In the context of this interface the term `data set' refers to a list of `named MPI values' that is used by functions performing cryptographic operations; a named MPI value is a an MPI value, associated with a label.
Such data sets are used for representing keys, since keys simply consist of a variable amount of numbers. Furthermore some functions return data sets to the caller that are to be provided to other functions.
This section documents the data types, symbols and functions that are relevant for working with data sets.
The following flags are supported:
Creates a new, empty data set and stores it in data.
Add the value mpi to data with the label name. If flags contains GCRY_AC_FLAG_COPY, the data set will contain copies of name and mpi. If flags contains GCRY_AC_FLAG_DEALLOC or GCRY_AC_FLAG_COPY, the values contained in the data set will be deallocated when they are to be removed from the data set.
Create a copy of the data set data and store it in data_cp. FIXME: exact semantics undefined.
Returns the number of named MPI values inside of the data set data.
Store the value labelled with name found in data in mpi. If flags contains GCRY_AC_FLAG_COPY, store a copy of the mpi value contained in the data set. mpi may be NULL (this might be useful for checking the existence of an MPI with extracting it).
Stores in name and mpi the named mpi value contained in the data set data with the index idx. If flags contains GCRY_AC_FLAG_COPY, store copies of the values contained in the data set. name or mpi may be NULL.
Destroys any values contained in the data set data.
This function converts the data set data into a newly created S-Expression, which is to be stored in sexp; identifiers is a NULL terminated list of C strings, which specifies the structure of the S-Expression.
If identifiers is a list of pointers to the strings “foo” and “bar” and if data is a data set containing the values “val1 = 0x01” and “val2 = 0x02”, then the resulting S-Expression will look like this: (foo (bar ((val1 0x01) (val2 0x02))).
This function converts the S-Expression sexp into a newly created data set, which is to be stored in data; identifiers is a NULL terminated list of C strings, which specifies the structure of the S-Expression. If the list of identifiers does not match the structure of the S-Expression, the function fails.