libobjc/objc/sarray.h

   1 /* Sparse Arrays for Objective C dispatch tables
   2    Copyright (C) 1993, 1995, 1996, 2004 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 2, 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 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 59 Temple Place - Suite 330,
  20 Boston, MA 02111-1307, USA.  */
  21
  22 /* As a special exception, if you link this library with files
  23    compiled with GCC to produce an executable, this does not cause
  24    the resulting executable to be covered by the GNU General Public License.
  25    This exception does not however invalidate any other reasons why
  26    the executable file might be covered by the GNU General Public License.  */
  27
  28 #ifndef __sarray_INCLUDE_GNU
  29 #define __sarray_INCLUDE_GNU
  30
  31 #include <objc/thr.h>
  32
  33 #define OBJC_SPARSE2            /* 2-level sparse array */
  34 /* #define OBJC_SPARSE3 */      /* 3-level sparse array */
  35
  36 #ifdef OBJC_SPARSE2
  37 extern const char* __objc_sparse2_id;
  38 #endif
  39
  40 #ifdef OBJC_SPARSE3
  41 extern const char* __objc_sparse3_id;
  42 #endif
  43
  44 #include <stddef.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 #ifdef __cplusplus
  56 }
  57 #endif /* __cplusplus */
  58
  59
  60 #include <assert.h>
  61
  62 /* An unsigned integer of same size as a pointer */
  63 #define SIZET_BITS (sizeof(size_t)*8)
  64
  65 #if defined(__sparc__) || defined(OBJC_SPARSE2)
  66 #define PRECOMPUTE_SELECTORS
  67 #endif
  68
  69 #ifdef OBJC_SPARSE3
  70
  71 /* Buckets are 8 words each */
  72 #define BUCKET_BITS 3
  73 #define BUCKET_SIZE (1<<BUCKET_BITS)
  74 #define BUCKET_MASK (BUCKET_SIZE-1)
  75
  76 /* Indices are 16 words each */
  77 #define INDEX_BITS 4
  78 #define INDEX_SIZE (1<<INDEX_BITS)
  79 #define INDEX_MASK (INDEX_SIZE-1)
  80
  81 #define INDEX_CAPACITY (BUCKET_SIZE*INDEX_SIZE)
  82
  83 #else /* OBJC_SPARSE2 */
  84
  85 /* Buckets are 32 words each */
  86 #define BUCKET_BITS 5
  87 #define BUCKET_SIZE (1<<BUCKET_BITS)
  88 #define BUCKET_MASK (BUCKET_SIZE-1)
  89
  90 #endif /* OBJC_SPARSE2 */
  91
  92 typedef size_t sidx;
  93
  94 #ifdef PRECOMPUTE_SELECTORS
  95
  96 struct soffset {
  97 #ifdef OBJC_SPARSE3
  98   unsigned int unused : SIZET_BITS/4;
  99   unsigned int eoffset : SIZET_BITS/4;
 100   unsigned int boffset : SIZET_BITS/4;
 101   unsigned int ioffset : SIZET_BITS/4;
 102 #else /* OBJC_SPARSE2 */
 103 #ifdef __sparc__
 104   unsigned long boffset : (SIZET_BITS - 2) - BUCKET_BITS;
 105   unsigned int eoffset : BUCKET_BITS;
 106   unsigned int unused  : 2;
 107 #else
 108   unsigned int boffset : SIZET_BITS/2;
 109   unsigned int eoffset : SIZET_BITS/2;
 110 #endif
 111 #endif /* OBJC_SPARSE2 */
 112 };
 113
 114 union sofftype {
 115   struct soffset off;
 116   sidx idx;
 117 };
 118
 119 #endif /* not PRECOMPUTE_SELECTORS */
 120
 121 union sversion {
 122   int   version;
 123   void *next_free;
 124 };
 125
 126 struct sbucket {
 127   void* elems[BUCKET_SIZE];     /* elements stored in array */
 128   union sversion        version;                /* used for copy-on-write */
 129 };
 130
 131 #ifdef OBJC_SPARSE3
 132
 133 struct sindex {
 134   struct sbucket* buckets[INDEX_SIZE];
 135   union sversion        version;                /* used for copy-on-write */
 136 };
 137
 138 #endif /* OBJC_SPARSE3 */
 139
 140 struct sarray {
 141 #ifdef OBJC_SPARSE3
 142   struct sindex** indices;
 143   struct sindex* empty_index;
 144 #else /* OBJC_SPARSE2 */
 145   struct sbucket** buckets;
 146 #endif  /* OBJC_SPARSE2 */
 147   struct sbucket* empty_bucket;
 148   union sversion        version;                /* used for copy-on-write */
 149   short ref_count;
 150   struct sarray* is_copy_of;
 151   size_t capacity;
 152 };
 153
 154 #ifdef __cplusplus
 155 extern "C" {
 156 #endif /* __cplusplus */
 157
 158 struct sarray* sarray_new(int, void* default_element);
 159 void sarray_free(struct sarray*);
 160 struct sarray* sarray_lazy_copy(struct sarray*);
 161 void sarray_realloc(struct sarray*, int new_size);
 162 void sarray_at_put(struct sarray*, sidx indx, void* elem);
 163 void sarray_at_put_safe(struct sarray*, sidx indx, void* elem);
 164
 165 struct sarray* sarray_hard_copy(struct sarray*); /* ... like the name? */
 166 void sarray_remove_garbage(void);
 167 \f
 168
 169 #ifdef PRECOMPUTE_SELECTORS
 170 /* Transform soffset values to ints and vica verca */
 171 static inline unsigned int
 172 soffset_decode(sidx indx)
 173 {
 174   union sofftype x;
 175   x.idx = indx;
 176 #ifdef OBJC_SPARSE3
 177   return x.off.eoffset
 178     + (x.off.boffset*BUCKET_SIZE)
 179       + (x.off.ioffset*INDEX_CAPACITY);
 180 #else /* OBJC_SPARSE2 */
 181   return x.off.eoffset + (x.off.boffset*BUCKET_SIZE);
 182 #endif /* OBJC_SPARSE2 */
 183 }
 184
 185 static inline sidx
 186 soffset_encode(size_t offset)
 187 {
 188   union sofftype x;
 189   x.off.eoffset = offset%BUCKET_SIZE;
 190 #ifdef OBJC_SPARSE3
 191   x.off.boffset = (offset/BUCKET_SIZE)%INDEX_SIZE;
 192   x.off.ioffset = offset/INDEX_CAPACITY;
 193 #else /* OBJC_SPARSE2 */
 194   x.off.boffset = offset/BUCKET_SIZE;
 195 #endif
 196   return (sidx)x.idx;
 197 }
 198
 199 #else /* not PRECOMPUTE_SELECTORS */
 200
 201 static inline size_t
 202 soffset_decode(sidx indx)
 203 {
 204   return indx;
 205 }
 206
 207 static inline sidx
 208 soffset_encode(size_t offset)
 209 {
 210   return offset;
 211 }
 212 #endif /* not PRECOMPUTE_SELECTORS */
 213
 214 /* Get element from the Sparse array `array' at offset `indx' */
 215
 216 static inline void* sarray_get(struct sarray* array, sidx indx)
 217 {
 218 #ifdef PRECOMPUTE_SELECTORS
 219   union sofftype x;
 220   x.idx = indx;
 221 #ifdef OBJC_SPARSE3
 222   return
 223     array->
 224       indices[x.off.ioffset]->
 225         buckets[x.off.boffset]->
 226           elems[x.off.eoffset];
 227 #else /* OBJC_SPARSE2 */
 228   return array->buckets[x.off.boffset]->elems[x.off.eoffset];
 229 #endif /* OBJC_SPARSE2 */
 230 #else /* not PRECOMPUTE_SELECTORS */
 231 #ifdef OBJC_SPARSE3
 232   return array->
 233     indices[indx/INDEX_CAPACITY]->
 234       buckets[(indx/BUCKET_SIZE)%INDEX_SIZE]->
 235         elems[indx%BUCKET_SIZE];
 236 #else /* OBJC_SPARSE2 */
 237   return array->buckets[indx/BUCKET_SIZE]->elems[indx%BUCKET_SIZE];
 238 #endif /* not OBJC_SPARSE3 */
 239 #endif /* not PRECOMPUTE_SELECTORS */
 240 }
 241
 242 static inline void* sarray_get_safe(struct sarray* array, sidx indx)
 243 {
 244   if(soffset_decode(indx) < array->capacity)
 245     return sarray_get(array, indx);
 246   else
 247     return (array->empty_bucket->elems[0]);
 248 }
 249
 250 #ifdef __cplusplus
 251 }
 252 #endif /* __cplusplus */
 253
 254 #endif /* __sarray_INCLUDE_GNU */