Hashtable C Reference Documentation
Hashtable
Current Version: 11.0.0
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.
topDebugLogFilePath
void CkHashtable_putDebugLogFilePath(HCkHashtable cHandle, const char *newVal);
const char *CkHashtable_debugLogFilePath(HCkHashtable cHandle);
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
LastErrorHtml
const char *CkHashtable_lastErrorHtml(HCkHashtable cHandle);
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
const char *CkHashtable_lastErrorText(HCkHashtable cHandle);
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
const char *CkHashtable_lastErrorXml(HCkHashtable cHandle);
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
void CkHashtable_putLastMethodSuccess(HCkHashtable cHandle, BOOL newVal);
Indicates the success or failure of the most recent method call: TRUE means success, FALSE means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages.
Utf8
void CkHashtable_putUtf8(HCkHashtable cHandle, BOOL newVal);
When set to TRUE, all const char * arguments and return values are interpreted as UTF-8 strings. When set to FALSE, they are interpreted as ANSI strings.
In Chilkat v11.0.0 and later, the default value is TRUE. Before v11.0.0, it was FALSE.
VerboseLogging
void CkHashtable_putVerboseLogging(HCkHashtable cHandle, BOOL newVal);
If set to TRUE, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is FALSE. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
Version
const char *CkHashtable_version(HCkHashtable cHandle);
Methods
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.
ContainsIntKey
Determines if a given key is contained within the hash table. Returns TRUE if the key exists, otherwise returns FALSE.
GetKeys
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.
ToQueryString
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.