reactos/lib/sdk/crt/misc/lock.c

   1 /*
   2  * Copyright (c) 2002, TransGaming Technologies Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #include <precomp.h>
  20
  21 #define NDEBUG
  22 #include <internal/debug.h>
  23 #include <internal/mtdll.h>
  24
  25 typedef struct
  26 {
  27   BOOL             bInit;
  28   CRITICAL_SECTION crit;
  29 } LOCKTABLEENTRY;
  30
  31 static LOCKTABLEENTRY lock_table[ _TOTAL_LOCKS ];
  32
  33 static __inline void msvcrt_mlock_set_entry_initialized( int locknum, BOOL initialized )
  34 {
  35   lock_table[ locknum ].bInit = initialized;
  36 }
  37
  38 static __inline void msvcrt_initialize_mlock( int locknum )
  39 {
  40   InitializeCriticalSection( &(lock_table[ locknum ].crit) );
  41   msvcrt_mlock_set_entry_initialized( locknum, TRUE );
  42 }
  43
  44 static __inline void msvcrt_uninitialize_mlock( int locknum )
  45 {
  46   DeleteCriticalSection( &(lock_table[ locknum ].crit) );
  47   msvcrt_mlock_set_entry_initialized( locknum, FALSE );
  48 }
  49
  50 /**********************************************************************
  51  *     msvcrt_init_mt_locks (internal)
  52  *
  53  * Initialize the table lock. All other locks will be initialized
  54  * upon first use.
  55  *
  56  */
  57 void msvcrt_init_mt_locks(void)
  58 {
  59   int i;
  60
  61   DPRINT( "initializing mtlocks\n" );
  62
  63   /* Initialize the table */
  64   for( i=0; i < _TOTAL_LOCKS; i++ )
  65   {
  66     msvcrt_mlock_set_entry_initialized( i, FALSE );
  67   }
  68
  69   /* Initialize our lock table lock */
  70   msvcrt_initialize_mlock( _LOCKTAB_LOCK );
  71 }
  72
  73 /**********************************************************************
  74  *     msvcrt_free_mt_locks (internal)
  75  *
  76  * Uninitialize all mt locks. Assume that neither _lock or _unlock will
  77  * be called once we're calling this routine (ie _LOCKTAB_LOCK can be deleted)
  78  *
  79  */
  80 void msvcrt_free_mt_locks(void)
  81 {
  82   int i;
  83
  84   DPRINT(": uninitializing all mtlocks\n" );
  85
  86   /* Uninitialize the table */
  87   for( i=0; i < _TOTAL_LOCKS; i++ )
  88   {
  89     if( lock_table[ i ].bInit == TRUE )
  90     {
  91       msvcrt_uninitialize_mlock( i );
  92     }
  93   }
  94 }
  95
  96
  97 /**********************************************************************
  98  *              _lock (MSVCRT.@)
  99  */
 100 void _lock( int locknum )
 101 {
 102   DPRINT( "(%d)\n", locknum );
 103
 104   /* If the lock doesn't exist yet, create it */
 105   if( lock_table[ locknum ].bInit == FALSE )
 106   {
 107     /* Lock while we're changing the lock table */
 108     _lock( _LOCKTAB_LOCK );
 109
 110     /* Check again if we've got a bit of a race on lock creation */
 111     if( lock_table[ locknum ].bInit == FALSE )
 112     {
 113       DPRINT( ": creating lock #%d\n", locknum );
 114       msvcrt_initialize_mlock( locknum );
 115     }
 116
 117     /* Unlock ourselves */
 118     _unlock( _LOCKTAB_LOCK );
 119   }
 120
 121   EnterCriticalSection( &(lock_table[ locknum ].crit) );
 122 }
 123
 124 /**********************************************************************
 125  *              _unlock (MSVCRT.@)
 126  *
 127  * NOTE: There is no error detection to make sure the lock exists and is acquired.
 128  */
 129 void _unlock( int locknum )
 130 {
 131   DPRINT( "(%d)\n", locknum );
 132
 133   LeaveCriticalSection( &(lock_table[ locknum ].crit) );
 134 }
 135