universalservice/include/internal/c89_relo.h

#ifndef UNS_FORMAT_C89_H
#define UNS_FORMAT_C89_H
/* Copyright (C) 2024 Peter McGoron
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this program. If not, see
 * <https://www.gnu.org/licenses/>.
*/

#include "uns.h"

/* This is a strictly C89+ header format with relocation pointers and
 * lengths.
 *
 * Forwarding pointers need to be stored in the header because in strict
 * C, arithmetic on pointers is undefined for pointers not pointing into
 * the same object.
 *
 * The length of the string is limited to "len" bytes and is stored as
 * a `uns_sword`. If the word is negative, then the region is a record,
 * and if the number is positive then the region is just bytes.
 */

struct uns_c89_relo_hdr {
	void *relo;
	uns_sword len;
};
#define uns_c89_relo_get_hdr(p)((struct uns_c89_relo_hdr *)(p) - 1)

size_t uns_c89_relo_get_len(void *p);
size_t uns_c89_relo_get_record_len(void *p);

#define uns_c89_relo_get_relo(p) (uns_c89_relo_get_hdr(p)->relo)
#define uns_c89_relo_set_relo(p, v) (uns_c89_relo_get_relo(p) = (v))
#define uns_c89_relo_is_record(p) (uns_c89_relo_get_hdr(p)->len < 0)

void *uns_c89_relo_init(void *p, size_t len_size, int is_record);

void uns_c89_relo_record_set(Uns_ptr rec, size_t i, void *v);
void *uns_c89_relo_record_get(Uns_ptr rec, size_t i);

#endif