libobjc/objc/sarray.h

   1 /* Sparse Arrays for Objective C dispatch tables
   2    Copyright (C) 1993, 1995, 1996, 2004, 2009 Free Software Foundation, Inc.
   3    Contributed by Kresten Krab Thorup.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 3, or (at your option)
  10 any later version.
  11
  12 GCC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 Under Section 7 of GPL version 3, you are granted additional
  18 permissions described in the GCC Runtime Library Exception, version
  19 3.1, as published by the Free Software Foundation.
  20
  21 You should have received a copy of the GNU General Public License and
  22 a copy of the GCC Runtime Library Exception along with this program;
  23 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 <http://www.gnu.org/licenses/>.  */
  25
  26
  27 #ifndef __sarray_INCLUDE_GNU
  28 #define __sarray_INCLUDE_GNU
  29
  30 #include "thr.h"
  31
  32 #define OBJC_SPARSE2            /* 2-level sparse array */
  33 /* #define OBJC_SPARSE3 */      /* 3-level sparse array */
  34
  35 #ifdef OBJC_SPARSE2
  36 extern const char* __objc_sparse2_id;
  37 #endif
  38
  39 #ifdef OBJC_SPARSE3
  40 extern const char* __objc_sparse3_id;
  41 #endif
  42
  43 #include <stddef.h>
  44 #include <assert.h>
  45
  46 #ifdef __cplusplus
  47 extern "C" {
  48 #endif /* __cplusplus */
  49
  50 extern int nbuckets;            /* for stats */
  51 extern int nindices;
  52 extern int narrays;
  53 extern int idxsize;
  54
  55 /* An unsigned integer of same size as a pointer */
  56 #define SIZET_BITS (sizeof(size_t)*8)
  57
  58 #if defined(__sparc__) || defined(OBJC_SPARSE2)
  59 #define PRECOMPUTE_SELECTORS
  60 #endif
  61
  62 #ifdef OBJC_SPARSE3
  63
  64 /* Buckets are 8 words each */
  65 #define BUCKET_BITS 3
  66 #define BUCKET_SIZE (1<<BUCKET_BITS)
  67 #define BUCKET_MASK (BUCKET_SIZE-1)
  68
  69 /* Indices are 16 words each */
  70 #define INDEX_BITS 4
  71 #define INDEX_SIZE (1<<INDEX_BITS)
  72 #define INDEX_MASK (INDEX_SIZE-1)
  73
  74 #define INDEX_CAPACITY (BUCKET_SIZE*INDEX_SIZE)
  75
  76 #else /* OBJC_SPARSE2 */
  77
  78 /* Buckets are 32 words each */
  79 #define BUCKET_BITS 5
  80 #define BUCKET_SIZE (1<<BUCKET_BITS)
  81 #define BUCKET_MASK (BUCKET_SIZE-1)
  82
  83 #endif /* OBJC_SPARSE2 */
  84
  85 typedef size_t sidx;
  86
  87 #ifdef PRECOMPUTE_SELECTORS
  88
  89 struct soffset {
  90 #ifdef OBJC_SPARSE3
  91   unsigned int unused : SIZET_BITS/4;
  92   unsigned int eoffset : SIZET_BITS/4;
  93   unsigned int boffset : SIZET_BITS/4;
  94   unsigned int ioffset : SIZET_BITS/4;
  95 #else /* OBJC_SPARSE2 */
  96 #ifdef __sparc__
  97   unsigned long boffset : (SIZET_BITS - 2) - BUCKET_BITS;
  98   unsigned int eoffset : BUCKET_BITS;
  99   unsigned int unused  : 2;
 100 #else
 101   unsigned int boffset : SIZET_BITS/2;
 102   unsigned int eoffset : SIZET_BITS/2;
 103 #endif
 104 #endif /* OBJC_SPARSE2 */
 105 };
 106
 107 union sofftype {
 108   struct soffset off;
 109   sidx idx;
 110 };
 111
 112 #endif /* not PRECOMPUTE_SELECTORS */
 113
 114 union sversion {
 115   int   version;
 116   void *next_free;
 117 };
 118
 119 struct sbucket {
 120   void* elems[BUCKET_SIZE];     /* elements stored in array */
 121   union sversion        version;                /* used for copy-on-write */
 122 };
 123
 124 #ifdef OBJC_SPARSE3
 125
 126 struct sindex {
 127   struct sbucket* buckets[INDEX_SIZE];
 128   union sversion        version;                /* used for copy-on-write */
 129 };
 130
 131 #endif /* OBJC_SPARSE3 */
 132
 133 struct sarray {
 134 #ifdef OBJC_SPARSE3
 135   struct sindex** indices;
 136   struct sindex* empty_index;
 137 #else /* OBJC_SPARSE2 */
 138   struct sbucket** buckets;
 139 #endif  /* OBJC_SPARSE2 */
 140   struct sbucket* empty_bucket;
 141   union sversion        version;                /* used for copy-on-write */
 142   short ref_count;
 143   struct sarray* is_copy_of;
 144   size_t capacity;
 145 };
 146
 147 struct sarray* sarray_new(int, void* default_element);
 148 void sarray_free(struct sarray*);
 149 struct sarray* sarray_lazy_copy(struct sarray*);
 150 void sarray_realloc(struct sarray*, int new_size);
 151 void sarray_at_put(struct sarray*, sidx indx, void* elem);
 152 void sarray_at_put_safe(struct sarray*, sidx indx, void* elem);
 153
 154 struct sarray* sarray_hard_copy(struct sarray*); /* ... like the name? */
 155 void sarray_remove_garbage(void);
 156 \f
 157
 158 #ifdef PRECOMPUTE_SELECTORS
 159 /* Transform soffset values to ints and vica verca */
 160 static inline unsigned int
 161 soffset_decode(sidx indx)
 162 {
 163   union sofftype x;
 164   x.idx = indx;
 165 #ifdef OBJC_SPARSE3
 166   return x.off.eoffset
 167     + (x.off.boffset*BUCKET_SIZE)
 168       + (x.off.ioffset*INDEX_CAPACITY);
 169 #else /* OBJC_SPARSE2 */
 170   return x.off.eoffset + (x.off.boffset*BUCKET_SIZE);
 171 #endif /* OBJC_SPARSE2 */
 172 }
 173
 174 static inline sidx
 175 soffset_encode(size_t offset)
 176 {
 177   union sofftype x;
 178   x.off.eoffset = offset%BUCKET_SIZE;
 179 #ifdef OBJC_SPARSE3
 180   x.off.boffset = (offset/BUCKET_SIZE)%INDEX_SIZE;
 181   x.off.ioffset = offset/INDEX_CAPACITY;
 182 #else /* OBJC_SPARSE2 */
 183   x.off.boffset = offset/BUCKET_SIZE;
 184 #endif
 185   return (sidx)x.idx;
 186 }
 187
 188 #else /* not PRECOMPUTE_SELECTORS */
 189
 190 static inline size_t
 191 soffset_decode(sidx indx)
 192 {
 193   return indx;
 194 }
 195
 196 static inline sidx
 197 soffset_encode(size_t offset)
 198 {
 199   return offset;
 200 }
 201 #endif /* not PRECOMPUTE_SELECTORS */
 202
 203 /* Get element from the Sparse array `array' at offset `indx' */
 204
 205 static inline void* sarray_get(struct sarray* array, sidx indx)
 206 {
 207 #ifdef PRECOMPUTE_SELECTORS
 208   union sofftype x;
 209   x.idx = indx;
 210 #ifdef OBJC_SPARSE3
 211   return
 212     array->
 213       indices[x.off.ioffset]->
 214         buckets[x.off.boffset]->
 215           elems[x.off.eoffset];
 216 #else /* OBJC_SPARSE2 */
 217   return array->buckets[x.off.boffset]->elems[x.off.eoffset];
 218 #endif /* OBJC_SPARSE2 */
 219 #else /* not PRECOMPUTE_SELECTORS */
 220 #ifdef OBJC_SPARSE3
 221   return array->
 222     indices[indx/INDEX_CAPACITY]->
 223       buckets[(indx/BUCKET_SIZE)%INDEX_SIZE]->
 224         elems[indx%BUCKET_SIZE];
 225 #else /* OBJC_SPARSE2 */
 226   return array->buckets[indx/BUCKET_SIZE]->elems[indx%BUCKET_SIZE];
 227 #endif /* not OBJC_SPARSE3 */
 228 #endif /* not PRECOMPUTE_SELECTORS */
 229 }
 230
 231 static inline void* sarray_get_safe(struct sarray* array, sidx indx)
 232 {
 233   if(soffset_decode(indx) < array->capacity)
 234     return sarray_get(array, indx);
 235   else
 236     return (array->empty_bucket->elems[0]);
 237 }
 238
 239 #ifdef __cplusplus
 240 }
 241 #endif /* __cplusplus */
 242
 243 #endif /* __sarray_INCLUDE_GNU */