Add bxs_ltrim() to bxstring module

src/bxstring.c

@@ -398,6 +398,24 @@ bxstr_t *bxs_trim(bxstr_t *pString)
 
 
 
+uint32_t *bxs_ltrim(bxstr_t *pString, size_t max)
+{
+    if (pString == NULL) {
+        return NULL;
+    }
+
+    size_t num_trimmed = BMIN(max, pString->num_chars_visible);
+    for (size_t i = 0; i < max; i++) {
+        if (!is_blank(pString->memory[pString->visible_char[i]])) {
+            num_trimmed = i;
+            break;
+        }
+    }
+    return u32_strdup(pString->memory + pString->first_char[num_trimmed]);
+}
+
+
+
 bxstr_t *bxs_rtrim(bxstr_t *pString)
 {
     if (pString == NULL) {

src/bxstring.h

@@ -179,6 +179,16 @@ uint32_t *bxs_unindent_ptr(bxstr_t *pString);
 bxstr_t *bxs_trim(bxstr_t *pString);
 
 
+/**
+ * Create a new string from which up to `max` leading spaces have been removed along with associated invisible
+ * characters.
+ * @param pString the string to trim, which will not be modified
+ * @param max the maximum number of leading spaces to remove
+ * @return a new, trimmed string
+ */
+uint32_t *bxs_ltrim(bxstr_t *pString, size_t max);
+
+
 /**
  * Create a new string from which all trailing whitespace have been removed.
  * @param pString the string to trim, which will not be modified

utest/bxstring_test.c

@@ -914,6 +914,95 @@ void test_bxs_trim_none(void **state)
 
 
 
+void test_bxs_ltrim2(void **state)
+{
+    UNUSED(state);
+
+    uint32_t *ustr32 = u32_strconv_from_arg("\xe2\x80\x83 \x1b[38;5;203m\xe2\x80\x82\x1b[0m X", "UTF-8");
+    /* em-space, space, en-space, space, X */
+    bxstr_t *bxstr = bxs_from_unicode(ustr32);
+    uint32_t *expected = u32_strconv_from_arg("\x1b[38;5;203m\xe2\x80\x82\x1b[0m X", "UTF-8");
+
+    uint32_t *actual = bxs_ltrim(bxstr, 2);
+    
+    assert_non_null(actual);
+    assert_int_equal(0, u32_strcmp(expected, actual));
+
+    BFREE(ustr32);
+    BFREE(actual);
+    BFREE(expected);
+    bxs_free(bxstr);
+}
+
+
+
+void test_bxs_ltrim5(void **state)
+{
+    UNUSED(state);
+
+    uint32_t *ustr32 = u32_strconv_from_arg("\xe2\x80\x83 \x1b[38;5;203m\xe2\x80\x82\x1b[0m abc", "UTF-8");
+    /* em-space, space, en-space, space, abc */
+    bxstr_t *bxstr = bxs_from_unicode(ustr32);
+    uint32_t *expected = u32_strconv_from_arg("abc", "ASCII");
+
+    uint32_t *actual = bxs_ltrim(bxstr, 5);
+    
+    assert_non_null(actual);
+    assert_int_equal(0, u32_strcmp(expected, actual));
+
+    BFREE(ustr32);
+    BFREE(actual);
+    BFREE(expected);
+    bxs_free(bxstr);
+}
+
+
+
+void test_bxs_ltrim_empty(void **state)
+{
+    UNUSED(state);
+
+    uint32_t *actual = bxs_ltrim(NULL, 2);
+    assert_null(actual);
+
+    uint32_t *ustr32 = u32_strconv_from_arg("\xe2\x80\x83 \x1b[38;5;203m\xe2\x80\x82\x1b[0m X", "UTF-8");
+    /* em-space, space, en-space, space, X */
+    bxstr_t *bxstr = bxs_from_unicode(ustr32);
+
+    actual = bxs_ltrim(bxstr, 0);
+    assert_ptr_not_equal(ustr32, actual);
+    assert_int_equal(0, u32_strcmp(ustr32, actual));
+
+    BFREE(ustr32);
+    BFREE(actual);
+    bxs_free(bxstr);
+}
+
+
+
+void test_bxs_ltrim_max(void **state)
+{
+    UNUSED(state);
+
+    uint32_t *ustr32 = u32_strconv_from_arg("\xe2\x80\x83 \x1b[38;5;203m\xe2\x80\x82\x1b[0m ", "UTF-8");
+    /* em-space, space, en-space, space */
+    bxstr_t *bxstr = bxs_from_unicode(ustr32);
+    uint32_t *expected = new_empty_string32();
+
+    uint32_t *actual = bxs_ltrim(bxstr, 20);
+    
+    assert_non_null(actual);
+    assert_int_equal(0, u32_strlen(actual));
+    assert_int_equal(0, u32_strcmp(expected, actual));
+
+    BFREE(ustr32);
+    BFREE(actual);
+    BFREE(expected);
+    bxs_free(bxstr);
+}
+
+
+
 void test_bxs_rtrim(void **state)
 {
     UNUSED(state);

utest/bxstring_test.h

@@ -67,6 +67,11 @@ void test_bxs_trim(void **state);
 void test_bxs_trim_blanks(void **state);
 void test_bxs_trim_none(void **state);
 
+void test_bxs_ltrim2(void **state);
+void test_bxs_ltrim5(void **state);
+void test_bxs_ltrim_empty(void **state);
+void test_bxs_ltrim_max(void **state);
+
 void test_bxs_rtrim(void **state);
 void test_bxs_rtrim_empty(void **state);
 

utest/main.c

@@ -157,6 +157,10 @@ int main(void)
         cmocka_unit_test_setup(test_bxs_trim, beforeTest),
         cmocka_unit_test_setup(test_bxs_trim_blanks, beforeTest),
         cmocka_unit_test_setup(test_bxs_trim_none, beforeTest),
+        cmocka_unit_test_setup(test_bxs_ltrim2, beforeTest),
+        cmocka_unit_test_setup(test_bxs_ltrim5, beforeTest),
+        cmocka_unit_test_setup(test_bxs_ltrim_empty, beforeTest),
+        cmocka_unit_test_setup(test_bxs_ltrim_max, beforeTest),
         cmocka_unit_test_setup(test_bxs_rtrim, beforeTest),
         cmocka_unit_test_setup(test_bxs_rtrim_empty, beforeTest),
         cmocka_unit_test_setup(test_bxs_append_spaces, beforeTest),