From b8ade145405ee0c9b9319108a6ef05bc17e3dc83 Mon Sep 17 00:00:00 2001
From: Patrick Pelissier <patrick.pelissier@gmail.com>
Date: Thu, 23 Feb 2017 23:07:52 +0100
Subject: [PATCH] Add ALGO_EXTRACT

---
 m-algo.h           | 30 ++++++++++++++++++++++++++++--
 tests/test-malgo.c | 19 +++++++++++++++++++
 2 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/m-algo.h b/m-algo.h
index f910fd3b..6e8a349f 100644
--- a/m-algo.h
+++ b/m-algo.h
@@ -39,7 +39,12 @@
 #define ALGO_MAP(container, cont_oplist, ...)                  \
   M_IF_NARGS_EQ1(__VA_ARGS__)                                  \
   (ALGOI_MAP(container, cont_oplist, __VA_ARGS__),             \
-   ALGOI_MAP_ARG(name, cont_oplist, __VA_ARGS__ ))
+   ALGOI_MAP_ARG(container, cont_oplist, __VA_ARGS__ ))
+
+#define ALGO_EXTRACT(contD, contDop, contS, contSop, ...)                \
+  M_IF_NARGS_EQ1(__VA_ARGS__)                                           \
+  (ALGOI_EXTRACT(contD, contDop, contS, contSop, __VA_ARGS__),          \
+   ALGOI_EXTRACT_ARG(contD, contDop, contS, contSop, __VA_ARGS__ ))
 
 /********************************** INTERNAL ************************************/
 
@@ -203,7 +208,6 @@
 //TODO: const_iterator & CM_EACH missing...
 //TODO: Algorithm missing
 // nth_element, reduce, find_last, find_if, count_if, ...
-//TODO: Copy from a container to another if condition.
 
 #define ALGOI_MAP(container, cont_oplist, func)                         \
   for M_EACH(item, l, cont_oplist) {                                    \
@@ -215,4 +219,26 @@
     func(__VA_ARGS__, *item);                                           \
   }                                                                     \
 
+#define ALGOI_EXTRACT(contDst, contDstOplist,                           \
+                      contSrc, contSrcOplist,                           \
+                      condFunc) do {                                    \
+    M_GET_CLEAN contDstOplist (contDst);                                \
+    for M_EACH(item, contSrc, contSrcOplist) {                          \
+        if (condFunc (*item))                                           \
+          M_GET_PUSH contDstOplist (contDst, *item);                    \
+    }                                                                   \
+    M_IF_METHOD(REVERSE, contDstOplist) (M_GET_REVERSE contDstOplist (contDstOplist);, ) \
+  } while (0)
+
+#define ALGOI_EXTRACT_ARG(contDst, contDstOplist,                       \
+                          contSrc, contSrcOplist,                       \
+                          condFunc, ...) do {                           \
+    M_GET_CLEAN contDstOplist (contDst);                                \
+    for M_EACH(item, contSrc, contSrcOplist) {                          \
+        if (condFunc (__VA_ARGS__, *item))                              \
+          M_GET_PUSH contDstOplist (contDst, *item);                    \
+    }                                                                   \
+    M_IF_METHOD(REVERSE, contDstOplist) (M_GET_REVERSE contDstOplist (contDstOplist);, ) \
+  } while (0)
+
 #endif
diff --git a/tests/test-malgo.c b/tests/test-malgo.c
index 105435d4..2d89e3c4 100644
--- a/tests/test-malgo.c
+++ b/tests/test-malgo.c
@@ -73,10 +73,29 @@ static void test_string(void)
   list_string_clear(l);
 }
 
+static void test_extract(void)
+{
+  list_int_t l;
+  list_int_init (l);
+  for(int i = -100; i < 100; i++)
+    list_int_push_back (l, i);
+  array_int_t a;
+  array_int_init(a);
+#define cond(d) ((d) > 0)
+  ALGO_EXTRACT(a, ARRAY_OPLIST(int), l, LIST_OPLIST(int), cond);
+  assert(array_int_size(a) == 99);
+#define cond2(c, d) ((d) > (c))
+  ALGO_EXTRACT(a, ARRAY_OPLIST(int), l, LIST_OPLIST(int), cond2, 10);
+  assert(array_int_size(a) == 89);
+  array_int_clear(a);
+  list_int_clear(l);
+}
+
 int main(void)
 {
   test_list();
   test_array();
   test_string();
+  test_extract();
   exit(0);
 }