1 /* go-map-delete.c -- delete an entry from a map.
2 
3    Copyright 2009 The Go Authors. All rights reserved.
4    Use of this source code is governed by a BSD-style
5    license that can be found in the LICENSE file.  */
6 
7 #include <stddef.h>
8 #include <stdlib.h>
9 
10 #include "runtime.h"
11 #include "malloc.h"
12 #include "go-alloc.h"
13 #include "go-assert.h"
14 #include "map.h"
15 
16 /* Delete the entry matching KEY from MAP.  */
17 
18 void
__go_map_delete(struct __go_map * map,const void * key)19 __go_map_delete (struct __go_map *map, const void *key)
20 {
21   const struct __go_map_descriptor *descriptor;
22   const struct __go_type_descriptor *key_descriptor;
23   uintptr_t key_offset;
24   const FuncVal *equalfn;
25   size_t key_hash;
26   size_t key_size;
27   size_t bucket_index;
28   void **pentry;
29 
30   if (map == NULL)
31     return;
32 
33   descriptor = map->__descriptor;
34 
35   key_descriptor = descriptor->__map_descriptor->__key_type;
36   key_offset = descriptor->__key_offset;
37   key_size = key_descriptor->__size;
38   if (key_size == 0)
39     return;
40 
41   __go_assert (key_size != -1UL);
42   equalfn = key_descriptor->__equalfn;
43 
44   key_hash = __go_call_hashfn (key_descriptor->__hashfn, key, key_size);
45   bucket_index = key_hash % map->__bucket_count;
46 
47   pentry = map->__buckets + bucket_index;
48   while (*pentry != NULL)
49     {
50       char *entry = (char *) *pentry;
51       if (__go_call_equalfn (equalfn, key, entry + key_offset, key_size))
52 	{
53 	  *pentry = *(void **) entry;
54 	  if (descriptor->__entry_size >= TinySize)
55 	    __go_free (entry);
56 	  map->__element_count -= 1;
57 	  break;
58 	}
59       pentry = (void **) entry;
60     }
61 }
62