/*

 * Copyright (c) 2009, 2010, 2011, 2012, 2017, 2019 Nicira, Inc.

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at:

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <config.h>

#include "simap.h"

#include "hash.h"

#include "util.h"

static size_t hash_name(const char *, size_t length);

static struct simap_node *simap_find__(const struct simap *,

                                       const char *name, size_t name_len,

                                       size_t hash);

static struct simap_node *simap_add_nocopy__(struct simap *,

                                             char *name, unsigned int data,

                                             size_t hash);

static int compare_nodes_by_name(const void *a_, const void *b_);

/* Initializes 'simap' as an empty string-to-integer map. */

void

simap_init(struct simap *simap)

{

    hmap_init(&simap->map);

}

/* Frees all the data that 'simap' contains. */

void

simap_destroy(struct simap *simap)

{

    if (simap) {

        simap_clear(simap);

        hmap_destroy(&simap->map);

    }

}

/* Exchanges the contents of 'a' and 'b'. */

void

simap_swap(struct simap *a, struct simap *b)

{

    hmap_swap(&a->map, &b->map);

}

/* Adjusts 'simap' so that it is still valid after it has been moved around in

 * memory (e.g. due to realloc()). */

void

simap_moved(struct simap *simap)

{

    hmap_moved(&simap->map);

}

/* Removes all of the mappings from 'simap' and frees them. */

void

simap_clear(struct simap *simap)

{

    struct simap_node *node;

    SIMAP_FOR_EACH_SAFE (node, simap) {

        hmap_remove(&simap->map, &node->node);

        free(node->name);

        free(node);

    }

}

/* Returns true if 'simap' contains no mappings, false if it contains at least

 * one. */

bool

simap_is_empty(const struct simap *simap)

{

    return hmap_is_empty(&simap->map);

}

/* Returns the number of mappings in 'simap'. */

size_t

simap_count(const struct simap *simap)

{

    ovs_assert(simap);

    return hmap_count(&simap->map);

}

/* Inserts a mapping from 'name' to 'data' into 'simap', replacing any

 * existing mapping for 'name'.  Returns true if a new mapping was added,

 * false if an existing mapping's value was replaced.

 *

 * The caller retains ownership of 'name'. */

bool

simap_put(struct simap *simap, const char *name, unsigned int data)

{

    size_t length = strlen(name);

    size_t hash = hash_name(name, length);

    struct simap_node *node;

    node = simap_find__(simap, name, length, hash);

    if (node) {

        node->data = data;

        return false;

    } else {

        simap_add_nocopy__(simap, xmemdup0(name, length), data, hash);

        return true;

    }

}

/* Increases the data value in the mapping for 'name' by 'amt', or inserts a

 * mapping from 'name' to 'amt' if no such mapping exists.  Returns the

 * new total data value for the mapping.

 *

 * If 'amt' is zero, this function does nothing and returns 0.  That is, this

 * function won't create a mapping with a initial value of 0.

 *

 * The caller retains ownership of 'name'. */

unsigned int

simap_increase(struct simap *simap, const char *name, unsigned int amt)

{

    if (amt) {

        size_t length = strlen(name);

        size_t hash = hash_name(name, length);

        struct simap_node *node;

        node = simap_find__(simap, name, length, hash);

        if (node) {

            node->data += amt;

        } else {

            node = simap_add_nocopy__(simap, xmemdup0(name, length),

                                      amt, hash);

        }

        return node->data;

    } else {

        return 0;

    }

}

/* Deletes 'node' from 'simap' and frees its associated memory. */

void

simap_delete(struct simap *simap, struct simap_node *node)

{

    hmap_remove(&simap->map, &node->node);

    free(node->name);

    free(node);

}

/* Searches for 'name' in 'simap'.  If found, deletes it and returns true.  If

 * not found, returns false without modifying 'simap'. */

bool

simap_find_and_delete(struct simap *simap, const char *name)

{

    struct simap_node *node = simap_find(simap, name);

    if (node) {

        simap_delete(simap, node);

        return true;

    }

    return false;

}

/* Searches 'simap' for a mapping with the given 'name'.  Returns it, if found,

 * or a null pointer if not. */

struct simap_node *

simap_find(const struct simap *simap, const char *name)

{

    return simap_find_len(simap, name, strlen(name));

}

/* Searches 'simap' for a mapping whose name is the first 'name_len' bytes

 * starting at 'name'.  Returns it, if found, or a null pointer if not. */

struct simap_node *

simap_find_len(const struct simap *simap, const char *name, size_t len)

{

    return simap_find__(simap, name, len, hash_name(name, len));

}

/* Searches 'simap' for a mapping with the given 'name'.  Returns the

 * associated data value, if found, otherwise zero. */

unsigned int

simap_get(const struct simap *simap, const char *name)

{

    struct simap_node *node = simap_find(simap, name);

    return node ? node->data : 0;

}

/* Returns true if 'simap' contains a copy of 'name', false otherwise. */

bool

simap_contains(const struct simap *simap, const char *name)

{

    return simap_find(simap, name) != NULL;

}

/* Returns an array that contains a pointer to each mapping in 'simap',

 * ordered alphabetically by name.  The returned array has simap_count(simap)

 * elements.

 *

 * The caller is responsible for freeing the returned array (with free()).  It

 * should not free the individual "simap_node"s in the array, because they are

 * still part of 'simap'. */

const struct simap_node **

simap_sort(const struct simap *simap)

{

    if (simap_is_empty(simap)) {

        return NULL;

    } else {

        const struct simap_node **nodes;

        struct simap_node *node;

        size_t i, n;

        n = simap_count(simap);

        nodes = xmalloc(n * sizeof *nodes);

        i = 0;

        SIMAP_FOR_EACH (node, simap) {

            nodes[i++] = node;

        }

        ovs_assert(i == n);

        qsort(nodes, n, sizeof *nodes, compare_nodes_by_name);

        return nodes;

    }

}

/* Returns true if the two maps are equal, meaning that they have the same set

 * of key-value pairs, otherwise false. */

bool

simap_equal(const struct simap *a, const struct simap *b)

{

    if (simap_count(a) != simap_count(b)) {

        return false;

    }

    const struct simap_node *an;

    SIMAP_FOR_EACH (an, a) {

        const struct simap_node *bn = simap_find(b, an->name);

        if (!bn || an->data != bn->data) {

            return false;

        }

    }

    return true;

}

uint32_t

simap_hash(const struct simap *simap)

{

    uint32_t hash = 0;

    const struct simap_node *node;

    SIMAP_FOR_EACH (node, simap) {

        hash ^= hash_int(node->data,

                         hash_name(node->name, strlen(node->name)));

    }

    return hash;

}

static size_t

hash_name(const char *name, size_t length)

{

    return hash_bytes(name, length, 0);

}

static struct simap_node *

simap_find__(const struct simap *simap, const char *name, size_t name_len,

             size_t hash)

{

    struct simap_node *node;

    HMAP_FOR_EACH_WITH_HASH (node, node, hash, &simap->map) {

        if (!strncmp(node->name, name, name_len) && !node->name[name_len]) {

            return node;

        }

    }

    return NULL;

}

static struct simap_node *

simap_add_nocopy__(struct simap *simap, char *name, unsigned int data,

                   size_t hash)

{

    struct simap_node *node = xmalloc(sizeof *node);

    node->name = name;

    node->data = data;

    hmap_insert(&simap->map, &node->node, hash);

    return node;

}

static int

compare_nodes_by_name(const void *a_, const void *b_)

{

    const struct simap_node *const *a = a_;

    const struct simap_node *const *b = b_;

    return strcmp((*a)->name, (*b)->name);

}