Make it work with c++17 (#3)

Fixes #2 , make astr compile and test with C++17

Author: a4z

CMakeLists.txt

@@ -1,16 +1,12 @@
 
 cmake_minimum_required(VERSION 3.27)
 
-project(astr VERSION 0.2.1 LANGUAGES CXX)
+project(astr VERSION 0.3.0 LANGUAGES CXX)
 
 if(PROJECT_IS_TOP_LEVEL)
     # make git ignore the build directory
     file(WRITE ${CMAKE_BINARY_DIR}/.gitignore "*")
-    set(CMAKE_CXX_STANDARD 20)
-    set(CMAKE_CXX_EXTENSIONS OFF)
-    SET(CMAKE_COMPILE_WARNING_AS_ERROR ON) # turn off with --compile-no-warning-as-error
     set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
-
     list(PREPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_LIST_DIR}/cmake")
     include(setup_compiler)
     include(default_flags)

cmake/setup_compiler.cmake

@@ -23,11 +23,12 @@ endif(NOT isMultiConfig)
 
 # Off, we do not want to annoy potential packager
 # option(WARN_ERROR "Thread warnings as errors. Default OFF" OFF)
-
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 17)
+set(CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 SET(CMAKE_COMPILE_WARNING_AS_ERROR ON) # turn off with --compile-no-warning-as-error
 
+
 if(APPLE AND CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
   # https://stackoverflow.com/questions/77153800/xcode-15-c-compilation-errors
   # TODO ...

include/a4z/astr.hpp

@@ -50,7 +50,11 @@ namespace a4z {
                     "Wanted sized T cannot be greater than actual size N");
       astr<T + 1> result;
       constexpr std::size_t start = N - T - 1;  // N > T is asserted above
-      std::copy(data + start, data + N, result.data);
+      // cpp20, not yet
+      // std::copy(data + start, data + N, result.data);
+      for (size_t i = start; i < N; ++i) {
+        result.data[i - start] = data[i];
+      }
       return result;
     }
 
@@ -60,7 +64,11 @@ namespace a4z {
                     "Wanted sized T cannot be greater than actual size N");
       astr<T + 1> result;
       constexpr std::size_t last = T;
-      std::copy(data, data + last, result.data);
+      // cpp20, not yet
+      // std::copy(data, data + last, result.data);
+      for (size_t i = 0; i < last; ++i) {
+        result.data[i] = data[i];
+      }
       return result;
     }
   };
@@ -149,7 +157,7 @@ namespace a4z {
     return npos;  // Not found
   }
 
-  consteval bool on_windows() {
+  constexpr bool on_windows() {
 #ifdef _WIN32
     return true;
 #else

include/a4z/filename.hpp

@@ -14,13 +14,13 @@ namespace a4z {
   constexpr char slash = on_windows() ? '\\' : '/';
 
 #define a4z_file_name                                                          \
-  []() consteval {                                                             \
+  []() constexpr {                                                             \
     constexpr const char* str = __FILE__;                                      \
     constexpr auto len = a4z::cstr_len(str);                                   \
     constexpr auto start{a4z::find_nth_r_occurrence(__FILE__, a4z::slash, 2)}; \
     static_assert(start != a4z::npos);                                         \
     constexpr std::size_t astr_len = len - start;                              \
-    char data[astr_len];                                                       \
+    char data[astr_len] = {0};                                                 \
     for (std::size_t i = 0; i < astr_len; ++i) {                               \
       data[i] = *(str + start + i + 1);                                        \
     }                                                                          \

tests/base/filename_test.cpp

@@ -82,14 +82,22 @@ SCENARIO("Test with filename macro") {
     constexpr auto fn = a4z_file_name();
 
     WHEN("checking if it starts with base") {
-      const auto starts_with_base = std::string(fn.c_str()).starts_with("base");
+      // cpp20
+      // const auto starts_with_base =
+      // std::string(fn.c_str()).starts_with("base");
+      const char* base = "base";
+      auto start_str = fn.first_n<4>();
+      const auto starts_with_base = a4z::equal(base, start_str.c_str());
       THEN("we find it at the expected position") {
         CHECK(starts_with_base);
       }
     }
     AND_WHEN("checking if it ends with ") {
-      const auto ends_with_filename =
-          std::string(fn.c_str()).ends_with("filename_test.cpp");
+      const char* filename = "filename_test.cpp";
+      auto end_str = fn.last_n<17>();
+      const auto ends_with_filename = a4z::equal(filename, end_str.c_str());
+      // cpp20
+      // std::string(fn.c_str()).ends_with("filename_test.cpp");
       THEN("we find it at the expected position") {
         CHECK(ends_with_filename);
       }