Hashtable C Reference Documentation
Hashtable
Current Version: 9.5.0.98
Represents a collection of key/value pairs that are stored in a hash table.
Note: This class was added in Chilkat v9.5.0.51
Create/Dispose
HCkHashtable instance = CkHashtable_Create(); // ... CkHashtable_Dispose(instance);
Creates an instance of the HCkHashtable object and returns a handle ("void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.
Objects created by calling CkHashtable_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkHashtable_Dispose.
Properties
Count
The number of items (strings/integers) contained in the hash table.
topLastMethodSuccess
void CkHashtable_putLastMethodSuccess(HCkHashtable cHandle, BOOL newVal);
Indicate whether the last method call succeeded or failed. A value of TRUE indicates success, a value of FALSE indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:
- Any method that returns a string.
- Any method returning a Chilkat object, binary bytes, or a date/time.
- Any method returning a standard boolean status value where success = TRUE and failure = FALSE.
- Any method returning an integer where failure is defined by a return value less than zero.
Note: Methods that do not fit the above requirements will always set this property equal to TRUE. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.
topUtf8
void CkHashtable_putUtf8(HCkHashtable cHandle, BOOL newVal);
When set to TRUE, all "const char *" arguments are interpreted as utf-8 strings. If set to FALSE (the default), then "const char *" arguments are interpreted as ANSI strings. Also, when set to TRUE, and Chilkat method returning a "const char *" is returning the utf-8 representation. If set to FALSE, all "const char *" return values are ANSI strings.
topMethods
AddFromXmlSb
Adds to the hash table from XML previously created by calling ToXmlSb.
Returns TRUE for success, FALSE for failure.
AddInt
Adds or replaces an entry with the given key and integer value to the hash table. Returns TRUE if a new hash entry was added or replaced. Returns FALSE if an out-of-memory condition occurred.
Returns TRUE for success, FALSE for failure.
topAddQueryParams
Adds URL query parameters into the hashtable. The queryParams has the form: "field1=value1&field2=value2&field3=value3...". It is assumed that the values are URL encoded, and this method automatically URL decodes the values prior to inserting into the hashtable.
Returns TRUE for success, FALSE for failure.
AddStr
Adds or replaces an entry with the given key and string value to the hash table. Returns TRUE if a new hash entry was added or replaced. Returns FALSE if an out-of-memory condition occurred.
Returns TRUE for success, FALSE for failure.
topClear
Removes all elements from the Hashtable.
topClearWithNewCapacity
Removes all elements from the Hashtable and re-sizes with the specified capacity.
The capacity is the number of buckets in the hash table. In the case of a "hash collision", a single bucket stores multiple entries, which must be searched sequentially. One rule of thumb is to set the capacity to twice the number of expected items to be hashed. It's also preferable to set the capacity to a prime number. (The 1st 10,000 prime numbers are listed here: https://primes.utm.edu/lists/small/10000.txt )
The initial default capacity of the hash table is 521.
Returns TRUE for success, FALSE for failure.
topContains
Determines if a given key is contained within the hash table. Returns TRUE if the key exists, otherwise returns FALSE.
topContainsIntKey
Determines if a given key is contained within the hash table. Returns TRUE if the key exists, otherwise returns FALSE.
topGetKeys
Appends the complete set of hashtable key strings to strTable.
Returns TRUE for success, FALSE for failure.
LookupInt
Returns the integer value associated with the specified key. If the key is not in the hash table, the return value is 0.
topLookupStr
const char *CkHashtable_lookupStr(HCkHashtable cHandle, const char *key);
Returns the string value associated with the specified key.
Returns TRUE for success, FALSE for failure.
topRemove
Removes the entry with the specified key from the hash table. Returns TRUE if the key existed and was removed. Returns FALSE if the key did not already exist.
topToQueryString
const char *CkHashtable_toQueryString(HCkHashtable cHandle);
Serializes the hash table to a query string such as key1=value1&key2=value2&key3=value3 where each value is URL encoded.
Returns TRUE for success, FALSE for failure.
ToXmlSb
Serializes the hash table to XML format. The XML is appended to sbXml.
Returns TRUE for success, FALSE for failure.