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Annotation of 43BSD/contrib/X/Xlib/XMakeAssoc.c, revision 1.1.1.1

1.1       root        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: }

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