From bb22003bc0c577dbaa678607995232ddc9f8406f Mon Sep 17 00:00:00 2001
From: Mattias Andrée <maandree@operamail.com>
Date: Tue, 1 Sep 2015 17:02:44 +0200
Subject: add strfry
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Signed-off-by: Mattias Andrée <maandree@operamail.com>
---
 TODO                |  3 +--
 include/string.h    | 13 +++++++++++++
 src/string/strfry.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 2 deletions(-)
 create mode 100644 src/string/strfry.c

diff --git a/TODO b/TODO
index df35127..f10d3ed 100644
--- a/TODO
+++ b/TODO
@@ -1,9 +1,8 @@
 functions to lock and unlock pages  (3.4.3 p76)
 character class determination for wide characters  (4.3 p82)
 collation functions  (5.6 p109)
-strfry  (5.9  p124)
 trivial encryption  (5.10 p124)
-encdoe binary data  (5.11 p125)
+encode binary data  (5.11 p125)
 argz and envz vectors  (5.12 p127)
 characer-set handling  (6 p133)
 locales and internationalisation  (7 p181)
diff --git a/include/string.h b/include/string.h
index c988b2e..68a0134 100644
--- a/include/string.h
+++ b/include/string.h
@@ -1091,6 +1091,19 @@ char* __gnu_basename(const char*)
 #endif
 
 
+#if defined(_GNU_SOURCE) && !defined(__PORTABLE)
+/**
+ * Shuffles all bytes in a string.
+ * 
+ * This is a GNU joke extension.
+ * 
+ * @param   anagram  An anagram of the output, will be modified.
+ * @retrun           The string, which will `== anagram`.
+ */
+char* strfry(char* anagram);
+#endif
+
+
 
 #endif
 
diff --git a/src/string/strfry.c b/src/string/strfry.c
new file mode 100644
index 0000000..f020202
--- /dev/null
+++ b/src/string/strfry.c
@@ -0,0 +1,46 @@
+/**
+ * slibc — Yet another C library
+ * Copyright © 2015  Mattias Andrée (maandree@member.fsf.org)
+ * 
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program 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 <string.h>
+#include <stdlib.h>
+
+
+/* Sattolo Cycles. */
+
+
+
+/**
+ * Shuffles all bytes in a string.
+ * 
+ * This is a GNU joke extension.
+ * 
+ * @param   anagram  An anagram of the output, will be modified.
+ * @retrun           The string, which will `== anagram`.
+ */
+char* strfry(char* anagram)
+{
+  size_t i, j;
+  char t;
+  if (anagram == NULL)
+    return NULL;
+  for (i = strlen(anagram); --i;)
+    {
+      j = (int)((double)rand() / (RAND_MAX + 1));
+      t = anagram[i], anagram[i] = anagram[j], anagram[j] = t;
+    }
+}
+
-- 
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