# HG changeset patch
# User Mike Becker <universe@uap-core.de>
# Date 1684672676 -7200
# Node ID 8c6edaccaef154089dcea37de817e31036b567db
# Parent  0d5447230044ed4981f2b1eae12e9756814da7a8
add empty map implementation - fixes #259

diff -r 0d5447230044 -r 8c6edaccaef1 src/CMakeLists.txt
--- a/src/CMakeLists.txt	Sun May 21 14:04:34 2023 +0200
+++ b/src/CMakeLists.txt	Sun May 21 14:37:56 2023 +0200
@@ -7,6 +7,7 @@
         linked_list.c
         tree.c
         buffer.c
+        map.c
         hash_key.c
         hash_map.c
         basic_mempool.c
diff -r 0d5447230044 -r 8c6edaccaef1 src/cx/map.h
--- a/src/cx/map.h	Sun May 21 14:04:34 2023 +0200
+++ b/src/cx/map.h	Sun May 21 14:37:56 2023 +0200
@@ -158,6 +158,8 @@
     void *value;
 };
 
+extern CxMap *const cxEmptyMap;
+
 /**
  * Advises the map to store copies of the objects (default mode of operation).
  *
diff -r 0d5447230044 -r 8c6edaccaef1 src/map.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/map.c	Sun May 21 14:37:56 2023 +0200
@@ -0,0 +1,90 @@
+/*
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
+ *
+ * Copyright 2023 Mike Becker, Olaf Wintermann All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *   1. Redistributions of source code must retain the above copyright
+ *      notice, this list of conditions and the following disclaimer.
+ *
+ *   2. Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "cx/map.h"
+
+// <editor-fold desc="empty map implementation">
+
+static void cx_empty_map_noop(__attribute__((__unused__)) CxMap *map) {
+    // this is a noop, but MUST be implemented
+}
+
+static void *cx_empty_map_get(
+        __attribute__((__unused__)) CxMap const *map,
+        __attribute__((__unused__)) CxHashKey key
+) {
+    return NULL;
+}
+
+static bool cx_empty_map_iter_valid(__attribute__((__unused__)) void const *iter) {
+    return false;
+}
+
+static CxIterator cx_empty_map_iterator(struct cx_map_s const *map) {
+    CxIterator iter = {0};
+    iter.src_handle = map;
+    iter.base.valid = cx_empty_map_iter_valid;
+    return iter;
+}
+
+static CxMutIterator cx_empty_map_miterator(struct cx_map_s *map) {
+    CxMutIterator iter = {0};
+    iter.src_handle = map;
+    iter.base.valid = cx_empty_map_iter_valid;
+    return iter;
+}
+
+static struct cx_map_class_s cx_empty_map_class = {
+    cx_empty_map_noop,
+    cx_empty_map_noop,
+    NULL,
+    cx_empty_map_get,
+    NULL,
+    cx_empty_map_iterator,
+    cx_empty_map_iterator,
+    cx_empty_map_iterator,
+    cx_empty_map_miterator,
+    cx_empty_map_miterator,
+    cx_empty_map_miterator,
+};
+
+CxMap cx_empty_map = {
+        NULL,
+        NULL,
+        0,
+        0,
+        NULL,
+        NULL,
+        NULL,
+        false,
+        &cx_empty_map_class
+};
+
+CxMap * const cxEmptyMap = &cx_empty_map;
+
+// </editor-fold>
diff -r 0d5447230044 -r 8c6edaccaef1 tests/test_map.cpp
--- a/tests/test_map.cpp	Sun May 21 14:04:34 2023 +0200
+++ b/tests/test_map.cpp	Sun May 21 14:37:56 2023 +0200
@@ -472,3 +472,51 @@
     cxMapDestroy(map);
     EXPECT_TRUE(allocator.verify());
 }
+
+TEST(EmptyMap, Size) {
+    auto map = cxEmptyMap;
+
+    EXPECT_EQ(map->size, 0);
+}
+
+TEST(EmptyMap, Iterator) {
+    auto map = cxEmptyMap;
+
+    auto it1 = cxMapIterator(map);
+    auto it2 = cxMapIteratorValues(map);
+    auto it3 = cxMapIteratorKeys(map);
+    auto it4 = cxMapMutIterator(map);
+    auto it5 = cxMapMutIteratorValues(map);
+    auto it6 = cxMapMutIteratorKeys(map);
+
+    EXPECT_FALSE(cxIteratorValid(it1));
+    EXPECT_FALSE(cxIteratorValid(it2));
+    EXPECT_FALSE(cxIteratorValid(it3));
+    EXPECT_FALSE(cxIteratorValid(it4));
+    EXPECT_FALSE(cxIteratorValid(it5));
+    EXPECT_FALSE(cxIteratorValid(it6));
+
+    int c = 0;
+    cx_foreach(void*, data, it1) c++;
+    cx_foreach(void*, data, it2) c++;
+    cx_foreach(void*, data, it3) c++;
+    cx_foreach(void*, data, it4) c++;
+    cx_foreach(void*, data, it5) c++;
+    cx_foreach(void*, data, it6) c++;
+    EXPECT_EQ(c, 0);
+}
+
+TEST(EmptyMap, NoOps) {
+    auto map = cxEmptyMap;
+
+    ASSERT_NO_FATAL_FAILURE(cxMapClear(map));
+    ASSERT_NO_FATAL_FAILURE(cxMapRehash(map));
+    ASSERT_NO_FATAL_FAILURE(cxMapDestroy(map));
+}
+
+TEST(EmptyMap, Get) {
+    auto map = cxEmptyMap;
+
+    CxHashKey key = cx_hash_key_str("test");
+    EXPECT_EQ(cxMapGet(map, key), nullptr);
+}