NAME
wchar_t_net_size - Calculates the necessary buffer size for code set
conversion from a local code set to a network code
set
Used by client and server applications.
SYNOPSIS
#include <dce/rpc.h>
void wchar_t_net_size( rpc_binding_handle_t binding,
unsigned32 network_code_set_value,
unsigned32 local_buffer_size,
idl_cs_convert_t *conversion_type,
unsigned32 *network_buffer_size,
error_status_t *status );
PARAMETERS
Input
binding
Specifies the target binding handle from which to obtain buffer
size evaluation information. When called from the client stub,
this value is the binding handle of a compatible server returned
by the rpc_ns_binding_import_next() or rpc_ns_binding_select()
routine. When called from the server stub, this value is a
pointer to binding infor mation that the client stub passed in
the RPC call.
network_code_set_value
The registered hexadecimal integer value that represents the code
set to be used to transmit character data over the network. In
general, the "network" code set is the code set that the client
application's code sets evaluation routine has determined to be
compatible for this client and server. When the caller is the
client stub, this value is the sending tag. When the caller is
the server stub, this value is the receiving tag.
local_buffer_size
The size, in units of wchar_t, of the buffer that is allocated
for the international character data. This value is the local
value of the size_is variable for the array; that is, the value
is the size of the marshalled string if no conversion is done.
Output
conversion_type
A pointer to the enumerated type defined in dce/idlbase.h that
indicates whether data conversion is necessary and whether or
not the existing buffer is sufficient for storing the results of
the conversion. Because wchar_t to cs_byte conversion always
takes place, and because wchar_t and cs_byte are different units,
the conversion type returned is always idl_cs_new_buffer_convert,
which means that the converted data must be written to a new
buffer.
network_buffer_size
A pointer to the buffer size that needs to be allocated to contain
the converted data, in units of idl_byte. This value is to be used
as the network value of the size_is variable for the array, and is
non-NULL only if a conformant or conformant varying array is to be
marshalled. A value of NULL in this parameter indicates that a
fixed or varying array is to be marshalled.
status
Returns the status code from this routine. This status code
indicates whether the routine completed successfully or, if not,
why not.
The possible status codes and their meanings are as follows:
rpc_s_ok Success.
rpc_s_ss_incompatible_codesets
The specified code set does not match the code set
specified in the sending tag in the binding handle.
If this error occurs in the server stub, an exception
is raised to the client application.
When invoked from the server stub, this routine calls the routines
dcs_cs_loc_to_rgy() and rpc_rgy_get_max_bytes(). If either of these
routines returns an error, the wchar_t_net_size() routine raises an
exception to the client application.
DESCRIPTION
The wchar_t_net_size() routine belongs to a set of DCE RPC routines
for use by client and server applications that are transferring
international character data in a heterogeneous character set and
code sets environment.
The wchar_t_net_size() routine is one of the DCE RPC buffer sizing
routines that RPC stubs use before they marshall or unmarshall data
to determine whether or not the buffers allocated for code set
conversion need to be enlarged to hold the converted data. The
buffer sizing routines determine the type of conversion required
and calculate the size of the necessary buffer (if a conformant or
conformant varying array is to be marshalled). The RPC stub then
allocates a buffer of that size before it calls one of the code set
conversion routines.
Client and server stubs call the wchar_t_*_size routines when the
wchar_t type has been specified as the local data type with the
cs_char attribute in the attribute configuration file for the
application. Applications do not call the wchar_t_net_size() routine
directly. Client and server stubs call the routine before they
marshall any data. The stubs pass the routine a binding handle and a
code set value that identifies the code set to be used to transfer
international character data over the network. The stubs also specify
the local storage size of the data, in units of wchar_t.
When called from a client stub, the wchar_t_net_size routine
determines the value of conversion_type from conversion method and
tag information set up in the binding handle by a code sets
evaluation routine or a tag-setting routine. Since wchar_t and
idl_byte are completely different data types, the routine always
sets the value to idl_cs_new_buffer_convert. The routine sets the
conversion_type parameter to this value and, if a conformant or
conformant varying array is to be marshalled, calculates a new
buffer size by multiplying the value of local_buffer_size by the
byte size for wchar_t. The routine returns the new buffer size in
the network_buffer_size parameter. The size is specified in units
of idl_byte, which is the network representation used for
international character data.
In cases where the binding handle does not contain the results of
character and code sets evaluation, or where it is being called from
the server stub, the wchar_t_net_size routine determines the value of
conversion_type itself using the local code set value and the code set
value passed in the network_code_set_value parameter, and returns the
appropriate conversion_type value. If a conformant or conformant
varying array is to be marshalled, and the routine finds that a new
buffer is required to hold the converted data, the routine calculates
the size of this new buffer (by multiplying the value of
local_buffer_size by sizeof(wchar_t); that is, the number of bytes
required to encode one wchar_t data type, returns the results, in
units of idl_byte, in network_buffer_size.
Permissions Required
No permissions are required.
RETURN VALUES
No value is returned.
RELATED INFORMATION
Functions: byte_local_size
byte_net_size
wchar_t_local_size