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

   1 /* Copyright    Massachusetts Institute of Technology    1985   */
   2 #include "copyright.h"
   3
   4
   5 #include <config.h>
   6 #include <X11/Xlib.h>
   7 #include <errno.h>
   8 #include "X10.h"
   9
  10 #ifndef NULL
  11 #define NULL 0
  12 #endif
  13
  14 extern int errno;
  15
  16 /*
  17  * XCreateAssocTable - Create an XAssocTable.  The size argument should be
  18  * a power of two for efficiency reasons.  Some size suggestions: use 32
  19  * buckets per 100 objects;  a reasonable maximum number of object per
  20  * buckets is 8.  If there is an error creating the XAssocTable, a NULL
  21  * pointer is returned.
  22  */
  23 XAssocTable *XCreateAssocTable(size)
  24         register int size;              /* Desired size of the table. */
  25 {
  26         register XAssocTable *table;    /* XAssocTable to be initialized. */
  27         register XAssoc *buckets;       /* Pointer to the first bucket in */
  28                                         /* the bucket array. */
  29
  30         /* Malloc the XAssocTable. */
  31         if ((table = (XAssocTable *)malloc(sizeof(XAssocTable))) == NULL) {
  32                 /* malloc call failed! */
  33                 errno = ENOMEM;
  34                 return(NULL);
  35         }
  36
  37         /* calloc the buckets (actually just their headers). */
  38         buckets = (XAssoc *)calloc((unsigned)size, (unsigned)sizeof(XAssoc));
  39         if (buckets == NULL) {
  40                 /* calloc call failed! */
  41                 errno = ENOMEM;
  42                 return(NULL);
  43         }
  44
  45         /* Insert table data into the XAssocTable structure. */
  46         table->buckets = buckets;
  47         table->size = size;
  48
  49         while (--size >= 0) {
  50                 /* Initialize each bucket. */
  51                 buckets->prev = buckets;
  52                 buckets->next = buckets;
  53                 buckets++;
  54         }
  55
  56         return(table);
  57 }
  58
  59 /* arch-tag: 5df3237d-ada0-4345-a3ab-282cafb397aa
  60    (do not change this comment) */