# HG changeset patch
# User Mike Becker <universe@uap-core.de>
# Date 1734276485 -3600
# Node ID 2911c1f4a57023a0d77c2fcfb14a7a2bda73c4e7
# Parent  1f22de6977a186b489a65a3401073956d877b436
add shortcut to binary search when array size is one

diff -r 1f22de6977a1 -r 2911c1f4a570 src/array_list.c
--- a/src/array_list.c	Sun Dec 15 16:10:19 2024 +0100
+++ b/src/array_list.c	Sun Dec 15 16:28:05 2024 +0100
@@ -435,6 +435,9 @@
         return 0;
     }
 
+    // special case: there is only one element and that is smaller
+    if (size == 1) return 0;
+
     // check the last array element
     result = cmp_func(elem, array + elem_size * (size - 1));
     if (result >= 0) {
diff -r 1f22de6977a1 -r 2911c1f4a570 tests/test_list.c
--- a/tests/test_list.c	Sun Dec 15 16:10:19 2024 +0100
+++ b/tests/test_list.c	Sun Dec 15 16:28:05 2024 +0100
@@ -250,6 +250,30 @@
         CX_TEST_ASSERT(18 == cx_array_binary_search_inf(array, 18, sizeof(int), &s, cx_cmp_int));
         CX_TEST_ASSERT(0 == cx_array_binary_search_sup(array, 18, sizeof(int), &s, cx_cmp_int));
         CX_TEST_ASSERT(18 == cx_array_binary_search(array, 18, sizeof(int), &s, cx_cmp_int));
+
+        // special case - size 0
+        s = 40;
+        CX_TEST_ASSERT(0 == cx_array_binary_search_inf(array, 0, sizeof(int), &s, cx_cmp_int));
+        CX_TEST_ASSERT(0 == cx_array_binary_search_sup(array, 0, sizeof(int), &s, cx_cmp_int));
+        CX_TEST_ASSERT(0 == cx_array_binary_search(array, 0, sizeof(int), &s, cx_cmp_int));
+
+        // special case - size 1, searched element is smaller
+        s = 30;
+        CX_TEST_ASSERT(1 == cx_array_binary_search_inf(array, 1, sizeof(int), &s, cx_cmp_int));
+        CX_TEST_ASSERT(0 == cx_array_binary_search_sup(array, 1, sizeof(int), &s, cx_cmp_int));
+        CX_TEST_ASSERT(1 == cx_array_binary_search(array, 1, sizeof(int), &s, cx_cmp_int));
+
+        // special case - size 1, searched element is larger
+        s = 50;
+        CX_TEST_ASSERT(0 == cx_array_binary_search_inf(array, 1, sizeof(int), &s, cx_cmp_int));
+        CX_TEST_ASSERT(1 == cx_array_binary_search_sup(array, 1, sizeof(int), &s, cx_cmp_int));
+        CX_TEST_ASSERT(1 == cx_array_binary_search(array, 1, sizeof(int), &s, cx_cmp_int));
+
+        // special case - size 1, element matches
+        s = 40;
+        CX_TEST_ASSERT(0 == cx_array_binary_search_inf(array, 1, sizeof(int), &s, cx_cmp_int));
+        CX_TEST_ASSERT(0 == cx_array_binary_search_sup(array, 1, sizeof(int), &s, cx_cmp_int));
+        CX_TEST_ASSERT(0 == cx_array_binary_search(array, 1, sizeof(int), &s, cx_cmp_int));
     }
 }