fixed division, undefined behaviors and some improvements (#33)

* testing using ctest

* emove old testing script

* added github workflow CI

* updated CI

* added unit test for macros

* F16() and F16C() are both rounding allways, so fix16_from_dbl should as well

* added tests for strign operations, but these functions are in my opinion unreliable and tests are failing

* removed old unittests

* removed old unittests from cmake

* problem with division using gcc

* improved benchmark

* clarification of problem with division

* attempt to fix

* fixed some undefined behaviors, fixed division

8 files changed, 298 insertions, 10 deletions

diff --git a/tests/tests.c b/tests/tests.c
index cef9710..d06ee26 100644
--- a/tests/tests.c
+++ b/tests/tests.c
@@ -1,7 +1,9 @@
 #include "tests.h"
 #include "tests_basic.h"
 #include "tests_lerp.h"
+#include "tests_macros.h"
 #include "tests_sqrt.h"
+#include "tests_str.h"
 #include <stdio.h>
 
 const fix16_t testcases[] = {
@@ -32,14 +34,41 @@ const fix16_t testcases[] = {
 
     // Tiny random numbers
     -171, -359, 491, 844, 158, -413, -422, -737, -575, -330, -376, 435, -311,
-    116, 715, -1024, -487, 59, 724, 993
-};
+    116, 715, -1024, -487, 59, 724, 993};
 
 unsigned stack_depth = 0;
 
 int main()
 {
-    printf("\033[1;34m\nVARIANT: \033[39m"STR2(PREFIX)"\033[0m\n");
+    printf("\033[1;34m\nVARIANT: \033[39m" STR2(PREFIX) "\033[0m\n");
+#if 0
+    fix16_t a      = 65536;
+    fix16_t b      = -2147483648;
+    fix16_t result = fix16_div(a, b);
+
+    double fa      = fix16_to_dbl(a);
+    double fb      = fix16_to_dbl(b);
+    double fresult = fa / fb;
+
+    double max = fix16_to_dbl(fix16_maximum);
+    double min = fix16_to_dbl(fix16_minimum);
+
+    printf("result  %i, %.20f\n", result, fix16_to_dbl(result));
+    printf("fresult %i, %.20f\n", fix16_from_dbl(fresult), fresult);
+
+    if ((fa / fb) > max || (fa / fb) < min)
+    {
+#ifndef FIXMATH_NO_OVERFLOW
+        ASSERT_EQ_INT(result, fix16_overflow);
+#endif
+    }
+    else
+    {
+        ASSERT_NEAR_DOUBLE(fresult, fix16_to_dbl(result),
+                           fix16_to_dbl(fix16_eps), "%i / %i \n", a, b);
+    }
+
+#else
     TEST(test_abs());
     TEST(test_add());
     TEST(test_mul());
@@ -47,5 +76,8 @@ int main()
     TEST(test_sub());
     TEST(test_sqrt());
     TEST(test_lerp());
+    TEST(test_macros());
+    //TEST(test_str());
+#endif
     return 0;
 }
diff --git a/tests/tests.cmake b/tests/tests.cmake
index 5f6c90b..c07b69d 100644
--- a/tests/tests.cmake
+++ b/tests/tests.cmake
@@ -15,15 +15,22 @@ set(nn08 PREFIX=nn08 FIXMATH_NO_OVERFLOW FIXMATH_NO_ROUNDING FIXMATH_OPTIMIZE_8B
 
 enable_testing()
 
+#-fno-sanitize-recover
+set(sanitizer_opts -fsanitize=undefined)
+
 add_custom_target(make_tests)
 
 function(create_variant name defs)
     add_library(libfixmath_${name} STATIC ${libfixmath-srcs})
     target_compile_definitions(libfixmath_${name} PRIVATE ${defs})
+    target_compile_options(libfixmath_${name} PRIVATE ${sanitizer_opts})
+    target_link_options(libfixmath_${name} PRIVATE ${sanitizer_opts})
     add_executable(tests_${name} ${tests-srcs})
     target_link_libraries(tests_${name} PRIVATE libfixmath_${name} m)
     target_include_directories(tests_${name} PRIVATE ${CMAKE_SOURCE_DIR})
     target_compile_definitions(tests_${name} PRIVATE ${defs})
+    target_compile_options(tests_${name} PRIVATE ${sanitizer_opts})
+    target_link_options(tests_${name} PRIVATE ${sanitizer_opts})
     add_dependencies(make_tests tests_${name})
     add_test(NAME tests_${name} COMMAND tests_${name})
 endfunction()
diff --git a/tests/tests.h b/tests/tests.h
index 6bd8e4d..72e7801 100644
--- a/tests/tests.h
+++ b/tests/tests.h
@@ -5,14 +5,15 @@
 #include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 extern unsigned stack_depth;
 
 #define delta(a, b) (((a) >= (b)) ? (a) - (b) : (b) - (a))
 
 #define COMMENT(x) printf("\n----" x "----\n");
-#define STR(x)     #x
-#define STR2(x)    STR(x)
+#define STR(x) #x
+#define STR2(x) STR(x)
 #define TEST(x)                                                       \
     do                                                                \
     {                                                                 \
@@ -71,6 +72,34 @@ extern unsigned stack_depth;
         }                                                                    \
     } while (0)
 
+#define ASSERT_EQ_STR(a, b)                                                  \
+    do                                                                       \
+    {                                                                        \
+        size_t la = strlen(a);                                               \
+        size_t lb = strlen(b);                                               \
+        if (la != lb)                                                        \
+        {                                                                    \
+            fflush(stdout);                                                  \
+            fflush(stderr);                                                  \
+            fprintf(stderr,                                                  \
+                    "\033[31;1m FAILED:\033[22;39m%*sASSERT_EQ a: %s, b: "   \
+                    "%s\033[0m at: %s(), " __FILE__ ":" STR2(__LINE__) "\n", \
+                    stack_depth, "", (a), (b), __func__);                    \
+            return 1;                                                        \
+        }                                                                    \
+        int res = strncmp((a), (b), la);                                     \
+        if (res != 0)                                                        \
+        {                                                                    \
+            fflush(stdout);                                                  \
+            fflush(stderr);                                                  \
+            fprintf(stderr,                                                  \
+                    "\033[31;1m FAILED:\033[22;39m%*sASSERT_EQ a: %s, b: "   \
+                    "%s\033[0m at: %s(), " __FILE__ ":" STR2(__LINE__) "\n", \
+                    stack_depth, "", (a), (b), __func__);                    \
+            return 1;                                                        \
+        }                                                                    \
+    } while (0)
+
 extern const fix16_t testcases[102];
 
 #define TESTCASES_COUNT (sizeof(testcases) / sizeof(testcases[0]))
diff --git a/tests/tests_basic.c b/tests/tests_basic.c
index 6037ae2..8fd3580 100644
--- a/tests/tests_basic.c
+++ b/tests/tests_basic.c
@@ -5,11 +5,11 @@ int test_abs_short(void)
 {
     for (unsigned i = 0; i < TESTCASES_COUNT; ++i)
     {
-        fix16_t a       = testcases[i];
-        double  fa      = fix16_to_dbl(a);
-        fix16_t result  = fix16_abs(a);
-        double  fresult = fabs(fa);
-        double  min     = fix16_to_dbl(fix16_minimum);
+        fix16_t a      = testcases[i];
+        double fa      = fix16_to_dbl(a);
+        fix16_t result = fix16_abs(a);
+        double fresult = fabs(fa);
+        double min     = fix16_to_dbl(fix16_minimum);
         if (fa <= min)
         {
 #ifndef FIXMATH_NO_OVERFLOW
diff --git a/tests/tests_macros.c b/tests/tests_macros.c
new file mode 100644
index 0000000..bb80c79
--- /dev/null
+++ b/tests/tests_macros.c
@@ -0,0 +1,100 @@
+#include "tests_macros.h"
+#include "tests.h"
+
+#define DO_TEST(i, m)                                         \
+    do                                                        \
+    {                                                         \
+        ASSERT_EQ_INT(F16(i##.##m), F16C(i, m));              \
+        ASSERT_EQ_INT(F16(i##.##m), fix16_from_dbl(i##.##m)); \
+    } while (0)
+
+int test_macros()
+{
+    DO_TEST(1, 234);
+    DO_TEST(0, 0);
+    DO_TEST(1, 0);
+    DO_TEST(-1, 0);
+    DO_TEST(1, 5);
+    DO_TEST(-1, 5);
+    DO_TEST(000000, 00000);
+    DO_TEST(0, 00001);
+    DO_TEST(0, 00010);
+    DO_TEST(0, 1);
+    DO_TEST(0, 10001);
+    DO_TEST(0, 11000);
+    DO_TEST(25, 133);
+    DO_TEST(32767, 00000);
+    DO_TEST(32767, 00001);
+    DO_TEST(32767, 99999);
+    DO_TEST(0, 25);
+    DO_TEST(0, 99555);
+    DO_TEST(0, 99998);
+    DO_TEST(0, 99999);
+    DO_TEST(-1, 1);
+    DO_TEST(-25, 133);
+    DO_TEST(-32767, 00001);
+    DO_TEST(-32768, 00000);
+
+    /* Random values */
+    DO_TEST(0, 02267);
+    DO_TEST(1, 49887);
+    DO_TEST(0, 27589);
+    DO_TEST(0, 38393);
+    DO_TEST(0, 08934);
+    DO_TEST(0, 95820);
+    DO_TEST(0, 95596);
+    DO_TEST(72, 10642);
+    DO_TEST(0, 48939);
+    DO_TEST(3, 37797);
+    DO_TEST(1, 09194);
+    DO_TEST(0, 08605);
+    DO_TEST(3, 04349);
+    DO_TEST(3, 95401);
+    DO_TEST(15, 36292);
+    DO_TEST(56, 09242);
+    DO_TEST(0, 54071);
+    DO_TEST(27, 08953);
+    DO_TEST(0, 03913);
+    DO_TEST(1, 32707);
+    DO_TEST(4, 50117);
+    DO_TEST(0, 24990);
+    DO_TEST(44, 77319);
+    DO_TEST(2, 59139);
+    DO_TEST(0, 16279);
+    DO_TEST(17, 14712);
+    DO_TEST(11, 54281);
+    DO_TEST(0, 02768);
+    DO_TEST(0, 39278);
+    DO_TEST(0, 19369);
+    DO_TEST(-0, 04534);
+    DO_TEST(-0, 00349);
+    DO_TEST(-2, 30380);
+    DO_TEST(-0, 03061);
+    DO_TEST(-7, 50065);
+    DO_TEST(-3, 97050);
+    DO_TEST(-0, 43898);
+    DO_TEST(-3, 49876);
+    DO_TEST(-1, 35942);
+    DO_TEST(-10, 81154);
+    DO_TEST(-0, 26676);
+    DO_TEST(-9, 52134);
+    DO_TEST(-0, 42592);
+    DO_TEST(-0, 05424);
+    DO_TEST(-0, 62461);
+    DO_TEST(-0, 21562);
+    DO_TEST(-0, 22366);
+    DO_TEST(-0, 09074);
+    DO_TEST(-1, 29527);
+    DO_TEST(-4, 98427);
+    DO_TEST(-0, 10721);
+    DO_TEST(-11, 39446);
+    DO_TEST(-451, 53916);
+    DO_TEST(-0, 04279);
+    DO_TEST(-3, 36543);
+    DO_TEST(-0, 01003);
+    DO_TEST(-12, 08326);
+    DO_TEST(-1, 07143);
+    DO_TEST(-1, 07737);
+    DO_TEST(-0, 22957);
+    return 0;
+}
diff --git a/tests/tests_macros.h b/tests/tests_macros.h
new file mode 100644
index 0000000..75ab0f3
--- /dev/null
+++ b/tests/tests_macros.h
@@ -0,0 +1,6 @@
+#ifndef TESTS_MACROS_H
+#define TESTS_MACROS_H
+
+int test_macros();
+
+#endif // TESTS_MACROS_H
diff --git a/tests/tests_str.c b/tests/tests_str.c
new file mode 100644
index 0000000..d893ffb
--- /dev/null
+++ b/tests/tests_str.c
@@ -0,0 +1,108 @@
+#include "tests_str.h"
+#include "tests.h"
+
+int test_str_to()
+{
+    char buf[13];
+    fix16_to_str(fix16_from_dbl(1234.5678), buf, 4);
+    ASSERT_EQ_STR(buf, "1234.5678");
+
+    fix16_to_str(fix16_from_dbl(-1234.5678), buf, 4);
+    ASSERT_EQ_STR(buf, "-1234.5678");
+
+    fix16_to_str(0, buf, 0);
+    ASSERT_EQ_STR(buf, "0");
+
+    fix16_to_str(fix16_from_dbl(0.9), buf, 0);
+    ASSERT_EQ_STR(buf, "1");
+
+    fix16_to_str(1, buf, 5);
+    ASSERT_EQ_STR(buf, "0.00002");
+
+    fix16_to_str(-1, buf, 5);
+    ASSERT_EQ_STR(buf, "-0.00002");
+
+    fix16_to_str(65535, buf, 5);
+    ASSERT_EQ_STR(buf, "0.99998");
+
+    fix16_to_str(65535, buf, 4);
+    ASSERT_EQ_STR(buf, "1.0000");
+
+    fix16_to_str(fix16_maximum, buf, 5);
+    ASSERT_EQ_STR(buf, "32767.99998");
+
+    fix16_to_str(fix16_minimum, buf, 5);
+    ASSERT_EQ_STR(buf, "-32768.00000");
+
+    return 0;
+}
+
+int test_str_from()
+{
+    ASSERT_EQ_INT(fix16_from_str("1234.5678"), fix16_from_dbl(1234.5678));
+    ASSERT_EQ_INT(fix16_from_str("-1234.5678"), fix16_from_dbl(-1234.5678));
+    ASSERT_EQ_INT(fix16_from_str("   +1234,56780   "),
+                  fix16_from_dbl(1234.5678));
+
+    ASSERT_EQ_INT(fix16_from_str("0"), 0);
+    ASSERT_EQ_INT(fix16_from_str("1"), fix16_one);
+    ASSERT_EQ_INT(fix16_from_str("1.0"), fix16_one);
+    ASSERT_EQ_INT(fix16_from_str("1.0000000000"), fix16_one);
+
+    ASSERT_EQ_INT(fix16_from_str("0.00002"), 1);
+    ASSERT_EQ_INT(fix16_from_str("0.99998"), 65535);
+
+    ASSERT_EQ_INT(fix16_from_str("32767.99998"), fix16_maximum);
+    ASSERT_EQ_INT(fix16_from_str("-32768.00000"), fix16_minimum);
+
+    return 0;
+}
+
+int test_str_extended()
+{
+
+    fix16_t value = fix16_minimum;
+    char testbuf[13];
+    char goodbuf[13];
+
+    while (value < fix16_maximum)
+    {
+        double fvalue = fix16_to_dbl(value);
+
+        /* Turns out we have to jump through some hoops to round
+            doubles perfectly for printing:
+            http://stackoverflow.com/questions/994764/rounding-doubles-5-sprintf
+            */
+        fvalue = round(fvalue * 100000.) / 100000.;
+
+        snprintf(goodbuf, 13, "%0.5f", fvalue);
+        fix16_to_str(value, testbuf, 5);
+
+        if (strcmp(goodbuf, testbuf) != 0)
+        {
+            printf("Value (fix16_t)%d gave %s, should be %s\n", value, testbuf,
+                   goodbuf);
+            return 1;
+        }
+
+        fix16_t roundtrip = fix16_from_str(testbuf);
+        if (roundtrip != value)
+        {
+            printf("Roundtrip failed: (fix16_t)%d -> %s -> (fix16_t)%d\n",
+                   value, testbuf, roundtrip);
+            return 1;
+        }
+
+        value += 0x10001;
+    }
+
+    return 0;
+}
+
+int test_str()
+{
+    TEST(test_str_to());
+    TEST(test_str_from());
+    TEST(test_str_extended());
+    return 0;
+}
diff --git a/tests/tests_str.h b/tests/tests_str.h
new file mode 100644
index 0000000..bb072ea
--- /dev/null
+++ b/tests/tests_str.h
@@ -0,0 +1,6 @@
+#ifndef TESTS_STR_H
+#define TESTS_STR_H
+
+int test_str();
+
+#endif // TESTS_STR_H