monado/src/xrt/auxiliary/util/u_hashset.cpp

// Copyright 2019-2020, Collabora, Ltd.
// SPDX-License-Identifier: BSL-1.0
/*!
 * @file
 * @brief  Hashset struct header.
 * @author Jakob Bornecrantz <jakob@collabora.com>
 * @ingroup aux_util
 */

#include "util/u_misc.h"
#include "util/u_hashset.h"

#include <cstring>
#include <string>
#include <unordered_map>
#include <vector>


/*
 *
 * Private structs and defines.
 *
 */

struct u_hashset
{
	std::unordered_map<std::string, struct u_hashset_item *> map = {};
};


/*
 *
 * "Exported" functions.
 *
 */

extern "C" int
u_hashset_create(struct u_hashset **out_hashset)
{
	auto hs = new u_hashset;
	*out_hashset = hs;
	return 0;
}

extern "C" int
u_hashset_destroy(struct u_hashset **hs)
{
	delete *hs;
	*hs = NULL;
	return 0;
}

extern "C" int
u_hashset_find_str(struct u_hashset *hs,
                   const char *str,
                   size_t length,
                   struct u_hashset_item **out_item)
{
	std::string key = std::string(str, length);
	auto search = hs->map.find(key);

	if (search != hs->map.end()) {
		*out_item = search->second;
		return 0;
	}
	return -1;
}

extern "C" int
u_hashset_find_c_str(struct u_hashset *hs,
                     const char *c_str,
                     struct u_hashset_item **out_item)
{
	size_t length = strlen(c_str);
	return u_hashset_find_str(hs, c_str, length, out_item);
}

extern "C" int
u_hashset_insert_item(struct u_hashset *hs, struct u_hashset_item *item)
{
	std::string key = std::string(item->c_str(), item->length);
	hs->map[key] = item;
	return 0;
}

extern "C" int
u_hashset_create_and_insert_str(struct u_hashset *hs,
                                const char *str,
                                size_t length,
                                struct u_hashset_item **out_item)
{
	struct u_hashset_item *dummy = NULL;
	struct u_hashset_item *item = NULL;
	size_t size = 0;
	int ret;

	ret = u_hashset_find_str(hs, str, length, &dummy);
	if (ret >= 0) {
		return -1;
	}

	size += sizeof(struct u_hashset_item); // Hashset item.
	size += length;                        // String.
	size += 1;                             // Null terminate it.

	// Now allocate and setup the path.
	item = U_CALLOC_WITH_CAST(struct u_hashset_item, size);
	if (item == NULL) {
		return -1;
	}

	item->length = length;
	// Yes a const cast! D:
	char *store = const_cast<char *>(item->c_str());
	for (size_t i = 0; i < length; i++) {
		store[i] = str[i];
	}
	store[length] = '\0';

	std::string key = std::string(item->c_str(), item->length);
	hs->map[key] = item;

	*out_item = item;

	return 0;
}

extern "C" int
u_hashset_create_and_insert_str_c(struct u_hashset *hs,
                                  const char *c_str,
                                  struct u_hashset_item **out_item)
{
	size_t length = strlen(c_str);
	return u_hashset_create_and_insert_str(hs, c_str, length, out_item);
}

extern "C" int
u_hashset_erase_item(struct u_hashset *hs, struct u_hashset_item *item)
{
	std::string key = std::string(item->c_str(), item->length);
	hs->map.erase(key);
	return 0;
}

extern "C" int
u_hashset_erase_str(struct u_hashset *hs, const char *str, size_t length)
{
	std::string key = std::string(str, length);
	hs->map.erase(key);
	return 0;
}

extern "C" int
u_hashset_erase_c_str(struct u_hashset *hs, const char *c_str)
{
	size_t length = strlen(c_str);
	return u_hashset_erase_str(hs, c_str, length);
}

extern "C" void
u_hashset_clear_and_call_for_each(struct u_hashset *hs,
                                  u_hashset_callback cb,
                                  void *priv)
{
	std::vector<struct u_hashset_item *> tmp;
	tmp.reserve(hs->map.size());

	for (auto &n : hs->map) {
		tmp.push_back(n.second);
	}

	hs->map.clear();

	for (auto n : tmp) {
		cb(n, priv);
	}
}