guacamole-spice-protocol/libguac/include/pool.h

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 * The contents of this file are subject to the Mozilla Public License Version
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 *
 * The Original Code is libguac.
 *
 * The Initial Developer of the Original Code is
 * Michael Jumper.
 * Portions created by the Initial Developer are Copyright (C) 2010
 * the Initial Developer. All Rights Reserved.
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 *
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#ifndef _GUAC_POOL_H
#define _GUAC_POOL_H

/**
 * Provides functions and structures for maintaining dynamically allocated and freed
 * pools of integers.
 *
 * @file pool.h
 */

typedef struct guac_pool_int guac_pool_int;

typedef struct guac_pool {

    /**
     * The minimum number of integers which must have been returned by guac_pool_next_int
     * before previously-used and freed integers are allowed to be returned.
     */
    int min_size;

    /**
     * The next integer to be released (after no more integers remain in the pool.
     */
    int __next_value;

    /**
     * The first integer in the pool, if any.
     */
    guac_pool_int* __head;

    /**
     * The last integer in the pool, if any.
     */
    guac_pool_int* __tail;

} guac_pool;

/**
 * Represents a single layer within the Guacamole protocol.
 */
struct guac_pool_int {

    /**
     * The integer value of this pool entry.
     */
    int value;

    /**
     * The next available (unused) guac_pool_int in the list of
     * allocated but free'd ints.
     */
    guac_pool_int* __next;

};

/**
 * Allocates a new guac_pool having the given minimum size.
 *
 * @param size The minimum number of integers which must have been returned by
 *             guac_pool_next_int before freed integers (previously used integers)
 *             are allowed to be returned.
 * @return A new, empty guac_pool, having the given minimum size.
 */
guac_pool* guac_pool_alloc(int size);

/**
 * Frees the given guac_pool.
 *
 * @param pool The guac_pool to free.
 */
void guac_pool_free(guac_pool* pool);

/**
 * Returns the next available integer from the given guac_pool. All integers returned are
 * non-negative, and are returned in sequences, starting from 0.
 *
 * @param pool The guac_pool to retrieve an integer from.
 * @return The next available integer, which may be either an integer not yet returned
 *         by a call to guac_pool_next_int, or an integer which was previosly returned,
 *         but has since been freed.
 */
int guac_pool_next_int(guac_pool* pool);

/**
 * Frees the given integer back into the given guac_pool. The integer given will be
 * available for future calls to guac_pool_next_int.
 *
 * @param pool The guac_pool to free the given integer into.
 * @param value The integer which should be readded to the given pool, such that it can
 *              be received by a future call to guac_pool_next_int.
 */
void guac_pool_free_int(guac_pool* pool, int value);

#endif