Typically, a stream is destroyed, recreated, and then associated with a new file. However, you can bypass these steps and reassociate a new file with an existing stream as long as the file is of the same data type as the stream was created to handle. For example, in the case of waveaudio, if you had a 16-bit 11KB WAVE stream, the file you want to associate with the stream must be of the same data type and sub type.
Note that only one data object may be associated with a stream once the stream is created, and it is specific to a particular stream handler (source or target). Associations may be changed, but the stream cannot be active; it must be stopped first (discard stop, flush stop, or EOS).
/*************************************************
* Reassociate The Stream Handlers with the new
* stream object if the stream has been created
* in the correct direction already.
*************************************************/
if (ulpInstance->ulCreateFlag == PREROLL_STATE)
{
/*********************************************
* Fill in Associate Control Block Info for
* file system stream handler (FSSH). FSSH will
* use the mmio handle we are associating to
* stream information.
*********************************************/
ulpInstance->StreamInfo.acbmmio.ulObjType = ACBTYPE_MMIO;
ulpInstance->StreamInfo.acbmmio.ulACBLen = sizeof (ACB_MMIO);
ulpInstance->StreamInfo.acbmmio.hmmio = ulpInstance->hmmio;
/***********************************************
* Associate FileSystem as source if Playing. Note
* the association is always done with the file
* system stream handler since it is involved with
* mmio operations. If you try this with the
* audio stream handler, you will get invalid
* handle back.
***********************************************/
if (AMPMIX.ulOperation == OPERATION_PLAY)
{
ulrc = SpiAssociate ( ulpInstance->StreamInfo.hStream,
ulpInstance->StreamInfo.hidASource,
(PVOID) &ulpInstance->StreamInfo.acbmmio );
}
/***********************************************
* Associate FileSystem as target if recording
***********************************************/
else
{
ulrc = SpiAssociate ( ulpInstance->StreamInfo.hStream,
ulpInstance->StreamInfo.hidATarget,
(PVOID) &ulpInstance->StreamInfo.acbmmio );
} /* else we are in record mode */