extern size_t base64_encode_alloc (const char *in, size_t inlen, char **out);
extern void base64_decode_ctx_init (struct base64_decode_context *ctx);
extern bool base64_decode_ctx (struct base64_decode_context *ctx,
extern size_t base64_encode_alloc (const char *in, size_t inlen, char **out);
extern void base64_decode_ctx_init (struct base64_decode_context *ctx);
extern bool base64_decode_ctx (struct base64_decode_context *ctx,