Hashtable Unicode C Reference Documentation

Hashtable

Current Version: 9.5.0.75

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

HCkHashtableW instance = CkHashtableW_Create();
// ...
CkHashtableW_Dispose(instance);
HCkHashtableW CkHashtableW_Create(void);

Creates an instance of the HCkHashtableW object and returns a handle ("void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.

void CkHashtableW_Dispose(HCkHashtableW handle);

Objects created by calling CkHashtableW_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 CkHashtableW_Dispose.

Properties

LastMethodSuccess
BOOL CkHashtableW_getLastMethodSuccess(HCkHashtableW cHandle);
void CkHashtableW_putLastMethodSuccess(HCkHashtableW 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.

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Methods

AddFromXmlSb
BOOL CkHashtableW_AddFromXmlSb(HCkHashtableW cHandle, HCkStringBuilderW sbXml);
Introduced in version 9.5.0.64

Adds to the hash table from XML previously created by calling ToXmlSb.

Returns TRUE for success, FALSE for failure.

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AddInt
BOOL CkHashtableW_AddInt(HCkHashtableW cHandle, const wchar_t *key, int value);
Introduced in version 9.5.0.51

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.

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AddQueryParams
BOOL CkHashtableW_AddQueryParams(HCkHashtableW cHandle, const wchar_t *queryParams);
Introduced in version 9.5.0.62

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.

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AddStr
BOOL CkHashtableW_AddStr(HCkHashtableW cHandle, const wchar_t *key, const wchar_t *value);
Introduced in version 9.5.0.51

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.

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Clear
void CkHashtableW_Clear(HCkHashtableW cHandle);
Introduced in version 9.5.0.51

Removes all elements from the Hashtable.

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ClearWithNewCapacity
BOOL CkHashtableW_ClearWithNewCapacity(HCkHashtableW cHandle, int capacity);
Introduced in version 9.5.0.51

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.

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Contains
BOOL CkHashtableW_Contains(HCkHashtableW cHandle, const wchar_t *key);
Introduced in version 9.5.0.51

Determines if a given key is contained within the hash table. Returns TRUE if the key exists, otherwise returns FALSE.

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ContainsIntKey
BOOL CkHashtableW_ContainsIntKey(HCkHashtableW cHandle, int key);
Introduced in version 9.5.0.64

Determines if a given key is contained within the hash table. Returns TRUE if the key exists, otherwise returns FALSE.

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GetKeys
BOOL CkHashtableW_GetKeys(HCkHashtableW cHandle, HCkStringTableW strTable);
Introduced in version 9.5.0.62

Appends the complete set of hashtable key strings to strTable.

Returns TRUE for success, FALSE for failure.

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LookupInt
int CkHashtableW_LookupInt(HCkHashtableW cHandle, const wchar_t *key);
Introduced in version 9.5.0.51

Returns the integer value associated with the specified key. If the key is not in the hash table, the return value is 0.

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LookupStr
BOOL CkHashtableW_LookupStr(HCkHashtableW cHandle, const wchar_t *key, const wchar_t *outStr);
const wchar_t *CkHashtableW_lookupStr(HCkHashtableW cHandle, const wchar_t *key);
Introduced in version 9.5.0.51

Returns the string value associated with the specified key.

Returns TRUE for success, FALSE for failure.

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Remove
BOOL CkHashtableW_Remove(HCkHashtableW cHandle, const wchar_t *key);
Introduced in version 9.5.0.51

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.

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ToXmlSb
BOOL CkHashtableW_ToXmlSb(HCkHashtableW cHandle, HCkStringBuilderW sbXml);
Introduced in version 9.5.0.64

Serializes the hash table to XML format. The XML is appended to sbXml.

Returns TRUE for success, FALSE for failure.

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