WIP add btree_set

with node size of 256, as in abseil.
also using similar tricks as abseil, using much less memory per node.

GNUmakefile

@@ -144,7 +144,9 @@ TESTS = \
 
 ifneq ($(DEBUG),)
 TESTS += \
-	tests/func/test_map     \
+	tests/func/test_btree_set \
+	tests/func/test_btree_map \
+	tests/func/test_map       \
 	tests/func/test_unordered_map
 endif
 
@@ -186,6 +188,7 @@ perf: $(PERFS_C) $(PERFS_CC) tests/perf/arr/perf_arr_generate
 
 $(wildcard tests/perf/lst/perf*.cc?) : $(COMMON_H) ctl/list.h
 $(wildcard tests/perf/set/perf*.cc?) : $(COMMON_H) ctl/set.h
+$(wildcard tests/perf/btset/perf*.cc?) : $(COMMON_H) ctl/btree_set.h
 $(wildcard tests/perf/deq/perf*.cc?) : $(COMMON_H) ctl/deque.h
 $(wildcard tests/perf/pqu/perf*.cc?) : $(COMMON_H) ctl/priority_queue.h
 $(wildcard tests/perf/vec/perf*.cc?) : $(COMMON_H) ctl/vector.h
@@ -292,6 +295,8 @@ ctl/string.i:
 	$(call expand,$(subst .i,,$@))
 ctl/map.i:
 	$(call expand,$(subst .i,,$@),-DT=strint -DPOD)
+ctl/btree_map.i:
+	$(call expand,$(subst .i,,$@),-DT=strint -DPOD)
 ctl/unordered_map.i:
 	$(call expand,$(subst .i,,$@),-DT=strint -DPOD)
 ctl/array.i:
@@ -328,7 +333,11 @@ tests/func/test_queue:    .cflags $(COMMON_H) tests/test.h tests/func/digi.hh ct
 tests/func/test_set:      .cflags $(COMMON_H) tests/test.h tests/func/digi.hh ctl/set.h \
                           tests/func/test_set.cc
 	$(CXX) $(CXXFLAGS) -o $@ [email protected]
-tests/func/test_map:      .cflags $(H) tests/test.h tests/func/strint.hh ctl/set.h ctl/map.h tests/func/test_map.cc
+tests/func/test_btree_set: .cflags $(COMMON_H) tests/test.h tests/func/digi.hh ctl/btree_set.h \
+                          tests/func/test_btree_set.cc
+	$(CXX) $(CXXFLAGS) -o $@ [email protected]
+tests/func/test_map:      .cflags $(H) tests/test.h tests/func/strint.hh \
+                          tests/func/test_map.cc
 	$(CXX) $(CXXFLAGS) -o $@ [email protected]
 tests/func/test_unordered_set: .cflags $(COMMON_H) ctl/unordered_set.h \
                           tests/func/test_unordered_set.cc

README.md

@@ -61,6 +61,8 @@ all containers in ISO C99/C11:
 | [ctl/map.h](docs/map.md)                       | std::map             | map      |
 | [ctl/unordered_map.h](docs/unordered_map.md)   | std::unordered_map   | umap     |
 | [ctl/unordered_set.h](docs/unordered_set.md)   | std::unordered_set   | uset     |
+| [ctl/btree_set.h](docs/btree_set.md)           | absl::btree_set      | btset    |
+| [ctl/btree_map.h](docs/btree_map.md)           | absl::btree_map      | btmap    |
 |------------------------------------------------|----------------------|
 | [ctl/algorithm.h](docs/algorithm.md)           | `<algorithm>`        |
 | [ctl/numeric.h](docs/numeric.md)               | `<numeric>`          |
@@ -359,7 +361,6 @@ And in its grandiosity (esp. not header-only):
 
 ## Base Implementation Details
 
-
     array.h:            stack/heap allocated
     vector.h:           realloc
     string.h:           vector.h
@@ -371,6 +372,8 @@ And in its grandiosity (esp. not header-only):
     forward_list.h:     single linked list
     set.h:              red black tree
     map.h:              set.h
+    btree_set.h:        b-tree
+    btree_map.h:        - " -
     unordered_set.h:    hashed forward linked lists
     unordered_map.h:    unordered_set.h (pair in work)
     hashmap.h:          stanford hash for integer keys, intel only.