94 lines
3.0 KiB
C++
94 lines
3.0 KiB
C++
/* Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License, version 2.0, for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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#include "storage/csv/transparent_file.h"
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#include <mysql/psi/mysql_file.h>
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#include "my_sys.h" // MY_WME, MY_ALLOW_ZERO_PTR, MY_SEEK_SET
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PSI_memory_key csv_key_memory_Transparent_file;
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Transparent_file::Transparent_file() : lower_bound(0), buff_size(IO_SIZE) {
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buff = (uchar *)my_malloc(csv_key_memory_Transparent_file,
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buff_size * sizeof(uchar), MYF(MY_WME));
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}
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Transparent_file::~Transparent_file() { my_free(buff); }
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void Transparent_file::init_buff(File filedes_arg) {
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filedes = filedes_arg;
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/* read the beginning of the file */
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lower_bound = 0;
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mysql_file_seek(filedes, 0, MY_SEEK_SET, MYF(0));
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if (filedes && buff)
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upper_bound = mysql_file_read(filedes, buff, buff_size, MYF(0));
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}
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uchar *Transparent_file::ptr() { return buff; }
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my_off_t Transparent_file::start() { return lower_bound; }
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my_off_t Transparent_file::end() { return upper_bound; }
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my_off_t Transparent_file::read_next() {
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size_t bytes_read;
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/*
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No need to seek here, as the file managed by Transparent_file class
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always points to upper_bound byte
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*/
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if ((bytes_read = mysql_file_read(filedes, buff, buff_size, MYF(0))) ==
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MY_FILE_ERROR)
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return (my_off_t)-1;
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/* end of file */
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if (!bytes_read) return (my_off_t)-1;
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lower_bound = upper_bound;
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upper_bound += bytes_read;
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return lower_bound;
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}
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char Transparent_file::get_value(my_off_t offset) {
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size_t bytes_read;
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/* check boundaries */
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if ((lower_bound <= offset) && (((my_off_t)offset) < upper_bound))
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return buff[offset - lower_bound];
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mysql_file_seek(filedes, offset, MY_SEEK_SET, MYF(0));
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/* read appropriate portion of the file */
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if ((bytes_read = mysql_file_read(filedes, buff, buff_size, MYF(0))) ==
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MY_FILE_ERROR)
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return 0;
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lower_bound = offset;
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upper_bound = lower_bound + bytes_read;
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/* end of file */
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if (upper_bound == (my_off_t)offset) return 0;
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return buff[0];
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}
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