--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libtomcrypt/src/pk/asn1/der/generalizedtime/der_encode_generalizedtime.c	Fri Feb 09 21:44:05 2018 +0800
@@ -0,0 +1,108 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ */
+#include "tomcrypt.h"
+
+/**
+  @file der_encode_utctime.c
+  ASN.1 DER, encode a GeneralizedTime, Steffen Jaeckel
+  Based on der_encode_utctime.c
+*/
+
+#ifdef LTC_DER
+
+static const char * const baseten = "0123456789";
+
+#define STORE_V(y) do {\
+    out[x++] = der_ia5_char_encode(baseten[(y/10) % 10]); \
+    out[x++] = der_ia5_char_encode(baseten[y % 10]); \
+} while(0)
+
+#define STORE_V4(y) do {\
+    out[x++] = der_ia5_char_encode(baseten[(y/1000) % 10]); \
+    out[x++] = der_ia5_char_encode(baseten[(y/100) % 10]); \
+    out[x++] = der_ia5_char_encode(baseten[(y/10) % 10]); \
+    out[x++] = der_ia5_char_encode(baseten[y % 10]); \
+} while(0)
+
+/**
+  Encodes a Generalized time structure in DER format
+  @param gtime        The GeneralizedTime structure to encode
+  @param out          The destination of the DER encoding of the GeneralizedTime structure
+  @param outlen       [in/out] The length of the DER encoding
+  @return CRYPT_OK if successful
+*/
+int der_encode_generalizedtime(ltc_generalizedtime *gtime,
+                               unsigned char       *out,   unsigned long *outlen)
+{
+    unsigned long x, tmplen;
+    int           err;
+
+    LTC_ARGCHK(gtime != NULL);
+    LTC_ARGCHK(out     != NULL);
+    LTC_ARGCHK(outlen  != NULL);
+
+    if ((err = der_length_generalizedtime(gtime, &tmplen)) != CRYPT_OK) {
+       return err;
+    }
+    if (tmplen > *outlen) {
+        *outlen = tmplen;
+        return CRYPT_BUFFER_OVERFLOW;
+    }
+
+    /* store header */
+    out[0] = 0x18;
+
+    /* store values */
+    x = 2;
+    STORE_V4(gtime->YYYY);
+    STORE_V(gtime->MM);
+    STORE_V(gtime->DD);
+    STORE_V(gtime->hh);
+    STORE_V(gtime->mm);
+    STORE_V(gtime->ss);
+
+    if (gtime->fs) {
+       unsigned long divisor;
+       unsigned fs = gtime->fs;
+       unsigned len = 0;
+       out[x++] = der_ia5_char_encode('.');
+       divisor = 1;
+       do {
+          fs /= 10;
+          divisor *= 10;
+          len++;
+       } while(fs != 0);
+       while (len-- > 1) {
+          divisor /= 10;
+          out[x++] = der_ia5_char_encode(baseten[(gtime->fs/divisor) % 10]);
+       }
+       out[x++] = der_ia5_char_encode(baseten[gtime->fs % 10]);
+    }
+
+    if (gtime->off_mm || gtime->off_hh) {
+       out[x++] = der_ia5_char_encode(gtime->off_dir ? '-' : '+');
+       STORE_V(gtime->off_hh);
+       STORE_V(gtime->off_mm);
+    } else {
+       out[x++] = der_ia5_char_encode('Z');
+    }
+
+    /* store length */
+    out[1] = (unsigned char)(x - 2);
+
+    /* all good let's return */
+    *outlen = x;
+    return CRYPT_OK;
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */