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/* Sparse Arrays for Objective C dispatch tables
Copyright (C) 1993-2022 Free Software Foundation, Inc.
Contributed by Kresten Krab Thorup.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.
GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#ifndef __sarray_INCLUDE_GNU
#define __sarray_INCLUDE_GNU
#define OBJC_SPARSE2 /* 2-level sparse array. */
/* #define OBJC_SPARSE3 */ /* 3-level sparse array. */
#ifdef OBJC_SPARSE2
extern const char* __objc_sparse2_id;
#endif
#ifdef OBJC_SPARSE3
extern const char* __objc_sparse3_id;
#endif
#include <stddef.h>
extern int nbuckets; /* for stats */
extern int nindices;
extern int narrays;
extern int idxsize;
/* An unsigned integer of same size as a pointer. */
#define SIZET_BITS (sizeof (size_t) * 8)
#if defined (__sparc__) || defined (OBJC_SPARSE2)
#define PRECOMPUTE_SELECTORS
#endif
#ifdef OBJC_SPARSE3
/* Buckets are 8 words each. */
#define BUCKET_BITS 3
#define BUCKET_SIZE (1 << BUCKET_BITS)
#define BUCKET_MASK (BUCKET_SIZE - 1)
/* Indices are 16 words each. */
#define INDEX_BITS 4
#define INDEX_SIZE (1 << INDEX_BITS)
#define INDEX_MASK (INDEX_SIZE - 1)
#define INDEX_CAPACITY (BUCKET_SIZE * INDEX_SIZE)
#else /* OBJC_SPARSE2 */
/* Buckets are 32 words each. */
#define BUCKET_BITS 5
#define BUCKET_SIZE (1 << BUCKET_BITS)
#define BUCKET_MASK (BUCKET_SIZE - 1)
#endif /* OBJC_SPARSE2 */
typedef size_t sidx;
#ifdef PRECOMPUTE_SELECTORS
struct soffset
{
#ifdef OBJC_SPARSE3
unsigned int unused : SIZET_BITS / 4;
unsigned int eoffset : SIZET_BITS / 4;
unsigned int boffset : SIZET_BITS / 4;
unsigned int ioffset : SIZET_BITS / 4;
#else /* OBJC_SPARSE2 */
#ifdef __sparc__
unsigned long boffset : (SIZET_BITS - 2) - BUCKET_BITS;
unsigned int eoffset : BUCKET_BITS;
unsigned int unused : 2;
#else
unsigned int boffset : SIZET_BITS / 2;
unsigned int eoffset : SIZET_BITS / 2;
#endif
#endif /* OBJC_SPARSE2 */
};
union sofftype
{
struct soffset off;
sidx idx;
};
#endif /* not PRECOMPUTE_SELECTORS */
union sversion
{
int version;
void *next_free;
};
struct sbucket
{
/* Elements stored in array. */
void* elems[BUCKET_SIZE];
/* Used for copy-on-write. */
union sversion version;
};
#ifdef OBJC_SPARSE3
struct sindex
{
struct sbucket* buckets[INDEX_SIZE];
/* Used for copy-on-write. */
union sversion version;
};
#endif /* OBJC_SPARSE3 */
struct sarray
{
#ifdef OBJC_SPARSE3
struct sindex** indices;
struct sindex* empty_index;
#else /* OBJC_SPARSE2 */
struct sbucket** buckets;
#endif /* OBJC_SPARSE2 */
struct sbucket* empty_bucket;
/* Used for copy-on-write. */
union sversion version;
short ref_count;
struct sarray* is_copy_of;
size_t capacity;
};
struct sarray* sarray_new (int, void* default_element);
void sarray_free (struct sarray*);
struct sarray* sarray_lazy_copy (struct sarray*);
void sarray_realloc (struct sarray*, int new_size);
void sarray_at_put (struct sarray*, sidx indx, void* elem);
void sarray_at_put_safe (struct sarray*, sidx indx, void* elem);
struct sarray* sarray_hard_copy (struct sarray*); /* ... like the name ? */
void sarray_remove_garbage (void);
#ifdef PRECOMPUTE_SELECTORS
/* Transform soffset values to ints and vice versa. */
static inline unsigned int
soffset_decode (sidx indx)
{
union sofftype x;
x.idx = indx;
#ifdef OBJC_SPARSE3
return x.off.eoffset
+ (x.off.boffset * BUCKET_SIZE)
+ (x.off.ioffset * INDEX_CAPACITY);
#else /* OBJC_SPARSE2 */
return x.off.eoffset + (x.off.boffset * BUCKET_SIZE);
#endif /* OBJC_SPARSE2 */
}
static inline sidx
soffset_encode (size_t offset)
{
union sofftype x;
x.off.eoffset = offset % BUCKET_SIZE;
#ifdef OBJC_SPARSE3
x.off.boffset = (offset / BUCKET_SIZE) % INDEX_SIZE;
x.off.ioffset = offset / INDEX_CAPACITY;
#else /* OBJC_SPARSE2 */
x.off.boffset = offset / BUCKET_SIZE;
#endif
return (sidx)x.idx;
}
#else /* not PRECOMPUTE_SELECTORS */
static inline size_t
soffset_decode (sidx indx)
{
return indx;
}
static inline sidx
soffset_encode (size_t offset)
{
return offset;
}
#endif /* not PRECOMPUTE_SELECTORS */
/* Get element from the Sparse array `array' at offset `indx'. */
static inline void* sarray_get (struct sarray* array, sidx indx)
{
#ifdef PRECOMPUTE_SELECTORS
union sofftype x;
x.idx = indx;
#ifdef OBJC_SPARSE3
return array->
indices[x.off.ioffset]->
buckets[x.off.boffset]->
elems[x.off.eoffset];
#else /* OBJC_SPARSE2 */
return array->buckets[x.off.boffset]->elems[x.off.eoffset];
#endif /* OBJC_SPARSE2 */
#else /* not PRECOMPUTE_SELECTORS */
#ifdef OBJC_SPARSE3
return array->
indices[indx / INDEX_CAPACITY]->
buckets[(indx / BUCKET_SIZE) % INDEX_SIZE]->
elems[indx % BUCKET_SIZE];
#else /* OBJC_SPARSE2 */
return array->buckets[indx / BUCKET_SIZE]->elems[indx % BUCKET_SIZE];
#endif /* not OBJC_SPARSE3 */
#endif /* not PRECOMPUTE_SELECTORS */
}
static inline void* sarray_get_safe (struct sarray* array, sidx indx)
{
if (soffset_decode (indx) < array->capacity)
return sarray_get (array, indx);
else
return (array->empty_bucket->elems[0]);
}
#endif /* __sarray_INCLUDE_GNU */
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