-#ifndef CCAN_CAST_IF_TYPE_H
-#define CCAN_CAST_IF_TYPE_H
+/* CC0 (Public domain) - see LICENSE file for details */
+#ifndef CCAN_TYPESAFE_CB_H
+#define CCAN_TYPESAFE_CB_H
#include "config.h"
#if HAVE_TYPEOF && HAVE_BUILTIN_CHOOSE_EXPR && HAVE_BUILTIN_TYPES_COMPATIBLE_P
/**
- * cast_if_type - only cast an expression if test matches a given type
+ * typesafe_cb_cast - only cast an expression if it matches a given type
* @desttype: the type to cast to
- * @expr: the expression to cast
- * @test: the expression to test
* @oktype: the type we allow
+ * @expr: the expression to cast
*
* This macro is used to create functions which allow multiple types.
* The result of this macro is used somewhere that a @desttype type is
- * expected: if @test is exactly of type @oktype, then @expr will be
+ * expected: if @expr is exactly of type @oktype, then it will be
* cast to @desttype type, otherwise left alone.
*
* This macro can be used in static initializers.
*
* This is merely useful for warnings: if the compiler does not
- * support the primitives required for cast_if_type(), it becomes an
- * unconditional cast, and the @test and @oktype argument is not used. In
- * particular, this means that @oktype can be a type which uses
- * the "typeof": it will not be evaluated if typeof is not supported.
+ * support the primitives required for typesafe_cb_cast(), it becomes an
+ * unconditional cast, and the @oktype argument is not used. In
+ * particular, this means that @oktype can be a type which uses the
+ * "typeof": it will not be evaluated if typeof is not supported.
*
* Example:
* // We can take either an unsigned long or a void *.
* void _set_some_value(void *val);
* #define set_some_value(e) \
- * _set_some_value(cast_if_type(void *, (e), (e), unsigned long))
+ * _set_some_value(typesafe_cb_cast(void *, unsigned long, (e)))
*/
-#define cast_if_type(desttype, expr, test, oktype) \
- __builtin_choose_expr(__builtin_types_compatible_p(typeof(test), oktype), \
- (desttype)(expr), (expr))
+#define typesafe_cb_cast(desttype, oktype, expr) \
+ __builtin_choose_expr( \
+ __builtin_types_compatible_p(__typeof__(0?(expr):(expr)), \
+ oktype), \
+ (desttype)(expr), (expr))
#else
-#define cast_if_type(desttype, expr, test, oktype) ((desttype)(expr))
+#define typesafe_cb_cast(desttype, oktype, expr) ((desttype)(expr))
#endif
/**
- * cast_if_any - only cast an expression if it is one of the three given types
+ * typesafe_cb_cast3 - only cast an expression if it matches given types
* @desttype: the type to cast to
- * @expr: the expression to cast
- * @test: the expression to test
* @ok1: the first type we allow
* @ok2: the second type we allow
* @ok3: the third type we allow
+ * @expr: the expression to cast
*
- * This is a convenient wrapper for multiple cast_if_type() calls. You can
- * chain them inside each other (ie. use cast_if_any() for expr) if you need
- * more than 3 arguments.
+ * This is a convenient wrapper for multiple typesafe_cb_cast() calls.
+ * You can chain them inside each other (ie. use typesafe_cb_cast()
+ * for expr) if you need more than 3 arguments.
*
* Example:
* // We can take either a long, unsigned long, void * or a const void *.
* void _set_some_value(void *val);
* #define set_some_value(expr) \
- * _set_some_value(cast_if_any(void *, (expr), (expr), \
- * long, unsigned long, const void *))
+ * _set_some_value(typesafe_cb_cast3(void *,, \
+ * long, unsigned long, const void *,\
+ * (expr)))
*/
-#define cast_if_any(desttype, expr, test, ok1, ok2, ok3) \
- cast_if_type(desttype, \
- cast_if_type(desttype, \
- cast_if_type(desttype, (expr), (test), ok1), \
- (test), \
- ok2), \
- (test), \
- ok3)
+#define typesafe_cb_cast3(desttype, ok1, ok2, ok3, expr) \
+ typesafe_cb_cast(desttype, ok1, \
+ typesafe_cb_cast(desttype, ok2, \
+ typesafe_cb_cast(desttype, ok3, \
+ (expr))))
/**
* typesafe_cb - cast a callback function if it matches the arg
* @rtype: the return type of the callback function
+ * @atype: the (pointer) type which the callback function expects.
* @fn: the callback function to cast
* @arg: the (pointer) argument to hand to the callback function.
*
* If a callback function takes a single argument, this macro does
- * appropriate casts to a function which takes a single void * argument if the
- * callback provided matches the @arg (or a const or volatile version).
- *
- * It is assumed that @arg is of pointer type: usually @arg is passed
- * or assigned to a void * elsewhere anyway.
- *
- * This will not work with a NULL @fn argument: see typesafe_cb_def or
- * typesafe_cb_exact.
- *
- * Example:
- * void _register_callback(void (*fn)(void *arg), void *arg);
- * #define register_callback(fn, arg) \
- * _register_callback(typesafe_cb(void, (fn), (arg)), (arg))
- */
-#define typesafe_cb(rtype, fn, arg) \
- cast_if_type(rtype (*)(void *), (fn), (fn)(arg), rtype)
-
-/**
- * typesafe_cb_def - cast a callback fn if it matches arg (of defined type)
- * @rtype: the return type of the callback function
- * @fn: the callback function to cast
- * @arg: the (pointer) argument to hand to the callback function.
- *
- * This is typesafe_cb(), except the type must be defined (eg. if it's
- * struct foo *, the definition of struct foo must be visible). For many
- * applications, this is reasonable.
- *
- * This variant can accept @fn equal to NULL.
- *
- * Example:
- * void _register_callback(void (*fn)(void *arg), void *arg);
- * #define register_callback(fn, arg) \
- * _register_callback(typesafe_cb_def(void, (fn), (arg)), (arg))
- */
-#define typesafe_cb_def(rtype, fn, arg) \
- cast_if_any(rtype (*)(void *), (fn), &*(fn), \
- rtype (*)(typeof(*arg)*), \
- rtype (*)(const typeof(*arg)*), \
- rtype (*)(volatile typeof(*arg)*))
-
-/**
- * typesafe_cb_exact - cast a callback fn if it exactly matches arg
- * @rtype: the return type of the callback function
- * @fn: the callback function to cast
- * @arg: the (pointer) argument to hand to the callback function.
- *
- * This is typesafe_cb(), except the @fn can be NULL, or must exactly match
- * the @arg type (no const or volatile).
- *
- * Example:
- * void _register_callback(void (*fn)(void *arg), void *arg);
- * #define register_callback(fn, arg) \
- * _register_callback(typesafe_cb_exact(void, (fn), (arg)), (arg))
- */
-#define typesafe_cb_exact(rtype, fn, arg) \
- cast_if_type(rtype (*)(void *), (fn), &*(fn), rtype (*)(typeof(arg)))
-
-/**
- * typesafe_cb_const - cast a const callback function if it matches the arg
- * @rtype: the return type of the callback function
- * @fn: the callback function to cast
- * @arg: the (pointer) argument to hand to the callback function.
- *
- * If a callback function takes a single argument, this macro does appropriate
- * casts to a function which takes a single const void * argument if the
+ * appropriate casts to a function which takes a single atype argument if the
* callback provided matches the @arg.
*
* It is assumed that @arg is of pointer type: usually @arg is passed
* or assigned to a void * elsewhere anyway.
*
* Example:
- * void _register_callback(void (*fn)(const void *arg), const void *arg);
+ * void _register_callback(void (*fn)(void *arg), void *arg);
* #define register_callback(fn, arg) \
- * _register_callback(typesafe_cb_const(void, (fn), (arg)), (arg))
+ * _register_callback(typesafe_cb(void, (fn), void*, (arg)), (arg))
*/
-#define typesafe_cb_const(rtype, fn, arg) \
- cast_if_type(rtype (*)(const void *), (fn), (fn)(arg), rtype)
+#define typesafe_cb(rtype, atype, fn, arg) \
+ typesafe_cb_cast(rtype (*)(atype), \
+ rtype (*)(__typeof__(arg)), \
+ (fn))
/**
* typesafe_cb_preargs - cast a callback function if it matches the arg
* @rtype: the return type of the callback function
+ * @atype: the (pointer) type which the callback function expects.
* @fn: the callback function to cast
* @arg: the (pointer) argument to hand to the callback function.
*
*
* Example:
* void _register_callback(void (*fn)(int, void *arg), void *arg);
- * #define register_callback(fn, arg) \
- * _register_callback(typesafe_cb_preargs(void, (fn), (arg), int),\
+ * #define register_callback(fn, arg) \
+ * _register_callback(typesafe_cb_preargs(void, void *, \
+ * (fn), (arg), int), \
* (arg))
*/
-#define typesafe_cb_preargs(rtype, fn, arg, ...) \
- cast_if_type(rtype (*)(__VA_ARGS__, void *), (fn), &*(fn), \
- rtype (*)(__VA_ARGS__, typeof(arg)))
+#define typesafe_cb_preargs(rtype, atype, fn, arg, ...) \
+ typesafe_cb_cast(rtype (*)(__VA_ARGS__, atype), \
+ rtype (*)(__VA_ARGS__, __typeof__(arg)), \
+ (fn))
/**
* typesafe_cb_postargs - cast a callback function if it matches the arg
* @rtype: the return type of the callback function
+ * @atype: the (pointer) type which the callback function expects.
* @fn: the callback function to cast
* @arg: the (pointer) argument to hand to the callback function.
*
* Example:
* void _register_callback(void (*fn)(void *arg, int), void *arg);
* #define register_callback(fn, arg) \
- * _register_callback(typesafe_cb_postargs(void, (fn), (arg), int),\
+ * _register_callback(typesafe_cb_postargs(void, (fn), void *, \
+ * (arg), int), \
* (arg))
*/
-#define typesafe_cb_postargs(rtype, fn, arg, ...) \
- cast_if_type(rtype (*)(void *, __VA_ARGS__), (fn), &*(fn), \
- rtype (*)(typeof(arg), __VA_ARGS__))
-
-/**
- * typesafe_cb_cmp - cast a compare function if it matches the arg
- * @rtype: the return type of the callback function
- * @fn: the callback function to cast
- * @arg: the (pointer) argument(s) to hand to the compare function.
- *
- * If a callback function takes two matching-type arguments, this macro does
- * appropriate casts to a function which takes two const void * arguments if
- * the callback provided takes two a const pointers to @arg.
- *
- * It is assumed that @arg is of pointer type: usually @arg is passed
- * or assigned to a void * elsewhere anyway. Note also that the type
- * arg points to must be defined.
- *
- * Example:
- * void _my_qsort(void *base, size_t nmemb, size_t size,
- * int (*cmp)(const void *, const void *));
- * #define my_qsort(base, nmemb, cmpfn) \
- * _my_qsort((base), (nmemb), sizeof(*(base)), \
- * typesafe_cb_cmp(int, (cmpfn), (base)), (arg))
- */
-#define typesafe_cb_cmp(rtype, cmpfn, arg) \
- cast_if_type(rtype (*)(const void *, const void *), (cmpfn), &*(cmpfn), \
- rtype (*)(const typeof(*arg)*, const typeof(*arg)*))
-
+#define typesafe_cb_postargs(rtype, atype, fn, arg, ...) \
+ typesafe_cb_cast(rtype (*)(atype, __VA_ARGS__), \
+ rtype (*)(__typeof__(arg), __VA_ARGS__), \
+ (fn))
#endif /* CCAN_CAST_IF_TYPE_H */
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