From b64b3086f4392a564fb5dcc0c5a206cc58dbebd7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Mon, 21 Oct 2002 15:40:37 +0200
Subject: [PATCH] (sexp_transport_iterator_first): New file and function.
Rev: src/nettle/sexp-transport.c:1.1
---
sexp-transport.c | 118 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 118 insertions(+)
create mode 100644 sexp-transport.c
diff --git a/sexp-transport.c b/sexp-transport.c
new file mode 100644
index 00000000..7737891c
--- /dev/null
+++ b/sexp-transport.c
@@ -0,0 +1,118 @@
+/* sexp-transport.c
+ *
+ * Parsing s-expressions in transport format.
+ */
+
+/* nettle, low-level cryptographics library
+ *
+ * Copyright (C) 2002 Niels Möller
+ *
+ * The nettle library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or (at your
+ * option) any later version.
+ *
+ * The nettle library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with the nettle library; see the file COPYING.LIB. If not, write to
+ * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ */
+
+#include "sexp.h"
+
+#include "base64.h"
+
+#include <assert.h>
+#include <string.h>
+
+/* NOTE: Decodes the input string in place */
+int
+sexp_transport_iterator_first(struct sexp_iterator *iterator,
+ unsigned length, uint8_t *input)
+{
+ /* We first base64 decode any transport encoded sexp at the start of
+ * the input. */
+
+ unsigned in = 0;
+ unsigned out = 0;
+
+ while (in < length)
+ switch(input[in])
+ {
+ case ' ': /* SPC, TAB, LF, CR */
+ case '\t':
+ case '\n':
+ case '\r':
+ in++;
+ break;
+
+ case ';': /* Comments */
+ while (++in < length && input[in] != '\n')
+ ;
+ break;
+
+ case '{':
+ {
+ /* Found transport encoding */
+ struct base64_decode_ctx ctx;
+ unsigned end;
+
+ for (end = ++in; end < length && input[end] != '}'; end++)
+ ;
+
+ if (end == length)
+ return 0;
+
+ base64_decode_init(&ctx);
+
+ out += base64_decode_update(&ctx, input + out,
+ end - in, input + in);
+ if (!base64_decode_status(&ctx))
+ return 0;
+ in = end + 1;
+
+ break;
+ }
+ default:
+ /* Expression isn't in transport encoding. Rest of the input
+ * should be in canonical encoding. */
+ goto transport_done;
+ }
+
+ transport_done:
+
+ /* Here, we have two, possibly empty, input parts in canonical
+ * encoding:
+ *
+ * 0...out-1, in...length -1
+ *
+ * If the input was already in canonical encoding, out = 0 and in =
+ * amount of leading space.
+ *
+ * If all input was in transport encoding, in == length.
+ */
+ if (!out)
+ {
+ input += in;
+ length -= in;
+ }
+ else if (in == length)
+ length = out;
+ else if (out == in)
+ /* Unusual case, nothing happens */
+ ;
+ else
+ {
+ /* Both parts non-empty */
+ assert(out < in);
+ memmove(input + out, input + in, length - in);
+ length -= (in - out);
+ }
+
+ return sexp_iterator_first(iterator, length, input);
+}
--
GitLab