acmStreamSize
The acmStreamSize
function returns a recommended size for a source or destination buffer on an
ACM stream.
MMRESULT acmStreamSize(
|
HACMSTREAM
has, |
|
|
DWORD cbInput, |
|
|
LPDWORD pdwOutputBytes, |
|
|
DWORD fdwSize |
|
|
); |
|
Parameters
has
Handle of the
conversion stream.
cbInput
Size, in
bytes, of the source or destination buffer. The fdwSize flags specify what
the input parameter defines. This parameter must be nonzero.
pdwOutputBytes
Address of a
variable that contains the size, in bytes, of the source or destination buffer.
The fdwSize flags specify what the output parameter defines. If the acmStreamSize
function succeeds, this location will always be filled with a nonzero value.
fdwSize
Flags for the
stream size query. The following values are defined:
ACM_STREAMSIZEF_DESTINATION
The cbInput
parameter contains the size of the destination buffer. The pdwOutputBytes
parameter will receive the recommended source buffer size, in bytes.
ACM_STREAMSIZEF_SOURCE
The cbInput
parameter contains the size of the source buffer. The pdwOutputBytes
parameter will receive the recommended destination buffer size, in bytes.
Return Values
Returns zero
if successful or an error otherwise. Possible error values include the
following:
|
ACMERR_NOTPOSSIBLE |
The
requested operation cannot be performed. |
|
MMSYSERR_INVALFLAG |
At least
one flag is invalid. |
|
MMSYSERR_INVALHANDLE |
The specified
handle is invalid. |
|
MMSYSERR_INVALPARAM |
At least
one parameter is invalid. |
Remarks
An
application can use this function to determine suggested buffer sizes for
either source or destination buffers. The buffer sizes returned might be only
an estimation of the actual sizes required for conversion. Because actual
conversion sizes cannot always be determined without performing the conversion,
the sizes returned will usually be overestimated.
In the event
of an error, the location pointed to by pdwOutputBytes will receive
zero. This assumes that the pointer specified by pdwOutputBytes is
valid.