code.delx.au - gnu-emacs/blob - oldXMenu/XMakeAssoc.c

   1 /* Copyright    Massachusetts Institute of Technology    1985   */
   2
   3 #include "copyright.h"
   4
   5
   6 #include <config.h>
   7 #include <X11/Xlib.h>
   8 #include <X11/Xresource.h>
   9 #include "X10.h"
  10 #include <errno.h>
  11
  12 #ifndef NULL
  13 #define NULL 0
  14 #endif
  15
  16 extern int errno;
  17
  18 void emacs_insque();
  19 struct qelem {
  20         struct    qelem *q_forw;
  21         struct    qelem *q_back;
  22         char q_data[1];
  23 };
  24 /*
  25  * XMakeAssoc - Insert data into an XAssocTable keyed on an XId.
  26  * Data is inserted into the table only once.  Redundant inserts are
  27  * meaningless (but cause no problems).  The queue in each association
  28  * bucket is sorted (lowest XId to highest XId).
  29  */
  30 void
  31 XMakeAssoc(dpy, table, x_id, data)
  32         register Display *dpy;
  33         register XAssocTable *table;
  34         register XID x_id;
  35         register caddr_t data;
  36 {
  37         int hash;
  38         register XAssoc *bucket;
  39         register XAssoc *Entry;
  40         register XAssoc *new_entry;
  41
  42         /* Hash the XId to get the bucket number. */
  43         hash = x_id & (table->size - 1);
  44         /* Look up the bucket to get the entries in that bucket. */
  45         bucket = &table->buckets[hash];
  46         /* Get the first entry in the bucket. */
  47         Entry = bucket->next;
  48
  49         /* If (Entry != bucket), the bucket is empty so make */
  50         /* the new entry the first entry in the bucket. */
  51         /* if (Entry == bucket), the we have to search the */
  52         /* bucket. */
  53         if (Entry != bucket) {
  54                 /* The bucket isn't empty, begin searching. */
  55                 /* If we leave the for loop then we have either passed */
  56                 /* where the entry should be or hit the end of the bucket. */
  57                 /* In either case we should then insert the new entry */
  58                 /* before the current value of "Entry". */
  59                 for (; Entry != bucket; Entry = Entry->next) {
  60                         if (Entry->x_id == x_id) {
  61                                 /* Entry has the same XId... */
  62                                 if (Entry->display == dpy) {
  63                                         /* Entry has the same Display... */
  64                                         /* Therefore there is already an */
  65                                         /* entry with this XId and Display, */
  66                                         /* reset its data value and return. */
  67                                         Entry->data = data;
  68                                         return;
  69                                 }
  70                                 /* We found an association with the right */
  71                                 /* id but the wrong display! */
  72                                 continue;
  73                         }
  74                         /* If the current entry's XId is greater than the */
  75                         /* XId of the entry to be inserted then we have */
  76                         /* passed the location where the new XId should */
  77                         /* be inserted. */
  78                         if (Entry->x_id > x_id) break;
  79                 }
  80         }
  81
  82         /* If we are here then the new entry should be inserted just */
  83         /* before the current value of "Entry". */
  84         /* Create a new XAssoc and load it with new provided data. */
  85         new_entry = (XAssoc *) malloc(sizeof(XAssoc));
  86         new_entry->display = dpy;
  87         new_entry->x_id = x_id;
  88         new_entry->data = data;
  89
  90         /* Insert the new entry. */
  91         emacs_insque((struct qelem *)new_entry, (struct qelem *)Entry->prev);
  92 }
  93
  94 /* arch-tag: d7e3fb8a-f3b3-4c5d-a307-75ca67ec1b49
  95    (do not change this comment) */