From 557cd8e454547616a191ee6482873874436c3931 Mon Sep 17 00:00:00 2001
From: ligd <liguiding@pinecone.net>
Date: Sun, 27 Jan 2019 07:20:25 -0600
Subject: [PATCH] netutils/codecs/base64.c:  Add base64_[de|en]code_length()
 API

---
 include/netutils/base64.h |  2 ++
 netutils/codecs/base64.c  | 18 ++++++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/include/netutils/base64.h b/include/netutils/base64.h
index 6ca3c0a5d..d44600333 100644
--- a/include/netutils/base64.h
+++ b/include/netutils/base64.h
@@ -68,8 +68,10 @@ extern "C"
  ****************************************************************************/
 
 #ifdef CONFIG_CODECS_BASE64
+size_t    base64_encode_length(size_t len);
 FAR void *base64_encode(FAR const void *src, size_t len, FAR void *dst,
                         FAR size_t *out_len);
+size_t base64_decode_length(size_t len);
 FAR void *base64_decode(FAR const void *src, size_t len, FAR void *dst,
                         FAR size_t *out_len);
 FAR void *base64w_encode(FAR const void *src, size_t len, FAR void *dst,
diff --git a/netutils/codecs/base64.c b/netutils/codecs/base64.c
index 5a6eae658..b38155133 100644
--- a/netutils/codecs/base64.c
+++ b/netutils/codecs/base64.c
@@ -256,6 +256,15 @@ static char *_base64_decode(FAR const char *src, size_t len, FAR char *dst,
  * Public Functions
  ****************************************************************************/
 
+/****************************************************************************
+ * Name: base64_encode_length
+ ****************************************************************************/
+
+size_t base64_encode_length(size_t len)
+{
+  return (len + 2) / 3 * 4;
+}
+
 /****************************************************************************
  * Name: base64_encode
  ****************************************************************************/
@@ -266,6 +275,15 @@ FAR void *base64_encode(FAR const void *src, size_t len, FAR void *dst,
   return _base64_encode(src, len, dst, out_len, false);
 }
 
+/****************************************************************************
+ * Name: base64_decode_length
+ ****************************************************************************/
+
+size_t base64_decode_length(size_t len)
+{
+  return len * 3 / 4;
+}
+
 /****************************************************************************
  * Name: base64_decode
  ****************************************************************************/