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#include "exptable.h"
#include "table.h"
/* Implementation of a hashtable [exponent vectors, of fixed length] -->
* unsigned long int. */
/* The implementation uses table.{h,c}, which was written by David R. Hanson */
struct exponent_table
{
int nvars;
Table_T *table;
};
static int table_nvars; /* Set this before calling 'hash' */
unsigned int exp_hash(const void *x)
/* exp has type 'exponent' */
{
int i;
const int *xx = x;
unsigned int result = 0;
for (i = 0; i < table_nvars; i++) result += (xx[i] << 3);
return result;
}
int exp_cmp(const void *x, const void *y)
/* x, y are both of type 'exponent' */
{
int i;
const int *xx = x;
const int *yy = y;
for (i = 0; i < table_nvars; i++)
{
int cmp = xx[i] - yy[i];
if (cmp != 0) return cmp;
}
return 0;
}
exponent_table *exponent_table_new(int hint, int nvars)
{
exponent_table *result;
NEW(result);
result->nvars = nvars;
result->table = Table_new(hint, exp_cmp, exp_hash);
return result;
}
int exponent_table_length(exponent_table *E) { return Table_length(E->table); }
void exponent_table_free(exponent_table **E)
{
Table_free(&((*E)->table));
FREE(*E);
*E = 0;
}
long exponent_table_put(exponent_table *E, const exponent expon, long value)
/* Puts the element 'expon => value' into the table, and if an element is
already there, its value is returned, otherwise 0 is returned.
Thus, it is a good idea to not insert zero values into the table */
{
table_nvars = E->nvars;
return (long)Table_put(E->table, expon, (void *)value);
}
long exponent_table_get(exponent_table *E, const exponent expon)
/* Returns the value associated to 'expon', returning zero, if 'expon'
is not in the table */
{
table_nvars = E->nvars;
return (long)Table_get(E->table, expon);
}
const void **exponent_table_to_array(exponent_table *E)
{
return Table_toArray(E->table, NULL);
}
/*
// Local Variables:
// compile-command: "make -C $M2BUILDDIR/Macaulay2/e "
// indent-tabs-mode: nil
// End:
*/
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