diff options
Diffstat (limited to 'bfd/hash.c')
| -rw-r--r-- | bfd/hash.c | 93 |
1 files changed, 93 insertions, 0 deletions
@@ -299,6 +299,58 @@ SUBSUBSECTION /* The default number of entries to use when creating a hash table. */ #define DEFAULT_SIZE 4051 + +/* The following function returns a nearest prime number which is + greater than N, and near a power of two. Copied from libiberty. + Returns zero for ridiculously large N to signify an error. */ + +static unsigned long +higher_prime_number (unsigned long n) +{ + /* These are primes that are near, but slightly smaller than, a + power of two. */ + static const unsigned long primes[] = { + (unsigned long) 127, + (unsigned long) 2039, + (unsigned long) 32749, + (unsigned long) 65521, + (unsigned long) 131071, + (unsigned long) 262139, + (unsigned long) 524287, + (unsigned long) 1048573, + (unsigned long) 2097143, + (unsigned long) 4194301, + (unsigned long) 8388593, + (unsigned long) 16777213, + (unsigned long) 33554393, + (unsigned long) 67108859, + (unsigned long) 134217689, + (unsigned long) 268435399, + (unsigned long) 536870909, + (unsigned long) 1073741789, + (unsigned long) 2147483647, + /* 4294967291L */ + ((unsigned long) 2147483647) + ((unsigned long) 2147483644), + }; + + const unsigned long *low = &primes[0]; + const unsigned long *high = &primes[sizeof (primes) / sizeof (primes[0])]; + + while (low != high) + { + const unsigned long *mid = low + (high - low) / 2; + if (n >= *mid) + low = mid + 1; + else + high = mid; + } + + if (n >= *low) + return 0; + + return *low; +} + static size_t bfd_default_hash_table_size = DEFAULT_SIZE; /* Create a new hash table, given a number of entries. */ @@ -330,6 +382,7 @@ bfd_hash_table_init_n (struct bfd_hash_table *table, memset ((void *) table->table, 0, alloc); table->size = size; table->entsize = entsize; + table->count = 0; table->newfunc = newfunc; return TRUE; } @@ -402,6 +455,7 @@ bfd_hash_lookup (struct bfd_hash_table *table, if (copy) { char *new; + table->count ++; new = objalloc_alloc ((struct objalloc *) table->memory, len + 1); if (!new) @@ -417,6 +471,45 @@ bfd_hash_lookup (struct bfd_hash_table *table, hashp->next = table->table[index]; table->table[index] = hashp; + if (table->count > table->size * 3 / 4) + { + unsigned long newsize = higher_prime_number (table->size); + struct bfd_hash_entry **newtable; + unsigned int hi; + unsigned long alloc = newsize * sizeof (struct bfd_hash_entry *); + + /* If we can't find a higher prime, or we can't possibly alloc + that much memory, don't try to grow the table. */ + if (newsize == 0 || alloc / sizeof (struct bfd_hash_entry *) != newsize) + { + /* Lie. Stops us trying to grow again for a while. */ + table->count = 0; + return hashp; + } + + newtable = ((struct bfd_hash_entry **) + objalloc_alloc ((struct objalloc *) table->memory, alloc)); + memset ((PTR) newtable, 0, alloc); + + for (hi = 0; hi < table->size; hi ++) + while (table->table[hi]) + { + struct bfd_hash_entry *chain = table->table[hi]; + struct bfd_hash_entry *chain_end = chain; + int index; + + while (chain_end->next && chain_end->next->hash == chain->hash) + chain_end = chain_end->next; + + table->table[hi] = chain_end->next; + index = chain->hash % newsize; + chain_end->next = newtable[index]; + newtable[index] = chain; + } + table->table = newtable; + table->size = newsize; + } + return hashp; } |