[ccan] [PATCH 3/3] generator: Allow generators to take arguments
David Gibson
david at gibson.dropbear.id.au
Mon Feb 15 23:13:24 AEDT 2016
Using some serious macro magic, this patch extends generators to allow
them to take arbitrary arguments. The arguments are marshalled into a
structure placed at the far end of the generator's stack when it is
created. Then, they're unmarshalled back into C parameters when we first
context switch into the generator.
Signed-off-by: David Gibson <david at gibson.dropbear.id.au>
---
ccan/generator/_info | 1 +
ccan/generator/generator.h | 63 ++++++++++++++++++++++++++++++--------
ccan/generator/test/api.c | 38 ++++++++++++++++++++++-
ccan/generator/test/example-gens.c | 18 +++++++++++
ccan/generator/test/example-gens.h | 2 ++
5 files changed, 108 insertions(+), 14 deletions(-)
diff --git a/ccan/generator/_info b/ccan/generator/_info
index a6570e3..b0b7343 100644
--- a/ccan/generator/_info
+++ b/ccan/generator/_info
@@ -59,6 +59,7 @@ int main(int argc, char *argv[])
printf("ccan/ptrint\n");
printf("ccan/alignof\n");
printf("ccan/cppmagic\n");
+ printf("ccan/compiler\n");
return 0;
}
diff --git a/ccan/generator/generator.h b/ccan/generator/generator.h
index 6b2bd92..121f14a 100644
--- a/ccan/generator/generator.h
+++ b/ccan/generator/generator.h
@@ -23,6 +23,7 @@
#include <ccan/ptrint/ptrint.h>
#include <ccan/build_assert/build_assert.h>
#include <ccan/cppmagic/cppmagic.h>
+#include <ccan/compiler/compiler.h>
/*
* Internals - included just for the use of inlines and macros
@@ -40,6 +41,11 @@ static inline struct generator_ *generator_state_(const void *ret)
return (struct generator_ *)ret - 1;
}
+static inline void *generator_argp_(const void *ret)
+{
+ return generator_state_(ret)->base;
+}
+
struct generator_incomplete_;
#define generator_rtype_(gen_) \
@@ -77,8 +83,8 @@ void generator_free_(void *ret);
* Example:
* generator_declare(count_to_3, int);
*/
-#define generator_declare(name_, rtype_) \
- generator_t(rtype_) name_(void)
+#define generator_declare(name_, rtype_, ...) \
+ generator_t(rtype_) name_(generator_parms_outer_(__VA_ARGS__))
/**
* generator_def - define a generator function
@@ -97,11 +103,35 @@ void generator_free_(void *ret);
* generator_yield(3);
* }
*/
-#define generator_def_(name_, rtype_, storage_) \
- static void name_##_generator_(rtype_ *ret_); \
+#define generator_parm_(t_, n_) t_ n_
+#define generator_parms_(...) \
+ CPPMAGIC_2MAP(generator_parm_, __VA_ARGS__)
+#define generator_parms_inner_(...) \
+ CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__)) \
+ (, generator_parms_(__VA_ARGS__))()
+#define generator_parms_outer_(...) \
+ CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__)) \
+ (generator_parms_(__VA_ARGS__))(void)
+#define generator_argfield_(t_, n_) t_ n_;
+#define generator_argstruct_(...) \
+ struct { \
+ CPPMAGIC_JOIN(, CPPMAGIC_2MAP(generator_argfield_, \
+ __VA_ARGS__)) \
+ }
+#define generator_arg_unpack_(t_, n_) args->n_
+#define generator_args_unpack_(...) \
+ CPPMAGIC_IFELSE(CPPMAGIC_NONEMPTY(__VA_ARGS__)) \
+ (, CPPMAGIC_2MAP(generator_arg_unpack_, __VA_ARGS__))()
+#define generator_arg_pack_(t_, n_) args->n_ = n_
+#define generator_args_pack_(...) \
+ CPPMAGIC_JOIN(;, CPPMAGIC_2MAP(generator_arg_pack_, __VA_ARGS__))
+#define generator_def_(name_, rtype_, storage_, ...) \
+ static void name_##_generator_(rtype_ *ret_ \
+ generator_parms_inner_(__VA_ARGS__)); \
static void name_##_generator__(generator_wrapper_args_()) \
{ \
struct generator_ *gen; \
+ UNNEEDED generator_argstruct_(__VA_ARGS__) *args; \
CPPMAGIC_IFELSE(HAVE_POINTER_SAFE_MAKECONTEXT) \
() \
(ptrdiff_t hilo = ((ptrdiff_t)hi << (8*sizeof(int))) \
@@ -110,19 +140,26 @@ void generator_free_(void *ret);
BUILD_ASSERT(sizeof(struct generator_ *) \
<= 2*sizeof(int));) \
gen = generator_state_(ret); \
- name_##_generator_(ret); \
+ args = generator_argp_(ret); \
+ name_##_generator_(ret generator_args_unpack_(__VA_ARGS__)); \
gen->complete = true; \
setcontext(&gen->caller); \
assert(0); \
} \
- storage_ generator_t(rtype_) name_(void) \
+ storage_ generator_t(rtype_) \
+ name_(generator_parms_outer_(__VA_ARGS__)) \
{ \
- return generator_new_(name_##_generator__, \
- sizeof(rtype_)); \
+ generator_t(rtype_) gen = generator_new_(name_##_generator__, \
+ sizeof(rtype_)); \
+ UNNEEDED generator_argstruct_(__VA_ARGS__) *args = \
+ generator_argp_(gen); \
+ generator_args_pack_(__VA_ARGS__); \
+ return gen; \
} \
- static void name_##_generator_(rtype_ *ret_)
-#define generator_def(name_, rtype_) \
- generator_def_(name_, rtype_, )
+ static void name_##_generator_(rtype_ *ret_ \
+ generator_parms_inner_(__VA_ARGS__))
+#define generator_def(name_, rtype_, ...) \
+ generator_def_(name_, rtype_, , __VA_ARGS__)
/**
* generator_def_static - define a private / local generator function
@@ -132,8 +169,8 @@ void generator_free_(void *ret);
* As generator_def, but the resulting generator function will be
* local to this module.
*/
-#define generator_def_static(name_, rtype_) \
- generator_def_(name_, rtype_, static)
+#define generator_def_static(name_, rtype_, ...) \
+ generator_def_(name_, rtype_, static, __VA_ARGS__)
/**
* generator_yield - yield (return) a value from a generator
diff --git a/ccan/generator/test/api.c b/ccan/generator/test/api.c
index a5770fd..56e98cc 100644
--- a/ccan/generator/test/api.c
+++ b/ccan/generator/test/api.c
@@ -32,6 +32,40 @@ static void test1(void)
generator_free(state1);
}
+static void test2(void)
+{
+ generator_t(int) state2 = gen2(100);
+ int *ret;
+
+ ok1((ret = generator_next(state2)) != NULL);
+ ok1(*ret == 101);
+ ok1((ret = generator_next(state2)) != NULL);
+ ok1(*ret == 103);
+ ok1((ret = generator_next(state2)) != NULL);
+ ok1(*ret == 117);
+ ok1((ret = generator_next(state2)) == NULL);
+
+ generator_free(state2);
+}
+
+static void test3(void)
+{
+ int i;
+
+ for (i = 0; i < 4; i++) {
+ generator_t(const char *) state3 = gen3("test", i);
+ const char *s;
+ int j;
+
+ for (j = 0; j < i; j++) {
+ ok1(generator_next_val(s, state3));
+ ok1(streq(s, "test"));
+ }
+ ok1(!generator_next_val(s, state3));
+ generator_free(state3);
+ }
+}
+
static void testx(void)
{
generator_t(const char *) statex = genx();
@@ -52,9 +86,11 @@ static void testx(void)
int main(void)
{
/* This is how many tests you plan to run */
- plan_tests(8 + 9);
+ plan_tests(8 + 7 + 16 + 9);
test1();
+ test2();
+ test3();
testx();
/* This exits depending on whether all tests passed */
diff --git a/ccan/generator/test/example-gens.c b/ccan/generator/test/example-gens.c
index c554011..ec3157d 100644
--- a/ccan/generator/test/example-gens.c
+++ b/ccan/generator/test/example-gens.c
@@ -1,3 +1,5 @@
+#include <stdio.h>
+
#include <ccan/generator/generator.h>
#include "example-gens.h"
@@ -8,3 +10,19 @@ generator_def(gen1, int)
generator_yield(3);
generator_yield(17);
}
+
+generator_def(gen2, int, int, base)
+{
+ generator_yield(base + 1);
+ generator_yield(base + 3);
+ generator_yield(base + 17);
+}
+
+generator_def(gen3, const char *, const char *, str, int, count)
+{
+ int i;
+
+ for (i = 0; i < count; i++)
+ generator_yield(str);
+}
+
diff --git a/ccan/generator/test/example-gens.h b/ccan/generator/test/example-gens.h
index cf4ce3b..2b9076f 100644
--- a/ccan/generator/test/example-gens.h
+++ b/ccan/generator/test/example-gens.h
@@ -4,5 +4,7 @@
#include <ccan/generator/generator.h>
generator_declare(gen1, int);
+generator_declare(gen2, int, int, base);
+generator_declare(gen3, const char *, const char *, str, int, count);
#endif /* _EXAMPLE_GENS_H */
--
2.5.0
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