4.3BSD - /usr/src/new/X/Xlib/XMakeAssoc.c

   1: #include <X/mit-copyright.h>
   2: 
   3: /* $Header: XMakeAssoc.c,v 10.4 86/02/01 15:36:32 tony Rel $ */
   4: /* Copyright    Massachusetts Institute of Technology    1985	*/
   5: 
   6: #include "XlibInternal.h"
   7: 
   8: /*
   9:  * XMakeAssoc - Insert data into an XAssocTable keyed on an XId.
  10:  * Data is inserted into the table only once.  Redundant inserts are
  11:  * meaningless (but cause no problems).  The queue in each association
  12:  * bucket is sorted (lowest XId to highest XId).
  13:  */
  14: XMakeAssoc(table, x_id, data)
  15:     register XAssocTable *table;
  16:     register XId x_id;
  17:     register caddr_t data;
  18: {
  19:     int hash;
  20:     register XAssoc *bucket;
  21:     register XAssoc *entry;
  22:     register XAssoc *new_entry;
  23: 
  24:     /* Hash the XId to get the bucket number. */
  25:     hash = x_id & (table->size - 1);
  26:     /* Look up the bucket to get the entries in that bucket. */
  27:     bucket = &(*table->table)[hash];
  28:     /* Get the first entry in the bucket. */
  29:     entry = bucket->next;
  30: 
  31:     /* If (entry != bucket), the bucket is empty so make */
  32:     /* the new entry the first entry in the bucket. */
  33:     /* if (entry == bucket), the we have to search the */
  34:     /* bucket. */
  35:     if (entry != bucket) {
  36:         /* The bucket isn't empty, begin searching. */
  37:         /* If we leave the for loop then we have either passed */
  38:         /* where the entry should be or hit the end of the bucket. */
  39:         /* In either case we should then insert the new entry */
  40:         /* before the current value of "entry". */
  41:         for (entry; entry != bucket; entry = entry->next) {
  42:             if (entry->x_id == x_id) {
  43:                 /* Entry has the same XId... */
  44:                 if (entry->display == _XlibCurrentDisplay) {
  45:                     /* Entry has the same Display... */
  46:                     /* Therefore there is already an */
  47:                     /* entry with this XId and Display, */
  48:                     /* reset its data value and return. */
  49:                     entry->data = data;
  50:                     return;
  51:                 }
  52:                 /* We found an association with the right */
  53:                 /* id but the wrong display! */
  54:                 continue;
  55:             }
  56:             /* If the current entry's XId is greater than the */
  57:             /* XId of the entry to be inserted then we have */
  58:             /* passed the location where the new XId should */
  59:             /* be inserted. */
  60:             if (entry->x_id > x_id) break;
  61:         }
  62:         }
  63: 
  64:     /* If we are here then the new entry should be inserted just */
  65:     /* before the current value of "entry". */
  66:     /* Create a new XAssoc and load it with new provided data. */
  67:     new_entry = (XAssoc *)malloc(sizeof(XAssoc));
  68:     if (new_entry == NULL) {
  69:         /* Malloc failed! */
  70:         errno = ENOMEM;
  71:         _XIOError(_XlibCurrentDisplay);
  72:     }
  73:     new_entry->display = _XlibCurrentDisplay;
  74:     new_entry->x_id = x_id;
  75:     new_entry->data = data;
  76: 
  77:     /* Insert the new entry. */
  78:     insque(new_entry, entry->prev);
  79: }

Defined functions