mirror of
https://github.com/autc04/Retro68.git
synced 2024-11-19 18:46:30 +00:00
136 lines
3.6 KiB
C
136 lines
3.6 KiB
C
/* go-map-index.c -- find or insert an entry in a map.
|
|
|
|
Copyright 2009 The Go Authors. All rights reserved.
|
|
Use of this source code is governed by a BSD-style
|
|
license that can be found in the LICENSE file. */
|
|
|
|
#include <stddef.h>
|
|
#include <stdlib.h>
|
|
|
|
#include "runtime.h"
|
|
#include "go-alloc.h"
|
|
#include "go-assert.h"
|
|
#include "map.h"
|
|
|
|
/* Rehash MAP to a larger size. */
|
|
|
|
static void
|
|
__go_map_rehash (struct __go_map *map)
|
|
{
|
|
const struct __go_map_descriptor *descriptor;
|
|
const struct __go_type_descriptor *key_descriptor;
|
|
uintptr_t key_offset;
|
|
size_t key_size;
|
|
uintptr_t (*hashfn) (const void *, uintptr_t);
|
|
uintptr_t old_bucket_count;
|
|
void **old_buckets;
|
|
uintptr_t new_bucket_count;
|
|
void **new_buckets;
|
|
uintptr_t i;
|
|
|
|
descriptor = map->__descriptor;
|
|
|
|
key_descriptor = descriptor->__map_descriptor->__key_type;
|
|
key_offset = descriptor->__key_offset;
|
|
key_size = key_descriptor->__size;
|
|
hashfn = key_descriptor->__hashfn;
|
|
|
|
old_bucket_count = map->__bucket_count;
|
|
old_buckets = map->__buckets;
|
|
|
|
new_bucket_count = __go_map_next_prime (old_bucket_count * 2);
|
|
new_buckets = (void **) __go_alloc (new_bucket_count * sizeof (void *));
|
|
__builtin_memset (new_buckets, 0, new_bucket_count * sizeof (void *));
|
|
|
|
for (i = 0; i < old_bucket_count; ++i)
|
|
{
|
|
char* entry;
|
|
char* next;
|
|
|
|
for (entry = old_buckets[i]; entry != NULL; entry = next)
|
|
{
|
|
size_t key_hash;
|
|
size_t new_bucket_index;
|
|
|
|
/* We could speed up rehashing at the cost of memory space
|
|
by caching the hash code. */
|
|
key_hash = hashfn (entry + key_offset, key_size);
|
|
new_bucket_index = key_hash % new_bucket_count;
|
|
|
|
next = *(char **) entry;
|
|
*(char **) entry = new_buckets[new_bucket_index];
|
|
new_buckets[new_bucket_index] = entry;
|
|
}
|
|
}
|
|
|
|
__go_free (old_buckets);
|
|
|
|
map->__bucket_count = new_bucket_count;
|
|
map->__buckets = new_buckets;
|
|
}
|
|
|
|
/* Find KEY in MAP, return a pointer to the value. If KEY is not
|
|
present, then if INSERT is false, return NULL, and if INSERT is
|
|
true, insert a new value and zero-initialize it before returning a
|
|
pointer to it. */
|
|
|
|
void *
|
|
__go_map_index (struct __go_map *map, const void *key, _Bool insert)
|
|
{
|
|
const struct __go_map_descriptor *descriptor;
|
|
const struct __go_type_descriptor *key_descriptor;
|
|
uintptr_t key_offset;
|
|
_Bool (*equalfn) (const void*, const void*, uintptr_t);
|
|
size_t key_hash;
|
|
size_t key_size;
|
|
size_t bucket_index;
|
|
char *entry;
|
|
|
|
if (map == NULL)
|
|
{
|
|
if (insert)
|
|
runtime_panicstring ("assignment to entry in nil map");
|
|
return NULL;
|
|
}
|
|
|
|
descriptor = map->__descriptor;
|
|
|
|
key_descriptor = descriptor->__map_descriptor->__key_type;
|
|
key_offset = descriptor->__key_offset;
|
|
key_size = key_descriptor->__size;
|
|
__go_assert (key_size != 0 && key_size != -1UL);
|
|
equalfn = key_descriptor->__equalfn;
|
|
|
|
key_hash = key_descriptor->__hashfn (key, key_size);
|
|
bucket_index = key_hash % map->__bucket_count;
|
|
|
|
entry = (char *) map->__buckets[bucket_index];
|
|
while (entry != NULL)
|
|
{
|
|
if (equalfn (key, entry + key_offset, key_size))
|
|
return entry + descriptor->__val_offset;
|
|
entry = *(char **) entry;
|
|
}
|
|
|
|
if (!insert)
|
|
return NULL;
|
|
|
|
if (map->__element_count >= map->__bucket_count)
|
|
{
|
|
__go_map_rehash (map);
|
|
bucket_index = key_hash % map->__bucket_count;
|
|
}
|
|
|
|
entry = (char *) __go_alloc (descriptor->__entry_size);
|
|
__builtin_memset (entry, 0, descriptor->__entry_size);
|
|
|
|
__builtin_memcpy (entry + key_offset, key, key_size);
|
|
|
|
*(char **) entry = map->__buckets[bucket_index];
|
|
map->__buckets[bucket_index] = entry;
|
|
|
|
map->__element_count += 1;
|
|
|
|
return entry + descriptor->__val_offset;
|
|
}
|