/* f4opt.c   (c)Copyright Sequiter Software Inc., 1990-1994.  All rights reserved. */

#include "d4all.h"
#ifndef S4UNIX
#ifdef __TURBOC__
#pragma hdrstop
#endif
#endif

#ifndef S4OPTIMIZE_OFF
#ifdef S4DEBUG_DEV
#ifndef S4UNIX
#include <sys\stat.h>
#include <share.h>
#endif
#include <fcntl.h>
int S4FUNCTION file4write_part( char *buf, FILE4 S4PTR *file, long pos, unsigned len )
{
  int h1 ;
  unsigned rc ;
  long rc1 ;

  if ( file->in_use == 1 )
    return 0 ;
  file->in_use = 1 ;

  rc = h1 = -1 ;

  for ( ;; )
  {
    h1 = sopen( file->dup_name, (int)(O_BINARY | O_RDWR), SH_DENYRW, 0 ) ;
    if ( h1 < 0 )
      break ;

    rc1 = lseek( h1, pos, 0 ) ;
    if ( rc1 != pos )
      break ;

    rc1 = (unsigned)write( h1, buf, len ) ;

    if ( rc1 != len )
      break;

    rc = 0 ;
    break;
  }

  if ( h1 > 0 )
    close( h1 ) ;

  file->in_use = 0 ;
  return rc ;
}

int S4FUNCTION file4cmp_part( CODE4 *c4, char *buf, FILE4 *file, long pos, unsigned len )
{
  int h1, rc ;
  char buf1[512] ;
  long len_hold, rc1 ;

  if ( file->in_use == 1 )
    return 0 ;
  file->in_use = 1 ;

  len_hold = len ;

  if ( c4->error_code != 0 )
    return -1 ;

  h1 = rc = -1 ;

  h1 = sopen( file->dup_name, (int)(O_BINARY | O_RDONLY), SH_DENYRW, 0 ) ;

  if ( h1 > 0 )
    for( ;; )
    {
      rc1 = lseek( h1, pos, 0 ) ;
      if ( rc1 != pos )
        break ;

      rc1 = (unsigned)read( h1, buf1, sizeof( buf1 ) > len ? len : sizeof( buf1 ) ) ;
      if ( rc1 != sizeof( buf1 ) && rc1 != len )
        break ;

      if ( memcmp( buf + ( len_hold - len ), buf1, rc1 ) != 0 )
        break ;

      len -= rc1 ;
      if ( len == 0 )
      {
        rc = 0 ;
        break ;
      }

      pos += rc1 ;
    }

  if ( h1 > 0 )
    close( h1 ) ;

  file->in_use = 0 ;
  return rc ;
}

int S4FUNCTION file4cmp( FILE4 *f1 )
{
  int h1, rc ;
  unsigned rc2 ;
  char buf1[512], buf2[512] ;
  long rct, p1, rc1 ;

  if ( f1->in_use == 1 )
    return 0 ;
  f1->in_use = 1 ;

  if ( f1->code_base->error_code != 0 || sizeof( buf1 ) != sizeof( buf2 ) )
    return -1 ;

  p1 = 0L ;
  h1 = rc = -1 ;

  h1 = sopen( f1->dup_name, (int)(O_BINARY | O_RDONLY), SH_DENYRW, 0 ) ;

  if ( h1 > 0 )
    for( ;; )
    {
      rct = lseek( h1, p1, 0 ) ;
      if ( rct != p1 )
        break ;

      rc1 = (unsigned)read( h1, buf1, sizeof( buf1 ) ) ;
      f1->has_dup = 0 ;
      rc2 = file4read( f1, p1, buf2, sizeof( buf2 ) ) ;
      f1->has_dup = 1 ;

      if ( rc1 != rc2 )
        break ;

      if ( memcmp( buf1, buf2, rc1 ) != 0 )
        break ;

      if ( rc1 < sizeof( buf1 ) )
      {
        rc = 0 ;
        break ;
      }

      p1 += sizeof( buf1 ) ;
    }

  if ( h1 > 0 )
    close( h1 ) ;

  f1->code_base->error_code = 0 ;

  f1->in_use = 0 ;
  return rc ;
}

static int S4FUNCTION file4copyx( CODE4 *c4, FILE4 *f1, char *f2 )
{
  int h1, h2, rc ;
  long rct ;
  unsigned rc1, rc2 ;
  char buf[1024] ;
  long p1 ;

  if ( c4->error_code != 0 )
    return -1 ;

  h2 = -1 ;
  rc = -1 ;
  p1 = 0L ;

  h2 = sopen( f2, (int)(O_BINARY | O_RDWR), SH_DENYRW, 0 ) ;
  h1 = f1->hand ;

  if ( h1 > 0 && h2 > 0 )
    for( ;; )
    {
      rct = lseek( h1, p1, 0 ) ;
      if ( rct != p1 )
        break ;

      rct = lseek( h2, p1, 0 ) ;
      if ( rct != p1 )
        break ;

      rc1 = (unsigned)read( h1, buf, sizeof( buf ) ) ;
      rc2 = (unsigned)write( h2, buf, rc1 ) ;

      if ( rc1 != rc2 )
        break ;

      if ( rc1 < sizeof( buf ) )
      {
        rc = 0 ;
        break ;
      }

      p1 += sizeof( buf ) ;
    }

  if ( h2 > 0 )
    close( h2 ) ;

  return rc ;
}

static int S4FUNCTION file4copy( CODE4 *c4, char *f1, char *f2 )
{
  int h1, h2, rc ;
  long rct ;
  unsigned rc1, rc2 ;
  char buf[1024] ;
  long p1 ;

  if ( c4->error_code != 0 )
    return -1 ;

  h1 = h2 = -1 ;
  rc = -1 ;
  p1 = 0L ;

  h1 = sopen( f1, (int)(O_BINARY | O_RDWR), SH_DENYRW, 0 ) ;
  h2 = sopen( f2, (int)(O_BINARY | O_RDWR), SH_DENYRW, 0 ) ;

  if ( h1 > 0 && h2 > 0 )
    for( ;; )
    {
      rct = lseek( h1, p1, 0 ) ;
      if ( rct != p1 )
        break ;

      rct = lseek( h2, p1, 0 ) ;
      if ( rct != p1 )
        break ;

      rc1 = (unsigned)read( h1, buf, sizeof( buf ) ) ;
      rc2 = (unsigned)write( h2, buf, rc1 ) ;

      if ( rc1 != rc2 )
        break ;

      if ( rc1 < sizeof( buf ) )
      {
        rc = 0 ;
        break ;
      }

      p1 += sizeof( buf ) ;
    }

  if ( h1 > 0 )
    close( h1 ) ;

  if ( h2 > 0 )
    close( h2 ) ;

  return rc ;
}
#endif
#endif

int S4FUNCTION file4optimize( FILE4 *file, int opt_flag, int file_type )
{
#ifdef S4OPTIMIZE_OFF
  return 0 ;
#else
  OPT4 *opt ;
  int rc ;
#ifdef S4DEBUG_DEV
#ifndef S4OPTIMIZE_OFF
  char name_buf[255] ;
  int hand ;
#endif
#endif

#ifdef S4DEBUG
  if ( file == 0 || file_type < 0 || file_type > 3 || opt_flag < -1 || opt_flag > 1 )
    e4severe( e4parm, E4_F4OPTIMIZE ) ;
#endif

  rc = 0 ;

  opt = &file->code_base->opt ;

  if ( opt_flag == -1 )
#ifdef S4SINGLE
    opt_flag = 1 ;
#else
  opt_flag = ( file->is_exclusive || file->is_read_only ) ? 1 : 0 ;
#endif

  if ( opt_flag == 1 )
  {
    if ( file->do_buffer != 0 && file->type != OPT4NONE )  /* already optimized */
      return 0 ;
    if ( opt->num_buffers > 0 )
    {
      file->len = -1 ;
      file->hash_init = opt->hash_trail * opt->block_size ;
#ifdef S4DEBUG
      if ( file4len( file ) < 0 || opt->block_size == 0 )
        e4severe( e4info, E4_F4OPTIMIZE ) ;
#endif
      opt->hash_trail = (opt->hash_trail + file4len( file ) / opt->block_size) % opt->num_blocks ;
      file->do_buffer = 1 ;
    }
    else
      file->hash_init = - 1 ;

    if ( file->type == OPT4NONE )   /* add to list... */
      l4add( &opt->opt_files, file ) ;
    file->type = (char) file_type ;
    rc = file4optimize_write( file, file->code_base->optimize_write ) ;
#ifdef S4DEBUG_DEV
#ifndef S4OPTIMIZE_OFF
    strcpy( name_buf, file->name ) ;
    if ( name_buf[1] == ':' )
      name_buf[0] = 'C' ;
    u4name_make( file->dup_name, sizeof( file->dup_name ), "E:", "TEMP", name_buf ) ;

    hand = sopen( file->dup_name, O_CREAT | O_TRUNC | O_RDWR, SH_DENYWR, S_IREAD  | S_IWRITE ) ;

    if ( hand < 0 )
      file->has_dup = 0 ;
    else
    {
      close( hand ) ;
      if ( file4len( file ) > 0 )
      {
        if ( file4copyx( file->code_base, file, file->dup_name ) < 0 )
          file->has_dup = 0 ;
        else
          file->has_dup = 1 ;
      }
      else
        file->has_dup = 1 ;
    }
#endif
#endif
  }
  else  /* 0 */
  {
    if ( file->type == OPT4NONE )   /* not optimized */
      return 0 ;

#ifdef S4DEBUG_DEV
    if ( file->has_dup == 1 )
    {
      /* first do a final verification */
      if ( file->do_buffer == 1 || file->link.n == 0 )
        if ( file4cmp( file ) != 0 )
          e4severe( e4opt, "f4close() - file corruption" ) ;
      u4remove( file->dup_name ) ;
      file->has_dup = 0 ;
    }
#endif

    rc = file4optimize_write( file, 0 ) ;
    if ( rc == 0 )
    {
      if ( file4low_flush( file, 1 ) < 0 )
        return e4( file->code_base, e4opt_flush, 0 ) ;
      l4remove( &opt->opt_files, file ) ;
      file->type = OPT4NONE ;
      file->do_buffer = 0 ;
    }
  }

  return rc ;
#endif
}

/* opt_flag has the same definitions as C4CODE.optimize_write */
int S4FUNCTION file4optimize_write( FILE4 *file, int opt_flag )
{
#ifdef S4OPTIMIZE_OFF
  return 0 ;
#else
  int rc ;

  rc = 0 ;

#ifdef S4DEBUG
  if( file == 0 || opt_flag < -1 || opt_flag > 1 )
    e4severe( e4parm, E4_F4OPTIMIZE_WR ) ;
#endif

  if ( opt_flag == file->write_buffer )
    return rc ;

  switch ( opt_flag )
  {
  case 0:
    if ( file->do_buffer )
      rc = file4flush( file ) ;
    file->write_buffer = 0 ;
    break ;
  case  -1 :
#ifdef S4SINGLE
    if ( file->do_buffer )
      file->buffer_writes = 1 ;
    file->write_buffer = 1 ;
#else
    if ( file->is_exclusive == 0 )
    {
      if ( file->do_buffer )
      {
        rc = file4flush( file ) ;
        file->buffer_writes = 0 ;
      }
      file->write_buffer = 0 ;
    }
    else
    {
      if ( file->do_buffer )
        file->buffer_writes = 1 ;
      file->write_buffer = 1 ;
    }
#endif
    break ;
  case 1:
#ifndef S4SINGLE
    if ( file->is_exclusive == 1 )
#endif
      if ( file->do_buffer )
        file->buffer_writes = 1 ;
    file->write_buffer = 1 ;
    break ;
  default:
    return 0 ;
  }

  return rc ;
#endif
}

/* tries to actually turn on/off the write bufferring when locking/unlocking a file */
void S4FUNCTION file4set_write_opt( FILE4 *f4, int set_opt )
{
#ifndef S4OPTIMIZE_OFF
  if ( set_opt == f4->buffer_writes )
    return ;
  if ( set_opt == 1 && f4->write_buffer == 1 )
    f4->buffer_writes = 1 ;
  if ( set_opt == 0 && f4->write_buffer == 1 )
    f4->buffer_writes = 0 ;
#endif
}