runtime/objc-sel-set.m

   1 /*
   2  * Copyright (c) 1999-2004 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * objc-sel-set.h
  26  * A cut-down copy of CFSet used for SEL uniquing.
  27  */
  28
  29
  30 // NOTE: even on a 64-bit system, the implementation is still limited
  31 // to 32-bit integers (like, the count), but SEL can be any size.
  32
  33 #include <stdint.h>
  34 #import "objc-private.h"
  35 #import "objc-sel-set.h"
  36
  37 static const uint32_t __objc_sel_set_capacities[43] = {
  38     4, 8, 17, 29, 47, 76, 123, 199, 322, 521, 843, 1364, 2207, 3571, 5778, 9349,
  39     15127, 24476, 39603, 64079, 103682, 167761, 271443, 439204, 710647, 1149851, 1860498,
  40     3010349, 4870847, 7881196, 12752043, 20633239, 33385282, 54018521, 87403803, 141422324,
  41     228826127, 370248451, 599074578, 969323029, 1568397607, 2537720636U, UINT32_MAX
  42 };
  43
  44 static const uint32_t __objc_sel_set_buckets[42] = {    // primes
  45    5, 11, 23, 41, 67, 113, 199, 317, 521, 839, 1361, 2207, 3571, 5779, 9349, 15121,
  46    24473, 39607, 64081, 103681, 167759, 271429, 439199, 710641, 1149857, 1860503, 3010349,
  47    4870843, 7881193, 12752029, 20633237, 33385273, 54018521, 87403763, 141422317, 228826121,
  48    370248451, 599074561, 969323023, 1568397599, 2537720629U, 4106118251U
  49 };
  50
  51 struct __objc_sel_set {
  52     uint32_t _count;            /* number of slots used */
  53     uint32_t _capacity;         /* maximum number of used slots */
  54     uint32_t _bucketsNum;       /* number of slots */
  55     SEL *_buckets;              /* can be NULL if not allocated yet */
  56 };
  57
  58 struct __objc_sel_set_finds {
  59     SEL match;
  60     uint32_t nomatch;
  61 };
  62
  63 // candidate may not be 0; match is 0 if not present
  64 static struct __objc_sel_set_finds __objc_sel_set_findBuckets(struct __objc_sel_set *sset, SEL candidate) {
  65     struct __objc_sel_set_finds ret = {0, 0xffffffff};
  66     uint32_t probe = (uint32_t)_objc_strhash((const char *)candidate) % sset->_bucketsNum;
  67     for (;;) {
  68         SEL currentSel = sset->_buckets[probe];
  69         if (!currentSel) {
  70             ret.nomatch = probe;
  71             return ret;
  72         } else if (!ret.match && 0 == _objc_strcmp((const char *)currentSel, (const char *)candidate)) {
  73             ret.match = currentSel;
  74         }
  75         probe++;
  76         if (sset->_bucketsNum <= probe) {
  77             probe -= sset->_bucketsNum;
  78         }
  79     }
  80 }
  81
  82 // create a set with given starting capacity, will resize as needed
  83 __private_extern__ struct __objc_sel_set *__objc_sel_set_create(uint32_t capacity) {
  84     struct __objc_sel_set *sset = _malloc_internal(sizeof(struct __objc_sel_set));
  85     if (!sset) _objc_fatal("objc_sel_set failure");
  86     sset->_count = 0;
  87     uint32_t idx;
  88     for (idx = 0; __objc_sel_set_capacities[idx] < capacity; idx++);
  89     if (42 <= idx) _objc_fatal("objc_sel_set failure");
  90     sset->_capacity = __objc_sel_set_capacities[idx];
  91     sset->_bucketsNum = __objc_sel_set_buckets[idx];
  92     sset->_buckets = _calloc_internal(sset->_bucketsNum, sizeof(SEL));
  93     if (!sset->_buckets) _objc_fatal("objc_sel_set failure");
  94     return sset;
  95 }
  96
  97 // returns 0 on failure; candidate may not be 0
  98 __private_extern__ SEL __objc_sel_set_get(struct __objc_sel_set *sset, SEL candidate) {
  99     return __objc_sel_set_findBuckets(sset, candidate).match;
 100 }
 101
 102 // value may not be 0; should not be called unless it is known the value is not in the set
 103 __private_extern__ void __objc_sel_set_add(struct __objc_sel_set *sset, SEL value) {
 104     if (sset->_count == sset->_capacity) {
 105         SEL *oldbuckets = sset->_buckets;
 106         uint32_t oldnbuckets = sset->_bucketsNum;
 107         uint32_t idx, capacity = sset->_count + 1;
 108         for (idx = 0; __objc_sel_set_capacities[idx] < capacity; idx++);
 109         if (42 <= idx) _objc_fatal("objc_sel_set failure");
 110         sset->_capacity = __objc_sel_set_capacities[idx];
 111         sset->_bucketsNum = __objc_sel_set_buckets[idx];
 112         sset->_buckets = _calloc_internal(sset->_bucketsNum, sizeof(SEL));
 113         if (!sset->_buckets) _objc_fatal("objc_sel_set failure");
 114         for (idx = 0; idx < oldnbuckets; idx++) {
 115             SEL currentSel = oldbuckets[idx];
 116             if (currentSel) {
 117                 uint32_t nomatch = __objc_sel_set_findBuckets(sset, currentSel).nomatch;
 118                 sset->_buckets[nomatch] = currentSel;
 119             }
 120         }
 121         _free_internal(oldbuckets);
 122     }
 123     uint32_t nomatch = __objc_sel_set_findBuckets(sset, value).nomatch;
 124     sset->_buckets[nomatch] = value;
 125     sset->_count++;
 126 }