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/*
Copyright (C) 2020 Fredrik Johansson
This file is part of Calcium.
Calcium is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version. See <http://www.gnu.org/licenses/>.
*/
#include "ca_ext.h"
#include "ca_field.h"
ca_field_ptr ca_field_cache_lookup_qqbar(ca_field_cache_t cache, const qqbar_t x, ca_ctx_t ctx)
{
ulong xhash;
ca_field_ptr K;
slong i, loc;
xhash = qqbar_hash(x);
loc = xhash % ((ulong) cache->hash_size);
for (i = 0; i < cache->hash_size; i++)
{
/* not found */
if (cache->hash_table[loc] == -1)
return NULL;
K = cache->items[cache->hash_table[loc]];
/* found */
if (CA_FIELD_IS_NF(K) && qqbar_equal(x, CA_FIELD_NF_QQBAR(K)))
return K;
loc++;
if (loc == cache->hash_size)
loc = 0;
}
/* cannot happen */
flint_abort();
}
ulong
_ca_field_hash(ca_ext_struct ** ext, slong len, ca_ctx_t ctx)
{
ulong s;
slong i;
s = 0;
for (i = 0; i < len; i++)
s = s * CA_FIELD_HASH_C + CA_EXT_HASH(ext[i]);
return s;
}
ulong
ca_field_hash(const ca_field_t K, ca_ctx_t ctx)
{
return _ca_field_hash(K->ext, K->length, ctx);
}
static int _ca_field_equal_ext(const ca_field_t K, ca_ext_struct ** x, slong len, ca_ctx_t ctx)
{
slong i;
if (len != CA_FIELD_LENGTH(K))
return 0;
for (i = 0; i < len; i++)
if (CA_FIELD_EXT_ELEM(K, i) != x[i])
return 0;
return 1;
}
void
ca_field_init_set_ext(ca_field_t K, ca_ext_struct ** ext, slong len, ca_ctx_t ctx)
{
if (len == 0)
{
ca_field_init_qq(K, ctx);
}
else if (len == 1 && CA_EXT_IS_QQBAR(ext[0]))
{
CA_FIELD_LENGTH(K) = 1;
CA_FIELD_EXT(K) = flint_malloc(sizeof(ca_ext_ptr));
CA_FIELD_EXT_ELEM(K, 0) = ext[0];
CA_FIELD_IDEAL_P(K) = NULL;
CA_FIELD_IDEAL_LENGTH(K) = -1;
CA_FIELD_IDEAL_ALLOC(K) = 0;
CA_FIELD_HASH(K) = CA_EXT_HASH(ext[0]);
}
else
{
slong i;
ca_field_init_multi(K, len, ctx);
for (i = 0; i < len; i++)
ca_field_set_ext(K, i, ext[i], ctx);
}
}
ca_field_ptr ca_field_cache_insert_ext(ca_field_cache_t cache, ca_ext_struct ** x, slong length, ca_ctx_t ctx)
{
ulong xhash;
slong i, loc;
xhash = _ca_field_hash(x, length, ctx);
/* make room for inserting entry if needed */
if (cache->length == cache->alloc)
{
slong new_alloc;
new_alloc = FLINT_MAX(1, cache->alloc * 2);
cache->items = flint_realloc(cache->items, sizeof(ca_field_struct *) * new_alloc);
for (i = cache->alloc; i < new_alloc; i++)
cache->items[i] = flint_malloc(sizeof(ca_field_struct));
cache->alloc = new_alloc;
}
/* rehash if needed */
if (cache->length >= 0.5 * cache->hash_size)
{
slong new_size, j;
slong * new_table;
ulong thash;
new_size = cache->hash_size * 2;
new_table = flint_malloc(sizeof(slong) * new_size);
for (i = 0; i < new_size; i++)
new_table[i] = -1;
for (i = 0; i < cache->length; i++)
{
thash = ca_field_hash(cache->items[i], ctx);
j = thash % new_size;
while (new_table[j] != -1)
{
j++;
if (j == new_size)
j = 0;
}
new_table[j] = i;
}
flint_free(cache->hash_table);
cache->hash_size = new_size;
cache->hash_table = new_table;
}
loc = xhash % ((ulong) cache->hash_size);
for (i = 0; i < cache->hash_size; i++)
{
/* not found, so insert */
if (cache->hash_table[loc] == -1)
{
ca_field_ptr res;
ca_field_init_set_ext(cache->items[cache->length], x, length, ctx);
cache->hash_table[loc] = cache->length;
cache->length++;
/* save pointer; build_ideal can resize the cache */
res = cache->items[cache->length - 1];
ca_field_build_ideal(res, ctx);
return res;
}
/* found */
if (_ca_field_equal_ext(cache->items[cache->hash_table[loc]], x, length, ctx))
return cache->items[cache->hash_table[loc]];
loc++;
if (loc == cache->hash_size)
loc = 0;
}
/* cannot happen */
flint_abort();
}
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