"""Buffers used to hold null-terminated strings."""

from bgenBuffer import FixedOutputBufferType

from bgenStackBuffer import StackOutputBufferType

from bgenHeapBuffer import HeapOutputBufferType

class StringBufferMixIn:

    """Mix-in class to create various string buffer types.

    Strings are character arrays terminated by a null byte.

    (For input, this is also covered by stringptr.)

    For output, there are again three variants:

    - Fixed: size is a constant given in the documentation; or

    - Stack: size is passed to the C function but we decide on a size at

      code generation time so we can still allocate on the heap); or

    - Heap: size is passed to the C function and we let the Python caller

      pass a size.

    (Note that this doesn't cover output parameters in which a string

    pointer is returned.  These are actually easier (no allocation) but far

    less common.  I'll write the classes when there is demand.)

    """

    def getSizeDeclarations(self, name):

        return []

    def getAuxDeclarations(self, name):

        return []

    def getargsFormat(self):

        return "s"

    def getargsArgs(self, name):

        return "&%s__in__" % name

    def mkvalueFormat(self):

        return "s"

    def mkvalueArgs(self, name):

        return "%s__out__" % name

class FixedOutputStringType(StringBufferMixIn, FixedOutputBufferType):

    """Null-terminated output string -- passed without size.

    Instantiate with buffer size as parameter.

    """

class StackOutputStringType(StringBufferMixIn, StackOutputBufferType):

    """Null-terminated output string -- passed as (buffer, size).

    Instantiate with buffer size as parameter.

    """

class HeapOutputStringType(StringBufferMixIn, HeapOutputBufferType):

    """Null-terminated output string -- passed as (buffer, size).

    Instantiate without parameters.

    Call from Python with buffer size.

    """