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/* Sparse Arrays for Objective C dispatch tables

   Copyright (C) 1993, 1995, 1996, 2004 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 2, 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.

You should have received a copy of the GNU General Public License

along with GCC; see the file COPYING.  If not, write to

the Free Software Foundation, 51 Franklin Street, Fifth Floor,

Boston, MA 02110-1301, USA.  */

/* As a special exception, if you link this library with files

   compiled with GCC to produce an executable, this does not cause

   the resulting executable to be covered by the GNU General Public License.

   This exception does not however invalidate any other reasons why

   the executable file might be covered by the GNU General Public License.  */

#ifndef __sarray_INCLUDE_GNU

#define __sarray_INCLUDE_GNU

#include "thr.h"

#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>

#include <assert.h>

#ifdef __cplusplus

extern "C" {

#endif /* __cplusplus */

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 {

  void* elems[BUCKET_SIZE];     /* elements stored in array */

  union sversion        version;                /* used for copy-on-write */

};

#ifdef OBJC_SPARSE3

struct sindex {

  struct sbucket* buckets[INDEX_SIZE];

  union sversion        version;                /* used for copy-on-write */

};

#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;

  union sversion        version;                /* used for copy-on-write */

  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 vica verca */

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]);

}

#ifdef __cplusplus

}

#endif /* __cplusplus */

#endif /* __sarray_INCLUDE_GNU */