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, 51 Franklin Street, Fifth Floor,
  20 Boston, MA 02110-1301, 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 "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 #include <assert.h>
  46
  47 #ifdef __cplusplus
  48 extern "C" {
  49 #endif /* __cplusplus */
  50
  51 extern int nbuckets;            /* for stats */
  52 extern int nindices;
  53 extern int narrays;
  54 extern int idxsize;
  55
  56 /* An unsigned integer of same size as a pointer */
  57 #define SIZET_BITS (sizeof(size_t)*8)
  58
  59 #if defined(__sparc__) || defined(OBJC_SPARSE2)
  60 #define PRECOMPUTE_SELECTORS
  61 #endif
  62
  63 #ifdef OBJC_SPARSE3
  64
  65 /* Buckets are 8 words each */
  66 #define BUCKET_BITS 3
  67 #define BUCKET_SIZE (1<<BUCKET_BITS)
  68 #define BUCKET_MASK (BUCKET_SIZE-1)
  69
  70 /* Indices are 16 words each */
  71 #define INDEX_BITS 4
  72 #define INDEX_SIZE (1<<INDEX_BITS)
  73 #define INDEX_MASK (INDEX_SIZE-1)
  74
  75 #define INDEX_CAPACITY (BUCKET_SIZE*INDEX_SIZE)
  76
  77 #else /* OBJC_SPARSE2 */
  78
  79 /* Buckets are 32 words each */
  80 #define BUCKET_BITS 5
  81 #define BUCKET_SIZE (1<<BUCKET_BITS)
  82 #define BUCKET_MASK (BUCKET_SIZE-1)
  83
  84 #endif /* OBJC_SPARSE2 */
  85
  86 typedef size_t sidx;
  87
  88 #ifdef PRECOMPUTE_SELECTORS
  89
  90 struct soffset {
  91 #ifdef OBJC_SPARSE3
  92   unsigned int unused : SIZET_BITS/4;
  93   unsigned int eoffset : SIZET_BITS/4;
  94   unsigned int boffset : SIZET_BITS/4;
  95   unsigned int ioffset : SIZET_BITS/4;
  96 #else /* OBJC_SPARSE2 */
  97 #ifdef __sparc__
  98   unsigned long boffset : (SIZET_BITS - 2) - BUCKET_BITS;
  99   unsigned int eoffset : BUCKET_BITS;
 100   unsigned int unused  : 2;
 101 #else
 102   unsigned int boffset : SIZET_BITS/2;
 103   unsigned int eoffset : SIZET_BITS/2;
 104 #endif
 105 #endif /* OBJC_SPARSE2 */
 106 };
 107
 108 union sofftype {
 109   struct soffset off;
 110   sidx idx;
 111 };
 112
 113 #endif /* not PRECOMPUTE_SELECTORS */
 114
 115 union sversion {
 116   int   version;
 117   void *next_free;
 118 };
 119
 120 struct sbucket {
 121   void* elems[BUCKET_SIZE];     /* elements stored in array */
 122   union sversion        version;                /* used for copy-on-write */
 123 };
 124
 125 #ifdef OBJC_SPARSE3
 126
 127 struct sindex {
 128   struct sbucket* buckets[INDEX_SIZE];
 129   union sversion        version;                /* used for copy-on-write */
 130 };
 131
 132 #endif /* OBJC_SPARSE3 */
 133
 134 struct sarray {
 135 #ifdef OBJC_SPARSE3
 136   struct sindex** indices;
 137   struct sindex* empty_index;
 138 #else /* OBJC_SPARSE2 */
 139   struct sbucket** buckets;
 140 #endif  /* OBJC_SPARSE2 */
 141   struct sbucket* empty_bucket;
 142   union sversion        version;                /* used for copy-on-write */
 143   short ref_count;
 144   struct sarray* is_copy_of;
 145   size_t capacity;
 146 };
 147
 148 struct sarray* sarray_new(int, void* default_element);
 149 void sarray_free(struct sarray*);
 150 struct sarray* sarray_lazy_copy(struct sarray*);
 151 void sarray_realloc(struct sarray*, int new_size);
 152 void sarray_at_put(struct sarray*, sidx indx, void* elem);
 153 void sarray_at_put_safe(struct sarray*, sidx indx, void* elem);
 154
 155 struct sarray* sarray_hard_copy(struct sarray*); /* ... like the name? */
 156 void sarray_remove_garbage(void);
 157 \f
 158
 159 #ifdef PRECOMPUTE_SELECTORS
 160 /* Transform soffset values to ints and vica verca */
 161 static inline unsigned int
 162 soffset_decode(sidx indx)
 163 {
 164   union sofftype x;
 165   x.idx = indx;
 166 #ifdef OBJC_SPARSE3
 167   return x.off.eoffset
 168     + (x.off.boffset*BUCKET_SIZE)
 169       + (x.off.ioffset*INDEX_CAPACITY);
 170 #else /* OBJC_SPARSE2 */
 171   return x.off.eoffset + (x.off.boffset*BUCKET_SIZE);
 172 #endif /* OBJC_SPARSE2 */
 173 }
 174
 175 static inline sidx
 176 soffset_encode(size_t offset)
 177 {
 178   union sofftype x;
 179   x.off.eoffset = offset%BUCKET_SIZE;
 180 #ifdef OBJC_SPARSE3
 181   x.off.boffset = (offset/BUCKET_SIZE)%INDEX_SIZE;
 182   x.off.ioffset = offset/INDEX_CAPACITY;
 183 #else /* OBJC_SPARSE2 */
 184   x.off.boffset = offset/BUCKET_SIZE;
 185 #endif
 186   return (sidx)x.idx;
 187 }
 188
 189 #else /* not PRECOMPUTE_SELECTORS */
 190
 191 static inline size_t
 192 soffset_decode(sidx indx)
 193 {
 194   return indx;
 195 }
 196
 197 static inline sidx
 198 soffset_encode(size_t offset)
 199 {
 200   return offset;
 201 }
 202 #endif /* not PRECOMPUTE_SELECTORS */
 203
 204 /* Get element from the Sparse array `array' at offset `indx' */
 205
 206 static inline void* sarray_get(struct sarray* array, sidx indx)
 207 {
 208 #ifdef PRECOMPUTE_SELECTORS
 209   union sofftype x;
 210   x.idx = indx;
 211 #ifdef OBJC_SPARSE3
 212   return
 213     array->
 214       indices[x.off.ioffset]->
 215         buckets[x.off.boffset]->
 216           elems[x.off.eoffset];
 217 #else /* OBJC_SPARSE2 */
 218   return array->buckets[x.off.boffset]->elems[x.off.eoffset];
 219 #endif /* OBJC_SPARSE2 */
 220 #else /* not PRECOMPUTE_SELECTORS */
 221 #ifdef OBJC_SPARSE3
 222   return array->
 223     indices[indx/INDEX_CAPACITY]->
 224       buckets[(indx/BUCKET_SIZE)%INDEX_SIZE]->
 225         elems[indx%BUCKET_SIZE];
 226 #else /* OBJC_SPARSE2 */
 227   return array->buckets[indx/BUCKET_SIZE]->elems[indx%BUCKET_SIZE];
 228 #endif /* not OBJC_SPARSE3 */
 229 #endif /* not PRECOMPUTE_SELECTORS */
 230 }
 231
 232 static inline void* sarray_get_safe(struct sarray* array, sidx indx)
 233 {
 234   if(soffset_decode(indx) < array->capacity)
 235     return sarray_get(array, indx);
 236   else
 237     return (array->empty_bucket->elems[0]);
 238 }
 239
 240 #ifdef __cplusplus
 241 }
 242 #endif /* __cplusplus */
 243
 244 #endif /* __sarray_INCLUDE_GNU */