Metadatum Map

typedef struct cardano_metadatum_map_t cardano_metadatum_map_t

Represents a map of metadatum.

cardano_error_t cardano_metadatum_map_new(cardano_metadatum_map_t **metadatum_map)

Creates and initializes a new instance of a metadatum map.

This function allocates and initializes a new instance of cardano_metadatum_map_t, representing a map structure. It returns an error code to indicate the success or failure of the operation.

Usage Example: 

cardano_metadatum_map_t* metadatum_map = NULL;

// Attempt to create a new metadatum_map
cardano_error_t result = cardano_metadatum_map_new(&metadatum_map);

if (result == CARDANO_SUCCESS)
{
  // Use the metadatum_map

  // Once done, ensure to clean up and release the metadatum_map
  cardano_metadatum_map_unref(&metadatum_map);
}

Parameters:
cardano_metadatum_map_t **metadatum_map

[out] A pointer to a pointer to a cardano_metadatum_map_t object. Upon successful initialization, this will point to a newly created cardano_metadatum_map_t object. This object represents a “strong reference” to the metadatum_map, fully initialized and ready for use. The caller is responsible for managing the lifecycle of this object. Specifically, once the metadatum_map is no longer needed, the caller must release it by calling cardano_metadatum_map_unref.

Returns:

CARDANO_SUCCESS if the metadatum_map was successfully created, or an appropriate error code indicating the failure reason.

cardano_error_t cardano_metadatum_map_from_cbor(cardano_cbor_reader_t *reader, cardano_metadatum_map_t **metadatum_map)

Creates a metadatum map from a CBOR reader.

This function parses CBOR data using a provided cardano_cbor_reader_t and constructs a cardano_metadatum_map_t object. It assumes that the CBOR reader is set up correctly and that the CBOR data corresponds to the structure expected for a metadatum_map.

Usage Example: 

cardano_cbor_reader_t* reader = cardano_cbor_reader_new(cbor_data, data_size);
cardano_metadatum_map_t* metadatum_map = NULL;

cardano_error_t result = cardano_metadatum_map_from_cbor(reader, &metadatum_map);

if (result == CARDANO_SUCCESS)
{
  // Use the metadatum_map

  // Once done, ensure to clean up and release the metadatum_map
  cardano_metadatum_map_unref(&metadatum_map);
}
else
{
  const char* error = cardano_cbor_reader_get_last_error(reader);
  printf("Failed to decode metadatum_map: %s\n", error);
}

cardano_cbor_reader_unref(&reader); // Cleanup the CBOR reader

Note

If the function fails, the last error can be retrieved by calling cardano_cbor_reader_get_last_error with the reader. The caller is responsible for freeing the created cardano_metadatum_map_t object by calling cardano_metadatum_map_unref when it is no longer needed.

Parameters:
cardano_cbor_reader_t *reader

[in] A pointer to an initialized cardano_cbor_reader_t that is ready to read the CBOR-encoded metadatum_map data.

cardano_metadatum_map_t **metadatum_map

[out] A pointer to a pointer of cardano_metadatum_map_t that will be set to the address of the newly created metadatum_map object upon successful decoding.

Returns:

A cardano_error_t value indicating the outcome of the operation. Returns CARDANO_SUCCESS if the metadatum_map was successfully created, or an appropriate error code if an error occurred.

cardano_error_t cardano_metadatum_map_to_cbor(const cardano_metadatum_map_t *metadatum_map, cardano_cbor_writer_t *writer)

Serializes a metadatum map into CBOR format using a CBOR writer.

This function serializes the given cardano_metadatum_map_t object using a cardano_cbor_writer_t.

Usage Example: 

cardano_metadatum_map_t* metadatum_map = ...;
cardano_cbor_writer_t* writer = cardano_cbor_writer_new();

if (writer)
{
  cardano_error_t result = cardano_metadatum_map_to_cbor(metadatum_map, writer);

  if (result == CARDANO_SUCCESS)
  {
    // Use the writer's buffer containing the serialized data
  }
  else
  {
    const char* error_message = cardano_cbor_writer_get_last_error(writer);
    printf("Serialization failed: %s\n", error_message);
  }

  cardano_cbor_writer_unref(&writer);
}

cardano_metadatum_map_unref(&metadatum_map);

Parameters:
const cardano_metadatum_map_t *metadatum_map

[in] A constant pointer to the cardano_metadatum_map_t object that is to be serialized.

cardano_cbor_writer_t *writer

[out] A pointer to a cardano_cbor_writer_t where the CBOR serialized data will be written. The writer must already be initialized and ready to accept the data.

Returns:

Returns CARDANO_SUCCESS if the serialization is successful. If the metadatum_map or writer is NULL, returns CARDANO_ERROR_POINTER_IS_NULL.

cardano_error_t cardano_metadatum_map_to_cip116_json(const cardano_metadatum_map_t *map, cardano_json_writer_t *writer)

Serializes a cardano_metadatum_map_t to CIP-116 JSON.

Writes a single JSON object.

Each key and value is serialized using cardano_metadatum_to_cip116_json, so any valid metadatum type (map, list, int, bytes, string) is supported recursively.

The function always writes a complete JSON object (enclosed in { } ).

Parameters:
const cardano_metadatum_map_t *map

[in] A valid metadatum map to serialize.

cardano_json_writer_t *writer

[in] A valid JSON writer positioned where a value is expected.

Returns:

CARDANO_SUCCESS on success.

Returns:

CARDANO_ERROR_POINTER_IS_NULL if map or writer is NULL.

Returns:

CARDANO_ERROR_ENCODING if a pair cannot be retrieved or an element fails to serialize; a descriptive error is set on writer.

size_t cardano_metadatum_map_get_length(const cardano_metadatum_map_t *metadatum_map)

Retrieves the length of the metadatum_map.

This function returns the number of key-value pairs contained in the specified metadatum_map.

Usage Example: 

cardano_metadatum_map_t* metadatum_map = cardano_metadatum_map_new();

// Populate the metadatum_map with key-value pairs

size_t length = cardano_metadatum_map_get_length(metadatum_map);
printf("The length of the metadatum_map is: %zu\n", length);

cardano_metadatum_map_unref(&metadatum_map);

Parameters:
const cardano_metadatum_map_t *metadatum_map

[in] A constant pointer to the cardano_metadatum_map_t object for which the length is to be retrieved.

Returns:

The number of key-value pairs in the metadatum_map. Returns 0 if the metadatum_map is NULL.

cardano_error_t cardano_metadatum_map_get(cardano_metadatum_map_t *metadatum_map, cardano_metadatum_t *key, cardano_metadatum_t **element)

Retrieves the value associated with a given key in the metadatum map.

This function retrieves the value associated with the specified key in the provided metadatum map. It returns the value through the output parameter element. If the key is not found in the metadatum map, the output parameter element will be set to NULL.

Usage Example: 

cardano_metadatum_map_t* metadatum_map = cardano_metadatum_map_new();

// Populate the metadatum_map with key-value pairs

cardano_metadatum_t* key = ...; // Create a metadatum object representing the key
cardano_metadatum_t* value = NULL;
cardano_error_t result = cardano_metadatum_map_get(metadatum_map, key, &value);

if (result == CARDANO_SUCCESS && value != NULL)
{
  // Use the retrieved value
  // ...
  cardano_metadatum_unref(&value); // Clean up the value resource
}
else
{
  // Handle error or key not found
}

cardano_metadatum_unref(&key); // Clean up the key resource
cardano_metadatum_map_unref(&metadatum_map);

Parameters:
cardano_metadatum_map_t *metadatum_map

[in] A constant pointer to the cardano_metadatum_map_t object from which the value is to be retrieved.

cardano_metadatum_t *key

[in] The key whose associated value is to be retrieved from the metadatum_map.

cardano_metadatum_t **element

[out] A pointer to a variable where the retrieved value will be stored. If the key is found in the metadatum map, this variable will be set to the associated value. If the key is not found, this variable will be set to NULL. The caller is responsible for releasing the value by calling cardano_metadatum_unref.

Returns:

CARDANO_SUCCESS if the value associated with the key was successfully retrieved, or an appropriate error code if the input parameters are invalid or any other error occurs.

cardano_error_t cardano_metadatum_map_get_at(cardano_metadatum_map_t *metadatum_map, size_t index, cardano_metadatum_t **key, cardano_metadatum_t **element)

Retrieves the key/value pair at the given index from a metadatum map.

Returns the index-th entry of metadatum_map, providing both the key and the associated value via output parameters. The index is zero-based and must be less than the number of entries in the map.

On success, *key and *element receive strong references to the key and value at the requested position. The caller becomes responsible for releasing both by calling cardano_metadatum_unref on each.

Usage Example
size_t len = cardano_metadatum_map_get_length(map);

for (size_t i = 0; i < len; ++i)
{
  cardano_metadatum_t* key = NULL;
  cardano_metadatum_t* val = NULL;

  cardano_error_t rc = cardano_metadatum_map_get_at(map, i, &key, &val);
  if (rc != CARDANO_SUCCESS) {
    // handle error...
    break;
  }

  // Use key/val...

  cardano_metadatum_unref(&key);
  cardano_metadatum_unref(&val);
}

Note

The iteration order is the map’s internal order and may not correspond to insertion order.

Parameters:
cardano_metadatum_map_t *metadatum_map

[in] A pointer to the cardano_metadatum_map_t to query.

size_t index

[in] Zero-based index of the entry to retrieve.

cardano_metadatum_t **key

[out] Receives the key metadatum at index. Must not be NULL. On success, *key is non-NULL and must be released with cardano_metadatum_unref.

cardano_metadatum_t **element

[out] Receives the value metadatum at index. Must not be NULL. On success, *element is non-NULL and must be released with cardano_metadatum_unref.

Returns:

CARDANO_SUCCESS on success; an appropriate error code otherwise, e.g.:

cardano_error_t cardano_metadatum_map_insert(cardano_metadatum_map_t *metadatum_map, cardano_metadatum_t *key, cardano_metadatum_t *value)

Inserts a key-value pair into the metadatum map.

This function inserts the specified key-value pair into the provided metadatum map.

Usage Example: 

cardano_metadatum_map_t* metadatum_map = cardano_metadatum_map_new();

// Create key and value objects
cardano_metadatum_t* key = ...; // Create a metadatum object representing the key
cardano_metadatum_t* value = ...; // Create a metadatum object representing the value

// Insert the key-value pair into the metadatum_map
cardano_error_t result = cardano_metadatum_map_insert(metadatum_map, key, value);

if (result != CARDANO_SUCCESS)
{
  // Handle insertion failure
}

// Clean up key and value objects
cardano_metadatum_unref(&key);
cardano_metadatum_unref(&value);

cardano_metadatum_map_unref(&metadatum_map);

Parameters:
cardano_metadatum_map_t *metadatum_map

[in] A constant pointer to the cardano_metadatum_map_t object where the key-value pair is to be inserted.

cardano_metadatum_t *key

[in] The key to be inserted into the metadatum map. The caller is responsible for managing the lifecycle of the key object.

cardano_metadatum_t *value

[in] The value to be associated with the key and inserted into the metadatum_map. The caller is responsible for managing the lifecycle of the value object.

Returns:

CARDANO_SUCCESS if the key-value pair was successfully inserted, or an appropriate error code if the input parameters are invalid or any other error occurs.

cardano_error_t cardano_metadatum_map_get_keys(cardano_metadatum_map_t *metadatum_map, cardano_metadatum_list_t **keys)

Retrieves the keys from the metadatum map.

This function retrieves all the keys from the provided metadatum map and returns them as a list. The caller is responsible for managing the lifecycle of the returned list by calling cardano_metadatum_list_unref when it is no longer needed.

Usage Example: 

cardano_metadatum_map_t* metadatum_map = cardano_metadatum_map_new();

// Populate the metadatum_map with key-value pairs

cardano_metadatum_list_t* keys = NULL;
cardano_error_t result = cardano_metadatum_map_get_keys(metadatum_map, &keys);

if (result == CARDANO_SUCCESS)
{
  // Use the list of keys
  // Keys must also be freed if retrieved from the list

  // Once done, ensure to clean up and release the keys list
  cardano_metadatum_list_unref(&keys);
}
else
{
  // Handle error
}

cardano_metadatum_map_unref(&metadatum_map);

Parameters:
cardano_metadatum_map_t *metadatum_map

[in] A constant pointer to the cardano_metadatum_map_t object from which the keys are to be retrieved.

cardano_metadatum_list_t **keys

[out] A pointer to a variable where the retrieved keys will be stored as a list. If successful, this variable will be set to point to the list of keys. The caller is responsible for managing the lifecycle of this list. It must be released by calling cardano_metadatum_list_unref when no longer needed.

Returns:

CARDANO_SUCCESS if the keys were successfully retrieved, or an appropriate error code if the input parameters are invalid or any other error occurs.

cardano_error_t cardano_metadatum_map_get_values(cardano_metadatum_map_t *metadatum_map, cardano_metadatum_list_t **values)

Retrieves the values from the metadatum map.

This function retrieves all the values from the provided metadatum map and returns them as a list. The caller is responsible for managing the lifecycle of the returned list by calling cardano_metadatum_list_unref when it is no longer needed.

Usage Example: 

cardano_metadatum_map_t* metadatum_map = cardano_metadatum_map_new();

// Populate the metadatum_map with key-value pairs

cardano_metadatum_list_t* values = NULL;
cardano_error_t result = cardano_metadatum_map_get_values(metadatum_map, &values);

if (result == CARDANO_SUCCESS)
{
  // Use the list of values

  // Once done, ensure to clean up and release the values list
  // Values must also be freed if retrieved from the list
  cardano_metadatum_list_unref(&values);
}
else
{
  // Handle error
}

cardano_metadatum_map_unref(&metadatum_map);

Parameters:
cardano_metadatum_map_t *metadatum_map

[in] A constant pointer to the cardano_metadatum_map_t object from which the values are to be retrieved.

cardano_metadatum_list_t **values

[out] A pointer to a variable where the retrieved values will be stored as a list. If successful, this variable will be set to point to the list of values. The caller is responsible for managing the lifecycle of this list. It must be released by calling cardano_metadatum_list_unref when no longer needed.

Returns:

CARDANO_SUCCESS if the values were successfully retrieved, or an appropriate error code if the input parameters are invalid or any other error occurs.

bool cardano_metadatum_map_equals(const cardano_metadatum_map_t *lhs, const cardano_metadatum_map_t *rhs)

Checks if two metadatum maps are equal.

This function compares two metadatum maps for equality. Two metadatum maps are considered equal if they have the same keys and associated values.

Usage Example: 

cardano_metadatum_map_t* map1 = ...; // Populate the first metadatum map
cardano_metadatum_map_t* map2 = ...; // Populate the second metadatum map

if (cardano_metadatum_map_equals(map1, map2))
{
  // The two metadatum maps are equal
}
else
{
  // The two metadatum maps are not equal
}

Parameters:
const cardano_metadatum_map_t *lhs

[in] A constant pointer to the first cardano_metadatum_map_t object to be compared.

const cardano_metadatum_map_t *rhs

[in] A constant pointer to the second cardano_metadatum_map_t object to be compared.

Returns:

true if the two metadatum maps are equal, otherwise false.

void cardano_metadatum_map_unref(cardano_metadatum_map_t **metadatum_map)

Decrements the reference count of a metadatum_map object.

This function is responsible for managing the lifecycle of a cardano_metadatum_map_t object by decreasing its reference count. When the reference count reaches zero, the metadatum_map is finalized; its associated resources are released, and its memory is deallocated.

Usage Example: 

cardano_metadatum_map_t* metadatum_map = cardano_metadatum_map_new();

// Perform operations with the metadatum_map...

cardano_metadatum_map_unref(&metadatum_map);
// At this point, metadatum_map is NULL and cannot be used.

Note

After calling cardano_metadatum_map_unref, the pointer to the cardano_metadatum_map_t object will be set to NULL to prevent its reuse.

Parameters:
cardano_metadatum_map_t **metadatum_map

[inout] A pointer to the pointer of the metadatum_map object. This double indirection allows the function to set the caller’s pointer to NULL, avoiding dangling pointer issues after the object has been freed.

void cardano_metadatum_map_ref(cardano_metadatum_map_t *metadatum_map)

Increases the reference count of the cardano_metadatum_map_t object.

This function is used to manually increment the reference count of a metadatum_map object, indicating that another part of the code has taken ownership of it. This ensures the object remains allocated and valid until all owners have released their reference by calling cardano_metadatum_map_unref.

Usage Example: 

// Assuming metadatum_map is a previously created metadatum_map object

cardano_metadatum_map_ref(metadatum_map);

// Now metadatum_map can be safely used elsewhere without worrying about premature deallocation

Note

Always ensure that for every call to cardano_metadatum_map_ref there is a corresponding call to cardano_metadatum_map_unref to prevent memory leaks.

Parameters:
cardano_metadatum_map_t *metadatum_map

A pointer to the metadatum_map object whose reference count is to be incremented.

size_t cardano_metadatum_map_refcount(const cardano_metadatum_map_t *metadatum_map)

Retrieves the current reference count of the cardano_metadatum_map_t object.

This function returns the number of active references to a metadatum_map object. It’s useful for debugging purposes or managing the lifecycle of the object in complex scenarios.

Usage Example: 

// Assuming metadatum_map is a previously created metadatum_map object

size_t ref_count = cardano_metadatum_map_refcount(metadatum_map);

printf("Reference count: %zu\n", ref_count);

Warning

This function does not account for transitive references. A transitive reference occurs when an object holds a reference to another object, rather than directly to the cardano_metadatum_map_t. As such, the reported count may not fully represent the total number of conceptual references in cases where such transitive relationships exist.

Parameters:
const cardano_metadatum_map_t *metadatum_map

A pointer to the metadatum_map object whose reference count is queried. The object must not be NULL.

Returns:

The number of active references to the specified metadatum_map object. If the object is properly managed (i.e., every cardano_metadatum_map_ref call is matched with a cardano_metadatum_map_unref call), this count should reach zero right before the object is deallocated.

void cardano_metadatum_map_set_last_error(cardano_metadatum_map_t *metadatum_map, const char *message)

Sets the last error message for a given metadatum_map object.

Records an error message in the metadatum_map’s last_error buffer, overwriting any existing message. This is useful for storing descriptive error information that can be later retrieved. The message is truncated if it exceeds the buffer’s capacity.

Note

The error message is limited to 1023 characters, including the null terminator, due to the fixed size of the last_error buffer.

Parameters:
cardano_metadatum_map_t *metadatum_map

[in] A pointer to the cardano_metadatum_map_t instance whose last error message is to be set. If NULL, the function does nothing.

const char *message

[in] A null-terminated string containing the error message. If NULL, the metadatum_map’s last_error is set to an empty string, indicating no error.

const char *cardano_metadatum_map_get_last_error(const cardano_metadatum_map_t *metadatum_map)

Retrieves the last error message recorded for a specific metadatum_map.

This function returns a pointer to the null-terminated string containing the last error message set by cardano_metadatum_map_set_last_error for the given metadatum_map. If no error message has been set, or if the last_error buffer was explicitly cleared, an empty string is returned, indicating no error.

Note

The returned string points to internal storage within the object and must not be modified by the caller. The string remains valid until the next call to cardano_metadatum_map_set_last_error for the same metadatum_map, or until the metadatum_map is deallocated.

Parameters:
const cardano_metadatum_map_t *metadatum_map

[in] A pointer to the cardano_metadatum_map_t instance whose last error message is to be retrieved. If the metadatum_map is NULL, the function returns a generic error message indicating the null metadatum_map.

Returns:

A pointer to a null-terminated string containing the last error message for the specified metadatum_map. If the metadatum_map is NULL, “Object is NULL.” is returned to indicate the error.