Predefined data types

Here is the list of predefined types provided to bindings since version 4.

usage name description
AFB_PREDEFINED_TYPE_OPAQUE The opaque type is anything represented by its address
AFB_PREDEFINED_TYPE_STRINGZ Type of zero terminated string
AFB_PREDEFINED_TYPE_JSON Type of json string terminated by a zero
AFB_PREDEFINED_TYPE_JSON_C Type of json object as handled by libjson-c
AFB_PREDEFINED_TYPE_BYTEARRAY Type for arrays of bytes
AFB_PREDEFINED_TYPE_BOOL Type of boolean values
AFB_PREDEFINED_TYPE_I32 Type of signed 32 bit integers
AFB_PREDEFINED_TYPE_U32 Type of unsigned 32 bit integers
AFB_PREDEFINED_TYPE_I64 Type of signed 64 bit integers
AFB_PREDEFINED_TYPE_U64 Type of unsigned 64 bit integers
AFB_PREDEFINED_TYPE_DOUBLE Type of doubles

Below section describes the predefined types. For each of them, the following items are explained:

  • length: explain the meaning of the length
  • family: what is the family of the type
  • converters: implemented converters
  • updaters: implemented updaters
  • examples: some exemples of use

For all of them, data is represented by the address to its first byte.

AFB_PREDEFINED_TYPE_OPAQUE

The opaque type is anything represented by its address.

length

The length is not used

family

No family

converters

The type AFB_PREDEFINED_TYPE_OPAQUE converts to any of the below types:

  • AFB_PREDEFINED_TYPE_STRINGZ
  • AFB_PREDEFINED_TYPE_JSON
  • AFB_PREDEFINED_TYPE_JSON_C

The conversion implies the creation of a unique anchor for the given data and producing the string representation of that anchor. For example, if the created anchor for a data is the number 0x3f7c, the string representation of the opacified data is “#@3f7c”.

updaters

No updater

examples

In this example, an internal instance of context is wrapped to a data.

/**
 * Get the data referencing the context, create it if needed.
 * The returned data has its reference count incremented and the
 * caller MUST call afb_data_unref.
 * @param context the context to reference
 * @param data address to return the data representing the context
 * @return 0 on success, a negative code otherwise
 */
int data_of_context(struct context *context, afb_data_t *data)
{
   int code = 0;
   if (context->data == NULL)
      code = afb_create_data_raw(&context->data, AFB_PREDEFINED_TYPE_OPAQUE, context, 0, 0, 0);
   *data = afb_data_addref(context->data); /* neutral if context->data is NULL */
   return code;
}

AFB_PREDEFINED_TYPE_BYTEARRAY

Type for arrays of bytes

length

The count of byte in the array

family

No family

converters

No converter

updaters

No updater

examples

AFB_PREDEFINED_TYPE_STRINGZ

Type of zero terminated string UTF8, ASCII or any encoding compatible with zero terminated byte string.

length

The length in bytes including the tailing zero. A length of zero is compatible with an address of NULL value.

family

In the family of AFB_PREDEFINED_TYPE_BYTEARRAY

It means that any data of type AFB_PREDEFINED_TYPE_JSON is also naturally of type AFB_PREDEFINED_TYPE_BYTEARRAY.

converters

  • to AFB_PREDEFINED_TYPE_OPAQUE: if the string is a valid opaque representation of an opacified data, return that opacified data.

  • to AFB_PREDEFINED_TYPE_JSON: translate the string to its JSON representation. Example: the string HELLO produces "HELLO"

updaters

No updater

examples

In this first example, the created data is a static const C string:

   status = afb_create_data_raw(&data, AFB_PREDEFINED_TYPE_STRINGZ, "hello", 1+strlen("hello"), 0, 0);

In this second example, the created data is a copy of the other string value:

   status = afb_create_data_copy(&data, AFB_PREDEFINED_TYPE_STRINGZ, value, 1+strlen(value));

In this third example, the created data is a reference to field of value:

   status = afb_create_data_raw(&data, AFB_PREDEFINED_TYPE_STRINGZ, value->name, 1+strlen(value->name), unref_value, value);

Here the function unref_value is called when the created data is no more used, meaning that the value value->name isn’t needed anymore for the created data.

AFB_PREDEFINED_TYPE_JSON

Type of json string terminated by a zero, UTF8 or ASCII encoded.

length

The length in bytes including the tailing zero. A length of zero is compatible with an address of NULL value.

family

In the family of AFB_PREDEFINED_TYPE_STRINGZ.

It means that any data of type AFB_PREDEFINED_TYPE_JSON is also naturally of type AFB_PREDEFINED_TYPE_STRINGZ.

converters

  • to AFB_PREDEFINED_TYPE_OPAQUE: if the JSON string is a valid opaque representation of an opacified data, return that opacified data.

  • to AFB_PREDEFINED_TYPE_JSON_C: decode the JSON string to a json-c object and return a data holding it.

updaters

No updater

examples

AFB_PREDEFINED_TYPE_JSON_C

Type of json object as handled by libjson-c

length

The length is not used

family

No family

converters

  • to AFB_PREDEFINED_TYPE_OPAQUE: if the JSON string is a valid opaque representation of an opacified data, return that opacified data.

  • to AFB_PREDEFINED_TYPE_JSON: encode the json-c object to its JSON string representation and return a data holding it.

updaters

No updater

examples

AFB_PREDEFINED_TYPE_BOOL

Type of boolean values

length

Must be 1

family

No family

converters

  • to and from AFB_PREDEFINED_TYPE_JSON
  • to and from AFB_PREDEFINED_TYPE_JSON_C
  • to AFB_PREDEFINED_TYPE_I32
  • to AFB_PREDEFINED_TYPE_U32
  • to AFB_PREDEFINED_TYPE_I64
  • to AFB_PREDEFINED_TYPE_U64
  • to AFB_PREDEFINED_TYPE_DOUBLE

updaters

  • from AFB_PREDEFINED_TYPE_JSON
  • from AFB_PREDEFINED_TYPE_JSON_C
  • to AFB_PREDEFINED_TYPE_I32
  • to AFB_PREDEFINED_TYPE_U32
  • to AFB_PREDEFINED_TYPE_I64
  • to AFB_PREDEFINED_TYPE_U64
  • to AFB_PREDEFINED_TYPE_DOUBLE

examples

AFB_PREDEFINED_TYPE_I32

Type of signed 32 bit integers

length

Must be 4

family

No family

converters

  • to and from AFB_PREDEFINED_TYPE_JSON
  • to and from AFB_PREDEFINED_TYPE_JSON_C
  • to AFB_PREDEFINED_TYPE_I64
  • to AFB_PREDEFINED_TYPE_DOUBLE

updaters

  • from AFB_PREDEFINED_TYPE_JSON
  • from AFB_PREDEFINED_TYPE_JSON_C
  • to AFB_PREDEFINED_TYPE_I64
  • to AFB_PREDEFINED_TYPE_DOUBLE

examples

AFB_PREDEFINED_TYPE_U32

Type of unsigned 32 bit integers

length

Must be 4

family

No family

converters

  • to and from AFB_PREDEFINED_TYPE_JSON
  • to and from AFB_PREDEFINED_TYPE_JSON_C
  • to AFB_PREDEFINED_TYPE_I64
  • to AFB_PREDEFINED_TYPE_U64
  • to AFB_PREDEFINED_TYPE_DOUBLE

updaters

  • from AFB_PREDEFINED_TYPE_JSON
  • from AFB_PREDEFINED_TYPE_JSON_C
  • to AFB_PREDEFINED_TYPE_I64
  • to AFB_PREDEFINED_TYPE_U64
  • to AFB_PREDEFINED_TYPE_DOUBLE

examples

AFB_PREDEFINED_TYPE_I64

Type of signed 64 bit integers

length

Must be 8

family

No family

converters

  • to and from AFB_PREDEFINED_TYPE_JSON
  • to and from AFB_PREDEFINED_TYPE_JSON_C
  • to AFB_PREDEFINED_TYPE_DOUBLE

updaters

  • from AFB_PREDEFINED_TYPE_JSON
  • from AFB_PREDEFINED_TYPE_JSON_C
  • to AFB_PREDEFINED_TYPE_DOUBLE

examples

AFB_PREDEFINED_TYPE_U64

Type of unsigned 64 bit integers

length

Must be 8

family

No family

converters

  • to and from AFB_PREDEFINED_TYPE_JSON
  • to AFB_PREDEFINED_TYPE_DOUBLE

updaters

  • from AFB_PREDEFINED_TYPE_JSON
  • to AFB_PREDEFINED_TYPE_DOUBLE

examples

AFB_PREDEFINED_TYPE_DOUBLE

Type of doubles

length

Must be 8

family

No family

converters

  • to and from AFB_PREDEFINED_TYPE_JSON
  • to and from AFB_PREDEFINED_TYPE_JSON_C

updaters

  • from AFB_PREDEFINED_TYPE_JSON
  • from AFB_PREDEFINED_TYPE_JSON_C

examples