Added String Concatenation Feature

include/EmberLib/Util/EmberString.h

@@ -52,6 +52,19 @@ EmberString *strip_estring(EmberString *str);
  */
 int compare_estring(const EmberString *str, const EmberString *other);
 
+/**
+ * Concatenates two EmberStrings into a new EmberString. If one or both strings
+ * are NULL, ember_string_error will be set to EMBER_STRING_NULL_ARG. In the
+ * case of null arguments, if only one string is null, it will return a new
+ * EmberString that is essentially just the non-null string. If both strings are
+ * NULL, it will return a valid, but empty, EmberString.
+ *
+ * @param str The first string to concatenate.
+ * @param other The second string to concatenate.
+ * @return A string that is the concatenation of both input strings.
+ */
+EmberString *estring_concat(EmberString *str, EmberString *other);
+
 /*
  * Error Handling Stuff
  */

src/Util/EmberString.c

@@ -181,4 +181,38 @@ int compare_estring(const EmberString *str, const EmberString *other)
     {
         return 0;
     }
+}
+
+#include <stdio.h>
+EmberString *estring_concat(EmberString *str, EmberString *other)
+{
+    if(str == NULL)
+    {
+        error_val = EMBER_STRING_NULL_ARG;
+        if(!other)
+        {
+            return create_estring_from_cstr("", 0);
+        }
+        return create_estring_from_cstr(other->c_str, other->len);
+    }
+    if(other == NULL)
+    {
+        error_val = EMBER_STRING_NULL_ARG;
+        return create_estring_from_cstr(str->c_str, str->len);
+    }
+
+    EmberString *result = malloc(sizeof(EmberString));
+    result->len = str->len + other->len;
+    result->c_str = malloc(sizeof(char) * (result->len + 1));
+
+    for(size_t i = 0; i < str->len; i++)
+    {
+        result->c_str[i] = str->c_str[i];
+    }
+    for(size_t i = str->len; i < other->len+str->len; i++)
+    {
+        result->c_str[i] = other->c_str[i-str->len];
+    }
+    result->c_str[result->len] = '\0';
+    return result;
 }

tests/check_ember_string.c

@@ -82,6 +82,84 @@ START_TEST(test_ember_string_from_cstr)
 }
 END_TEST
 
+START_TEST(test_ember_string_concat)
+{
+    EmberString *str1 = create_estring_from_cstr("String1", 7);
+    EmberString *str2 = create_estring_from_cstr("String2", 7);
+    EmberString *empty = create_estring_from_cstr("", 0);
+    EmberString *null_str = NULL;
+
+    EmberString *result = estring_concat(str1, str2);
+    ck_assert_ptr_nonnull(result);
+    ck_assert_ptr_nonnull(result->c_str);
+    ck_assert_ptr_ne(result->c_str, str1->c_str);
+    ck_assert_ptr_ne(result->c_str, str2->c_str);
+    ck_assert_int_eq(result->len, str1->len+str2->len);
+    ck_assert_str_eq(result->c_str, "String1String2");
+    ck_assert_int_eq(ember_string_error(), EMBER_STRING_NO_ERR);
+
+    result = estring_concat(str2, str1);
+    ck_assert_ptr_nonnull(result);
+    ck_assert_ptr_nonnull(result->c_str);
+    ck_assert_ptr_ne(result->c_str, str1->c_str);
+    ck_assert_ptr_ne(result->c_str, str2->c_str);
+    ck_assert_int_eq(result->len, str1->len+str2->len);
+    ck_assert_str_eq(result->c_str, "String2String1");
+    ck_assert_int_eq(ember_string_error(), EMBER_STRING_NO_ERR);
+
+    result = estring_concat(str1, empty);
+    ck_assert_ptr_nonnull(result);
+    ck_assert_ptr_nonnull(result->c_str);
+    ck_assert_ptr_ne(result->c_str, str1->c_str);
+    ck_assert_ptr_ne(result->c_str, empty->c_str);
+    ck_assert_int_eq(result->len, str1->len);
+    ck_assert_str_eq(result->c_str, "String1");
+    ck_assert_int_eq(ember_string_error(), EMBER_STRING_NO_ERR);
+
+    result = estring_concat(str1, null_str);
+    ck_assert_ptr_nonnull(result);
+    ck_assert_ptr_nonnull(result->c_str);
+    ck_assert_ptr_ne(result->c_str, str1->c_str);
+    ck_assert_ptr_ne(result->c_str, empty->c_str);
+    ck_assert_int_eq(result->len, str1->len);
+    ck_assert_str_eq(result->c_str, "String1");
+    ck_assert_int_eq(ember_string_error(), EMBER_STRING_NULL_ARG);
+    clear_ember_string_error();
+
+    result = estring_concat(null_str, str2);
+    ck_assert_ptr_nonnull(result);
+    ck_assert_ptr_nonnull(result->c_str);
+    ck_assert_ptr_ne(result->c_str, str2->c_str);
+    ck_assert_ptr_ne(result->c_str, empty->c_str);
+    ck_assert_int_eq(result->len, str1->len);
+    ck_assert_str_eq(result->c_str, "String2");
+    ck_assert_int_eq(ember_string_error(), EMBER_STRING_NULL_ARG);
+    clear_ember_string_error();
+
+    result = estring_concat(null_str, null_str);
+    ck_assert_ptr_nonnull(result);
+    ck_assert_ptr_nonnull(result->c_str);
+    ck_assert_int_eq(result->len, empty->len);
+    ck_assert_str_eq(result->c_str, empty->c_str);
+    ck_assert_int_eq(ember_string_error(), EMBER_STRING_NULL_ARG);
+    clear_ember_string_error();
+
+    result = estring_concat(empty, empty);
+    ck_assert_ptr_nonnull(result);
+    ck_assert_ptr_nonnull(result->c_str);
+    ck_assert_ptr_ne(result->c_str, empty->c_str);
+    ck_assert_int_eq(result->len, empty->len);
+    ck_assert_str_eq(result->c_str, empty->c_str);
+    ck_assert_int_eq(ember_string_error(), EMBER_STRING_NO_ERR);
+    clear_ember_string_error();
+
+    destroy_estring(str1);
+    destroy_estring(str2);
+    destroy_estring(empty);
+    destroy_estring(result);
+}
+END_TEST
+
 Suite *ember_string_suite(void)
 {
     Suite *s;
@@ -93,6 +171,7 @@ Suite *ember_string_suite(void)
     tc_core = tcase_create("Core");
 
     tcase_add_test(tc_core, test_ember_string_from_cstr);
+    tcase_add_test(tc_core, test_ember_string_concat);
     suite_add_tcase(s, tc_core);
 
     return s;