static GslErrorType
wave_handle_open (GslDataHandle *data_handle,
GslDataHandleSetup *setup)
{
WaveHandle *whandle = (WaveHandle*) data_handle;
whandle->hfile = gsl_hfile_open (whandle->dhandle.name);
if (!whandle->hfile)
return gsl_error_from_errno (errno, GSL_ERROR_OPEN_FAILED);
else
{
GslLong l, fwidth = wave_format_byte_width (whandle->format);
/* convert size into n_values, i.e. float length */
l = whandle->hfile->n_bytes;
l -= MIN (l, whandle->byte_offset);
if (l >= fwidth)
{
l /= fwidth;
if (whandle->requested_length < 0)
setup->n_values = l;
else
setup->n_values = MIN (l, whandle->requested_length);
}
else
setup->n_values = 0;
setup->n_channels = whandle->n_channels;
setup->bit_depth = wave_format_bit_depth (whandle->format);
return GSL_ERROR_NONE;
}
}
/**
* @param file_name name of the file to open
* @return a new opened #GslRFile or NULL if an error occoured (errno set)
*
* Open a file for reading and create a GSL read only file handle for it.
* The motivation for using a #GslRFile over normal unix files
* is to reduce the amount of opened unix file descriptors by using
* a #GslHFile for the actual IO.
*/
GslRFile*
gsl_rfile_open (const gchar *file_name)
{
GslHFile *hfile = gsl_hfile_open (file_name);
GslRFile *rfile;
if (!hfile)
rfile = NULL;
else
{
rfile = sfi_new_struct0 (GslRFile, 1);
rfile->hfile = hfile;
rfile->offset = 0;
}
return rfile;
}