bgenstackbuffer.py

reduced python source for embedded apps

"""Buffers allocated on the stack."""


from bgenBuffer import FixedInputBufferType, FixedOutputBufferType


class StackOutputBufferType(FixedOutputBufferType):

	"""Fixed output buffer allocated on the stack -- passed as (buffer, size).

	Instantiate with the buffer size as parameter.
	"""

	def passOutput(self, name):
		return "%s__out__, %s" % (name, self.size)


class VarStackOutputBufferType(StackOutputBufferType):

	"""Output buffer allocated on the stack -- passed as (buffer, &size).

	Instantiate with the buffer size as parameter.
	"""

	def declareSize(self, name):
		Output("int %s__len__ = %s;", name, self.size)

	def passOutput(self, name):
		return "%s__out__, &%s__len__" % (name, name)

	def mkvalueArgs(self, name):
		return "%s__out__, (int)%s__len__" % (name, name)


class VarVarStackOutputBufferType(VarStackOutputBufferType):

	"""Output buffer allocated on the stack -- passed as (buffer, size, &size).

	Instantiate with the buffer size as parameter.
	"""

	def passOutput(self, name):
		return "%s__out__, %s__len__, &%s__len__" % (name, name, name)


class ReturnVarStackOutputBufferType(VarStackOutputBufferType):

	"""Output buffer allocated on the stack -- passed as (buffer, size) -> size.

	Instantiate with the buffer size as parameter.
	The function's return value is the size.
	(XXX Should have a way to suppress returning it separately, too.)
	"""

	def passOutput(self, name):
		return "%s__out__, %s__len__" % (name, name)

	def mkvalueArgs(self, name):
		return "%s__out__, (int)_rv" % name