~drizzle-trunk/drizzle/development : contents of plugin/filesystem_engine/transparent

~drizzle-trunk/drizzle/development : (revision 1964)

/* Copyright (C) 2003 MySQL 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 */


#include "config.h"
#include <cstdlib>
#include "drizzled/internal/my_sys.h"
#include "transparent_file.h"
#include "utility.h"

using namespace drizzled;

TransparentFile::TransparentFile() : lower_bound(0), buff_size(IO_SIZE)
{
  buff= static_cast<unsigned char *>(malloc(buff_size*sizeof(unsigned char)));
}

TransparentFile::~TransparentFile()
{
  free(buff);
}

void TransparentFile::init_buff(int filedes_arg)
{
  filedes= filedes_arg;
  /* read the beginning of the file */
  lower_bound= 0;
  lseek(filedes, 0, SEEK_SET);
  if (filedes && buff)
    upper_bound= ::read(filedes, buff, buff_size);
}

unsigned char *TransparentFile::ptr()
{
  return buff;
}

off_t TransparentFile::start()
{
  return lower_bound;
}

off_t TransparentFile::end()
{
  return upper_bound;
}

off_t TransparentFile::read_next()
{
  ssize_t bytes_read;

  /*
     No need to seek here, as the file managed by TransparentFile class
     always points to upper_bound byte
  */
  if ((bytes_read= ::read(filedes, buff, buff_size)) < 0)
    return (off_t) -1;

  /* end of file */
  if (!bytes_read)
    return (off_t) -1;

  lower_bound= upper_bound;
  upper_bound+= bytes_read;

  return lower_bound;
}


char TransparentFile::get_value(off_t offset)
{
  ssize_t bytes_read;

  /* check boundaries */
  if ((lower_bound <= offset) && (offset < upper_bound))
    return buff[offset - lower_bound];

  lseek(filedes, offset, SEEK_SET);
  /* read appropriate portion of the file */
  if ((bytes_read= ::read(filedes, buff, buff_size)) < 0)
    return 0;

  lower_bound= offset;
  upper_bound= lower_bound + bytes_read;

  /* end of file */
  if (upper_bound == offset)
    return 0;

  return buff[0];
}

1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	1	/* Copyright (C) 2003 MySQL AB
	2
	3	This program is free software; you can redistribute it and/or modify
	4	it under the terms of the GNU General Public License as published by
	5	the Free Software Foundation; version 2 of the License.
	6
	7	This program is distributed in the hope that it will be useful,
	8	but WITHOUT ANY WARRANTY; without even the implied warranty of
	9	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	10	GNU General Public License for more details.
	11
	12	You should have received a copy of the GNU General Public License
	13	along with this program; if not, write to the Free Software
1802.10.2 by Monty Taylor Update all of the copyright headers to include the correct address.	14	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	15
	16
	17	#include "config.h"
	18	#include <cstdlib>
	19	#include "drizzled/internal/my_sys.h"
	20	#include "transparent_file.h"
1548.4.94 by Zimin remove internal::my_read to use xread instead	21	#include "utility.h"
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	22
	23	using namespace drizzled;
	24
1548.5.3 by Zimin some name changes to be corresponding with drizzle's naming style.	25	TransparentFile::TransparentFile() : lower_bound(0), buff_size(IO_SIZE)
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	26	{
	27	buff= static_cast<unsigned char >(malloc(buff_sizesizeof(unsigned char)));
	28	}
	29
1548.5.3 by Zimin some name changes to be corresponding with drizzle's naming style.	30	TransparentFile::~TransparentFile()
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	31	{
	32	free(buff);
	33	}
	34
1548.5.3 by Zimin some name changes to be corresponding with drizzle's naming style.	35	void TransparentFile::init_buff(int filedes_arg)
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	36	{
	37	filedes= filedes_arg;
	38	/* read the beginning of the file */
	39	lower_bound= 0;
	40	lseek(filedes, 0, SEEK_SET);
	41	if (filedes && buff)
1548.4.112 by Zimin fix missing xread	42	upper_bound= ::read(filedes, buff, buff_size);
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	43	}
	44
1548.5.3 by Zimin some name changes to be corresponding with drizzle's naming style.	45	unsigned char *TransparentFile::ptr()
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	46	{
	47	return buff;
	48	}
	49
1548.5.3 by Zimin some name changes to be corresponding with drizzle's naming style.	50	off_t TransparentFile::start()
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	51	{
	52	return lower_bound;
	53	}
	54
1548.5.3 by Zimin some name changes to be corresponding with drizzle's naming style.	55	off_t TransparentFile::end()
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	56	{
	57	return upper_bound;
	58	}
	59
1548.5.3 by Zimin some name changes to be corresponding with drizzle's naming style.	60	off_t TransparentFile::read_next()
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	61	{
1548.4.94 by Zimin remove internal::my_read to use xread instead	62	ssize_t bytes_read;
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	63
	64	/*
1548.5.3 by Zimin some name changes to be corresponding with drizzle's naming style.	65	No need to seek here, as the file managed by TransparentFile class
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	66	always points to upper_bound byte
	67	*/
1548.4.111 by Zimin remove xread and xclose, but change xwrite to write_in_all.	68	if ((bytes_read= ::read(filedes, buff, buff_size)) < 0)
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	69	return (off_t) -1;
	70
	71	/* end of file */
	72	if (!bytes_read)
	73	return (off_t) -1;
	74
	75	lower_bound= upper_bound;
	76	upper_bound+= bytes_read;
	77
	78	return lower_bound;
	79	}
	80
	81
1548.5.3 by Zimin some name changes to be corresponding with drizzle's naming style.	82	char TransparentFile::get_value(off_t offset)
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	83	{
1548.4.94 by Zimin remove internal::my_read to use xread instead	84	ssize_t bytes_read;
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	85
	86	/* check boundaries */
	87	if ((lower_bound <= offset) && (offset < upper_bound))
	88	return buff[offset - lower_bound];
	89
	90	lseek(filedes, offset, SEEK_SET);
	91	/* read appropriate portion of the file */
1548.4.111 by Zimin remove xread and xclose, but change xwrite to write_in_all.	92	if ((bytes_read= ::read(filedes, buff, buff_size)) < 0)
1548.5.2 by Zimin shamelessly borrow these two files from CSV storage engine.	93	return 0;
	94
	95	lower_bound= offset;
	96	upper_bound= lower_bound + bytes_read;
	97
	98	/* end of file */
	99	if (upper_bound == offset)
	100	return 0;
	101
	102	return buff[0];
	103	}