Add bxs_filter_visible() and react to color options in bxs_to_output() in 'bxstring' module

src/bxstring.c

@@ -336,7 +336,15 @@ char *bxs_to_output(bxstr_t *pString)
     if (pString == NULL) {
         return strdup("NULL");
     }
-    return u32_strconv_to_output(pString->memory);
+
+    if (color_output_enabled) {
+        return u32_strconv_to_output(pString->memory);
+    }
+
+    uint32_t *vis = bxs_filter_visible(pString);
+    char *result = u32_strconv_to_output(vis);
+    BFREE(vis);
+    return result;
 }
 
 
@@ -370,6 +378,26 @@ int bxs_is_visible_char(bxstr_t *pString, size_t idx)
 
 
 
+uint32_t *bxs_filter_visible(bxstr_t *pString)
+{
+    uint32_t *result = NULL;
+    if (pString != NULL) {
+        if (pString->num_chars_invisible == 0) {
+            result = u32_strdup(pString->memory);
+        }
+        else {
+            result = (uint32_t *) calloc(pString->num_chars_visible + 1, sizeof(uint32_t));
+            for (size_t i = 0; i < pString->num_chars_visible; i++) {
+                set_char_at(result, i, pString->memory[pString->visible_char[i]]);
+            }
+            set_char_at(result, pString->num_chars_visible, char_nul);
+        }
+    }
+    return result;
+}
+
+
+
 int bxs_strcmp(bxstr_t *s1, bxstr_t *s2)
 {
     if (s1 == NULL) {

src/bxstring.h

@@ -143,7 +143,7 @@ bxstr_t *bxs_rtrim(bxstr_t *pString);
 /**
  * Convert the string into boxes' output encoding for proper printing on stdout.
  * @param pString the string to convert
- * @return the same string in the target (output) encoding
+ * @return the same string in the target (output) encoding, for which new memory has been allocated
  */
 char *bxs_to_output(bxstr_t *pString);
 
@@ -166,6 +166,15 @@ int bxs_is_empty(bxstr_t *pString);
 int bxs_is_visible_char(bxstr_t *pString, size_t idx);
 
 
+/**
+ * Filter the given string so that only the visible characters are returned.
+ * @param pString the string to filter (may be NULL, in which case NULL is returned)
+ * @return a new UTF-32 string which contains only the visible characters from the given string, or NULL when the
+ *      given string was NULL
+ */
+uint32_t *bxs_filter_visible(bxstr_t *pString);
+
+
 /**
  * Determine whether the given `pString` is a valid string under at least one condition. This will return `false` for
  * strings which should really never occur anywhere.

utest/bxstring_test.c

@@ -22,6 +22,7 @@
 #include <setjmp.h>
 #include <stdarg.h>
 #include <stddef.h>
+#include <unistr.h>
 
 #include <cmocka.h>
 #include <string.h>
@@ -932,6 +933,49 @@ void test_bxs_is_visible_char(void **state)
 
 
 
+void test_bxs_filter_visible(void **state)
+{
+    UNUSED(state);
+
+    uint32_t *ustr32 = u32_strconv_from_arg("\x1b[38;5;203mX\x1b[0m \x1b[38;5;203mY\x1b[0m", "ASCII");
+    assert_non_null(ustr32);
+    bxstr_t *input = bxs_from_unicode(ustr32);
+    uint32_t *expected = u32_strconv_from_arg("X Y", "ASCII");
+
+    uint32_t *actual = bxs_filter_visible(input);
+    assert_int_equal(0, u32_strcmp(expected, actual));
+
+    actual = bxs_filter_visible(NULL);
+    assert_null(actual);
+
+    BFREE(actual);
+    BFREE(expected);
+    BFREE(ustr32);
+    bxs_free(input);
+}
+
+
+
+void test_bxs_filter_visible_none(void **state)
+{
+    UNUSED(state);
+
+    uint32_t *ustr32 = u32_strconv_from_arg("plain", "ASCII");
+    assert_non_null(ustr32);
+    bxstr_t *input = bxs_from_unicode(ustr32);
+    uint32_t *expected = u32_strconv_from_arg("plain", "ASCII");
+
+    uint32_t *actual = bxs_filter_visible(input);
+    assert_int_equal(0, u32_strcmp(expected, actual));
+
+    BFREE(actual);
+    BFREE(expected);
+    BFREE(ustr32);
+    bxs_free(input);
+}
+
+
+
 void test_bxs_strcmp(void **state)
 {
     UNUSED(state);

utest/bxstring_test.h

@@ -69,6 +69,9 @@ void test_bxs_is_empty_null(void **state);
 
 void test_bxs_is_visible_char(void **state);
 
+void test_bxs_filter_visible(void **state);
+void test_bxs_filter_visible_none(void **state);
+
 void test_bxs_strcmp(void **state);
 
 void test_bxs_valid_anywhere_error(void **state);

utest/main.c

@@ -155,6 +155,9 @@ int main(void)
         cmocka_unit_test_setup(test_bxs_to_output, beforeTest),
         cmocka_unit_test_setup(test_bxs_is_empty_null, beforeTest),
         cmocka_unit_test_setup(test_bxs_is_visible_char, beforeTest),
+        cmocka_unit_test_setup(test_bxs_filter_visible, beforeTest),
+        cmocka_unit_test_setup(test_bxs_filter_visible_none, beforeTest),
+
         cmocka_unit_test_setup(test_bxs_strcmp, beforeTest),
         cmocka_unit_test_setup(test_bxs_valid_anywhere_error, beforeTest),
         cmocka_unit_test_setup(test_bxs_valid_in_filename_error, beforeTest),