519 lines
14 KiB
C
519 lines
14 KiB
C
/* Sparse Arrays for Objective C dispatch tables
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Copyright (C) 1993, 1995, 1996 Free Software Foundation, Inc.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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/* As a special exception, if you link this library with files
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compiled with GCC to produce an executable, this does not cause
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the resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why
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the executable file might be covered by the GNU General Public License. */
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#include "sarray.h"
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#include "runtime.h"
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#include <stdio.h>
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#include "assert.h"
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int nbuckets = 0; /* !T:MUTEX */
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int nindices = 0; /* !T:MUTEX */
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int narrays = 0; /* !T:MUTEX */
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int idxsize = 0; /* !T:MUTEX */
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static void * first_free_data = NULL; /* !T:MUTEX */
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#ifdef OBJC_SPARSE2
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const char* __objc_sparse2_id = "2 level sparse indices";
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#endif
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#ifdef OBJC_SPARSE3
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const char* __objc_sparse3_id = "3 level sparse indices";
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#endif
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/* This function removes any structures left over from free operations
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that were not safe in a multi-threaded environment. */
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void
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sarray_remove_garbage(void)
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{
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void **vp;
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void *np;
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objc_mutex_lock(__objc_runtime_mutex);
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vp = first_free_data;
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first_free_data = NULL;
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while (vp) {
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np = *vp;
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objc_free(vp);
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vp = np;
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}
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objc_mutex_unlock(__objc_runtime_mutex);
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}
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/* Free a block of dynamically allocated memory. If we are in multi-threaded
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mode, it is ok to free it. If not, we add it to the garbage heap to be
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freed later. */
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static void
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sarray_free_garbage(void *vp)
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{
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objc_mutex_lock(__objc_runtime_mutex);
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if (__objc_runtime_threads_alive == 1) {
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objc_free(vp);
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if (first_free_data)
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sarray_remove_garbage();
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}
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else {
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*(void **)vp = first_free_data;
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first_free_data = vp;
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}
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objc_mutex_unlock(__objc_runtime_mutex);
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}
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/* sarray_at_put : copies data in such a way as to be thread reader safe. */
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void
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sarray_at_put(struct sarray* array, sidx index, void* element)
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{
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#ifdef OBJC_SPARSE3
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struct sindex** the_index;
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struct sindex* new_index;
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#endif
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struct sbucket** the_bucket;
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struct sbucket* new_bucket;
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#ifdef OBJC_SPARSE3
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size_t ioffset;
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#endif
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size_t boffset;
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size_t eoffset;
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#ifdef PRECOMPUTE_SELECTORS
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union sofftype xx;
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xx.idx = index;
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#ifdef OBJC_SPARSE3
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ioffset = xx.off.ioffset;
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#endif
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boffset = xx.off.boffset;
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eoffset = xx.off.eoffset;
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#else /* not PRECOMPUTE_SELECTORS */
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#ifdef OBJC_SPARSE3
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ioffset = index/INDEX_CAPACITY;
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boffset = (index/BUCKET_SIZE)%INDEX_SIZE;
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eoffset = index%BUCKET_SIZE;
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#else
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boffset = index/BUCKET_SIZE;
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eoffset = index%BUCKET_SIZE;
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#endif
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#endif /* not PRECOMPUTE_SELECTORS */
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assert(soffset_decode(index) < array->capacity); /* Range check */
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#ifdef OBJC_SPARSE3
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the_index = &(array->indices[ioffset]);
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the_bucket = &((*the_index)->buckets[boffset]);
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#else
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the_bucket = &(array->buckets[boffset]);
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#endif
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if ((*the_bucket)->elems[eoffset] == element)
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return; /* great! we just avoided a lazy copy */
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#ifdef OBJC_SPARSE3
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/* First, perform lazy copy/allocation of index if needed */
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if ((*the_index) == array->empty_index) {
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/* The index was previously empty, allocate a new */
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new_index = (struct sindex*)objc_malloc(sizeof(struct sindex));
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memcpy(new_index, array->empty_index, sizeof(struct sindex));
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new_index->version.version = array->version.version;
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*the_index = new_index; /* Prepared for install. */
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the_bucket = &((*the_index)->buckets[boffset]);
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nindices += 1;
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} else if ((*the_index)->version.version != array->version.version) {
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/* This index must be lazy copied */
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struct sindex* old_index = *the_index;
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new_index = (struct sindex*)objc_malloc(sizeof(struct sindex));
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memcpy( new_index, old_index, sizeof(struct sindex));
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new_index->version.version = array->version.version;
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*the_index = new_index; /* Prepared for install. */
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the_bucket = &((*the_index)->buckets[boffset]);
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nindices += 1;
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}
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#endif /* OBJC_SPARSE3 */
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/* next, perform lazy allocation/copy of the bucket if needed */
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if ((*the_bucket) == array->empty_bucket) {
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/* The bucket was previously empty (or something like that), */
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/* allocate a new. This is the effect of `lazy' allocation */
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new_bucket = (struct sbucket*)objc_malloc(sizeof(struct sbucket));
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memcpy((void *) new_bucket, (const void*)array->empty_bucket,
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sizeof(struct sbucket));
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new_bucket->version.version = array->version.version;
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*the_bucket = new_bucket; /* Prepared for install. */
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nbuckets += 1;
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} else if ((*the_bucket)->version.version != array->version.version) {
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/* Perform lazy copy. */
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struct sbucket* old_bucket = *the_bucket;
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new_bucket = (struct sbucket*)objc_malloc(sizeof(struct sbucket));
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memcpy( new_bucket, old_bucket, sizeof(struct sbucket));
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new_bucket->version.version = array->version.version;
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*the_bucket = new_bucket; /* Prepared for install. */
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nbuckets += 1;
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}
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(*the_bucket)->elems[eoffset] = element;
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}
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void
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sarray_at_put_safe(struct sarray* array, sidx index, void* element)
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{
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if(soffset_decode(index) >= array->capacity)
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sarray_realloc(array, soffset_decode(index)+1);
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sarray_at_put(array, index, element);
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}
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struct sarray*
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sarray_new (int size, void* default_element)
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{
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struct sarray* arr;
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#ifdef OBJC_SPARSE3
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size_t num_indices = ((size-1)/(INDEX_CAPACITY))+1;
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struct sindex ** new_indices;
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#else /* OBJC_SPARSE2 */
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size_t num_indices = ((size-1)/BUCKET_SIZE)+1;
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struct sbucket ** new_buckets;
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#endif
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int counter;
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assert(size > 0);
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/* Allocate core array */
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arr = (struct sarray*) objc_malloc(sizeof(struct sarray));
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arr->version.version = 0;
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/* Initialize members */
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#ifdef OBJC_SPARSE3
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arr->capacity = num_indices*INDEX_CAPACITY;
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new_indices = (struct sindex**)
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objc_malloc(sizeof(struct sindex*)*num_indices);
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arr->empty_index = (struct sindex*) objc_malloc(sizeof(struct sindex));
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arr->empty_index->version.version = 0;
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narrays += 1;
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idxsize += num_indices;
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nindices += 1;
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#else /* OBJC_SPARSE2 */
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arr->capacity = num_indices*BUCKET_SIZE;
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new_buckets = (struct sbucket**)
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objc_malloc(sizeof(struct sbucket*)*num_indices);
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narrays += 1;
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idxsize += num_indices;
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#endif
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arr->empty_bucket = (struct sbucket*) objc_malloc(sizeof(struct sbucket));
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arr->empty_bucket->version.version = 0;
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nbuckets += 1;
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arr->ref_count = 1;
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arr->is_copy_of = (struct sarray*)0;
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for (counter=0; counter<BUCKET_SIZE; counter++)
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arr->empty_bucket->elems[counter] = default_element;
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#ifdef OBJC_SPARSE3
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for (counter=0; counter<INDEX_SIZE; counter++)
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arr->empty_index->buckets[counter] = arr->empty_bucket;
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for (counter=0; counter<num_indices; counter++)
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new_indices[counter] = arr->empty_index;
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#else /* OBJC_SPARSE2 */
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for (counter=0; counter<num_indices; counter++)
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new_buckets[counter] = arr->empty_bucket;
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#endif
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#ifdef OBJC_SPARSE3
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arr->indices = new_indices;
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#else /* OBJC_SPARSE2 */
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arr->buckets = new_buckets;
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#endif
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return arr;
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}
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/* Reallocate the sparse array to hold `newsize' entries
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Note: We really allocate and then free. We have to do this to ensure that
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any concurrent readers notice the update. */
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void
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sarray_realloc(struct sarray* array, int newsize)
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{
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#ifdef OBJC_SPARSE3
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size_t old_max_index = (array->capacity-1)/INDEX_CAPACITY;
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size_t new_max_index = ((newsize-1)/INDEX_CAPACITY);
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size_t rounded_size = (new_max_index+1)*INDEX_CAPACITY;
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struct sindex ** new_indices;
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struct sindex ** old_indices;
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#else /* OBJC_SPARSE2 */
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size_t old_max_index = (array->capacity-1)/BUCKET_SIZE;
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size_t new_max_index = ((newsize-1)/BUCKET_SIZE);
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size_t rounded_size = (new_max_index+1)*BUCKET_SIZE;
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struct sbucket ** new_buckets;
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struct sbucket ** old_buckets;
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#endif
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int counter;
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assert(newsize > 0);
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/* The size is the same, just ignore the request */
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if(rounded_size <= array->capacity)
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return;
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assert(array->ref_count == 1); /* stop if lazy copied... */
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/* We are asked to extend the array -- allocate new bucket table, */
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/* and insert empty_bucket in newly allocated places. */
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if(rounded_size > array->capacity)
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{
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#ifdef OBJC_SPARSE3
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new_max_index += 4;
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rounded_size = (new_max_index+1)*INDEX_CAPACITY;
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#else /* OBJC_SPARSE2 */
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new_max_index += 4;
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rounded_size = (new_max_index+1)*BUCKET_SIZE;
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#endif
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/* update capacity */
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array->capacity = rounded_size;
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#ifdef OBJC_SPARSE3
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/* alloc to force re-read by any concurrent readers. */
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old_indices = array->indices;
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new_indices = (struct sindex**)
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objc_malloc((new_max_index+1)*sizeof(struct sindex*));
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#else /* OBJC_SPARSE2 */
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old_buckets = array->buckets;
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new_buckets = (struct sbucket**)
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objc_malloc((new_max_index+1)*sizeof(struct sbucket*));
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#endif
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/* copy buckets below old_max_index (they are still valid) */
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for(counter = 0; counter <= old_max_index; counter++ ) {
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#ifdef OBJC_SPARSE3
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new_indices[counter] = old_indices[counter];
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#else /* OBJC_SPARSE2 */
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new_buckets[counter] = old_buckets[counter];
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#endif
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}
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#ifdef OBJC_SPARSE3
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/* reset entries above old_max_index to empty_bucket */
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for(counter = old_max_index+1; counter <= new_max_index; counter++)
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new_indices[counter] = array->empty_index;
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#else /* OBJC_SPARSE2 */
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/* reset entries above old_max_index to empty_bucket */
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for(counter = old_max_index+1; counter <= new_max_index; counter++)
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new_buckets[counter] = array->empty_bucket;
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#endif
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#ifdef OBJC_SPARSE3
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/* install the new indices */
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array->indices = new_indices;
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#else /* OBJC_SPARSE2 */
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array->buckets = new_buckets;
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#endif
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#ifdef OBJC_SPARSE3
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/* free the old indices */
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sarray_free_garbage(old_indices);
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#else /* OBJC_SPARSE2 */
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sarray_free_garbage(old_buckets);
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#endif
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idxsize += (new_max_index-old_max_index);
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return;
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}
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}
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/* Free a sparse array allocated with sarray_new */
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void
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sarray_free(struct sarray* array) {
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#ifdef OBJC_SPARSE3
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size_t old_max_index = (array->capacity-1)/INDEX_CAPACITY;
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struct sindex ** old_indices;
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#else
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size_t old_max_index = (array->capacity-1)/BUCKET_SIZE;
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struct sbucket ** old_buckets;
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#endif
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int counter = 0;
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assert(array->ref_count != 0); /* Freed multiple times!!! */
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if(--(array->ref_count) != 0) /* There exists copies of me */
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return;
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#ifdef OBJC_SPARSE3
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old_indices = array->indices;
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#else
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old_buckets = array->buckets;
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#endif
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if((array->is_copy_of) && ((array->is_copy_of->ref_count - 1) == 0))
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sarray_free(array->is_copy_of);
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/* Free all entries that do not point to empty_bucket */
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for(counter = 0; counter <= old_max_index; counter++ ) {
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#ifdef OBJC_SPARSE3
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struct sindex* idx = old_indices[counter];
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if((idx != array->empty_index) &&
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(idx->version.version == array->version.version)) {
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int c2;
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for(c2=0; c2<INDEX_SIZE; c2++) {
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struct sbucket* bkt = idx->buckets[c2];
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if((bkt != array->empty_bucket) &&
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(bkt->version.version == array->version.version))
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{
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sarray_free_garbage(bkt);
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nbuckets -= 1;
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}
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}
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sarray_free_garbage(idx);
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nindices -= 1;
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}
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#else /* OBJC_SPARSE2 */
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struct sbucket* bkt = array->buckets[counter];
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if ((bkt != array->empty_bucket) &&
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(bkt->version.version == array->version.version))
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{
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sarray_free_garbage(bkt);
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nbuckets -= 1;
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}
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#endif
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}
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#ifdef OBJC_SPARSE3
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/* free empty_index */
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if(array->empty_index->version.version == array->version.version) {
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sarray_free_garbage(array->empty_index);
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nindices -= 1;
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}
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#endif
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/* free empty_bucket */
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if(array->empty_bucket->version.version == array->version.version) {
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sarray_free_garbage(array->empty_bucket);
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nbuckets -= 1;
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}
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idxsize -= (old_max_index+1);
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narrays -= 1;
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#ifdef OBJC_SPARSE3
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/* free bucket table */
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sarray_free_garbage(array->indices);
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#else
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/* free bucket table */
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sarray_free_garbage(array->buckets);
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#endif
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/* free array */
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sarray_free_garbage(array);
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}
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/* This is a lazy copy. Only the core of the structure is actually */
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/* copied. */
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struct sarray*
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sarray_lazy_copy(struct sarray* oarr)
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{
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struct sarray* arr;
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#ifdef OBJC_SPARSE3
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size_t num_indices = ((oarr->capacity-1)/INDEX_CAPACITY)+1;
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struct sindex ** new_indices;
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#else /* OBJC_SPARSE2 */
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size_t num_indices = ((oarr->capacity-1)/BUCKET_SIZE)+1;
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struct sbucket ** new_buckets;
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#endif
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/* Allocate core array */
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arr = (struct sarray*) objc_malloc(sizeof(struct sarray)); /* !!! */
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arr->version.version = oarr->version.version + 1;
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#ifdef OBJC_SPARSE3
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arr->empty_index = oarr->empty_index;
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#endif
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arr->empty_bucket = oarr->empty_bucket;
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arr->ref_count = 1;
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oarr->ref_count += 1;
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arr->is_copy_of = oarr;
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arr->capacity = oarr->capacity;
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#ifdef OBJC_SPARSE3
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/* Copy bucket table */
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new_indices = (struct sindex**)
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objc_malloc(sizeof(struct sindex*)*num_indices);
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memcpy( new_indices,oarr->indices,
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sizeof(struct sindex*)*num_indices);
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arr->indices = new_indices;
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#else
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/* Copy bucket table */
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new_buckets = (struct sbucket**)
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objc_malloc(sizeof(struct sbucket*)*num_indices);
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memcpy( new_buckets,oarr->buckets,
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sizeof(struct sbucket*)*num_indices);
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arr->buckets = new_buckets;
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#endif
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idxsize += num_indices;
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narrays += 1;
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return arr;
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}
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