runtime/objc-sel-set.m

   1 /*
   2  * Copyright (c) 1999-2004,2008 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 #include "objc-private.h"
  35 #include "objc-sel-set.h"
  36
  37 #if !SUPPORT_MOD
  38 // mod-free power of 2 version
  39
  40 #define CONSTRAIN(val, range) ((val) & ((range)-1))
  41 #define SIZE 27
  42
  43 static const uint32_t __objc_sel_set_capacities[SIZE+1] = {
  44     3, 6, 12, 24, 48, 96, 192, 384, 768, 1536, 3072, 6144, 12288, 24576, 49152,
  45     98304, 196608, 393216, 786432, 1572864, 3145728, 6291456, 12582912, 25165824,
  46     50331648, 100663296, 201326592, UINT32_MAX
  47 };
  48
  49 static const uint32_t __objc_sel_set_buckets[SIZE] = {    // powers of 2
  50     4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536,
  51     131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432,
  52     67108864, 134217728, 268435456
  53 };
  54
  55 #else
  56 // prime version
  57
  58 #define CONSTRAIN(val, range) ((val) % (range))
  59 #define SIZE 42
  60
  61 static const uint32_t __objc_sel_set_capacities[SIZE+1] = {
  62     4, 8, 17, 29, 47, 76, 123, 199, 322, 521, 843, 1364, 2207, 3571, 5778, 9349,
  63     15127, 24476, 39603, 64079, 103682, 167761, 271443, 439204, 710647, 1149851, 1860498,
  64     3010349, 4870847, 7881196, 12752043, 20633239, 33385282, 54018521, 87403803, 141422324,
  65     228826127, 370248451, 599074578, 969323029, 1568397607, 2537720636U, UINT32_MAX
  66 };
  67
  68 static const uint32_t __objc_sel_set_buckets[SIZE] = {    // primes
  69    5, 11, 23, 41, 67, 113, 199, 317, 521, 839, 1361, 2207, 3571, 5779, 9349, 15121,
  70    24473, 39607, 64081, 103681, 167759, 271429, 439199, 710641, 1149857, 1860503, 3010349,
  71    4870843, 7881193, 12752029, 20633237, 33385273, 54018521, 87403763, 141422317, 228826121,
  72    370248451, 599074561, 969323023, 1568397599, 2537720629U, 4106118251U
  73 };
  74
  75 #endif
  76
  77 struct __objc_sel_set {
  78     uint32_t _count;            /* number of slots used */
  79     uint32_t _capacity;         /* maximum number of used slots */
  80     uint32_t _bucketsNum;       /* number of slots */
  81     SEL *_buckets;              /* can be NULL if not allocated yet */
  82 };
  83
  84 struct __objc_sel_set_finds {
  85     SEL match;
  86     uint32_t nomatch;
  87 };
  88
  89 // candidate may not be 0; match is 0 if not present
  90 static struct __objc_sel_set_finds __objc_sel_set_findBuckets(struct __objc_sel_set *sset, SEL candidate) {
  91     struct __objc_sel_set_finds ret = {0, 0xffffffff};
  92     uint32_t probe = CONSTRAIN((uint32_t)_objc_strhash((const char *)candidate), sset->_bucketsNum);
  93     for (;;) {
  94         SEL currentSel = sset->_buckets[probe];
  95         if (!currentSel) {
  96             ret.nomatch = probe;
  97             return ret;
  98         } else if (!ret.match && 0 == strcmp((const char *)currentSel, (const char *)candidate)) {
  99             ret.match = currentSel;
 100         }
 101         probe++;
 102         if (sset->_bucketsNum <= probe) {
 103             probe -= sset->_bucketsNum;
 104         }
 105     }
 106 }
 107
 108 // create a set with given starting capacity, will resize as needed
 109 PRIVATE_EXTERN struct __objc_sel_set *__objc_sel_set_create(uint32_t capacity) {
 110     uint32_t idx;
 111
 112     struct __objc_sel_set *sset = _malloc_internal(sizeof(struct __objc_sel_set));
 113     if (!sset) _objc_fatal("objc_sel_set failure");
 114     sset->_count = 0;
 115
 116     for (idx = 0; __objc_sel_set_capacities[idx] < capacity; idx++);
 117     if (SIZE <= idx) _objc_fatal("objc_sel_set failure");
 118     sset->_capacity = __objc_sel_set_capacities[idx];
 119     sset->_bucketsNum = __objc_sel_set_buckets[idx];
 120     sset->_buckets = _calloc_internal(sset->_bucketsNum, sizeof(SEL));
 121     if (!sset->_buckets) _objc_fatal("objc_sel_set failure");
 122     return sset;
 123 }
 124
 125 // returns 0 on failure; candidate may not be 0
 126 PRIVATE_EXTERN SEL __objc_sel_set_get(struct __objc_sel_set *sset, SEL candidate) {
 127     return __objc_sel_set_findBuckets(sset, candidate).match;
 128 }
 129
 130 // value may not be 0; should not be called unless it is known the value is not in the set
 131 PRIVATE_EXTERN void __objc_sel_set_add(struct __objc_sel_set *sset, SEL value) {
 132     if (sset->_count == sset->_capacity) {
 133         SEL *oldbuckets = sset->_buckets;
 134         uint32_t oldnbuckets = sset->_bucketsNum;
 135         uint32_t idx, capacity = sset->_count + 1;
 136         for (idx = 0; __objc_sel_set_capacities[idx] < capacity; idx++);
 137         if (SIZE <= idx) _objc_fatal("objc_sel_set failure");
 138         sset->_capacity = __objc_sel_set_capacities[idx];
 139         sset->_bucketsNum = __objc_sel_set_buckets[idx];
 140         sset->_buckets = _calloc_internal(sset->_bucketsNum, sizeof(SEL));
 141         if (!sset->_buckets) _objc_fatal("objc_sel_set failure");
 142         for (idx = 0; idx < oldnbuckets; idx++) {
 143             SEL currentSel = oldbuckets[idx];
 144             if (currentSel) {
 145                 uint32_t nomatch = __objc_sel_set_findBuckets(sset, currentSel).nomatch;
 146                 sset->_buckets[nomatch] = currentSel;
 147             }
 148         }
 149         _free_internal(oldbuckets);
 150     }
 151     {
 152         uint32_t nomatch = __objc_sel_set_findBuckets(sset, value).nomatch;
 153         sset->_buckets[nomatch] = value;
 154         sset->_count++;
 155     }
 156 }