SG_BEGIN_DECL()
/** @addtogroup GRAS_dd Data description
- * @brief Describing data to be exchanged (Communication facility)
- *
- * @section Overview
+ * @brief Describing data to be exchanged
*
* Since GRAS takes care of potential representation conversion when the platform is heterogeneous,
* any data which transits on the network must be described beforehand.
*
* There is several possible interfaces for this, ranging from the really completely automatic parsing to
- * completely manual. Let's study each of them from the simplest to the more advanced.
+ * completely manual. Let's study each of them from the simplest to the more advanced:
*
- * \warning At least, I would like to present those sections in the right order, but doxygen prevents me
- * from doing so. There is a weird bug I fail to circumvent here. The right order is naturally:
- * -# basic operations
- * -# Automatic parsing
- * -# Simple manual definitions
- * -# Callback Persistant State: Simple push/pop mechanism
- * -# Callback Persistant State: Full featured mechanism
- */
-/* @{*/
-
-/** @name 1. basic operations
+ * - Section \ref GRAS_dd_basic presents how to retrieve and use an already described type.
+ * - Section \ref GRAS_dd_auto shows how to get GRAS parsing your type description automagically. This
+ * is unfortunately not always possible (only works for some structures), but if it is for your data,
+ * this is definitly the way to go.
+ * - Section \ref GRAS_dd_manual presents how to build a description manually. This is useful when you want
+ * to describe an array or a pointer of pre-defined structures.
+ * - You sometimes need to exchange informations between descriptions at send or receive time. This is
+ * for example useful when your structure contains an array which size is given by another field of the
+ * structure.
+ * - Section \ref GRAS_dd_cb_simple provides a simple interface to do so, allowing to share integers stored on a stack.
+ * - Section \ref GRAS_dd_cb_full provides a full featured interface to do so, but it may reveal somehow difficult to use.
+ **/
+
+/** @defgroup GRAS_dd_basic Basic operations on data descriptions
+ * @ingroup GRAS_dd
+ * \htmlonly <!-- DOXYGEN_NAVBAR_LABEL="Basics" --> \endhtmlonly
*
* If you only want to send pre-existing types, simply retrieve the pre-defined description with
* the \ref gras_datadesc_by_name function. Existing types entail:
* - char (both signed and unsigned)
* - int (short, regular, long and long long, both signed and unsigned)
* - float and double
- * - string (which is indeed a reference to a dynamically sized array of char, strlen being used to retrive the size)
+ * - string (which is indeed a reference to a dynamically sized array of char, strlen being used to retrieve the size)
*
* Example:\verbatim gras_datadesc_type_t i = gras_datadesc_by_name("int");
gras_datadesc_type_t uc = gras_datadesc_by_name("unsigned char");
gras_datadesc_type_t str = gras_datadesc_by_name("string");\endverbatim
+ *
*/
/* @{ */
/* @} */
-/** @name 2. Automatic parsing
+/** @defgroup GRAS_dd_auto Automatic parsing of data descriptions
+ * @ingroup GRAS_dd
+ * \htmlonly <!-- DOXYGEN_NAVBAR_LABEL="Automatic parsing" --> \endhtmlonly
*
* If you need to declare a new datatype, this is the simplest way to describe it to GRAS. Simply
* enclose its type definition into a \ref GRAS_DEFINE_TYPE macro call, and you're set. Here is
* It specifies that the structure s_array contains five fields, that the \a father field is a simple reference,
* that the size of the array pointed by \a data is the \a length field, and that the \a matrix field is an array
* which size is the result of \a rows times \a cols.
+ *
+ * \warning Since GRAS_DEFINE_TYPE is a macro, you shouldn't put any comma in your type definition
+ * (comma separates macro args). For example, change \verbatim int a, b;\endverbatim to \verbatim int a;
+int b;\endverbatim
+ *
+ * \section gras_dd_define \#define and fixed size array
+ *
+ * If you want to exchange arrays which size is given at compilation time by a
+ * \#defined constant, you need to keep GRAS informed. It would be done the
+ * following way:
+
+\verbatim #define BLOCK_SIZE 32
+GRAS_DEFINE_TYPE(s_toto,
+struct {
+ double data[BLOCK_SIZE];
+} s_toto;)
+
+void register_messages() {
+ gras_datadesc_type_t toto_type;
+
+ gras_datadesc_set_const("BLOCK_SIZE",BLOCK_SIZE);
+ toto_type = gras_datadesc_by_symbol(s_toto);
+}\endverbatim
+ *
+ * The form <tt>gras_datadesc_set_const("BLOCK_SIZE",BLOCK_SIZE);</tt> ensures
+ * that when you change the definition of the constant, GRAS keeps informed of
+ * the right value. Passing the numerical value of the constant as second
+ * argument would be a bad idea to that regard. Of course, the call to
+ * gras_datadesc_set_const() should come before any gras_datadesc_by_symbol()
+ * containing references to it.
+ *
+ * \section GRAS_dd_multidim Defining multidimentional arrays
*
- * \warning The mecanism for multidimensional arrays is known to be fragile and cumbersome. If you want to use it,
+ * The mecanism for multidimensional arrays is known to be fragile and cumbersome. If you want to use it,
* you have to understand how it is implemented: the multiplication is performed using the sizes stack. In previous example,
* a \ref gras_datadesc_cb_push_int callback is added to the \a rows field and a \ref gras_datadesc_cb_push_int_mult one is
- * added to \a cols. So, when the structure is sent, the rows field push its value onto the stack, then the \a cols field
- * retrieve this value from the stack, compute (and push) the multiplication value. The \a matrix field can then retrive this
+ * added to \a cols. So, when the structure is sent, the \a rows field push its value onto the stack, then the \a cols field
+ * retrieve this value from the stack, compute (and push) the multiplication value. The \a matrix field can then retrieve this
* value by poping the array. There is several ways for this to go wrong:
- * - if the matrix field is placed before the sizes, the right value won't get pushed into the stack soon enough. Reorder your structure fields if needed.
+ * - if the matrix field is placed before the sizes, the right value won't get pushed into the stack soon enough.
+ * Reorder your structure fields if needed.
* - if you write GRAS_ANNOTE(size,cols*rows); in previous example (inverting rows and cols in annotation),
* \a rows will be given a \ref gras_datadesc_cb_push_int_mult. This cannot work since it will try to
* pop the value which will be pushed by \a cols <i>afterward</i>.
* - if you have more than one matrix in your structure, don't interleave the size. They are pushed/poped in the structure order.
- * - if some of the sizes are used in more than one matrix, you cannot use this mecanism -- sorry.
+ * - if some of the sizes are used in more than one matrix, you cannot use this mecanism -- sorry.
*
* If you cannot express your datadescs with this mechanism, you'll have to use the more advanced
- * (and somehow complex) one described below.
+ * (and somehow complex) one described in the \ref GRAS_dd_cb_full.
*
- * \warning Since GRAS_DEFINE_TYPE is a macro, you shouldn't put any comma in your type definition
- * (comma separates macro args). For example, change \verbatim int a, b;\endverbatim to \verbatim int a;
- int b;\endverbatim
+ * \section GRAS_dd_multifile Projects spanning over multiple files
+ *
+ * GRAS_DEFINE_TYPE declares some symbols to work, it needs some special
+ * care when used in several files. In such case, you want the regular type
+ * definition in all files, but the gras specific symbol defined in only
+ * one file. For example, consider the following gras project sketch.
+ *
+\verbatim #include <gras.h>
+
+GRAS_DEFINE_TYPE(my_type,struct my_type {
+ int a;
+ int b;
+ double c;
+});
+
+int client(int argc, char *argv[]) {
+ ...
+}
+
+int server(int argc, char *argv[]) {
+ ...
+}\endverbatim
+ *
+ * If you want to split this in two files (one for each kind of processes),
+ * you need to put the GRAS_DEFINE_TYPE block in a separate header. But
+ * then you cannot include this right away in all files because the extra
+ * symbols would be defined in dupplicate.
+ *
+ * You thus have to decide in which file the symbols will live. In that
+ * file, include the header without restriction:
+ *
+\verbatim #include "my_header.h"
+
+int client(int argc, char *argv[]) {
+ ...
+}\endverbatim
+
+ * And in the other files needing the C definitions without the extra GRAS
+ * symbols, declare the symbol GRAS_DEFINE_TYPE_EXTERN before:
+ *
+\verbatim #define GRAS_DEFINE_TYPE_EXTERN
+#include "my_header.h"
+
+int server(int argc, char *argv[]) {
+ ...
+}\endverbatim
+
+ *
*/
/** @{ */
* @hideinitializer
*/
#define GRAS_DEFINE_TYPE(name,def) \
- static const char * _gras_this_type_symbol_does_not_exist__##name=#def; def
-
+ const char * _gras_this_type_symbol_does_not_exist__##name=#def; def
+
+#ifndef DOXYGEN_SKIP /* doxygen don't like macro fun too much */
+# ifdef GRAS_DEFINE_TYPE_EXTERN
+# undef GRAS_DEFINE_TYPE
+# define GRAS_DEFINE_TYPE(name,def) def
+# undef GRAS_DEFINE_TYPE_EXTERN
+# endif
+#endif
+
+/** @brief if this symbol is defined, the \a GRAS_DEFINE_TYPE symbols live in another file.
+ * @hideinitializer
+ */
+#define GRAS_DEFINE_TYPE_EXTERN 1
+
+
+
/** @brief Retrieve a datadesc which was previously parsed
* @hideinitializer
*/
* @brief Add an annotation to a type to be automatically parsed
*/
#define GRAS_ANNOTE(key,val)
+
+/** @brief Defines the value of a define to the datatype parsing infrastructure
+ */
+void gras_datadesc_set_const(const char*name, int value);
/* @} */
gras_datadesc_type_t
gras_datadesc_parse(const char *name, const char *C_statement);
-/** @name 3. Simple manual definitions
+/** @defgroup GRAS_dd_manual Simple manual data description
+ * @ingroup GRAS_dd
*
* Here are the functions to use if you want to declare your description manually.
* The function names should be self-explanatory in most cases.
/* @} */
-/** @name 4. Callback Persistant State: Simple push/pop mechanism
+/** @defgroup GRAS_dd_cb_simple Data description with Callback Persistant State: Simple push/pop mechanism
+ * @ingroup GRAS_dd
*
* Sometimes, one of the callbacks need to leave information for the next ones. If this is a simple integer (such as
* an array size), you can use the functions described here. If not, you'll have to play with the complete cbps interface.
*
+ * \htmlonly <!-- DOXYGEN_NAVBAR_LABEL="Simple push/pop Callback State" -->\endhtmlonly
*
* Here is an example:\verbatim
struct s_array {
/* @} */
-/** @name 5. Callback Persistant State: Full featured mechanism
+/** @defgroup GRAS_dd_cb_full Data description with Callback Persistant State: Full featured interface
+ * @ingroup GRAS_dd
*
- * Sometimes, one of the callbacks need to leave information for the next ones. If the simple push/pop mechanism
- * introduced in previous section isn't enough, you can always use this full featured one.
+ * Sometimes, one of the callbacks need to leave information for the next
+ * ones. If the simple push/pop mechanism introduced in previous section
+ * isn't enough, you can always use this full featured one. The bad point is
+ * that it is quite badly documented...
+ *
+ * \htmlonly <!-- DOXYGEN_NAVBAR_LABEL="Full featured Callback State" -->\endhtmlonly
+ *
*/
/* @{ */