m_hash_stridx.h

/* The MIT License (MIT)
 * 
 * Copyright (c) 2015 Monetra Technologies, LLC.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
 
#ifndef __M_HASH_STRIDX_H__
#define __M_HASH_STRIDX_H__
 
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#include <mstdlib/base/m_defs.h>
#include <mstdlib/base/m_types.h>
 
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__BEGIN_DECLS
 
/*! \addtogroup m_hash_stridx Hashtable - String/Index
 *  \ingroup m_hashtable
 *
 * Hashtable, meant for storing string keys and index values.
 * This is primarily used for something like dereferencing a CSV column name to its position.
 *
 * References to the data will always be read-only.
 * All keys and values will be duplicated by the hashtable.
 *
 * @{
 */
 
struct M_hash_stridx;
/* Currently a direct map to M_hashtable private opaque type,
 * simply using casting to prevent the 'wrap' overhead of mallocing when it
 * is not necessary */
typedef struct M_hash_stridx M_hash_stridx_t;
 
struct M_hash_stridx_enum;
/* Used for enumerating a M_hash_stridx. */
typedef struct M_hash_stridx_enum M_hash_stridx_enum_t;
 
 
/*! Flags for controlling the behavior of the hashtable. */
typedef enum {
    M_HASH_STRIDX_NONE          = 0,      /*!< Case sensitive single value (new values replace). */
    M_HASH_STRIDX_CASECMP       = 1 << 0, /*!< Key compare is case insensitive. */
    M_HASH_STRIDX_KEYS_UPPER    = 1 << 1, /*!< Keys will be upper cased before being inserted. Should be used
                                               in conjunction with M_HASH_STRIDX_CASECMP. */
    M_HASH_STRIDX_KEYS_LOWER    = 1 << 2, /*!< Keys will be lower cased before being inserted. Should be used
                                               in conjunction with M_HASH_STRIDX_CASECMP. */
    M_HASH_STRIDX_KEYS_ORDERED  = 1 << 3, /*!< Keys should be ordered. Default is insertion order unless the
                                               sorted option is specified. */
    M_HASH_STRIDX_KEYS_SORTASC  = 1 << 4, /*!< When the keys are ordered sort them using the key_equality function. */
    M_HASH_STRIDX_KEYS_SORTDESC = 1 << 5, /*!< When the keys are ordered sort them using the key_equality function. */
    M_HASH_STRIDX_MULTI_VALUE   = 1 << 6, /*!< Allow keys to contain multiple values.
                                               Sorted in insertion order another sorting is specified. */
    M_HASH_STRIDX_MULTI_GETLAST = 1 << 7, /*!< When using get and get_direct function get the last value from the list
                                               when allowing multiple values. The default is to get the first value. */
    M_HASH_STRIDX_STATIC_SEED   = 1 << 8  /*!< Use a static seed for hash function initialization. This greatly reduces
                                               the security of the hashtable and removes collision attack protections.
                                               This should only be used as a performance optimization when creating
                                               millions of hashtables with static data specifically for quick look up.
                                               DO _NOT_ use this flag with any hashtable that could store user
                                               generated data! Be very careful about duplicating a hashtable that
                                               was created with this flag. All duplicates will use the static seed. */
} M_hash_stridx_flags_t;
 
 
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/*! Create a new hashtable.
 *
 * The hashtable will pre-allocate an array of buckets based on the rounded up size specified. Any hash collisions
 * will result in those collisions being chained together via a linked list. The hashtable will auto-expand by a
 * power of 2 when the fill percentage specified is reached. All key entries are compared in a case-insensitive
 * fashion, and are duplicated internally. Values are duplicated. Case is preserved for both keys and values.
 *
 * \param[in] size     Size of the hash table. If not specified as a power of 2, will
 *                     be rounded up to the nearest power of 2.
 * \param[in] fillpct  The maximum fill percentage before the hash table is expanded. If
 *                     0 is specified, the hashtable will never expand, otherwise the
 *                     value must be between 1 and 99 (recommended: 75).
 * \param[in] flags    M_hash_stridx_flags_t flags for modifying behavior.
 *
 * \return Allocated hashtable.
 *
 * \see M_hash_stridx_destroy
 */
M_API M_hash_stridx_t *M_hash_stridx_create(size_t size, M_uint8 fillpct, M_uint32 flags) M_MALLOC;
 
 
/*! Destroy the hashtable.
 *
 * \param[in] h Hashtable to destroy
 */
M_API void M_hash_stridx_destroy(M_hash_stridx_t *h) M_FREE(1);
 
 
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/*! Insert an entry into the hashtable.
 *
 * \param[in,out] h     Hashtable being referenced.
 * \param[in]     key   Key to insert.
 *                      A NULL or empty string is explicity disallowed.
 * \param[in]     value Value to insert into hashtable.
 *
 * \return M_TRUE on success, or M_FALSE on failure.
 */
M_API M_bool M_hash_stridx_insert(M_hash_stridx_t *h, const char *key, size_t value);
 
 
/*! Remove an entry from the hashtable.
 *
 * \param[in,out] h   Hashtable being referenced.
 * \param[in]     key Key to remove from the hashtable.
 *                    A NULL or empty string is explicitly disallowed.
 *
 * \return M_TRUE on success, or M_FALSE if key does not exist.
 */
M_API M_bool M_hash_stridx_remove(M_hash_stridx_t *h, const char *key);
 
 
/*! Retrieve the value for a key from the hashtable. 
 *
 * \param[in] h      Hashtable being referenced.
 * \param[in] key    Key for value.
 *                   A NULL or empty string is explicitly disallowed.
 * \param[out] value Pointer to value stored in the hashtable. Optional, pass NULL if not needed.
 *
 * \return M_TRUE if value retrieved, M_FALSE if key does not exist.
 */
M_API M_bool M_hash_stridx_get(const M_hash_stridx_t *h, const char *key, size_t *value);
 
 
/*! Retrieve the value for a key from the hashtable, and return it directly as the return value.
 *
 * This cannot be used if you need to differentiate between a key that doesn't exist vs a key with a 0 value.
 *
 * \param[in] h   Hashtable being referenced.
 * \param[in] key Key for value to retrieve from the hashtable.
 *                A NULL or empty string is explicitly disallowed.
 *
 * \return NULL if key doesn't exist or NULL value on file, otherwise the value.
 */
M_API size_t M_hash_stridx_get_direct(const M_hash_stridx_t *h, const char *key);
 
 
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/*! Wether the hashtable a multi value table.
 *
 * \param[in] h Hashtable being referenced.
 *
 * \return M_TRUE if a multi value hashtable.
 */
M_bool M_hash_stridx_is_multi(const M_hash_stridx_t *h);
 
 
/*! Get the number of values for a given key.
 *
 * \param[in]  h   Hashtable being referenced.
 * \param[in]  key Key for value to retrieve. 
 * \param[out] len The number of values.
 *
 * \return M_TRUE if length is retrieved, M_FALSE if key does not exist.
 */
M_API M_bool M_hash_stridx_multi_len(const M_hash_stridx_t *h, const char *key, size_t *len);
 
 
/*! Retrieve the value for a key from the given index when supporting muli-values.
 *
 * \param[in]  h     Hashtable being referenced.
 * \param[in]  key   Key for value to retrieve.
 * \param[in]  idx   The index the value resides at.
 * \param[out] value Pointer to value stored. Optional, pass NULL if not needed.
 *
 * \return M_TRUE if value retrieved, M_FALSE if key does not exist
 */
M_API M_bool M_hash_stridx_multi_get(const M_hash_stridx_t *h, const char *key, size_t idx, size_t *value);
 
 
/*! Retrieve the value for a key from the given index when supporting muli-values.
 *
 * \param[in] h   Hashtable being referenced.
 * \param[in] key Key for value to retrieve.
 * \param[in] idx The index the value resides at.
 *
 * \return M_TRUE if value retrieved, M_FALSE if key does not exist.
 */
M_API size_t M_hash_stridx_multi_get_direct(const M_hash_stridx_t *h, const char *key, size_t idx);
 
 
/*! Remove a value from the hashtable when supporting muli-values.
 *
 * If all values have been removed then the key will be removed.
 *
 * \param[in,out] h   Hashtable being referenced
 * \param[in]     key Key for value to retrieve.
 * \param[in]     idx The index the value resides at.
 *
 * \return M_TRUE if the value was removed, M_FALSE if key does not exist.
 */
M_API M_bool M_hash_stridx_multi_remove(M_hash_stridx_t *h, const char *key, size_t idx);
 
 
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/*! Retrieve the current size (number of buckets/slots, not necessarily used).
 *
 * \param[in] h Hashtable being referenced.
 *
 * \return Size of the hashtable
 */
M_API M_uint32 M_hash_stridx_size(const M_hash_stridx_t *h);
 
 
/*! Retrieve the number of collisions for hashtable entries that has occurred since creation.
 *
 * \param[in] h Hashtable being referenced.
 *
 * \return Number of collisions.
 */
M_API size_t M_hash_stridx_num_collisions(const M_hash_stridx_t *h);
 
 
/*! Retrieve the number of expansions/rehashes since creation.
 *
 * \param[in] h Hashtable being referenced.
 *
 * \return number of expansions/rehashes.
 */
M_API size_t M_hash_stridx_num_expansions(const M_hash_stridx_t *h);
 
 
/*! Retrieve the number of entries in the hashtable.
 *
 * This is the number of keys stored.
 *
 * \param[in] h Hashtable being referenced.
 *
 * \return number of entries in the hashtable.
 */
M_API size_t M_hash_stridx_num_keys(const M_hash_stridx_t *h);
 
 
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/*! Start an enumeration of the keys within a hashtable.
 *
 * \param[in]  h        Hashtable being referenced.
 * \param[out] hashenum Outputs an initialized state variable for starting an enumeration.
 *
 * \return Number of items in the hashtable
 *
 * \see M_hash_stridx_enumerate_free
 */
M_API size_t M_hash_stridx_enumerate(const M_hash_stridx_t *h, M_hash_stridx_enum_t **hashenum);
 
 
/*! Retrieve the next item from a hashtable enumeration.
 *
 * If multi-value, keys will appear multiple times as each value will be
 * retrieved individually.
 *
 * \param[in]     h        Hashtable being referenced.
 * \param[in,out] hashenum State variable for tracking the enumeration process.
 * \param[out]    key      Value of next enumerated key. Optional, pass NULL if not needed.
 * \param[out]    value    Value of next enumerated value. Optional, pass NULL if not needed.
 *
 * \return M_TRUE if enumeration succeeded, M_FALSE if no more keys.
 */
M_API M_bool M_hash_stridx_enumerate_next(const M_hash_stridx_t *h, M_hash_stridx_enum_t *hashenum, const char **key, size_t *value);
 
 
/*! Destroy an enumeration state.
 *
 * \param[in] hashenum Enumeration to destroy.
 */
M_API void M_hash_stridx_enumerate_free(M_hash_stridx_enum_t *hashenum);
 
 
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/*! Merge two hashtables together.
 *
 * The second (src) hashtable will be destroyed automatically upon completion of this function. Any key/value
 * pointers for the hashtable will be directly copied over to the destination hashtable, they will not be
 * duplicated. Any keys which exist in 'dest' that also exist in 'src' will be overwritten by the 'src' value.
 *
 * If dest and src are multi-value, all values from src will be copied into dest and the values from
 * dest will not be removed. If dest is not multi-value and src is, then only the last value in src will
 * be present in dest. If dest is multi-value and src is not, then the value from src will be added to dest.
 *
 * \param[in,out] dest Pointer by reference to the hashtable receiving the key/value pairs.
 *                     if dest is NULL, the src address will simply be copied to dest.
 * \param[in,out] src  Pointer to the hashtable giving up its key/value pairs.
 */
M_API void M_hash_stridx_merge(M_hash_stridx_t **dest, M_hash_stridx_t *src) M_FREE(2);
 
/*! Duplicate an existing hashtable.
 *
 * Copying all keys and values.
 *
 * \param[in] h Hashtable to be copied.
 *
 * \return Duplicated hashtable.
 */
M_API M_hash_stridx_t *M_hash_stridx_duplicate(const M_hash_stridx_t *h) M_MALLOC;
 
/*! @} */
 
__END_DECLS
 
#endif /* __M_HASH_STRIDX_H__ */