[ChangeLog]

When decoding, always allow newlines in input, with almost no
performance impact.
* src/base64.c (do_decode): Initialize decode context.
Call base64_decode one more time, after all input is processed.
(usage): When decoding, newlines are always accepted.

* tests/misc/base64: Add a bunch of tests, for the above.
* gl/lib/base64.c: Include <string.h>.
(base64_decode_ctx_init, get_4, decode_4): New functions.
(base64_decode): Efficiently handle interspersed newlines.
(base64_decode_alloc): Update signature.
* gl/lib/base64.h (struct base64_decode_context): Define.
(base64_decode_ctx_init): Add prototype.
(base64_decode, base64_decode_alloc): Update prototypes.
[doc/ChangeLog]
* coreutils.texi (base64 invocation): When decoding, newlines
are always accepted.

1 files changed, 11 insertions, 2 deletions

diff --git a/gl/lib/base64.h b/gl/lib/base64.h
index 6bb9a97f5..be858eaaf 100644
--- a/gl/lib/base64.h
+++ b/gl/lib/base64.h
@@ -29,6 +29,12 @@
    integer >= n/k, i.e., the ceiling of n/k.  */
 # define BASE64_LENGTH(inlen) ((((inlen) + 2) / 3) * 4)
 
+struct base64_decode_context
+{
+  unsigned int i;
+  char buf[4];
+};
+
 extern bool isbase64 (char ch);
 
 extern void base64_encode (const char *restrict in, size_t inlen,
@@ -36,10 +42,13 @@ extern void base64_encode (const char *restrict in, size_t inlen,
 
 extern size_t base64_encode_alloc (const char *in, size_t inlen, char **out);
 
-extern bool base64_decode (const char *restrict in, size_t inlen,
+extern void base64_decode_ctx_init (struct base64_decode_context *ctx);
+extern bool base64_decode (struct base64_decode_context *ctx,
+			   const char *restrict in, size_t inlen,
 			   char *restrict out, size_t *outlen);
 
-extern bool base64_decode_alloc (const char *in, size_t inlen,
+extern bool base64_decode_alloc (struct base64_decode_context *ctx,
+				 const char *in, size_t inlen,
 				 char **out, size_t *outlen);
 
 #endif /* BASE64_H */