Written by Fred Fish <fnf@cygnus.com>
Rewritten by Jim Blandy <jimb@cygnus.com>
- Copyright (C) 1999, 2000, 2002, 2003, 2007, 2008, 2009, 2010
+ Copyright (C) 1999, 2000, 2002, 2003, 2007, 2008, 2009, 2010, 2011
Free Software Foundation, Inc.
This file is part of GDB.
16 bits of hash values) hit, but the corresponding combined
length/data compare missed. */
unsigned long half_hash_miss_count;
+
+ /* Hash function to be used for this bcache object. */
+ unsigned long (*hash_function)(const void *addr, int length);
+
+ /* Compare function to be used for this bcache object. */
+ int (*compare_function)(const void *, const void *, int length);
};
-/* The old hash function was stolen from SDBM. This is what DB 3.0 uses now,
- * and is better than the old one.
- */
+/* The old hash function was stolen from SDBM. This is what DB 3.0
+ uses now, and is better than the old one. */
\f
unsigned long
hash(const void *addr, int length)
+{
+ return hash_continue (addr, length, 0);
+}
+
+/* Continue the calculation of the hash H at the given address. */
+
+unsigned long
+hash_continue (const void *addr, int length, unsigned long h)
{
const unsigned char *k, *e;
- unsigned long h;
k = (const unsigned char *)addr;
e = k+length;
- for (h=0; k< e;++k)
+ for (; k< e;++k)
{
h *=16777619;
h ^= *k;
struct bstring **new_bucket;
next = s->next;
- new_bucket = &new_buckets[(hash (&s->d.data, s->length)
+ new_bucket = &new_buckets[(bcache->hash_function (&s->d.data,
+ s->length)
% new_num_buckets)];
s->next = *new_bucket;
*new_bucket = s;
bcache->total_count++;
bcache->total_size += length;
- full_hash = hash (addr, length);
+ full_hash = bcache->hash_function (addr, length);
+
half_hash = (full_hash >> 16);
hash_index = full_hash % bcache->num_buckets;
if (s->half_hash == half_hash)
{
if (s->length == length
- && ! memcmp (&s->d.data, addr, length))
+ && bcache->compare_function (&s->d.data, addr, length))
return &s->d.data;
else
bcache->half_hash_miss_count++;
}
}
\f
+
+/* Compare the byte string at ADDR1 of lenght LENGHT to the
+ string at ADDR2. Return 1 if they are equal. */
+
+static int
+bcache_compare (const void *addr1, const void *addr2, int length)
+{
+ return memcmp (addr1, addr2, length) == 0;
+}
+
/* Allocating and freeing bcaches. */
+/* Allocated a bcache. HASH_FUNCTION and COMPARE_FUNCTION can be used
+ to pass in custom hash, and compare functions to be used by this
+ bcache. If HASH_FUNCTION is NULL hash() is used and if
+ COMPARE_FUNCTION is NULL memcmp() is used. */
+
struct bcache *
-bcache_xmalloc (void)
+bcache_xmalloc (unsigned long (*hash_function)(const void *, int length),
+ int (*compare_function)(const void *,
+ const void *,
+ int length))
{
/* Allocate the bcache pre-zeroed. */
struct bcache *b = XCALLOC (1, struct bcache);
+ if (hash_function)
+ b->hash_function = hash_function;
+ else
+ b->hash_function = hash;
+
+ if (compare_function)
+ b->compare_function = compare_function;
+ else
+ b->compare_function = bcache_compare;
return b;
}
print_percentage (int portion, int total)
{
if (total == 0)
- /* i18n: Like "Percentage of duplicates, by count: (not applicable)" */
+ /* i18n: Like "Percentage of duplicates, by count: (not applicable)". */
printf_filtered (_("(not applicable)\n"));
else
printf_filtered ("%3d%%\n", (int) (portion * 100.0 / total));
}
}
- /* To compute the median, we need the set of chain lengths sorted. */
+ /* To compute the median, we need the set of chain lengths
+ sorted. */
qsort (chain_length, c->num_buckets, sizeof (chain_length[0]),
compare_positive_ints);
qsort (entry_size, c->unique_count, sizeof (entry_size[0]),
if (c->unique_count > 0)
printf_filtered ("%ld\n", c->unique_size / c->unique_count);
else
- /* i18n: "Average entry size: (not applicable)" */
+ /* i18n: "Average entry size: (not applicable)". */
printf_filtered (_("(not applicable)\n"));
printf_filtered (_(" Median entry size: %d\n"), median_entry_size);
printf_filtered ("\n");
- printf_filtered (_(" Total memory used by bcache, including overhead: %ld\n"),
+ printf_filtered (_(" \
+Total memory used by bcache, including overhead: %ld\n"),
c->structure_size);
printf_filtered (_(" Percentage memory overhead: "));
print_percentage (c->structure_size - c->unique_size, c->unique_size);
print_percentage (c->total_size - c->structure_size, c->total_size);
printf_filtered ("\n");
- printf_filtered (_(" Hash table size: %3d\n"), c->num_buckets);
+ printf_filtered (_(" Hash table size: %3d\n"),
+ c->num_buckets);
printf_filtered (_(" Hash table expands: %lu\n"),
c->expand_count);
printf_filtered (_(" Hash table hashes: %lu\n"),
if (c->num_buckets > 0)
printf_filtered ("%3lu\n", c->unique_count / c->num_buckets);
else
- /* i18n: "Average hash chain length: (not applicable)" */
+ /* i18n: "Average hash chain length: (not applicable)". */
printf_filtered (_("(not applicable)\n"));
- printf_filtered (_(" Maximum hash chain length: %3d\n"), max_chain_length);
+ printf_filtered (_(" Maximum hash chain length: %3d\n"),
+ max_chain_length);
printf_filtered ("\n");
}