wernermisc/qpkg/id.c

/*
 * id.c - Registry of unique and alphabetically sorted identifiers
 *
 * Written 2010 by Werner Almesberger
 * Copyright 2010 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 <string.h>

#include "jrb.h"

#include "util.h"
#include "id.h"


static struct id *free_id = NULL;


static int do_comp_id(const struct id *a, const struct id *b)
{
	int len = a->len < b->len ? a->len : b->len;
	int cmp;

	cmp = memcmp(a->s, b->s, len);
	if (cmp)
		return cmp;
	return a->len < b->len ? -1 : a->len > b->len;
}


int comp_id(const void *a, const void *b)
{
	return do_comp_id(a, b);
}

struct tree *make_tree(int (*comp)(const void *a, const void *b))
{
	struct tree *tree;

	tree = alloc_type(struct tree);
	tree->comp = comp;
	tree->root = make_jrb();
	return tree;
}


struct id *make_id(struct tree *tree, const char *s, size_t len)
{
	struct id *id;

	if (!free_id)
		free_id = alloc_type(struct id);
	id = free_id;
	id->s = s;
	id->len = len;
	id->jrb = jrb_find_or_insert(tree->root, id, NULL, tree->comp);
	if (id->jrb->key != id)
		return id->jrb->key;
	free_id = NULL;
	return id;
}


const struct id *find_id(const struct tree *tree, const char *s, size_t len)
{
	struct id id = {
		.s = s,
		.len = len
	};
	struct jrb *node;

	node = jrb_find(tree->root, &id, tree->comp);
	return node ? node->key : NULL;
}


const struct id *first_id(const struct tree *tree)
{
	struct jrb *node;

	node = jrb_first(tree->root);
	return node ? node->key : NULL;
}


const struct id *next_id(const struct id *id)
{
	struct jrb *next;

	next = jrb_next(id->jrb);
	return next ? next->key : NULL;
}