--- /dev/null
+/****************************************************************************
+ * Copyright (c) 2008 Free Software Foundation, Inc. *
+ * *
+ * Permission is hereby granted, free of charge, to any person obtaining a *
+ * copy of this software and associated documentation files (the *
+ * "Software"), to deal in the Software without restriction, including *
+ * without limitation the rights to use, copy, modify, merge, publish, *
+ * distribute, distribute with modifications, sublicense, and/or sell *
+ * copies of the Software, and to permit persons to whom the Software is *
+ * furnished to do so, subject to the following conditions: *
+ * *
+ * The above copyright notice and this permission notice shall be included *
+ * in all copies or substantial portions of the Software. *
+ * *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS *
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. *
+ * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, *
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR *
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR *
+ * THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
+ * *
+ * Except as contained in this notice, the name(s) of the above copyright *
+ * holders shall not be used in advertising or otherwise to promote the *
+ * sale, use or other dealings in this Software without prior written *
+ * authorization. *
+ ****************************************************************************/
+
+/***************************************************************************
+* *
+* Author : Juergen Pfeifer *
+* *
+***************************************************************************/
+
+#include "form.priv.h"
+
+MODULE_ID("$Id: fty_generic.c,v 1.1 2008/11/18 08:50:04 juergen Exp $")
+
+/*
+ * This is not a full implementation of a field type, but adds some
+ * support for higher level languages with some restrictions to interop
+ * with C language. Especially the collection of arguments for the
+ * various fieldtypes is not based on the vararg C mechanism, but on a
+ * iterator based callback mechanism that allowes the high level language
+ * to provide the arguments as a structure. Most languages have mechanisms
+ * to layout structures so that they can be passed to C.
+ * The languages can register a new generic fieldtype dynamically and store
+ * a handle (key) to the calling object as an argument. Together with that
+ * it can register a freearg callback, so that the high level language
+ * remains in control of the memory management of the arguments they pass.
+ * The design idea is, that the high-level language - typically a OO
+ * language like C# or Java, uses it's own dispatching mechanisms
+ * (polymorphism) to call the proper check routines responsible for the
+ * argument type. So these language implement typically only one generic
+ * fieldtype they register with the forms library using this call.
+ *
+ * For that purpose we have extended the fieldtype struc by a new element
+ * that gets the arguments from a single struct passed by the caller.
+ *
+ */
+
+
+/*---------------------------------------------------------------------------
+| Facility : libnform
+| Function : static void *Generic_This_Type( void * arg )
+|
+| Description : We interpret the passed arg just as a handle the
+| calling language uses to keep track of its allocated
+| argument structures. We can simply copy it back.
+|
+| Return Values : Pointer to argument structure
++--------------------------------------------------------------------------*/
+static void *
+Generic_This_Type(void *arg)
+{
+ return (arg);
+}
+
+/*---------------------------------------------------------------------------
+| Facility : libnform
+| Function : FIELDTYPE *_nc_generic_fieldtype(
+| bool (* const field_check)(FIELD *,const void *),
+| bool (* const char_check) (int, const void *),
+| bool (*const next)(FORM*,FIELD*,const void*),
+| bool (*const prev)(FORM*,FIELD*,const void*),
+| void (*freecallback)(void*))
+|
+| Description : Create a new fieldtype. The application programmer must
+| write a field_check and a char_check function and give
+| them as input to this call. A callback to allow the
+| release of the allocated memory must also be provided.
+| For generic field types, we provide some more
+| information about the field as parameters.
+|
+| If an error occurs, errno is set to
+| E_BAD_ARGUMENT - invalid arguments
+| E_SYSTEM_ERROR - system error (no memory)
+|
+| Return Values : Fieldtype pointer or NULL if error occurred
++--------------------------------------------------------------------------*/
+NCURSES_EXPORT(FIELDTYPE *)
+_nc_generic_fieldtype(bool (*const field_check) (FORM*, FIELD *, const void *),
+ bool (*const char_check) (int, FORM*, FIELD*, const void *),
+ bool (*const next)(FORM*, FIELD*,const void*),
+ bool (*const prev)(FORM*, FIELD*,const void*),
+ void (*freecallback)(void*))
+{
+ int code = E_SYSTEM_ERROR;
+ FIELDTYPE* res = (FIELDTYPE*)0;
+
+ T((T_CALLED("_nc_generic_fieldtype(%p,%p,%p,%p,%p)"),
+ field_check, char_check, next, prev, freecallback));
+
+ if (field_check || char_check)
+ {
+ res = typeMalloc(FIELDTYPE,1);
+ if (res)
+ {
+ *res = *_nc_Default_FieldType;
+ res->status |= (_HAS_ARGS | _GENERIC);
+ res->fieldcheck.gfcheck = field_check;
+ res->charcheck.gccheck = char_check;
+ res->genericarg = Generic_This_Type;
+ res->freearg = freecallback;
+ res->enum_next.gnext = next;
+ res->enum_prev.gprev = prev;
+ code = E_OK;
+ }
+ }
+ else
+ code = E_BAD_ARGUMENT;
+
+ if (E_OK != code)
+ SET_ERROR(code);
+
+ returnFieldType(res);
+}
+
+
+/*---------------------------------------------------------------------------
+| Facility : libnform
+| Function : static TypeArgument *GenericArgument(
+| const FIELDTYPE* typ,
+| int (*argiterator)(void**),
+| int* err)
+|
+| Description : The iterator callback must browse through all fieldtype
+| parameters that have an argument associated with the
+| type. The iterator returns 1 if the operation to get
+| the next element was successfull, 0 otherwise. If the
+| iterator could move to the next argument, it fills
+| the void* pointer representing the argument into the
+| location provided as argument to the iterator.
+| The err reference is used to keep track of errors.
+|
+| Return Values : Pointer to argument structure
++--------------------------------------------------------------------------*/
+static TypeArgument*
+GenericArgument(const FIELDTYPE *typ,
+ int (*argiterator)(void**), int *err)
+{
+ TypeArgument *res = (TypeArgument *)0;
+
+ if (typ!=0 && (typ->status & _HAS_ARGS) != 0 && err!=0 && argiterator != 0)
+ {
+ if (typ->status & _LINKED_TYPE)
+ {
+ /* Composite fieldtypes keep track internally of their own memory */
+ TypeArgument* p = typeMalloc(TypeArgument,1);
+ if (p)
+ {
+ p->left = GenericArgument(typ->left, argiterator, err);
+ p->right = GenericArgument(typ->right, argiterator, err);
+ return p;
+ }
+ else
+ *err += 1;
+ }
+ else
+ {
+ assert(typ->genericarg != (void*)0);
+ if (typ->genericarg == 0)
+ *err += 1;
+ else
+ {
+ void* argp;
+ int valid = argiterator(&argp);
+ if (valid==0 || argp==0 ||
+ !(res = (TypeArgument*)typ->genericarg(argp)))
+ {
+ *err += 1;
+ }
+ }
+ }
+ }
+ return res;
+}
+
+/*---------------------------------------------------------------------------
+| Facility : libnform
+| Function : int _nc_set_generic_fieldtype(
+| FIELD* field,
+| FIELDTYPE* ftyp,
+| int (*argiterator)(void**))
+|
+| Description : Assign the fieldtype to the field and use the iterator
+| mechanism to get the arguments when a check is
+| performed.
+|
+| Return Values : E_OK if all went well
+| E_SYSTEM_ERROR if an error occurred
++--------------------------------------------------------------------------*/
+NCURSES_EXPORT(int)
+_nc_set_generic_fieldtype(FIELD *field,
+ FIELDTYPE* ftyp,
+ int (*argiterator)(void**))
+{
+ int code = E_SYSTEM_ERROR;
+ int err = 0;
+
+ if (field)
+ {
+ if (field && field->type)
+ _nc_Free_Type(field);
+
+ field->type = ftyp;
+ if (ftyp)
+ {
+ if (argiterator)
+ {
+ /* The precondition is that the iterator is reset */
+ field->arg = (void*)GenericArgument(field->type,argiterator,&err);
+
+ if (err)
+ {
+ _nc_Free_Argument(field->type, (TypeArgument*)(field->arg));
+ field->type = (FIELDTYPE*)0;
+ field->arg = (void*)0;
+ }
+ else
+ {
+ code = E_OK;
+ if (field->type)
+ field->type->ref++;
+ }
+ }
+ }
+ else
+ {
+ field->arg = (void*)0;
+ code = E_OK;
+ }
+ }
+ return code;
+}
+
+/*---------------------------------------------------------------------------
+| Facility : libnform
+| Function : WINDOW* _nc_form_cursor(
+| FORM* form,
+| int *pRow, int *pCol)
+|
+| Description : Get the current position of the form cursor position
+| We also return the field window
+|
+| Return Values : The fields Window or NULL on error
++--------------------------------------------------------------------------*/
+NCURSES_EXPORT(WINDOW*)
+_nc_form_cursor(const FORM* form, int* pRow, int* pCol)
+{
+ int code = E_SYSTEM_ERROR;
+ WINDOW* res = (WINDOW*)0;
+
+ if (!(form==0 || pRow==0 || pCol==0))
+ {
+ *pRow = form->currow;
+ *pCol = form->curcol;
+ res = form->w;
+ code = E_OK;
+ }
+ if (code != E_OK)
+ SET_ERROR(code);
+ return res;
+}
+
+
+/* fty_generic.c ends here */
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