[A] Add ft_strerror function

ChangeLog.md

@@ -7,6 +7,7 @@
 - `ft_ln` returns status of operation.
 - Add new table property `adding_strategy` (2 strategies available - replace(default) and insert).
 - Add function `ft_row_count` (`row_count` in C++ API) to get number of rows in the table.
+- Add function `ft_strerror` to get string descriptions of error codes.
 
 ### Bug fixes
 

docs/index.md

@@ -44,6 +44,7 @@ These pages contain the API documentation of **libfort** - simple library to cre
         - @link ft_set_default_printf_field_separator ft_set_default_printf_field_separator @endlink -- Set field separator for ft_printf, ft_printf_ln
         - @link ft_is_empty ft_is_empty @endlink -- check if table is empty
         - @link ft_row_count ft_row_count @endlink -- get number of rows in the table
+        - @link ft_strerror ft_strerror @endlink -- get string describing the error code
 
   - Data structures and types
     - @link ft_table_t ft_table_t @endlink -- table handler

lib/fort.c

@@ -3614,6 +3614,25 @@ void ft_set_memory_funcs(void *(*f_malloc)(size_t size), void (*f_free)(void *pt
     set_memory_funcs(f_malloc, f_free);
 }
 
+const char *ft_strerror(int error_code)
+{
+    switch (error_code) {
+        case FT_MEMORY_ERROR:
+            return "Libfort error (out of memory)";
+        case FT_ERROR:
+            return "Libfort error (general error)";
+        case FT_EINVAL:
+            return "Libfort error (invalid argument)";
+        case FT_INTERN_ERROR:
+            return "Libfort error (internal logic error)";
+        default:
+            if (error_code < 0)
+                return "Libfort unknown error";
+            else
+                return "Libfort success";
+    }
+}
+
 int ft_set_cell_span(ft_table_t *table, size_t row, size_t col, size_t hor_span)
 {
     assert(table);

lib/fort.h

@@ -73,10 +73,33 @@ SOFTWARE.
 /*****************************************************************************
  *               RETURN CODES
  *****************************************************************************/
+
+/**
+ * Operation successfully ended.
+ */
 #define FT_SUCCESS        0
+
+/**
+ * Memory allocation failed.
+ */
 #define FT_MEMORY_ERROR   -1
+
+/**
+ * General error.
+ */
 #define FT_ERROR          -2
+
+/**
+ * Invalid argument.
+ */
 #define FT_EINVAL         -3
+
+/**
+ *  Libfort internal logic error.
+ */
+#define FT_INTERN_ERROR   -4
+
+
 #define FT_IS_SUCCESS(arg) ((arg) >= 0)
 #define FT_IS_ERROR(arg) ((arg) < 0)
 
@@ -937,6 +960,16 @@ int ft_set_cell_span(ft_table_t *table, size_t row, size_t col, size_t hor_span)
 void ft_set_memory_funcs(void *(*f_malloc)(size_t size), void (*f_free)(void *ptr));
 
 
+/**
+ * Return string describing the `error_code`.
+ *
+ * @param error_code
+ *   Error code returned by the library.
+ * @return
+ *   String describing the error.
+ */
+const char *ft_strerror(int error_code);
+
 
 
 #ifdef FT_HAVE_WCHAR

src/fort.h

@@ -73,10 +73,33 @@ SOFTWARE.
 /*****************************************************************************
  *               RETURN CODES
  *****************************************************************************/
+
+/**
+ * Operation successfully ended.
+ */
 #define FT_SUCCESS        0
+
+/**
+ * Memory allocation failed.
+ */
 #define FT_MEMORY_ERROR   -1
+
+/**
+ * General error.
+ */
 #define FT_ERROR          -2
+
+/**
+ * Invalid argument.
+ */
 #define FT_EINVAL         -3
+
+/**
+ *  Libfort internal logic error.
+ */
+#define FT_INTERN_ERROR   -4
+
+
 #define FT_IS_SUCCESS(arg) ((arg) >= 0)
 #define FT_IS_ERROR(arg) ((arg) < 0)
 
@@ -937,6 +960,16 @@ int ft_set_cell_span(ft_table_t *table, size_t row, size_t col, size_t hor_span)
 void ft_set_memory_funcs(void *(*f_malloc)(size_t size), void (*f_free)(void *ptr));
 
 
+/**
+ * Return string describing the `error_code`.
+ *
+ * @param error_code
+ *   Error code returned by the library.
+ * @return
+ *   String describing the error.
+ */
+const char *ft_strerror(int error_code);
+
 
 
 #ifdef FT_HAVE_WCHAR

src/fort_impl.c

@@ -1018,6 +1018,25 @@ void ft_set_memory_funcs(void *(*f_malloc)(size_t size), void (*f_free)(void *pt
     set_memory_funcs(f_malloc, f_free);
 }
 
+const char *ft_strerror(int error_code)
+{
+    switch (error_code) {
+        case FT_MEMORY_ERROR:
+            return "Libfort error (out of memory)";
+        case FT_ERROR:
+            return "Libfort error (general error)";
+        case FT_EINVAL:
+            return "Libfort error (invalid argument)";
+        case FT_INTERN_ERROR:
+            return "Libfort error (internal logic error)";
+        default:
+            if (error_code < 0)
+                return "Libfort unknown error";
+            else
+                return "Libfort success";
+    }
+}
+
 int ft_set_cell_span(ft_table_t *table, size_t row, size_t col, size_t hor_span)
 {
     assert(table);

tests/CMakeLists.txt

@@ -12,6 +12,7 @@ add_executable(${PROJECT_NAME}_test_dev
     bb_tests/test_table_border_style.c
     bb_tests/test_table_properties.c
     bb_tests/test_memory_errors.c
+    bb_tests/test_error_codes.c
     tests.c
     test_utils.c)
 target_link_libraries(${PROJECT_NAME}_test_dev
@@ -30,6 +31,7 @@ add_executable(${PROJECT_NAME}_test
     bb_tests/test_table_border_style.c
     bb_tests/test_table_properties.c
     bb_tests/test_memory_errors.c
+    bb_tests/test_error_codes.c
     tests.c
     test_utils.c)
 target_link_libraries(${PROJECT_NAME}_test

tests/bb_tests/test_error_codes.c

@@ -0,0 +1,27 @@
+#include "tests.h"
+#include "fort.h"
+
+
+void test_error_codes(void)
+{
+    // Nonnegative code is success
+    {
+        assert_str_equal(ft_strerror(0), "Libfort success");
+        assert_str_equal(ft_strerror(1), "Libfort success");
+        assert_str_equal(ft_strerror(2), "Libfort success");
+        assert_str_equal(ft_strerror(42), "Libfort success");
+        assert_str_equal(ft_strerror(INT_MAX), "Libfort success");
+    }
+
+    // Error codes
+    {
+        assert_str_equal(ft_strerror(FT_MEMORY_ERROR), "Libfort error (out of memory)");
+        assert_str_equal(ft_strerror(FT_ERROR), "Libfort error (general error)");
+        assert_str_equal(ft_strerror(FT_EINVAL), "Libfort error (invalid argument)");
+        assert_str_equal(ft_strerror(FT_INTERN_ERROR), "Libfort error (internal logic error)");
+
+        assert_str_equal(ft_strerror(-42), "Libfort unknown error");
+        assert_str_equal(ft_strerror(-666), "Libfort unknown error");
+        assert_str_equal(ft_strerror(-INT_MAX), "Libfort unknown error");
+    }
+}

tests/main_test.c

@@ -24,6 +24,7 @@ void test_table_cell_properties(void);
 void test_table_text_styles(void);
 void test_table_tbl_properties(void);
 void test_memory_errors(void);
+void test_error_codes(void);
 #ifdef FT_HAVE_UTF8
 void test_utf8_table(void);
 #endif
@@ -60,6 +61,7 @@ struct test_case bb_test_suite [] = {
     {"test_table_tbl_properties", test_table_tbl_properties},
     {"test_table_text_styles", test_table_text_styles},
     {"test_memory_errors", test_memory_errors},
+    {"test_error_codes", test_error_codes},
 };
 
 #ifdef FORT_WB_TESTING_ENABLED