add str_append_format_padding

docs/changes.md

@@ -1,5 +1,8 @@
 # 最新动态
 
+2024/11/19
+  * 增加函数 str_append_format_padding
+
 2024/11/18
   * 完善 atomic(感谢兆坤提供补丁)
   * 修复拼写错误(感谢兆坤提供补丁)

src/tkc/str.c

@@ -1135,6 +1135,29 @@ ret_t str_append_format(str_t* str, uint32_t size, const char* format, ...) {
   return RET_OK;
 }
 
+ret_t str_append_format_padding(str_t* str, uint32_t size, const char* format, ...) {
+  va_list va;
+  int32_t ret = 0;
+  uint32_t old_size = 0;
+  return_value_if_fail(str != NULL && format != NULL, RET_BAD_PARAMS);
+  return_value_if_fail(str_extend(str, str->size + size + 1) == RET_OK, RET_OOM);
+
+  old_size = str->size;
+  va_start(va, format);
+  ret = tk_vsnprintf(str->str + str->size, size, format, va);
+  va_end(va);
+
+  return_value_if_fail(ret >= 0, RET_BAD_PARAMS);
+  str->size += ret;
+
+  if (str->size < (old_size + size)) {
+    uint32_t n = (old_size + size) - str->size;
+    str_append_n_chars(str, ' ', n);
+  }
+
+  return RET_OK;
+}
+
 ret_t str_append_json_pair(str_t* str, const char* key, const value_t* value) {
   ret_t ret;
   return_value_if_fail(str != NULL && key != NULL && value, RET_BAD_PARAMS);

src/tkc/str.h

@@ -810,6 +810,17 @@ ret_t str_format(str_t* str, uint32_t size, const char* format, ...);
  */
 ret_t str_append_format(str_t* str, uint32_t size, const char* format, ...);
 
+/**
+ * @method str_append_format_padding
+ * 通过格式追加字符串(字符串不够size长时，自动填充空格)。
+ * @param {str_t*} str str对象。
+ * @param {uint32_t} size format生成的字符串的最大长度(用于预先分配内存)。
+ * @param {const char*} format 格式。
+ *
+ * @return {ret_t} 返回RET_OK表示成功，否则表示失败。
+ */
+ret_t str_append_format_padding(str_t* str, uint32_t size, const char* format, ...);
+
 /**
  * @method str_append_json_pair
  * 追加json键值对。

tests/str_test.cc

@@ -48,7 +48,7 @@ TEST(Str, shrink) {
   str_append(&s, "1234");
   ASSERT_EQ(str_shrink(&s, 2), RET_OK);
   ASSERT_STREQ(s.str, "12");
-  
+
   ASSERT_EQ(str_shrink(&s, 20), RET_OK);
   ASSERT_STREQ(s.str, "12");
 
@@ -1080,4 +1080,45 @@ TEST(Str, str_append_json_pair) {
   ASSERT_STREQ(s->str, "\"x\":\"abc\"");
 
   str_reset(s);
+}
+
+TEST(Str, append_format_ex) {
+  str_t s;
+  str_init(&s, 0);
+  str_append(&s, "Name          Date          Temperature    Humidity\n");
+
+  str_append_format_padding(&s, 14, "Device%d", 1);
+  str_append_format_padding(&s, 14, "2024-11-01");
+  str_append_format_padding(&s, 16, "%2.2f \xC2\xB0\x43", 26.5);
+  str_append_format(&s, 14, "50\n");
+
+  str_append_format_padding(&s, 14, "Device%d", 2);
+  str_append_format_padding(&s, 14, "2024-11-02");
+  str_append_format_padding(&s, 16, "%2.2f \xC2\xB0\x43", (float)27);
+  str_append_format(&s, 14, "60\n");
+
+  log_debug("\n%s\n", s.str);
+
+  str_clear(&s);
+  str_append_format_padding(&s, 14, "Device%d", 2);
+  ASSERT_STREQ(s.str, "Device2       ");
+
+  str_clear(&s);
+  str_append_format_padding(&s, 14, "%2.4f", 2.5);
+  ASSERT_STREQ(s.str, "2.5000        ");
+
+  str_clear(&s);
+  str_append_format_padding(&s, 14, "%2.4f", 27.0);
+  ASSERT_STREQ(s.str, "27.0000       ");
+
+  str_clear(&s);
+  str_append_format_padding(&s, 14, "%2.4f", (float)27);
+  ASSERT_STREQ(s.str, "27.0000       ");
+
+  str_clear(&s);
+  float v = 27;
+  str_append_format_padding(&s, 14, "%2.4f", v);
+  ASSERT_STREQ(s.str, "27.0000       ");
+
+  str_reset(&s);
 }