1 files changed, 243 insertions, 0 deletions
diff --git a/libobjc/objc-private/sarray.h b/libobjc/objc-private/sarray.h
new file mode 100644
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+++ b/libobjc/objc-private/sarray.h
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+/* Sparse Arrays for Objective C dispatch tables
+   Copyright (C) 1993, 1995, 1996, 2004, 2009, 2010 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 */