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/* hash.c: hash table operations.
Copyright (C) 1994, 1995, 1996, 2011 Free Software Foundation, Inc.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
This library 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
#include "config.h"
#include "hash.h"
#include "str-list.h"
/* The hash function. We go for simplicity here. */
/* All our hash tables are related to filenames. */
#ifdef MONOCASE_FILENAMES
#define TRANSFORM(x) toupper (x)
#else
#define TRANSFORM(x) (x)
#endif
static unsigned
hash P2C(hash_table_type, table, const_string, key)
{
unsigned n = 0;
/* Our keys aren't often anagrams of each other, so no point in
weighting the characters. */
while (*key != 0)
n = (n + n + TRANSFORM (*key++)) % table.size;
return n;
}
hash_table_type
hash_create P1C(unsigned, size)
{
unsigned b;
hash_table_type ret;
ret.buckets = XTALLOC (size, hash_element_type *);
ret.size = size;
/* calloc's zeroes aren't necessarily NULL, according to ANSI, so be
safe. (Not that I know of any exceptions in reality.) */
for (b = 0; b <ret.size; b++)
ret.buckets[b] = NULL;
return ret;
}
/* Whether or not KEY is already in MAP, insert it and VALUE. Do not
duplicate the strings, in case they're being purposefully shared. */
void
hash_insert P3C(hash_table_type *, table, const_string, key,
const_string, value)
{
unsigned n = hash (*table, key);
hash_element_type *new_elt = XTALLOC1 (hash_element_type);
new_elt->key = key;
new_elt->value = value;
new_elt->next = NULL;
/* Insert the new element at the end of the list. */
if (!table->buckets[n])
/* first element in bucket is a special case. */
table->buckets[n] = new_elt;
else
{
hash_element_type *loc = table->buckets[n];
while (loc->next) /* Find the last element. */
loc = loc->next;
loc->next = new_elt; /* Insert the new one after. */
}
}
/* Look up STR in MAP. Return a (dynamically-allocated) list of the
corresponding strings or NULL if no match. */
#ifdef KPSE_DEBUG
/* Print the hash values as integers if this is nonzero. */
boolean kpse_debug_hash_lookup_int = false;
#endif
string *
hash_lookup P2C(hash_table_type, table, const_string, key)
{
hash_element_type *p;
str_list_type ret;
unsigned n = hash (table, key);
ret = str_list_init ();
/* Look at everything in this bucket. */
for (p = table.buckets[n]; p != NULL; p = p->next)
if (FILESTRCASEEQ (key, p->key))
/* Cast because the general str_list_type shouldn't force const data. */
str_list_add (&ret, (string) p->value);
/* If we found anything, mark end of list with null. */
if (STR_LIST (ret))
str_list_add (&ret, NULL);
#ifdef KPSE_DEBUG
if (KPSE_DEBUG_P (KPSE_DEBUG_HASH))
{
DEBUGF1 ("hash_lookup(%s) =>", key);
if (!STR_LIST (ret))
fputs (" (nil)\n", stderr);
else
{
string *r;
for (r = STR_LIST (ret); *r; r++)
{
putc (' ', stderr);
if (kpse_debug_hash_lookup_int)
fprintf (stderr, "%ld", (long) *r);
else
fputs (*r, stderr);
}
putc ('\n', stderr);
}
fflush (stderr);
}
#endif
return STR_LIST (ret);
}
/* We only print nonempty buckets, to decrease output volume. */
void
hash_print P2C(hash_table_type, table, boolean, summary_only)
{
unsigned b;
unsigned total_elements = 0, total_buckets = 0;
for (b = 0; b < table.size; b++) {
hash_element_type *bucket = table.buckets[b];
if (bucket) {
unsigned len = 1;
hash_element_type *tb;
total_buckets++;
if (!summary_only) fprintf (stderr, "%4d ", b);
for (tb = bucket->next; tb != NULL; tb = tb->next)
len++;
if (!summary_only) fprintf (stderr, ":%-5d", len);
total_elements += len;
if (!summary_only) {
for (tb = bucket; tb != NULL; tb = tb->next)
fprintf (stderr, " %s=>%s", tb->key, tb->value);
putc ('\n', stderr);
}
}
}
fprintf (stderr,
"%u buckets, %u nonempty (%u%%); %u entries, average chain %.1f.\n",
table.size,
total_buckets,
100 * total_buckets / table.size,
total_elements,
total_buckets ? total_elements / (double) total_buckets : 0.0);
}
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