rom/oop/obtainattrbase.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: OOP function OOP_ObtainAttrBase
   6     Lang: english
   7 */
   8
   9 #include "intern.h"
  10 #include "hash.h"
  11 /*****************************************************************************
  12
  13     NAME */
  14 #include <string.h>
  15
  16 #include <proto/exec.h>
  17 #include <exec/memory.h>
  18 #include <aros/libcall.h>
  19
  20 #include <aros/debug.h>
  21
  22         AROS_LH1(OOP_AttrBase, OOP_ObtainAttrBase,
  23
  24 /*  SYNOPSIS */
  25         AROS_LHA(STRPTR         , interfaceID, A0),
  26
  27 /*  LOCATION */
  28         struct Library *, OOPBase, 6, OOP)
  29
  30 /*  FUNCTION
  31         Maps a globally unique string interface ID into
  32         a numeric AttrBase ID that is unique on
  33         pr. machine basis. The AttrBase can be combiner
  34         with attribute offsets to generate attribute IDs.
  35
  36
  37
  38     INPUTS
  39         interfaceID     - globally unique interface identifier.
  40                           for which to obtain an attrbase.
  41
  42     RESULT
  43         Numeric AttrBase that is unique for this machine.
  44         A return value of 0 means that the call failed.
  45
  46     NOTES
  47         Obtained attrbases should be released with ReleasAttrBase().
  48
  49     EXAMPLE
  50         #define aTimer_CurrentTime    (__AB_Timer + aoTime_CurrentTime)
  51
  52         ..
  53         __AB_Timer = OOP_ObtainAttrBase(IID_Timer);
  54
  55         SetAttrs(timer, aTimer_CurrentTime, "10:37:00");
  56
  57
  58     BUGS
  59
  60     SEE ALSO
  61
  62     INTERNALS
  63
  64     HISTORY
  65
  66 ******************************************************************************/
  67 {
  68     AROS_LIBFUNC_INIT
  69
  70     /* Look up ID */
  71     struct iid_bucket *idb;
  72     struct HashTable *iidtable = GetOBase(OOPBase)->ob_IIDTable;
  73     ULONG base = -1UL;
  74
  75     EnterFunc(bug("OOP_ObtainAttrBase(interfaceID=%s)\n", interfaceID));
  76
  77     ObtainSemaphore(&GetOBase(OOPBase)->ob_IIDTableLock);
  78
  79
  80     /* Has ID allready been mapped to a numeric ID ? */
  81     idb = (struct iid_bucket *)iidtable->Lookup(iidtable, (IPTR)interfaceID, GetOBase(OOPBase));
  82     if (idb)
  83     {
  84
  85         /* If so, it has been stored in the hashtable, and we have
  86         ** to return the same numeric ID now.
  87         */
  88         if (idb->attrbase == (ULONG)-1)
  89         {
  90             idb->attrbase = GetOBase(OOPBase)->ob_CurrentAttrBase ++;
  91         }
  92
  93         base = idb->attrbase;
  94         base <<= NUM_METHOD_BITS;
  95
  96         D(bug("Bucket found: id=%ld\n", base));
  97     }
  98     else
  99     {
 100
 101         D(bug("No existing bucket\n"));
 102
 103
 104         /* If not, then map it and create a new bucket in the
 105         ** hashtable to store it
 106         */
 107         idb = AllocMem(sizeof (struct iid_bucket), MEMF_ANY|MEMF_CLEAR);
 108         if (idb)
 109         {
 110             idb->interface_id = AllocVec(strlen(interfaceID) + 1, MEMF_ANY);
 111             if (idb->interface_id)
 112             {
 113                 D(bug("Allocated bucket\n"));
 114                 strcpy(idb->interface_id, interfaceID);
 115
 116                 /* Get next free ID, and increase the free ID count to mark it as used */
 117                 base = idb->attrbase = ++ GetOBase(OOPBase)->ob_CurrentAttrBase;
 118
 119                 base <<= NUM_METHOD_BITS;
 120
 121                 /* Methodbase not inited yet */
 122                 idb->methodbase = -1UL;
 123
 124                 /* Insert bucket into hash table */
 125                 InsertBucket(iidtable, (struct Bucket *)idb, GetOBase(OOPBase));
 126             }
 127             else
 128             {
 129                 FreeMem(idb, sizeof (struct iid_bucket));
 130
 131 /* Throw exception here ? */
 132                 base = 0UL;
 133             }
 134         }
 135     }
 136
 137     if (base)
 138     {
 139         /* Increase refcount of bucket */
 140         idb->refcount ++;
 141     }
 142
 143     ReleaseSemaphore(&GetOBase(OOPBase)->ob_IIDTableLock);
 144
 145     ReturnInt ("OOP_ObtainAttrBase", AttrBase, base);
 146
 147     AROS_LIBFUNC_EXIT
 148
 149 } /* OOP_ObtainAttrBase  */
 150