/* An expandable hash tables datatype.
- Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
+ Copyright (C) 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
Contributed by Vladimir Makarov (vmakarov@cygnus.com).
This file is part of the libiberty library.
{
/* These are primes that are near, but slightly smaller than, a
power of two. */
- static unsigned long primes[] = {
- (unsigned long) 2,
+ static const unsigned long primes[] = {
(unsigned long) 7,
(unsigned long) 13,
(unsigned long) 31,
((unsigned long) 2147483647) + ((unsigned long) 2147483644),
};
- unsigned long* low = &primes[0];
- unsigned long* high = &primes[sizeof(primes) / sizeof(primes[0])];
+ const unsigned long *low = &primes[0];
+ const unsigned long *high = &primes[sizeof(primes) / sizeof(primes[0])];
while (low != high)
{
- unsigned long* mid = low + (high - low) / 2;
+ const unsigned long *mid = low + (high - low) / 2;
if (n > *mid)
low = mid + 1;
else
/* This function creates table with length slightly longer than given
source length. Created hash table is initiated as empty (all the
hash table entries are EMPTY_ENTRY). The function returns the
- created hash table. Memory allocation must not fail. */
+ created hash table, or NULL if memory allocation fails. */
htab_t
-htab_create (size, hash_f, eq_f, del_f)
+htab_create_alloc (size, hash_f, eq_f, del_f, alloc_f, free_f)
size_t size;
htab_hash hash_f;
htab_eq eq_f;
htab_del del_f;
+ htab_alloc alloc_f;
+ htab_free free_f;
{
htab_t result;
size = higher_prime_number (size);
- result = (htab_t) xcalloc (1, sizeof (struct htab));
- result->entries = (PTR *) xcalloc (size, sizeof (PTR));
+ result = (htab_t) (*alloc_f) (1, sizeof (struct htab));
+ if (result == NULL)
+ return NULL;
+ result->entries = (PTR *) (*alloc_f) (size, sizeof (PTR));
+ if (result->entries == NULL)
+ {
+ if (free_f != NULL)
+ (*free_f) (result);
+ return NULL;
+ }
result->size = size;
result->hash_f = hash_f;
result->eq_f = eq_f;
result->del_f = del_f;
- result->return_allocation_failure = 0;
+ result->alloc_f = alloc_f;
+ result->free_f = free_f;
return result;
}
-/* This function creates table with length slightly longer than given
- source length. The created hash table is initiated as empty (all the
- hash table entries are EMPTY_ENTRY). The function returns the created
- hash table. Memory allocation may fail; it may return NULL. */
+/* As above, but use the variants of alloc_f and free_f which accept
+ an extra argument. */
htab_t
-htab_try_create (size, hash_f, eq_f, del_f)
+htab_create_alloc_ex (size, hash_f, eq_f, del_f, alloc_arg, alloc_f,
+ free_f)
size_t size;
htab_hash hash_f;
htab_eq eq_f;
htab_del del_f;
+ PTR alloc_arg;
+ htab_alloc_with_arg alloc_f;
+ htab_free_with_arg free_f;
{
htab_t result;
size = higher_prime_number (size);
- result = (htab_t) calloc (1, sizeof (struct htab));
+ result = (htab_t) (*alloc_f) (alloc_arg, 1, sizeof (struct htab));
if (result == NULL)
return NULL;
-
- result->entries = (PTR *) calloc (size, sizeof (PTR));
+ result->entries = (PTR *) (*alloc_f) (alloc_arg, size, sizeof (PTR));
if (result->entries == NULL)
{
- free (result);
+ if (free_f != NULL)
+ (*free_f) (alloc_arg, result);
return NULL;
}
-
result->size = size;
result->hash_f = hash_f;
result->eq_f = eq_f;
result->del_f = del_f;
- result->return_allocation_failure = 1;
+ result->alloc_arg = alloc_arg;
+ result->alloc_with_arg_f = alloc_f;
+ result->free_with_arg_f = free_f;
return result;
}
+/* Update the function pointers and allocation parameter in the htab_t. */
+
+void
+htab_set_functions_ex (htab, hash_f, eq_f, del_f, alloc_arg, alloc_f, free_f)
+ htab_t htab;
+ htab_hash hash_f;
+ htab_eq eq_f;
+ htab_del del_f;
+ PTR alloc_arg;
+ htab_alloc_with_arg alloc_f;
+ htab_free_with_arg free_f;
+{
+ htab->hash_f = hash_f;
+ htab->eq_f = eq_f;
+ htab->del_f = del_f;
+ htab->alloc_arg = alloc_arg;
+ htab->alloc_with_arg_f = alloc_f;
+ htab->free_with_arg_f = free_f;
+}
+
+/* These functions exist solely for backward compatibility. */
+
+#undef htab_create
+htab_t
+htab_create (size, hash_f, eq_f, del_f)
+ size_t size;
+ htab_hash hash_f;
+ htab_eq eq_f;
+ htab_del del_f;
+{
+ return htab_create_alloc (size, hash_f, eq_f, del_f, xcalloc, free);
+}
+
+htab_t
+htab_try_create (size, hash_f, eq_f, del_f)
+ size_t size;
+ htab_hash hash_f;
+ htab_eq eq_f;
+ htab_del del_f;
+{
+ return htab_create_alloc (size, hash_f, eq_f, del_f, calloc, free);
+}
+
/* This function frees all memory allocated for given hash table.
Naturally the hash table must already exist. */
&& htab->entries[i] != DELETED_ENTRY)
(*htab->del_f) (htab->entries[i]);
- free (htab->entries);
- free (htab);
+ if (htab->free_f != NULL)
+ {
+ (*htab->free_f) (htab->entries);
+ (*htab->free_f) (htab);
+ }
+ else if (htab->free_with_arg_f != NULL)
+ {
+ (*htab->free_with_arg_f) (htab->alloc_arg, htab->entries);
+ (*htab->free_with_arg_f) (htab->alloc_arg, htab);
+ }
}
/* This function clears all entries in the given hash table. */
hashval_t hash;
{
size_t size = htab->size;
- hashval_t hash2 = 1 + hash % (size - 2);
unsigned int index = hash % size;
+ PTR *slot = htab->entries + index;
+ hashval_t hash2;
+ if (*slot == EMPTY_ENTRY)
+ return slot;
+ else if (*slot == DELETED_ENTRY)
+ abort ();
+
+ hash2 = 1 + hash % (size - 2);
for (;;)
{
- PTR *slot = htab->entries + index;
+ index += hash2;
+ if (index >= size)
+ index -= size;
+ slot = htab->entries + index;
if (*slot == EMPTY_ENTRY)
return slot;
else if (*slot == DELETED_ENTRY)
abort ();
-
- index += hash2;
- if (index >= size)
- index -= size;
}
}
PTR *oentries;
PTR *olimit;
PTR *p;
+ PTR *nentries;
+ size_t nsize;
oentries = htab->entries;
olimit = oentries + htab->size;
- htab->size = higher_prime_number (htab->size * 2);
+ /* Resize only when table after removal of unused elements is either
+ too full or too empty. */
+ if ((htab->n_elements - htab->n_deleted) * 2 > htab->size
+ || ((htab->n_elements - htab->n_deleted) * 8 < htab->size
+ && htab->size > 32))
+ nsize = higher_prime_number ((htab->n_elements - htab->n_deleted) * 2);
+ else
+ nsize = htab->size;
- if (htab->return_allocation_failure)
- {
- PTR *nentries = (PTR *) calloc (htab->size, sizeof (PTR *));
- if (nentries == NULL)
- return 0;
- htab->entries = nentries;
- }
+ if (htab->alloc_with_arg_f != NULL)
+ nentries = (PTR *) (*htab->alloc_with_arg_f) (htab->alloc_arg, nsize,
+ sizeof (PTR *));
else
- htab->entries = (PTR *) xcalloc (htab->size, sizeof (PTR *));
+ nentries = (PTR *) (*htab->alloc_f) (nsize, sizeof (PTR *));
+ if (nentries == NULL)
+ return 0;
+ htab->entries = nentries;
+ htab->size = nsize;
htab->n_elements -= htab->n_deleted;
htab->n_deleted = 0;
}
while (p < olimit);
- free (oentries);
+ if (htab->free_f != NULL)
+ (*htab->free_f) (oentries);
+ else if (htab->free_with_arg_f != NULL)
+ (*htab->free_with_arg_f) (htab->alloc_arg, oentries);
return 1;
}
unsigned int index;
hashval_t hash2;
size_t size;
+ PTR entry;
if (insert == INSERT && htab->size * 3 <= htab->n_elements * 4
&& htab_expand (htab) == 0)
return NULL;
size = htab->size;
- hash2 = 1 + hash % (size - 2);
index = hash % size;
htab->searches++;
first_deleted_slot = NULL;
+ entry = htab->entries[index];
+ if (entry == EMPTY_ENTRY)
+ goto empty_entry;
+ else if (entry == DELETED_ENTRY)
+ first_deleted_slot = &htab->entries[index];
+ else if ((*htab->eq_f) (entry, element))
+ return &htab->entries[index];
+
+ hash2 = 1 + hash % (size - 2);
for (;;)
{
- PTR entry = htab->entries[index];
+ htab->collisions++;
+ index += hash2;
+ if (index >= size)
+ index -= size;
+
+ entry = htab->entries[index];
if (entry == EMPTY_ENTRY)
- {
- if (insert == NO_INSERT)
- return NULL;
-
- htab->n_elements++;
-
- if (first_deleted_slot)
- {
- *first_deleted_slot = EMPTY_ENTRY;
- return first_deleted_slot;
- }
-
- return &htab->entries[index];
- }
-
- if (entry == DELETED_ENTRY)
+ goto empty_entry;
+ else if (entry == DELETED_ENTRY)
{
if (!first_deleted_slot)
first_deleted_slot = &htab->entries[index];
}
- else if ((*htab->eq_f) (entry, element))
+ else if ((*htab->eq_f) (entry, element))
return &htab->entries[index];
-
- htab->collisions++;
- index += hash2;
- if (index >= size)
- index -= size;
}
+
+ empty_entry:
+ if (insert == NO_INSERT)
+ return NULL;
+
+ htab->n_elements++;
+
+ if (first_deleted_slot)
+ {
+ *first_deleted_slot = EMPTY_ENTRY;
+ return first_deleted_slot;
+ }
+
+ return &htab->entries[index];
}
/* Like htab_find_slot_with_hash, but compute the hash value from the
argument. */
void
-htab_traverse (htab, callback, info)
+htab_traverse_noresize (htab, callback, info)
htab_t htab;
htab_trav callback;
PTR info;
{
- PTR *slot = htab->entries;
- PTR *limit = slot + htab->size;
+ PTR *slot;
+ PTR *limit;
+
+ slot = htab->entries;
+ limit = slot + htab->size;
do
{
while (++slot < limit);
}
+/* Like htab_traverse_noresize, but does resize the table when it is
+ too empty to improve effectivity of subsequent calls. */
+
+void
+htab_traverse (htab, callback, info)
+ htab_t htab;
+ htab_trav callback;
+ PTR info;
+{
+ if ((htab->n_elements - htab->n_deleted) * 8 < htab->size)
+ htab_expand (htab);
+
+ htab_traverse_noresize (htab, callback, info);
+}
+
/* Return the current size of given hash table. */
size_t
return r;
}
+
+/* DERIVED FROM:
+--------------------------------------------------------------------
+lookup2.c, by Bob Jenkins, December 1996, Public Domain.
+hash(), hash2(), hash3, and mix() are externally useful functions.
+Routines to test the hash are included if SELF_TEST is defined.
+You can use this free for any purpose. It has no warranty.
+--------------------------------------------------------------------
+*/
+
+/*
+--------------------------------------------------------------------
+mix -- mix 3 32-bit values reversibly.
+For every delta with one or two bit set, and the deltas of all three
+ high bits or all three low bits, whether the original value of a,b,c
+ is almost all zero or is uniformly distributed,
+* If mix() is run forward or backward, at least 32 bits in a,b,c
+ have at least 1/4 probability of changing.
+* If mix() is run forward, every bit of c will change between 1/3 and
+ 2/3 of the time. (Well, 22/100 and 78/100 for some 2-bit deltas.)
+mix() was built out of 36 single-cycle latency instructions in a
+ structure that could supported 2x parallelism, like so:
+ a -= b;
+ a -= c; x = (c>>13);
+ b -= c; a ^= x;
+ b -= a; x = (a<<8);
+ c -= a; b ^= x;
+ c -= b; x = (b>>13);
+ ...
+ Unfortunately, superscalar Pentiums and Sparcs can't take advantage
+ of that parallelism. They've also turned some of those single-cycle
+ latency instructions into multi-cycle latency instructions. Still,
+ this is the fastest good hash I could find. There were about 2^^68
+ to choose from. I only looked at a billion or so.
+--------------------------------------------------------------------
+*/
+/* same, but slower, works on systems that might have 8 byte hashval_t's */
+#define mix(a,b,c) \
+{ \
+ a -= b; a -= c; a ^= (c>>13); \
+ b -= c; b -= a; b ^= (a<< 8); \
+ c -= a; c -= b; c ^= ((b&0xffffffff)>>13); \
+ a -= b; a -= c; a ^= ((c&0xffffffff)>>12); \
+ b -= c; b -= a; b = (b ^ (a<<16)) & 0xffffffff; \
+ c -= a; c -= b; c = (c ^ (b>> 5)) & 0xffffffff; \
+ a -= b; a -= c; a = (a ^ (c>> 3)) & 0xffffffff; \
+ b -= c; b -= a; b = (b ^ (a<<10)) & 0xffffffff; \
+ c -= a; c -= b; c = (c ^ (b>>15)) & 0xffffffff; \
+}
+
+/*
+--------------------------------------------------------------------
+hash() -- hash a variable-length key into a 32-bit value
+ k : the key (the unaligned variable-length array of bytes)
+ len : the length of the key, counting by bytes
+ level : can be any 4-byte value
+Returns a 32-bit value. Every bit of the key affects every bit of
+the return value. Every 1-bit and 2-bit delta achieves avalanche.
+About 36+6len instructions.
+
+The best hash table sizes are powers of 2. There is no need to do
+mod a prime (mod is sooo slow!). If you need less than 32 bits,
+use a bitmask. For example, if you need only 10 bits, do
+ h = (h & hashmask(10));
+In which case, the hash table should have hashsize(10) elements.
+
+If you are hashing n strings (ub1 **)k, do it like this:
+ for (i=0, h=0; i<n; ++i) h = hash( k[i], len[i], h);
+
+By Bob Jenkins, 1996. bob_jenkins@burtleburtle.net. You may use this
+code any way you wish, private, educational, or commercial. It's free.
+
+See http://burtleburtle.net/bob/hash/evahash.html
+Use for hash table lookup, or anything where one collision in 2^32 is
+acceptable. Do NOT use for cryptographic purposes.
+--------------------------------------------------------------------
+*/
+
+hashval_t iterative_hash (k_in, length, initval)
+ const PTR k_in; /* the key */
+ register size_t length; /* the length of the key */
+ register hashval_t initval; /* the previous hash, or an arbitrary value */
+{
+ register const unsigned char *k = (const unsigned char *)k_in;
+ register hashval_t a,b,c,len;
+
+ /* Set up the internal state */
+ len = length;
+ a = b = 0x9e3779b9; /* the golden ratio; an arbitrary value */
+ c = initval; /* the previous hash value */
+
+ /*---------------------------------------- handle most of the key */
+#ifndef WORDS_BIGENDIAN
+ /* On a little-endian machine, if the data is 4-byte aligned we can hash
+ by word for better speed. This gives nondeterministic results on
+ big-endian machines. */
+ if (sizeof (hashval_t) == 4 && (((size_t)k)&3) == 0)
+ while (len >= 12) /* aligned */
+ {
+ a += *(hashval_t *)(k+0);
+ b += *(hashval_t *)(k+4);
+ c += *(hashval_t *)(k+8);
+ mix(a,b,c);
+ k += 12; len -= 12;
+ }
+ else /* unaligned */
+#endif
+ while (len >= 12)
+ {
+ a += (k[0] +((hashval_t)k[1]<<8) +((hashval_t)k[2]<<16) +((hashval_t)k[3]<<24));
+ b += (k[4] +((hashval_t)k[5]<<8) +((hashval_t)k[6]<<16) +((hashval_t)k[7]<<24));
+ c += (k[8] +((hashval_t)k[9]<<8) +((hashval_t)k[10]<<16)+((hashval_t)k[11]<<24));
+ mix(a,b,c);
+ k += 12; len -= 12;
+ }
+
+ /*------------------------------------- handle the last 11 bytes */
+ c += length;
+ switch(len) /* all the case statements fall through */
+ {
+ case 11: c+=((hashval_t)k[10]<<24);
+ case 10: c+=((hashval_t)k[9]<<16);
+ case 9 : c+=((hashval_t)k[8]<<8);
+ /* the first byte of c is reserved for the length */
+ case 8 : b+=((hashval_t)k[7]<<24);
+ case 7 : b+=((hashval_t)k[6]<<16);
+ case 6 : b+=((hashval_t)k[5]<<8);
+ case 5 : b+=k[4];
+ case 4 : a+=((hashval_t)k[3]<<24);
+ case 3 : a+=((hashval_t)k[2]<<16);
+ case 2 : a+=((hashval_t)k[1]<<8);
+ case 1 : a+=k[0];
+ /* case 0: nothing left to add */
+ }
+ mix(a,b,c);
+ /*-------------------------------------------- report the result */
+ return c;
+}
projects / gcc.git / blobdiff