oldXMenu/XCrAssoc.c

   1 /* Copyright    Massachusetts Institute of Technology    1985   */
   2 #include "copyright.h"
   3
   4
   5 #include <config.h>
   6 #include <stdlib.h>
   7 #include <X11/Xlib.h>
   8 #include <errno.h>
   9 #include "X10.h"
  10
  11 #ifndef NULL
  12 #define NULL 0
  13 #endif
  14
  15 /*
  16  * XCreateAssocTable - Create an XAssocTable.  The size argument should be
  17  * a power of two for efficiency reasons.  Some size suggestions: use 32
  18  * buckets per 100 objects;  a reasonable maximum number of object per
  19  * buckets is 8.  If there is an error creating the XAssocTable, a NULL
  20  * pointer is returned.
  21  */
  22 XAssocTable *XCreateAssocTable(register int size)
  23                                         /* Desired size of the table. */
  24 {
  25         register XAssocTable *table;    /* XAssocTable to be initialized. */
  26         register XAssoc *buckets;       /* Pointer to the first bucket in */
  27                                         /* the bucket array. */
  28
  29         /* Malloc the XAssocTable. */
  30         if ((table = (XAssocTable *)malloc(sizeof(XAssocTable))) == NULL) {
  31                 /* malloc call failed! */
  32                 errno = ENOMEM;
  33                 return(NULL);
  34         }
  35
  36         /* calloc the buckets (actually just their headers). */
  37         buckets = (XAssoc *)calloc((unsigned)size, (unsigned)sizeof(XAssoc));
  38         if (buckets == NULL) {
  39                 /* calloc call failed! */
  40                 errno = ENOMEM;
  41                 return(NULL);
  42         }
  43
  44         /* Insert table data into the XAssocTable structure. */
  45         table->buckets = buckets;
  46         table->size = size;
  47
  48         while (--size >= 0) {
  49                 /* Initialize each bucket. */
  50                 buckets->prev = buckets;
  51                 buckets->next = buckets;
  52                 buckets++;
  53         }
  54
  55         return(table);
  56 }
  57