/*
 * relop.c - Relational operators
 *
 * Copyright 2012 by Werner Almesberger
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */


#include <stdlib.h>
#include <stdio.h>

#include "relop.h"


/*
 * Operator to use for
 *
 * (A op B) -> forall X: !(X opa A) -> !(X opb B))
 *
 * This is for unlimited sets of values. For limited sets of values, we could
 * decide also in some edge cases, but let's save such sophistication for
 * later.
 */


static const enum relop unreachable_op[idx_n][idx_n] = {
#include "unreachable.inc"
};


static int relop2index(enum relop op)
{
	switch (op) {
	case rel_lt:
		return idx_lt;
	case rel_le:
		return idx_le;
	case rel_eq:
		return idx_eq;
	case rel_ge:
		return idx_ge;
	case rel_gt:
		return idx_gt;
	default:
		abort();
	}
}


int relop_unreachable(enum relop opa, enum relop opb,
    const void *a, const void *b,
    int (*cmp)(const void *a, enum relop op, const void *b, const void *user),
    const void *user)
{
	return cmp(a,
	    unreachable_op[relop2index(opa)][relop2index(opb)], b, user);
}


void dump_relop(FILE *file, enum relop op)
{
	switch (op) {
	case rel_lt:
		fprintf(file, "<");
		break;
	case rel_le:
		fprintf(file, "<=");
		break;
	case rel_eq:
		fprintf(file, "=");
		break;
	case rel_ge:
		fprintf(file, ">=");
		break;
	case rel_gt:
		fprintf(file, ">");
		break;
	default:
		abort();
	}
}