eina: add API eina_strftime

Summary:
Add new API eina_strftime API in eina_str

@feature

Test Plan: test case and example also updated

Reviewers: tasn, cedric

Reviewed By: cedric

Subscribers: cedric

Differential Revision: https://phab.enlightenment.org/D3148

Signed-off-by: Cedric BAIL <cedric@osg.samsung.com>

AUTHORS

@@ -53,6 +53,7 @@ ChunEon Park (Hermet) <hermet@hermet.pe.kr>
 Rajeev Ranjan (Rajeev) <rajeev.r@samsung.com> <rajeev.jnnce@gmail.com>
 Subodh Kumar <s7158.kumar@samsung.com>
 Michelle Legrand <legrand.michelle@outlook.com>
+Shilpa Singh <shilpa.singh@samsung.com> <shilpasingh.o@gmail.com>
 
 Eet
 ---

src/examples/eina/eina_str_01.c

@@ -14,6 +14,9 @@ int main(int argc EINA_UNUSED, char **argv EINA_UNUSED)
    char *part2 = "There are many copies. And they have a plan.";
    char **arr;
    int i;
+   char *time_arr;
+   time_t curr_time;
+   struct tm *info;
 
    eina_init();
 
@@ -58,7 +61,13 @@ int main(int argc EINA_UNUSED, char **argv EINA_UNUSED)
    eina_strlcat(str, "humans", 14);
    printf("%s\n", str);
    free(str);
-   
+
+   curr_time = time(NULL);
+   info = localtime(&curr_time);
+   time_arr = eina_strftime("%d/%m/%Y", info);
+   printf("Today's Date: %s\n", time_arr);
+   free(time_arr);
+
    eina_shutdown();
 
    return 0;

src/lib/eina/eina_str.c

@@ -374,6 +374,39 @@ eina_strlcat(char *dst, const char *src, size_t siz)
    return(dlen + (s - src)); /* count does not include NUL */
 }
 
+EAPI char *
+eina_strftime(const char *format, const struct tm *tm)
+{
+   const size_t flen = strlen(format);
+   size_t buflen = 16; // An arbitrary starting size
+   char *buf = NULL;
+
+   do {
+      char *tmp;
+      size_t len;
+
+      tmp = realloc(buf, buflen * sizeof(char));
+      if (!tmp) goto on_error;
+      buf = tmp;
+
+      len = strftime(buf, buflen, format, tm);
+      // Check if we have the expected result and return it.
+      if ((len > 0 && len < buflen) || (len == 0 && flen == 0))
+        {
+           tmp = realloc(buf, ((len + 1) * sizeof(char)));
+           buf = tmp;
+           return buf;
+        }
+
+      /* Possibly buf overflowed - try again with a bigger buffer */
+      buflen <<= 1; // multiply buffer size by 2
+   } while (buflen < 128 * flen);
+
+ on_error:
+   free(buf);
+   return NULL;
+}
+
 EAPI Eina_Bool
 eina_str_has_prefix(const char *str, const char *prefix)
 {

src/lib/eina/eina_str.h

@@ -355,6 +355,32 @@ static inline size_t eina_strlen_bounded(const char *str, size_t maxlen) EINA_PU
  * @since 1.13
  */
 EAPI unsigned char *eina_memdup(unsigned char *mem, size_t size, Eina_Bool terminate);
+
+/**
+ * @brief Create and update the buffer based on strftime output.
+ *
+ * @param tm Pointer to a tm structure needed by strftime.
+ * @param format String containing format specifiers needed by strftime.
+ * @return Updated buffer based on strftime output
+ *
+ * This will create a buffer of exact required size based on strftime output
+ * once use is complete the buffer has to be freed using free.
+ *
+ * Example usage:
+ * @code
+ * time_t curr_time;
+ * struct tm *info;
+ * char *buf;
+ * curr_time = time(NULL);
+ * info = localtime(&curr_time);
+ * buf = eina_strftime("%I:%M%p", info);
+ * //after use
+ * free(buf);
+ * @endcode
+ *
+ * @since 1.16.0
+ */
+EAPI char *eina_strftime(const char *format, const struct tm *tm);
 #include "eina_inline_str.x"
 
 /**

src/tests/eina/eina_test_str.c

@@ -347,6 +347,24 @@ START_TEST(str_memdup)
 }
 END_TEST
 
+START_TEST(str_strftime)
+{
+   time_t curr_time;
+   struct tm *info;
+   char *buf;
+   eina_init();
+
+   curr_time = time(NULL);
+   info = localtime(&curr_time);
+
+   buf = eina_strftime("%I:%M%p", info);
+   fail_if(buf == NULL);
+   free(buf);
+
+   eina_shutdown();
+}
+END_TEST
+
 #ifdef HAVE_ICONV
 START_TEST(str_convert)
 {
@@ -385,6 +403,7 @@ eina_test_str(TCase *tc)
    tcase_add_test(tc, str_lcat_lcpy);
    tcase_add_test(tc, str_join_len);
    tcase_add_test(tc, str_memdup);
+   tcase_add_test(tc, str_strftime);
 #ifdef HAVE_ICONV
    tcase_add_test(tc, str_convert);
 #endif