Unspent Transaction Output (UTxO)¶

typedef struct cardano_utxo_t cardano_utxo_t¶

Represents a unspent output (UTxO).

cardano_error_t cardano_utxo_new(cardano_transaction_input_t *input, cardano_transaction_output_t *output, cardano_utxo_t **utxo)¶

Creates a new UTXO (Unspent Transaction Output) object.

This function creates and initializes a new cardano_utxo_t object by associating a transaction input with its corresponding transaction output. UTXOs represent unspent outputs from previous transactions that can be used as inputs in new transactions.

Usage Example:

cardano_transaction_input_t* input = ...;  // Assume input is initialized
cardano_transaction_output_t* output = ...;  // Assume output is initialized
cardano_utxo_t* utxo = NULL;

cardano_error_t result = cardano_utxo_new(input, output, &utxo);
if (result == CARDANO_SUCCESS)
{
  // UTXO successfully created, use utxo as needed

  // Clean up when done
  cardano_utxo_unref(&utxo);
}
else
{
  printf("Failed to create UTXO: %s\n", cardano_error_to_string(result));
}

// Clean up input and output when no longer needed
cardano_transaction_input_unref(&input);
cardano_transaction_output_unref(&output);

Note

A UTXO links a specific input to its corresponding output, representing spendable value in the Cardano blockchain. The newly created UTXO object must be properly freed by the caller using cardano_utxo_unref when it is no longer needed.

Parameters:¶

cardano_transaction_input_t *input¶

[in] A pointer to an initialized cardano_transaction_input_t object, representing the transaction input. This parameter must not be NULL.

cardano_transaction_output_t *output¶

[in] A pointer to an initialized cardano_transaction_output_t object, representing the corresponding transaction output. This parameter must not be NULL.

cardano_utxo_t **utxo¶

[out] A double pointer to a cardano_utxo_t object. On successful creation, this will point to the newly created UTXO object. The caller is responsible for managing the lifecycle of this object and must release it by calling cardano_utxo_unref when it is no longer needed.

Returns:¶

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the UTXO was successfully created. If either input, output, or utxo is NULL, returns CARDANO_ERROR_POINTER_IS_NULL.

cardano_error_t cardano_utxo_from_cbor(cardano_cbor_reader_t *reader, cardano_utxo_t **utxo)¶

Creates a cardano_utxo_t from a CBOR reader.

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

Usage Example:

cardano_cbor_reader_t* reader = cardano_cbor_reader_new(cbor_data, data_size);
cardano_utxo_t* utxo = NULL;

cardano_error_t result = cardano_utxo_from_cbor(reader, &utxo);

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

  // Once done, ensure to clean up and release the utxo
  cardano_utxo_unref(&utxo);
}
else
{
  const char* error = cardano_cbor_reader_get_last_error(reader);
  printf("Failed to decode utxo: %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_utxo_t object by calling cardano_utxo_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 data.

cardano_utxo_t **utxo¶

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

Returns:¶

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

cardano_error_t cardano_utxo_to_cbor(const cardano_utxo_t *utxo, cardano_cbor_writer_t *writer)¶

Serializes utxo into CBOR format using a CBOR writer.

This function serializes the given cardano_utxo_t object using a cardano_cbor_writer_t.

Usage Example:

cardano_utxo_t* utxo = ...;
cardano_cbor_writer_t* writer = cardano_cbor_writer_new();

if (writer)
{
  cardano_error_t result = cardano_utxo_to_cbor(utxo, 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_utxo_unref(&utxo);

Parameters:¶

const cardano_utxo_t *utxo¶

[in] A constant pointer to the cardano_utxo_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 utxo or writer is NULL, returns CARDANO_ERROR_POINTER_IS_NULL.

cardano_error_t cardano_utxo_to_cip116_json(const cardano_utxo_t *utxo, cardano_json_writer_t *writer)¶

Serializes a transaction unspent output (UTXO) to CIP-116 JSON.

The function writes the full JSON object, including the surrounding braces. Keys are written in the order: “input”, “output”.

Parameters:¶

const cardano_utxo_t *utxo¶

[in] Pointer to a valid cardano_utxo_t.

cardano_json_writer_t *writer¶

[in] Pointer to a valid cardano_json_writer_t.

Returns:¶

CARDANO_SUCCESS On success. CARDANO_ERROR_POINTER_IS_NULL If utxo or writer is NULL. Other Any error propagated from nested writers.

cardano_transaction_input_t *cardano_utxo_get_input(cardano_utxo_t *utxo)¶

Retrieves the transaction input from a UTXO.

This function fetches the transaction input associated with a given cardano_utxo_t object. The transaction input represents the source of the UTXO, which can be used as an input in a new transaction.

Usage Example:

cardano_utxo_t* utxo = ...; // Assume utxo is already initialized
cardano_transaction_input_t* input = cardano_utxo_get_input(utxo);

if (input != NULL)
{
  // Use the transaction input as needed

  // Clean up when done
  cardano_transaction_input_unref(&input);
}
else
{
  printf("Failed to retrieve the transaction input.\n");
}

// Clean up the utxo when no longer needed
cardano_utxo_unref(&utxo);

Note

The transaction input refers to the previous transaction from which the UTXO originates, representing a spendable output.

Parameters:¶

cardano_utxo_t *utxo¶

[in] A pointer to an initialized cardano_utxo_t object. This parameter must not be NULL.

Returns:¶

A pointer to a cardano_transaction_input_t object representing the transaction input of the UTXO. The returned object is a new reference, and the caller is responsible for managing its lifecycle. Specifically, the caller must release the object by calling cardano_transaction_input_unref when it is no longer needed. If the utxo is NULL, the function returns NULL.

cardano_error_t cardano_utxo_set_input(cardano_utxo_t *utxo, cardano_transaction_input_t *input)¶

Sets the transaction input for a UTXO.

This function assigns a transaction input to the specified cardano_utxo_t object. The transaction input represents the source of the UTXO, which can be used as an input in a new transaction.

Usage Example:

cardano_utxo_t* utxo = ...; // Assume utxo is initialized
cardano_transaction_input_t* input = ...; // Assume input is initialized

cardano_error_t result = cardano_utxo_set_input(utxo, input);
if (result == CARDANO_SUCCESS)
{
  printf("Transaction input successfully set for the UTXO.\n");
}
else
{
  printf("Failed to set transaction input: %s\n", cardano_error_to_string(result));
}

// Clean up resources
cardano_transaction_input_unref(&input);
cardano_utxo_unref(&utxo);

Note

This function increases the reference count of the input object, meaning the caller retains ownership of the input and must release it by calling cardano_transaction_input_unref when it is no longer needed.

Parameters:¶

cardano_utxo_t *utxo¶

[inout] A pointer to an initialized cardano_utxo_t object where the input will be set. This parameter must not be NULL.

cardano_transaction_input_t *input¶

[in] A pointer to an initialized cardano_transaction_input_t object representing the input to be associated with the UTXO. This parameter must not be NULL.

Returns:¶

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the transaction input was successfully set. If either utxo or input is NULL, returns CARDANO_ERROR_POINTER_IS_NULL.

cardano_transaction_output_t *cardano_utxo_get_output(cardano_utxo_t *utxo)¶

Retrieves the transaction output from a UTXO.

This function fetches the transaction output associated with a given cardano_utxo_t object. The transaction output represents the destination of the UTXO, indicating the amount of value and recipient.

Usage Example:

cardano_utxo_t* utxo = ...; // Assume utxo is already initialized
cardano_transaction_output_t* output = cardano_utxo_get_output(utxo);

if (output != NULL)
{
  // Use the transaction output as needed

  // Clean up when done
  cardano_transaction_output_unref(&output);
}
else
{
  printf("Failed to retrieve the transaction output.\n");
}

// Clean up the utxo when no longer needed
cardano_utxo_unref(&utxo);

Note

The transaction output refers to the recipient and the amount of value in the UTXO, representing spendable value.

Parameters:¶

cardano_utxo_t *utxo¶

[in] A pointer to an initialized cardano_utxo_t object. This parameter must not be NULL.

Returns:¶

A pointer to a cardano_transaction_output_t object representing the transaction output of the UTXO. The returned object is a new reference, and the caller is responsible for managing its lifecycle. Specifically, the caller must release the object by calling cardano_transaction_output_unref when it is no longer needed. If the utxo is NULL, the function returns NULL.

cardano_error_t cardano_utxo_set_output(cardano_utxo_t *utxo, cardano_transaction_output_t *output)¶

Sets the transaction output for a UTXO.

This function assigns a transaction output to the specified cardano_utxo_t object. The transaction output represents the destination of the UTXO, including the amount of value and the recipient’s address.

Usage Example:

cardano_utxo_t* utxo = ...; // Assume utxo is initialized
cardano_transaction_output_t* output = ...; // Assume output is initialized

cardano_error_t result = cardano_utxo_set_output(utxo, output);
if (result == CARDANO_SUCCESS)
{
  printf("Transaction output successfully set for the UTXO.\n");
}
else
{
  printf("Failed to set transaction output: %s\n", cardano_error_to_string(result));
}

// Clean up resources
cardano_transaction_output_unref(&output);
cardano_utxo_unref(&utxo);

Note

This function increases the reference count of the output object, meaning the caller retains ownership of the output and must release it by calling cardano_transaction_output_unref when it is no longer needed.

Parameters:¶

cardano_utxo_t *utxo¶

[inout] A pointer to an initialized cardano_utxo_t object where the output will be set. This parameter must not be NULL.

cardano_transaction_output_t *output¶

[in] A pointer to an initialized cardano_transaction_output_t object representing the output to be associated with the UTXO. This parameter must not be NULL.

Returns:¶

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the transaction output was successfully set. If either utxo or output is NULL, returns CARDANO_ERROR_POINTER_IS_NULL.

bool cardano_utxo_equals(const cardano_utxo_t *lhs, const cardano_utxo_t *rhs)¶

Compares two UTxO objects for equality.

This function compares two UTxO objects to determine if they are equal.

Usage Example:

cardano_utxo_t* utxo1 = NULL;
cardano_utxo_t* utxo2 = NULL;

// Assume utxo1 and utxo2 are initialized properly

bool are_equal = cardano_utxo_equals(utxo1, utxo2);

if (are_equal)
{
  printf("The utxo objects are equal.\n");
}
else
{
  printf("The utxo objects are not equal.\n");
}

// Clean up
cardano_utxo_unref(&utxo1);
cardano_utxo_unref(&utxo2);

Parameters:¶

const cardano_utxo_t *lhs¶

[in] Pointer to the first UTxO object.

const cardano_utxo_t *rhs¶

[in] Pointer to the second UTxO object.

Returns:¶

true if the utxo objects are equal, false otherwise.

void cardano_utxo_unref(cardano_utxo_t **utxo)¶

Decrements the reference count of a cardano_utxo_t object.

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

Usage Example:

cardano_utxo_t* utxo = cardano_utxo_new(major, minor);

// Perform operations with the utxo...

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

Note

After calling cardano_utxo_unref, the pointer to the cardano_utxo_t object will be set to NULL to prevent its reuse.

Parameters:¶

cardano_utxo_t **utxo¶

[inout] A pointer to the pointer of the utxo 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_utxo_ref(cardano_utxo_t *utxo)¶

Increases the reference count of the cardano_utxo_t object.

This function is used to manually increment the reference count of an cardano_utxo_t 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_utxo_unref.

Usage Example:

// Assuming utxo is a previously created utxo object

cardano_utxo_ref(utxo);

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

Note

Always ensure that for every call to cardano_utxo_ref there is a corresponding call to cardano_utxo_unref to prevent memory leaks.

Parameters:¶

cardano_utxo_t *utxo¶

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

size_t cardano_utxo_refcount(const cardano_utxo_t *utxo)¶

Retrieves the current reference count of the cardano_utxo_t object.

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

Usage Example:

// Assuming utxo is a previously created utxo object

size_t ref_count = cardano_utxo_refcount(utxo);

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_utxo_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_utxo_t *utxo¶

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

Returns:¶

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

void cardano_utxo_set_last_error(cardano_utxo_t *utxo, const char *message)¶

Sets the last error message for a given cardano_utxo_t object.

Records an error message in the utxo’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_utxo_t *utxo¶

[in] A pointer to the cardano_utxo_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 utxo’s last_error is set to an empty string, indicating no error.

const char *cardano_utxo_get_last_error(const cardano_utxo_t *utxo)¶

Retrieves the last error message recorded for a specific utxo.

This function returns a pointer to the null-terminated string containing the last error message set by cardano_utxo_set_last_error for the given utxo. 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_utxo_set_last_error for the same utxo, or until the utxo is deallocated.

Parameters:¶

const cardano_utxo_t *utxo¶

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

Returns:¶

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