release/src/router/mysql/storage/innodb_plugin/mach/mach0data.c

   1 /*****************************************************************************
   2
   3 Copyright (c) 1995, 2009, Innobase Oy. All Rights Reserved.
   4
   5 This program is free software; you can redistribute it and/or modify it under
   6 the terms of the GNU General Public License as published by the Free Software
   7 Foundation; version 2 of the License.
   8
   9 This program is distributed in the hope that it will be useful, but WITHOUT
  10 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  11 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
  12
  13 You should have received a copy of the GNU General Public License along with
  14 this program; if not, write to the Free Software Foundation, Inc.,
  15 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  16
  17 *****************************************************************************/
  18
  19 /******************************************************************//**
  20 @file mach/mach0data.c
  21 Utilities for converting data from the database file
  22 to the machine format.
  23
  24 Created 11/28/1995 Heikki Tuuri
  25 ***********************************************************************/
  26
  27 #include "mach0data.h"
  28
  29 #ifdef UNIV_NONINL
  30 #include "mach0data.ic"
  31 #endif
  32
  33 /*********************************************************//**
  34 Reads a ulint in a compressed form if the log record fully contains it.
  35 @return pointer to end of the stored field, NULL if not complete */
  36 UNIV_INTERN
  37 byte*
  38 mach_parse_compressed(
  39 /*==================*/
  40         byte*   ptr,    /*!< in: pointer to buffer from where to read */
  41         byte*   end_ptr,/*!< in: pointer to end of the buffer */
  42         ulint*  val)    /*!< out: read value (< 2^32) */
  43 {
  44         ulint   flag;
  45
  46         ut_ad(ptr && end_ptr && val);
  47
  48         if (ptr >= end_ptr) {
  49
  50                 return(NULL);
  51         }
  52
  53         flag = mach_read_from_1(ptr);
  54
  55         if (flag < 0x80UL) {
  56                 *val = flag;
  57                 return(ptr + 1);
  58
  59         } else if (flag < 0xC0UL) {
  60                 if (end_ptr < ptr + 2) {
  61                         return(NULL);
  62                 }
  63
  64                 *val = mach_read_from_2(ptr) & 0x7FFFUL;
  65
  66                 return(ptr + 2);
  67
  68         } else if (flag < 0xE0UL) {
  69                 if (end_ptr < ptr + 3) {
  70                         return(NULL);
  71                 }
  72
  73                 *val = mach_read_from_3(ptr) & 0x3FFFFFUL;
  74
  75                 return(ptr + 3);
  76         } else if (flag < 0xF0UL) {
  77                 if (end_ptr < ptr + 4) {
  78                         return(NULL);
  79                 }
  80
  81                 *val = mach_read_from_4(ptr) & 0x1FFFFFFFUL;
  82
  83                 return(ptr + 4);
  84         } else {
  85                 ut_ad(flag == 0xF0UL);
  86
  87                 if (end_ptr < ptr + 5) {
  88                         return(NULL);
  89                 }
  90
  91                 *val = mach_read_from_4(ptr + 1);
  92                 return(ptr + 5);
  93         }
  94 }
  95
  96 /*********************************************************//**
  97 Reads a dulint in a compressed form if the log record fully contains it.
  98 @return pointer to end of the stored field, NULL if not complete */
  99 UNIV_INTERN
 100 byte*
 101 mach_dulint_parse_compressed(
 102 /*=========================*/
 103         byte*   ptr,    /*!< in: pointer to buffer from where to read */
 104         byte*   end_ptr,/*!< in: pointer to end of the buffer */
 105         dulint* val)    /*!< out: read value */
 106 {
 107         ulint   high;
 108         ulint   low;
 109         ulint   size;
 110
 111         ut_ad(ptr && end_ptr && val);
 112
 113         if (end_ptr < ptr + 5) {
 114
 115                 return(NULL);
 116         }
 117
 118         high = mach_read_compressed(ptr);
 119
 120         size = mach_get_compressed_size(high);
 121
 122         ptr += size;
 123
 124         if (end_ptr < ptr + 4) {
 125
 126                 return(NULL);
 127         }
 128
 129         low = mach_read_from_4(ptr);
 130
 131         *val = ut_dulint_create(high, low);
 132
 133         return(ptr + 4);
 134 }