base64: added Curl_base64url_encode()

This is now used by the http2 code. It has two different symbols at the
end of the base64 table to make the output "url safe".

Bug: https://github.com/tatsuhiro-t/nghttp2/issues/62

lib/base64.c

@@ -5,7 +5,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2013, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -37,9 +37,14 @@
 #include "memdebug.h"
 
 /* ---- Base64 Encoding/Decoding Table --- */
-static const char table64[]=
+static const char base64[]=
   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
+/* The Base 64 encoding with an URL and filename safe alphabet, RFC 4648
+   section 5 */
+static const char base64url[]=
+  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";
+
 static size_t decodeQuantum(unsigned char *dest, const char *src)
 {
   size_t padding = 0;
@@ -54,7 +59,7 @@ static size_t decodeQuantum(unsigned char *dest, const char *src)
       padding++;
     }
     else {
-      p = table64;
+      p = base64;
 
       while(*p && (*p != *s)) {
         v++;
@@ -167,24 +172,8 @@ CURLcode Curl_base64_decode(const char *src,
   return CURLE_OK;
 }
 
-/*
+static CURLcode base64_encode(const char *table64,
- * Curl_base64_encode()
+                              struct SessionHandle *data,
- *
- * Given a pointer to an input buffer and an input size, encode it and
- * return a pointer in *outptr to a newly allocated memory area holding
- * encoded data. Size of encoded data is returned in variable pointed by
- * outlen.
- *
- * Input length of 0 indicates input buffer holds a NUL-terminated string.
- *
- * Returns CURLE_OK on success, otherwise specific error code. Function
- * output shall not be considered valid unless CURLE_OK is returned.
- *
- * When encoded data length is 0, returns NULL in *outptr.
- *
- * @unittest: 1302
- */
-CURLcode Curl_base64_encode(struct SessionHandle *data,
                               const char *inputbuff, size_t insize,
                               char **outptr, size_t *outlen)
 {
@@ -274,4 +263,52 @@ CURLcode Curl_base64_encode(struct SessionHandle *data,
 
   return CURLE_OK;
 }
+
+/*
+ * Curl_base64_encode()
+ *
+ * Given a pointer to an input buffer and an input size, encode it and
+ * return a pointer in *outptr to a newly allocated memory area holding
+ * encoded data. Size of encoded data is returned in variable pointed by
+ * outlen.
+ *
+ * Input length of 0 indicates input buffer holds a NUL-terminated string.
+ *
+ * Returns CURLE_OK on success, otherwise specific error code. Function
+ * output shall not be considered valid unless CURLE_OK is returned.
+ *
+ * When encoded data length is 0, returns NULL in *outptr.
+ *
+ * @unittest: 1302
+ */
+CURLcode Curl_base64_encode(struct SessionHandle *data,
+                            const char *inputbuff, size_t insize,
+                            char **outptr, size_t *outlen)
+{
+  return base64_encode(base64, data, inputbuff, insize, outptr, outlen);
+}
+
+/*
+ * Curl_base64url_encode()
+ *
+ * Given a pointer to an input buffer and an input size, encode it and
+ * return a pointer in *outptr to a newly allocated memory area holding
+ * encoded data. Size of encoded data is returned in variable pointed by
+ * outlen.
+ *
+ * Input length of 0 indicates input buffer holds a NUL-terminated string.
+ *
+ * Returns CURLE_OK on success, otherwise specific error code. Function
+ * output shall not be considered valid unless CURLE_OK is returned.
+ *
+ * When encoded data length is 0, returns NULL in *outptr.
+ *
+ * @unittest:
+ */
+CURLcode Curl_base64url_encode(struct SessionHandle *data,
+                               const char *inputbuff, size_t insize,
+                               char **outptr, size_t *outlen)
+{
+  return base64_encode(base64url, data, inputbuff, insize, outptr, outlen);
+}
 /* ---- End of Base64 Encoding ---- */

lib/curl_base64.h

@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2011, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -25,6 +25,9 @@
 CURLcode Curl_base64_encode(struct SessionHandle *data,
                             const char *inputbuff, size_t insize,
                             char **outptr, size_t *outlen);
+CURLcode Curl_base64url_encode(struct SessionHandle *data,
+                               const char *inputbuff, size_t insize,
+                               char **outptr, size_t *outlen);
 
 CURLcode Curl_base64_decode(const char *src,
                             unsigned char **outptr, size_t *outlen);

lib/http2.c

@@ -504,7 +504,7 @@ CURLcode Curl_http2_request_upgrade(Curl_send_buffer *req,
   }
   conn->proto.httpc.binlen = binlen;
 
-  result = Curl_base64_encode(conn->data, (const char *)binsettings, binlen,
+  result = Curl_base64url_encode(conn->data, (const char *)binsettings, binlen,
                                  &base64, &blen);
   if(result)
     return result;