common: Add z-base-32 encoder.

* common/zb32.c: New.
* common/t-zb32.c: New.
* common/Makefile.am (common_sources): Add zb82.c
(module_tests): Add t-zb32.

4 files changed, 235 insertions, 2 deletions

diff --git a/common/Makefile.am b/common/Makefile.am
index 21f779c8a..f1cf28c89 100644
--- a/common/Makefile.am
+++ b/common/Makefile.am
@@ -72,7 +72,7 @@ common_sources = \
 	homedir.c \
 	gettime.c gettime.h \
 	yesno.c \
-	b64enc.c b64dec.c \
+	b64enc.c b64dec.c zb32.c \
 	convert.c \
 	percent.c \
 	miscellaneous.c \
@@ -166,7 +166,7 @@ jnlib_tests += t-w32-reg
 endif
 module_tests = t-convert t-percent t-gettime t-sysutils t-sexputil \
 	       t-session-env t-openpgp-oid t-ssh-utils t-dns-cert \
-	       t-mapstrings
+	       t-mapstrings t-zb32
 if !HAVE_W32CE_SYSTEM
 module_tests += t-exechelp
 endif
@@ -202,3 +202,4 @@ t_openpgp_oid_LDADD = $(t_common_ldadd)
 t_ssh_utils_LDADD = $(t_common_ldadd)
 t_dns_cert_LDADD = $(t_common_ldadd) $(DNSLIBS)
 t_mapstrings_LDADD = $(t_common_ldadd)
+t_zb32_LDADD = $(t_common_ldadd)
diff --git a/common/t-zb32.c b/common/t-zb32.c
new file mode 100644
index 000000000..7d509da54
--- /dev/null
+++ b/common/t-zb32.c
@@ -0,0 +1,110 @@
+/* t-zb32.c - Module tests for zb32.c
+ * Copyright (C) 2014  Werner Koch
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either
+ *
+ *   - the GNU Lesser General Public License as published by the Free
+ *     Software Foundation; either version 3 of the License, or (at
+ *     your option) any later version.
+ *
+ * or
+ *
+ *   - the GNU General Public License as published by the Free
+ *     Software Foundation; either version 2 of the License, or (at
+ *     your option) any later version.
+ *
+ * or both in parallel, as here.
+ *
+ * This file 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "util.h"
+
+#define pass()  do { ; } while(0)
+#define fail(a)  do { fprintf (stderr, "%s:%d: test %d failed\n",\
+                               __FILE__,__LINE__, (a));          \
+                     errcount++;                                 \
+                   } while(0)
+
+static int errcount;
+
+
+static void
+test_zb32enc (void)
+{
+  static struct {
+    size_t datalen;
+    char *data;
+    const char *expected;
+  } tests[] = {
+    /* From the DESIGN document.  */
+    {  1, "\x00", "y" },
+    {  1, "\x80", "o" },
+    {  2, "\x40", "e" },
+    {  2, "\xc0", "a" },
+    { 10, "\x00\x00", "yy" },
+    { 10, "\x80\x80", "on" },
+    { 20, "\x8b\x88\x80", "tqre" },
+    { 24, "\xf0\xbf\xc7", "6n9hq" },
+    { 24, "\xd4\x7a\x04", "4t7ye" },
+    /* The next vector is strange: The DESIGN document from 2007 gives
+       "8ik66o" as result, the revision from 2009 gives "6im5sd".  I
+       look at it for quite some time and came to the conclusion that
+       "6im54d" is the right encoding.  */
+    { 30, "\xf5\x57\xbd\x0c", "6im54d" },
+    /* From ccrtp's Java code.  */
+    { 40, "\x01\x01\x01\x01\x01", "yryonyeb" },
+    { 15, "\x01\x01", "yry" },
+    { 80, "\x01\x01\x01\x01\x01\x01\x01\x01\x01\x01", "yryonyebyryonyeb" },
+    { 15, "\x81\x81", "ogy" },
+    { 16, "\x81\x81", "ogyo" },
+    { 20, "\x81\x81\x81", "ogya" },
+    { 64, "\x81\x81\x81\x81\x81\x81\x81\x81", "ogyadycbogyan" },
+    /* More tests.  */
+    { 0,  "", "" }
+  };
+  int tidx;
+  char *output;
+
+  for (tidx = 0; tidx < DIM(tests); tidx++)
+    {
+      output = zb32_encode (tests[tidx].data, tests[tidx].datalen);
+      if (!output)
+        {
+          fprintf (stderr, "%s:%d: error encoding test %d: %s\n",
+                   __FILE__, __LINE__, tidx, strerror (errno));
+          exit (1);
+        }
+      /* puts (output); */
+      if (strcmp (output, tests[tidx].expected))
+        fail (tidx);
+      xfree (output);
+    }
+}
+
+
+int
+main (int argc, char **argv)
+{
+  (void)argc;
+  (void)argv;
+
+  test_zb32enc ();
+
+  return !!errcount;
+}
diff --git a/common/util.h b/common/util.h
index 4b3cbfc4d..4dad163c3 100644
--- a/common/util.h
+++ b/common/util.h
@@ -164,6 +164,8 @@ gpg_error_t b64dec_proc (struct b64state *state, void *buffer, size_t length,
 gpg_error_t b64dec_finish (struct b64state *state);
 
 
+/*-- zb32.c --*/
+char *zb32_encode (const void *data, unsigned int databits);
 
 
 /*-- sexputil.c */
diff --git a/common/zb32.c b/common/zb32.c
new file mode 100644
index 000000000..05aa0eac8
--- /dev/null
+++ b/common/zb32.c
@@ -0,0 +1,120 @@
+/* zb32.c - z-base-32 functions
+ * Copyright (C) 2014  Werner Koch
+ *
+ * This file is part of GnuPG.
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of either
+ *
+ *   - the GNU Lesser General Public License as published by the Free
+ *     Software Foundation; either version 3 of the License, or (at
+ *     your option) any later version.
+ *
+ * or
+ *
+ *   - the GNU General Public License as published by the Free
+ *     Software Foundation; either version 2 of the License, or (at
+ *     your option) any later version.
+ *
+ * or both in parallel, as here.
+ *
+ * This file 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+
+#include "util.h"
+
+
+/* Zooko's base32 variant. See RFC-6189 and
+   http://philzimmermann.com/docs/human-oriented-base-32-encoding.txt
+   Caller must xfree the returned string.  Returns NULL and sets ERRNO
+   on error.  To avoid integer overflow DATALEN is limited to 2^16
+   bytes.  Note, that DATABITS is measured in bits!.  */
+char *
+zb32_encode (const void *data, unsigned int databits)
+{
+  static char const zb32asc[32] = {'y','b','n','d','r','f','g','8',
+                                   'e','j','k','m','c','p','q','x',
+                                   'o','t','1','u','w','i','s','z',
+                                   'a','3','4','5','h','7','6','9' };
+  const unsigned char *s;
+  char *output, *d;
+  size_t datalen;
+
+  datalen = (databits + 7) / 8;
+  if (datalen > (1 << 16))
+    {
+      errno = EINVAL;
+      return NULL;
+    }
+
+  d = output = xtrymalloc (8 * (datalen / 5)
+                           + 2 * (datalen % 5)
+                           - ((datalen%5)>2)
+                           + 1);
+  if (!output)
+    return NULL;
+
+  /* I use straightforward code.  The compiler should be able to do a
+     better job on optimization than me and it is easier to read.  */
+  for (s = data; datalen >= 5; s += 5, datalen -= 5)
+    {
+      *d++ = zb32asc[((s[0]      ) >> 3)               ];
+      *d++ = zb32asc[((s[0] &   7) << 2) | (s[1] >> 6) ];
+      *d++ = zb32asc[((s[1] &  63) >> 1)               ];
+      *d++ = zb32asc[((s[1] &   1) << 4) | (s[2] >> 4) ];
+      *d++ = zb32asc[((s[2] &  15) << 1) | (s[3] >> 7) ];
+      *d++ = zb32asc[((s[3] & 127) >> 2)               ];
+      *d++ = zb32asc[((s[3] &   3) << 3) | (s[4] >> 5) ];
+      *d++ = zb32asc[((s[4] &  31)     )               ];
+    }
+
+  switch (datalen)
+    {
+    case 4:
+      *d++ = zb32asc[((s[0]      ) >> 3)               ];
+      *d++ = zb32asc[((s[0] &   7) << 2) | (s[1] >> 6) ];
+      *d++ = zb32asc[((s[1] &  63) >> 1)               ];
+      *d++ = zb32asc[((s[1] &   1) << 4) | (s[2] >> 4) ];
+      *d++ = zb32asc[((s[2] &  15) << 1) | (s[3] >> 7) ];
+      *d++ = zb32asc[((s[3] & 127) >> 2)               ];
+      *d++ = zb32asc[((s[3] &   3) << 3)               ];
+      break;
+    case 3:
+      *d++ = zb32asc[((s[0]      ) >> 3)               ];
+      *d++ = zb32asc[((s[0] &   7) << 2) | (s[1] >> 6) ];
+      *d++ = zb32asc[((s[1] &  63) >> 1)               ];
+      *d++ = zb32asc[((s[1] &   1) << 4) | (s[2] >> 4) ];
+      *d++ = zb32asc[((s[2] &  15) << 1)               ];
+      break;
+    case 2:
+      *d++ = zb32asc[((s[0]      ) >> 3)               ];
+      *d++ = zb32asc[((s[0] &   7) << 2) | (s[1] >> 6) ];
+      *d++ = zb32asc[((s[1] &  63) >> 1)               ];
+      *d++ = zb32asc[((s[1] &   1) << 4)               ];
+      break;
+    case 1:
+      *d++ = zb32asc[((s[0]      ) >> 3)               ];
+      *d++ = zb32asc[((s[0] &   7) << 2)               ];
+      break;
+    default:
+      break;
+    }
+  *d = 0;
+
+  /* Need to strip some bytes if not a multiple of 40.  */
+  output[(databits + 5 - 1) / 5] = 0;
+  return output;
+}