->sign, h_size ) ;
      #else
     rc =  read( index_ptr->dos_file, (char *)&index_ptr->root, h_size ) ;
      #endif
   }

   if ( rc != h_size )
   {
      close( index_ptr->dos_file );
      base_ptr->index_ref =  h4free ( (char **) &v4index, index_ref ) ;
      u4error( E_READ, name, (char *) 0 ) ;
      return( -1 ) ;
   }

   /* Do some checks on the index file header */
   #ifdef CLIPPER
   if ( index_ptr->key_len   >    MAX_KEY_SIZE   ||
    index_ptr->key_len   <= 0           ||
    index_ptr->keys_max  != 2* index_ptr->keys_half  ||
    index_ptr->keys_half <= 0           ||
    index_ptr->group_len != index_ptr->key_len+ 8  ||
       (index_ptr->sign != 0x6    &&  index_ptr->sign != 0x106) )
   #else
   if ( index_ptr->key_len   > MAX_KEY_SIZE    ||
    index_ptr->key_len  <= 0  ||
    index_ptr->key_len+8 > index_ptr->group_len  ||
    index_ptr->keys_max  < 4  ||
    index_ptr->keys_max  > 50 )
   #endif
   {
      close( index_ptr->dos_file );
      base_ptr->index_ref =  h4free ( (char **) &v4index, index_ref ) ;
      u4error( E_BAD_NDX, index_ptr->name, (char *) 0 ) ;
      return( -1 ) ;
   }

   index_ptr->base_ref = v4cur_base ;

   if (e4parse( index_ptr->expression, &index_ptr->compile ) < 0)
   {
      close( index_ptr->dos_file ) ;
      base_ptr->index_ref =  h4free( (char **) &v4index, index_ref ) ;
      return( -1) ;
   }
   memcpy( base_ptr->old_buf, base_ptr->buffer, base_ptr->buffer_len ) ;
   memset( base_ptr->buffer, (int) ' ', (size_t) base_ptr->buffer_len ) ;
   result = (char *) e4exec( index_ptr->compile)  ;
   memcpy( base_ptr->buffer, base_ptr->old_buf, base_ptr->buffer_len ) ;
   rc = 0 ;

   if ( result == (char *) 0)  rc =  -1 ;

   /* Check Key Lengths and Types */
   if ( e4type() == 'L'  &&  rc == 0 )
   {
      u4error( E_I_TYPE, index_ptr->name, (char *) 0 ) ;
      rc =  -1 ;
   }

   #ifdef CLIPPER
      if ( e4type() == 'C'  &&  strlen(result) !=  index_ptr->key_len )
      {
     u4error( E_I_CHANGED, index_ptr->name, (char *) 0 ) ;
     rc =  -1 ;
      }
   #else
      if ( index_ptr->int_or_date != 0    && e4type() == 'C' && rc == 0)
      {
     u4error( E_I_CHANGED, index_ptr->name, (char *) 0 ) ;
     rc =  -1 ;
      }

      if ( e4type() == 'C'  &&  strlen(result) !=  index_ptr->key_len )
      {
     u4error( E_I_CHANGED, index_ptr->name, (char *) 0 ) ;
     rc =  -1 ;
      }
   #endif

   if ( rc != 0 )
   {
      h4free_memory( index_ptr->compile ) ;
      close( index_ptr->dos_file ) ;
      base_ptr->index_ref =  h4free( (char **) &v4index, index_ref ) ;
      return( -1) ;
   }

   #ifdef CLIPPER
      if ( index_ptr->sign == 0x106 )
     index_ptr->unique =  1 ;
   #endif

   index_ptr->block_last =  index_ptr->block_first = index_ptr->block_ref =  -1;
   index_ptr->block_max     =  v4block_max ;
   index_ptr->i_type     =  e4type() ;
   index_ptr->lock     =   0 ;
   base_ptr->current_index=  index_ref ;

   return( index_ref );
}