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94 lines
2.3 KiB
C
94 lines
2.3 KiB
C
/*****************************************************************************
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Copyright (c) 1995, 2009, Innobase Oy. All Rights Reserved.
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program; if not, write to the Free Software Foundation, Inc.,
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51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*****************************************************************************/
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/******************************************************************//**
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@file mach/mach0data.c
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Utilities for converting data from the database file
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to the machine format.
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Created 11/28/1995 Heikki Tuuri
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***********************************************************************/
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#include "mach0data.h"
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#ifdef UNIV_NONINL
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#include "mach0data.ic"
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#endif
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/*********************************************************//**
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Reads a ulint in a compressed form if the log record fully contains it.
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@return pointer to end of the stored field, NULL if not complete */
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UNIV_INTERN
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byte*
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mach_parse_compressed(
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/*==================*/
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byte* ptr, /*!< in: pointer to buffer from where to read */
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byte* end_ptr,/*!< in: pointer to end of the buffer */
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ulint* val) /*!< out: read value (< 2^32) */
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{
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ulint flag;
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ut_ad(ptr && end_ptr && val);
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if (ptr >= end_ptr) {
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return(NULL);
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}
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flag = mach_read_from_1(ptr);
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if (flag < 0x80UL) {
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*val = flag;
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return(ptr + 1);
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} else if (flag < 0xC0UL) {
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if (end_ptr < ptr + 2) {
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return(NULL);
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}
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*val = mach_read_from_2(ptr) & 0x7FFFUL;
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return(ptr + 2);
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} else if (flag < 0xE0UL) {
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if (end_ptr < ptr + 3) {
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return(NULL);
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}
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*val = mach_read_from_3(ptr) & 0x3FFFFFUL;
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return(ptr + 3);
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} else if (flag < 0xF0UL) {
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if (end_ptr < ptr + 4) {
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return(NULL);
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}
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*val = mach_read_from_4(ptr) & 0x1FFFFFFFUL;
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return(ptr + 4);
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} else {
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ut_ad(flag == 0xF0UL);
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if (end_ptr < ptr + 5) {
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return(NULL);
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}
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*val = mach_read_from_4(ptr + 1);
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return(ptr + 5);
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}
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}
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