1 files changed, 58 insertions, 0 deletions
diff --git a/astrftime.c b/astrftime.c
new file mode 100644
index 0000000..4c10654
--- /dev/null
+++ b/astrftime.c
@@ -0,0 +1,58 @@
+#define _POSIX_C_SOURCE 200809L
+
+#include "utils.h"
+#include <errno.h>
+#include <locale.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+char *astrftime(const char *const fmt, const struct tm *const tm)
+{
+    char *ret = NULL, *s = NULL;
+    size_t n = sizeof ".";
+    const locale_t l = newlocale(LC_TIME_MASK, "POSIX", (locale_t)0);
+
+    if (l == (locale_t)0)
+    {
+        fprintf(stderr, "%s: newlocale(3): %s\n", __func__, strerror(errno));
+        goto end;
+    }
+    else if (!(s = malloc(n)))
+    {
+        fprintf(stderr, "%s: malloc(3): %s\n", __func__, strerror(errno));
+        goto end;
+    }
+
+    for (;;)
+    {
+        const int res = strftime_l(s, n, fmt, tm, l);
+
+        if (!res)
+        {
+            char *const ss = realloc(s, ++n);
+
+            if (!s)
+            {
+                fprintf(stderr, "%s: realloc(3): %s\n", __func__,
+                    strerror(errno));
+                goto end;
+            }
+
+            s = ss;
+        }
+        else
+            break;
+    }
+
+    ret = s;
+
+end:
+
+    if (!ret)
+        free(s);
+
+    freelocale(l);
+    return ret;
+}