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Merge pull request #196 from rgerhards/improve-performance

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Performance improvements
This commit is contained in:
Eric Haszlakiewicz
2015-09-28 22:25:29 -04:00
parent 1757a31750 c4f8cc34df
commit 12916e229c
5 changed files with 253 additions and 93 deletions
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109
linkhash.h
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@@ -41,6 +41,23 @@ extern "C" {
*/
#define LH_FREED (void*)-2
/**
* default string hash function
*/
#define JSON_C_STR_HASH_DFLT 0
/**
* perl-like string hash function
*/
#define JSON_C_STR_HASH_PERLLIKE 1
/**
* This function sets the hash function to be used for strings.
* Must be one of the JSON_C_STR_HASH_* values.
* @returns 0 - ok, -1 if parameter was invalid
*/
int json_global_set_string_hash(const int h);
struct lh_entry;
/**
@@ -64,6 +81,7 @@ struct lh_entry {
* The key.
*/
void *k;
int k_is_constant;
/**
* The value.
*/
@@ -92,36 +110,6 @@ struct lh_table {
*/
int count;
/**
* Number of collisions.
*/
int collisions;
/**
* Number of resizes.
*/
int resizes;
/**
* Number of lookups.
*/
int lookups;
/**
* Number of inserts.
*/
int inserts;
/**
* Number of deletes.
*/
int deletes;
/**
* Name of the hash table.
*/
const char *name;
/**
* The first entry.
*/
@@ -143,16 +131,6 @@ struct lh_table {
};
/**
* Pre-defined hash and equality functions
*/
extern unsigned long lh_ptr_hash(const void *k);
extern int lh_ptr_equal(const void *k1, const void *k2);
extern unsigned long lh_char_hash(const void *k);
extern int lh_char_equal(const void *k1, const void *k2);
/**
* Convenience list iterator.
*/
@@ -171,7 +149,6 @@ for(entry = table->head; entry && ((tmp = entry->next) || 1); entry = tmp)
* Create a new linkhash table.
* @param size initial table size. The table is automatically resized
* although this incurs a performance penalty.
* @param name the table name.
* @param free_fn callback function used to free memory for entries
* when lh_table_free or lh_table_delete is called.
* If NULL is provided, then memory for keys and values
@@ -184,7 +161,7 @@ for(entry = table->head; entry && ((tmp = entry->next) || 1); entry = tmp)
* and C strings respectively.
* @return a pointer onto the linkhash table.
*/
extern struct lh_table* lh_table_new(int size, const char *name,
extern struct lh_table* lh_table_new(int size,
lh_entry_free_fn *free_fn,
lh_hash_fn *hash_fn,
lh_equal_fn *equal_fn);
@@ -197,7 +174,7 @@ extern struct lh_table* lh_table_new(int size, const char *name,
* @param free_fn callback function used to free memory for entries.
* @return a pointer onto the linkhash table.
*/
extern struct lh_table* lh_kchar_table_new(int size, const char *name,
extern struct lh_table* lh_kchar_table_new(int size,
lh_entry_free_fn *free_fn);
@@ -209,7 +186,7 @@ extern struct lh_table* lh_kchar_table_new(int size, const char *name,
* @param free_fn callback function used to free memory for entries.
* @return a pointer onto the linkhash table.
*/
extern struct lh_table* lh_kptr_table_new(int size, const char *name,
extern struct lh_table* lh_kptr_table_new(int size,
lh_entry_free_fn *free_fn);
@@ -231,6 +208,21 @@ extern void lh_table_free(struct lh_table *t);
extern int lh_table_insert(struct lh_table *t, void *k, const void *v);
/**
* Insert a record into the table. This one accepts the key's hash in additon
* to the key. This is an exension to support functions that need to calculate
* the hash several times and allows them to do it just once and then pass
* in the hash to all utility functions. Depending on use case, this can be a
* very considerate performance improvement.
* @param t the table to insert into.
* @param k a pointer to the key to insert.
* @param v a pointer to the value to insert.
* @param h hash value of the key to insert
* @param opts opts, a subset of JSON_OBJECT_ADD_* flags is supported
*/
extern int lh_table_insert_w_hash(struct lh_table *t, void *k, const void *v, const unsigned long h, const unsigned opts);
/**
* Lookup a record into the table.
* @param t the table to lookup
@@ -239,6 +231,19 @@ extern int lh_table_insert(struct lh_table *t, void *k, const void *v);
*/
extern struct lh_entry* lh_table_lookup_entry(struct lh_table *t, const void *k);
/**
* Lookup a record into the table. This one accepts the key's hash in additon
* to the key. This is an exension to support functions that need to calculate
* the hash several times and allows them to do it just once and then pass
* in the hash to all utility functions. Depending on use case, this can be a
* very considerate performance improvement.
* @param t the table to lookup
* @param k a pointer to the key to lookup
* @param h hash value of the key to lookup
* @return a pointer to the record structure of the value or NULL if it does not exist.
*/
extern struct lh_entry* lh_table_lookup_entry_w_hash(struct lh_table *t, const void *k, const unsigned long h);
/**
* Lookup a record into the table
* @param t the table to lookup
@@ -285,6 +290,22 @@ extern int lh_table_length(struct lh_table *t);
void lh_abort(const char *msg, ...);
void lh_table_resize(struct lh_table *t, int new_size);
/**
* Calculate the hash of a key for a given table.
* This is an exension to support functions that need to calculate
* the hash several times and allows them to do it just once and then pass
* in the hash to all utility functions. Depending on use case, this can be a
* very considerate performance improvement.
* @param t the table (used to obtain hash function)
* @param k a pointer to the key to lookup
* @return the key's hash
*/
static inline unsigned long lh_get_hash(const struct lh_table *t, const void *k)
{
return t->hash_fn(k);
}
#ifdef __cplusplus
}
#endif