failed approach

gomspace/libutil/include/gs/util/base16.h

@@ -0,0 +1,90 @@
+#ifndef GS_UTIL_BASE16_H
+#define GS_UTIL_BASE16_H
+/*
+ * Copyright (C) 2010 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * 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 2 of the
+ * License, or 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+/**
+   @file
+
+   Encoding and decoding base16 arrays to and from strings.
+*/
+
+#include <gs/util/error.h>
+#include <string.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+   Calculate length of base16-encoded data
+
+   @param raw_len Raw data length
+   @return Encoded string length (excluding NUL)
+*/
+static inline size_t base16_encoded_len(size_t raw_len)
+{
+    return (2 * raw_len);
+}
+
+/**
+   Calculate maximum length of base16-decoded string
+   @param encoded Encoded string
+   @return Maximum length of raw data
+*/
+static inline size_t base16_decoded_max_len(const char *encoded)
+{
+    return ((strlen(encoded) + 1) / 2);
+}
+
+/**
+   Base16-encode data
+
+   The buffer must be the correct length for the encoded string.  Use
+   something like
+ 
+      char buf[ base16_encoded_len ( len ) + 1 ];
+ 
+   (the +1 is for the terminating NUL) to provide a buffer of the
+   correct size.
+
+   @param raw Raw data
+   @param len Length of raw data
+   @param encoded Buffer for encoded string
+*/
+void base16_encode(const uint8_t *raw, size_t len, char *encoded);
+
+/**
+   Base16-decode data
+
+   The buffer must be large enough to contain the decoded data.  Use
+   something like
+
+       char buf[ base16_decoded_max_len ( encoded ) ];
+
+   to provide a buffer of the correct size.
+
+   @param encoded Encoded string
+   @param raw Raw data
+   @return Length of raw data, or negative error (gs_error_t)
+*/
+int base16_decode(const char *encoded, uint8_t *raw);
+
+#ifdef __cplusplus
+}
+#endif
+#endif