1 files changed, 138 insertions, 0 deletions
diff --git a/src/libstrongswan/plugins/bliss/bliss_huffman_coder.c b/src/libstrongswan/plugins/bliss/bliss_huffman_coder.c
new file mode 100644
index 000000000..018ae0efa
--- /dev/null
+++ b/src/libstrongswan/plugins/bliss/bliss_huffman_coder.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2014 Andreas Steffen
+ * HSR Hochschule fuer Technik Rapperswil
+ *
+ * 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 (at your
+ * option) any later version.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY;https://www.hsr.ch/HSR-intern-Anmeldung.4409.0.html?&no_cache=1 without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "bliss_huffman_coder.h"
+
+typedef struct private_bliss_huffman_coder_t private_bliss_huffman_coder_t;
+
+/**
+ * Private data structure for bliss_huffman_coder_t object
+ */
+struct private_bliss_huffman_coder_t {
+	/**
+	 * Public interface.
+	 */
+	bliss_huffman_coder_t public;
+
+	/**
+	 * Bitpacker to write to or read from
+	 */
+	bliss_bitpacker_t *packer;
+
+	/**
+	 * Huffman code table to be used
+	 */
+	bliss_huffman_code_t *code;
+
+	/**
+     * Maximum index into tuples table
+	 */
+	int index_max;
+
+	/**
+     * Number of encoded or decoded bits
+	 */
+	size_t bits;
+
+};
+
+METHOD(bliss_huffman_coder_t, get_bits, size_t,
+	private_bliss_huffman_coder_t *this)
+{
+	return this->bits;
+}
+
+METHOD(bliss_huffman_coder_t, encode, bool,
+	private_bliss_huffman_coder_t *this, int32_t z1, int16_t z2)
+{
+	uint32_t code;
+	uint16_t bits;
+	int index;
+
+	index = z1 * (2*this->code->n_z2 - 1) + z2 + this->code->n_z2 - 1;
+	if (index >= this->index_max)
+	{
+		DBG1(DBG_LIB, "index exceeded in Huffman encoding table");
+		return FALSE;
+	}
+	code = this->code->tuples[index].code;
+	bits = this->code->tuples[index].bits;
+	if (!this->packer->write_bits(this->packer, code, bits))
+	{
+		DBG1(DBG_LIB, "bitpacker exceeded its buffer");
+		return FALSE;
+	}
+	this->bits += bits;
+
+	return TRUE;
+}
+
+METHOD(bliss_huffman_coder_t, decode, bool,
+	private_bliss_huffman_coder_t *this, int32_t *z1, int16_t *z2)
+{
+	bliss_huffman_code_node_t *node;
+	uint32_t bit;
+
+	node = this->code->nodes;
+	while (node->tuple == BLISS_HUFFMAN_CODE_NO_TUPLE)
+	{
+		if (node->node_0 == BLISS_HUFFMAN_CODE_NO_NODE ||
+			node->node_1 == BLISS_HUFFMAN_CODE_NO_NODE)
+		{
+			DBG1(DBG_LIB, "error in Huffman decoding table");
+			return FALSE;
+		}
+		if (!this->packer->read_bits(this->packer, &bit, 1))
+		{
+			DBG1(DBG_LIB, "bitpacker depleted its buffer");
+			return FALSE;
+		}
+		node = &this->code->nodes[bit ? node->node_1 : node->node_0];
+		this->bits++;
+	}
+	*z1 = node->tuple / (2*this->code->n_z2 - 1);
+	*z2 = node->tuple - (2*this->code->n_z2 - 1) * (*z1) - this->code->n_z2 + 1;
+
+	return TRUE;
+}
+
+METHOD(bliss_huffman_coder_t, destroy, void,
+	private_bliss_huffman_coder_t *this)
+{
+	free(this);
+}
+
+/**
+ * See header.
+ */
+bliss_huffman_coder_t *bliss_huffman_coder_create(bliss_huffman_code_t *code,
+												  bliss_bitpacker_t *packer)
+{
+	private_bliss_huffman_coder_t *this;
+
+	INIT(this,
+		.public = {
+			.get_bits = _get_bits,
+			.encode = _encode,
+			.decode = _decode,
+			.destroy = _destroy,
+		},
+		.packer = packer,
+		.code = code,
+		.index_max = (2*code->n_z2 - 1) * code->n_z1,		
+	);
+
+	return &this->public;
+}