/*
Port from c++ is protected by a GNU Lesser GPLv3
Copyright © 2013 Sylvain BERTRAND <sylvain.bertrand@gmail.com>
                                  <sylware@legeek.net>       
*/
#define _GNU_SOURCE
#include <string.h>
#include <stdlib.h>

#include "hb.h"
#include "hb-private.h"
#include "hb-atomic-private.h"

/*this is actually hb_language_t type*/
struct hb_language_impl_t {
	const char s[1];
};

/*XXX:should go in lib "global init"*/
static const char canon_map[256] = {
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, '-', 0, 0,
	'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 0, 0, 0, 0, 0, 0,
	'-', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
	    'n', 'o',
	'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 0, 0, 0, 0, '-',
	0, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
	    'o',
	'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 0, 0, 0, 0, 0
};

static hb_bool_t lang_equal(hb_language_t v1, const void *v2)
{
	const unsigned char *p1;
	const unsigned char *p2;

	p1 = (const unsigned char *)v1;
	p2 = (const unsigned char *)v2;

	while (*p1 && *p1 == canon_map[*p2])
		p1++, p2++;
	return *p1 == canon_map[*p2];
}

struct hb_language_item_t {
	struct hb_language_item_t *next;
	hb_language_t lang;
};

static hb_language_t lang_assign(const char *s)
{
	unsigned char *p;

	hb_language_t lang = (hb_language_t) strdup(s);
	for (p = (unsigned char *)lang; *p; p++)
		*p = canon_map[*p];
	return lang;
}

/*Thread-safe lock-free language list*/

static struct hb_language_item_t *lang_items;

static struct hb_language_item_t *language_item_find_or_insert(const char *key)
{
	struct hb_language_item_t *first_lang_item =
	    hb_atomic_ptr_get(&lang_items);

	while (1) {
		struct hb_language_item_t *lang_item;

		for (lang_item = first_lang_item; lang_item;
		     lang_item = lang_item->next)
			if (lang_equal(lang_item->lang, key))
				return lang_item;

		/*Not found; allocate one. */
		lang_item = calloc(1, sizeof(*lang_item));
		if (!lang_item)
			return NULL;
		lang_item->next = first_lang_item;
		lang_item->lang = lang_assign(key);

		if (hb_atomic_ptr_cmpexch
		    (&lang_items, &first_lang_item, &lang_item))
			return lang_item;
		free(lang_item);
	}
}

hb_language_t hb_language_from_string(const char *str, int len)
{
	struct hb_language_item_t *item;

	if (!str || !len || !*str)
		return HB_LANGUAGE_INVALID;

	if (len >= 0) {
		char strbuf[64];

		len = MIN(len, (int)sizeof(strbuf) - 1);
		str = (char *)memcpy(strbuf, str, len);
		strbuf[len] = '\0';
	}

	item = language_item_find_or_insert(str);
	return item ? item->lang : HB_LANGUAGE_INVALID;
}

hb_tag_t hb_tag_from_string(const char *str, int len)
{
	char tag[4];
	unsigned i;

	if (!str || !len || !*str)
		return HB_TAG_NONE;

	if (len < 0 || len > 4)
		len = 4;
	for (i = 0; i < (unsigned)len && str[i]; ++i)
		tag[i] = str[i];
	for (; i < 4; ++i)
		tag[i] = ' ';
	return HB_TAG_CHAR4(tag);
}

const char *hb_language_to_string(hb_language_t language)
{
	/*This is actually NULL-safe! */
	return language->s;
}

hb_bool_t hb_version_atleast(unsigned int major,unsigned int minor,unsigned int micro)
{
  return HB_VERSION_ATLEAST(major,minor,micro);
}