--- /dev/null
+/* Set operations on pointers
+ Copyright (C) 2004, 2006, 2007 Free Software Foundation, Inc.
+
+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.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3. If not see
+<http://www.gnu.org/licenses/>. */
+
+#include "config.h"
+#include "system.h"
+#include "pointer-set.h"
+
+/* A pointer set is represented as a simple open-addressing hash
+ table. Simplifications: The hash code is based on the value of the
+ pointer, not what it points to. The number of buckets is always a
+ power of 2. Null pointers are a reserved value. Deletion is not
+ supported (yet). There is no mechanism for user control of hash
+ function, equality comparison, initial size, or resizing policy. */
+
+struct pointer_set_t
+{
+ size_t log_slots;
+ size_t n_slots; /* n_slots = 2^log_slots */
+ size_t n_elements;
+
+ const void **slots;
+};
+
+/* Use the multiplicative method, as described in Knuth 6.4, to obtain
+ a hash code for P in the range [0, MAX). MAX == 2^LOGMAX.
+
+ Summary of this method: Multiply p by some number A that's
+ relatively prime to 2^sizeof(size_t). The result is two words.
+ Discard the most significant word, and return the most significant
+ N bits of the least significant word. As suggested by Knuth, our
+ choice for A is the integer part of (ULONG_MAX + 1.0) / phi, where phi
+ is the golden ratio.
+
+ We don't need to do anything special for full-width multiplication
+ because we're only interested in the least significant word of the
+ product, and unsigned arithmetic in C is modulo the word size. */
+
+static inline size_t
+hash1 (const void *p, unsigned long max, unsigned long logmax)
+{
+#if HOST_BITS_PER_LONG == 32
+ const unsigned long A = 0x9e3779b9u;
+#elif HOST_BITS_PER_LONG == 64
+ const unsigned long A = 0x9e3779b97f4a7c16ul;
+#else
+ const unsigned long A
+ = (ULONG_MAX + 1.0L) * 0.6180339887498948482045868343656381177203L;
+#endif
+ const unsigned long shift = HOST_BITS_PER_LONG - logmax;
+
+ return ((A * (unsigned long) p) >> shift) & (max - 1);
+}
+
+/* Allocate an empty pointer set. */
+struct pointer_set_t *
+pointer_set_create (void)
+{
+ struct pointer_set_t *result = XNEW (struct pointer_set_t);
+
+ result->n_elements = 0;
+ result->log_slots = 8;
+ result->n_slots = (size_t) 1 << result->log_slots;
+
+ result->slots = XCNEWVEC (const void *, result->n_slots);
+ return result;
+}
+
+/* Reclaims all memory associated with PSET. */
+void
+pointer_set_destroy (struct pointer_set_t *pset)
+{
+ XDELETEVEC (pset->slots);
+ XDELETE (pset);
+}
+
+/* Returns nonzero if PSET contains P. P must be nonnull.
+
+ Collisions are resolved by linear probing. */
+int
+pointer_set_contains (const struct pointer_set_t *pset, const void *p)
+{
+ size_t n = hash1 (p, pset->n_slots, pset->log_slots);
+
+ while (true)
+ {
+ if (pset->slots[n] == p)
+ return 1;
+ else if (pset->slots[n] == 0)
+ return 0;
+ else
+ {
+ ++n;
+ if (n == pset->n_slots)
+ n = 0;
+ }
+ }
+}
+
+/* Subroutine of pointer_set_insert. Return the insertion slot for P into
+ an empty element of SLOTS, an array of length N_SLOTS. */
+static inline size_t
+insert_aux (const void *p, const void **slots, size_t n_slots, size_t log_slots)
+{
+ size_t n = hash1 (p, n_slots, log_slots);
+ while (true)
+ {
+ if (slots[n] == p || slots[n] == 0)
+ return n;
+ else
+ {
+ ++n;
+ if (n == n_slots)
+ n = 0;
+ }
+ }
+}
+
+/* Inserts P into PSET if it wasn't already there. Returns nonzero
+ if it was already there. P must be nonnull. */
+int
+pointer_set_insert (struct pointer_set_t *pset, const void *p)
+{
+ size_t n;
+
+ /* For simplicity, expand the set even if P is already there. This can be
+ superfluous but can happen at most once. */
+ if (pset->n_elements > pset->n_slots / 4)
+ {
+ size_t new_log_slots = pset->log_slots + 1;
+ size_t new_n_slots = pset->n_slots * 2;
+ const void **new_slots = XCNEWVEC (const void *, new_n_slots);
+ size_t i;
+
+ for (i = 0; i < pset->n_slots; ++i)
+ {
+ const void *value = pset->slots[i];
+ n = insert_aux (value, new_slots, new_n_slots, new_log_slots);
+ new_slots[n] = value;
+ }
+
+ XDELETEVEC (pset->slots);
+ pset->n_slots = new_n_slots;
+ pset->log_slots = new_log_slots;
+ pset->slots = new_slots;
+ }
+
+ n = insert_aux (p, pset->slots, pset->n_slots, pset->log_slots);
+ if (pset->slots[n])
+ return 1;
+
+ pset->slots[n] = p;
+ ++pset->n_elements;
+ return 0;
+}
+
+/* Pass each pointer in PSET to the function in FN, together with the fixed
+ parameter DATA. If FN returns false, the iteration stops. */
+
+void pointer_set_traverse (const struct pointer_set_t *pset,
+ bool (*fn) (const void *, void *), void *data)
+{
+ size_t i;
+ for (i = 0; i < pset->n_slots; ++i)
+ if (pset->slots[i] && !fn (pset->slots[i], data))
+ break;
+}
+
+\f
+/* A pointer map is represented the same way as a pointer_set, so
+ the hash code is based on the address of the key, rather than
+ its contents. Null keys are a reserved value. Deletion is not
+ supported (yet). There is no mechanism for user control of hash
+ function, equality comparison, initial size, or resizing policy. */
+
+struct pointer_map_t
+{
+ size_t log_slots;
+ size_t n_slots; /* n_slots = 2^log_slots */
+ size_t n_elements;
+
+ const void **keys;
+ void **values;
+};
+
+/* Allocate an empty pointer map. */
+struct pointer_map_t *
+pointer_map_create (void)
+{
+ struct pointer_map_t *result = XNEW (struct pointer_map_t);
+
+ result->n_elements = 0;
+ result->log_slots = 8;
+ result->n_slots = (size_t) 1 << result->log_slots;
+
+ result->keys = XCNEWVEC (const void *, result->n_slots);
+ result->values = XCNEWVEC (void *, result->n_slots);
+ return result;
+}
+
+/* Reclaims all memory associated with PMAP. */
+void pointer_map_destroy (struct pointer_map_t *pmap)
+{
+ XDELETEVEC (pmap->keys);
+ XDELETEVEC (pmap->values);
+ XDELETE (pmap);
+}
+
+/* Returns a pointer to the value to which P maps, if PMAP contains P. P
+ must be nonnull. Return NULL if PMAP does not contain P.
+
+ Collisions are resolved by linear probing. */
+void **
+pointer_map_contains (const struct pointer_map_t *pmap, const void *p)
+{
+ size_t n = hash1 (p, pmap->n_slots, pmap->log_slots);
+
+ while (true)
+ {
+ if (pmap->keys[n] == p)
+ return &pmap->values[n];
+ else if (pmap->keys[n] == 0)
+ return NULL;
+ else
+ {
+ ++n;
+ if (n == pmap->n_slots)
+ n = 0;
+ }
+ }
+}
+
+/* Inserts P into PMAP if it wasn't already there. Returns a pointer
+ to the value. P must be nonnull. */
+void **
+pointer_map_insert (struct pointer_map_t *pmap, const void *p)
+{
+ size_t n;
+
+ /* For simplicity, expand the map even if P is already there. This can be
+ superfluous but can happen at most once. */
+ if (pmap->n_elements > pmap->n_slots / 4)
+ {
+ size_t new_log_slots = pmap->log_slots + 1;
+ size_t new_n_slots = pmap->n_slots * 2;
+ const void **new_keys = XCNEWVEC (const void *, new_n_slots);
+ void **new_values = XCNEWVEC (void *, new_n_slots);
+ size_t i;
+
+ for (i = 0; i < pmap->n_slots; ++i)
+ if (pmap->keys[i])
+ {
+ const void *key = pmap->keys[i];
+ n = insert_aux (key, new_keys, new_n_slots, new_log_slots);
+ new_keys[n] = key;
+ new_values[n] = pmap->values[i];
+ }
+
+ XDELETEVEC (pmap->keys);
+ XDELETEVEC (pmap->values);
+ pmap->n_slots = new_n_slots;
+ pmap->log_slots = new_log_slots;
+ pmap->keys = new_keys;
+ pmap->values = new_values;
+ }
+
+ n = insert_aux (p, pmap->keys, pmap->n_slots, pmap->log_slots);
+ if (!pmap->keys[n])
+ {
+ ++pmap->n_elements;
+ pmap->keys[n] = p;
+ }
+
+ return &pmap->values[n];
+}
+
+/* Pass each pointer in PMAP to the function in FN, together with the pointer
+ to the value and the fixed parameter DATA. If FN returns false, the
+ iteration stops. */
+
+void pointer_map_traverse (const struct pointer_map_t *pmap,
+ bool (*fn) (const void *, void **, void *), void *data)
+{
+ size_t i;
+ for (i = 0; i < pmap->n_slots; ++i)
+ if (pmap->keys[i] && !fn (pmap->keys[i], &pmap->values[i], data))
+ break;
+}
projects / msp430-gcc.git / blobdiff