/* -*-  Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2011 University of California, Los Angeles
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Ilya Moiseenko <iliamo@cs.ucla.edu>
 */

/**
 * @file ccn/coding.h
 * 
 * Details of the ccn binary wire encoding.
 *
 * Part of the CCNx C Library.
 *
 * Copyright (C) 2008-2010 Palo Alto Research Center, Inc.
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 * This 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 this library;
 * if not, write to the Free Software Foundation, Inc., 51 Franklin Street,
 * Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef CCN_CODING_DEFINED
#define CCN_CODING_DEFINED

#include <sys/types.h>
#include <stddef.h>

#define CCN_TT_BITS 3
#define CCN_TT_MASK ((1 << CCN_TT_BITS) - 1)
#define CCN_MAX_TINY ((1 << (7-CCN_TT_BITS)) - 1)
#define CCN_TT_HBIT ((unsigned char)(1 << 7))

/**
 * Type tag for a ccnb start marker.
 */
enum ccn_tt {
  CCN_EXT,        /**< starts composite extension - numval is subtype */
  CCN_TAG,        /**< starts composite - numval is tagnamelen-1 */ 
  CCN_DTAG,       /**< starts composite - numval is tagdict index (enum ccn_dtag) */
  CCN_ATTR,       /**< attribute - numval is attrnamelen-1, value follows */
  CCN_DATTR,      /**< attribute numval is attrdict index */
  CCN_BLOB,       /**< opaque binary data - numval is byte count */
  CCN_UDATA,      /**< UTF-8 encoded character data - numval is byte count */
  CCN_NO_TOKEN    /**< should not occur in encoding */
};

/** CCN_CLOSE terminates composites */
#define CCN_CLOSE ((unsigned char)(0))

enum ccn_ext_subtype {
  /* skip smallest values for now */
  CCN_PROCESSING_INSTRUCTIONS = 16 /* <?name:U value:U?> */
};

/**
 * DTAG identifies ccnb-encoded elements.
 * c.f. tagname.csvdict
 * See the gen_enum_dtag script for help updating these.
 */
enum ccn_dtag {
  CCN_DTAG_Any = 13,
  CCN_DTAG_Name = 14,
  CCN_DTAG_Component = 15,
  CCN_DTAG_Certificate = 16,
  CCN_DTAG_Collection = 17,
  CCN_DTAG_CompleteName = 18,
  CCN_DTAG_Content = 19,
  CCN_DTAG_SignedInfo = 20,
  CCN_DTAG_ContentDigest = 21,
  CCN_DTAG_ContentHash = 22,
  CCN_DTAG_Count = 24,
  CCN_DTAG_Header = 25,
  CCN_DTAG_Interest = 26,	/* 20090915 */
  CCN_DTAG_Key = 27,
  CCN_DTAG_KeyLocator = 28,
  CCN_DTAG_KeyName = 29,
  CCN_DTAG_Length = 30,
  CCN_DTAG_Link = 31,
  CCN_DTAG_LinkAuthenticator = 32,
  CCN_DTAG_NameComponentCount = 33,	/* DeprecatedInInterest */
  CCN_DTAG_RootDigest = 36,
  CCN_DTAG_Signature = 37,
  CCN_DTAG_Start = 38,
  CCN_DTAG_Timestamp = 39,
  CCN_DTAG_Type = 40,
  CCN_DTAG_Nonce = 41,
  CCN_DTAG_Scope = 42,
  CCN_DTAG_Exclude = 43,
  CCN_DTAG_Bloom = 44,
  CCN_DTAG_BloomSeed = 45,
  CCN_DTAG_AnswerOriginKind = 47,
  CCN_DTAG_InterestLifetime = 48,
  CCN_DTAG_Witness = 53,
  CCN_DTAG_SignatureBits = 54,
  CCN_DTAG_DigestAlgorithm = 55,
  CCN_DTAG_BlockSize = 56,
  CCN_DTAG_FreshnessSeconds = 58,
  CCN_DTAG_FinalBlockID = 59,
  CCN_DTAG_PublisherPublicKeyDigest = 60,
  CCN_DTAG_PublisherCertificateDigest = 61,
  CCN_DTAG_PublisherIssuerKeyDigest = 62,
  CCN_DTAG_PublisherIssuerCertificateDigest = 63,
  CCN_DTAG_ContentObject = 64,	/* 20090915 */
  CCN_DTAG_WrappedKey = 65,
  CCN_DTAG_WrappingKeyIdentifier = 66,
  CCN_DTAG_WrapAlgorithm = 67,
  CCN_DTAG_KeyAlgorithm = 68,
  CCN_DTAG_Label = 69,
  CCN_DTAG_EncryptedKey = 70,
  CCN_DTAG_EncryptedNonceKey = 71,
  CCN_DTAG_WrappingKeyName = 72,
  CCN_DTAG_Action = 73,
  CCN_DTAG_FaceID = 74,
  CCN_DTAG_IPProto = 75,
  CCN_DTAG_Host = 76,
  CCN_DTAG_Port = 77,
  CCN_DTAG_MulticastInterface = 78,
  CCN_DTAG_ForwardingFlags = 79,
  CCN_DTAG_FaceInstance = 80,
  CCN_DTAG_ForwardingEntry = 81,
  CCN_DTAG_MulticastTTL = 82,
  CCN_DTAG_MinSuffixComponents = 83,
  CCN_DTAG_MaxSuffixComponents = 84,
  CCN_DTAG_ChildSelector = 85,
  CCN_DTAG_RepositoryInfo = 86,
  CCN_DTAG_Version = 87,
  CCN_DTAG_RepositoryVersion = 88,
  CCN_DTAG_GlobalPrefix = 89,
  CCN_DTAG_LocalName = 90,
  CCN_DTAG_Policy = 91,
  CCN_DTAG_Namespace = 92,
  CCN_DTAG_GlobalPrefixName = 93,
  CCN_DTAG_PolicyVersion = 94,
  CCN_DTAG_KeyValueSet = 95,
  CCN_DTAG_KeyValuePair = 96,
  CCN_DTAG_IntegerValue = 97,
  CCN_DTAG_DecimalValue = 98,
  CCN_DTAG_StringValue = 99,
  CCN_DTAG_BinaryValue = 100,
  CCN_DTAG_NameValue = 101,
  CCN_DTAG_Entry = 102,
  CCN_DTAG_ACL = 103,
  CCN_DTAG_ParameterizedName = 104,
  CCN_DTAG_Prefix = 105,
  CCN_DTAG_Suffix = 106,
  CCN_DTAG_Root = 107,
  CCN_DTAG_ProfileName = 108,
  CCN_DTAG_Parameters = 109,
  CCN_DTAG_InfoString = 110,
  CCN_DTAG_StatusResponse = 112,
  CCN_DTAG_StatusCode = 113,
  CCN_DTAG_StatusText = 114,
  CCN_DTAG_SequenceNumber = 256,
  CCN_DTAG_CCNProtocolDataUnit = 17702112
};

struct ccn_dict_entry {
  int index;              /**< matches enum ccn_dtag above */
  const char *name;       /**< textual name of dtag */
};

struct ccn_dict {
  int count;              /**< Count of elements in the table */
  const struct ccn_dict_entry *dict; /**< the table entries */
};

/**
 * Table for translating from DTAGs to names and vice versa.
 */
extern const struct ccn_dict ccn_dtag_dict; /* matches enum ccn_dtag above */

struct ccn_skeleton_decoder { /* initialize to all 0 */
  ssize_t index;          /**< Number of bytes processed */
  int state;              /**< Decoder state */
  int nest;               /**< Element nesting */
  size_t numval;          /**< Current numval, meaning depends on state */
  size_t token_index;     /**< Starting index of most-recent token */
  size_t element_index;   /**< Starting index of most-recent element */
};

/**
 * The decoder state is one of these, possibly with some
 * additional bits set for internal use.  A complete parse
 * ends up in state 0 or an error state.  Not all possible
 * error states are listed here.
 */
enum ccn_decoder_state {
  CCN_DSTATE_INITIAL = 0,
  CCN_DSTATE_NEWTOKEN,
  CCN_DSTATE_NUMVAL,
  CCN_DSTATE_UDATA,
  CCN_DSTATE_TAGNAME,
  CCN_DSTATE_ATTRNAME,
  CCN_DSTATE_BLOB,
  /* All error states are negative */
  CCN_DSTATE_ERR_OVERFLOW = -1,
  CCN_DSTATE_ERR_ATTR     = -2,       
  CCN_DSTATE_ERR_CODING   = -3,
  CCN_DSTATE_ERR_NEST     = -4, 
  CCN_DSTATE_ERR_BUG      = -5
};

/**
 * If the CCN_DSTATE_PAUSE bit is set in the decoder state,
 * the decoder will return just after recognizing each token.
 * In this instance, use CCN_GET_TT_FROM_DSTATE() to extract
 * the token type from the decoder state;
 * CCN_CLOSE will be reported as CCN_NO_TOKEN.
 * The pause bit persists, so the end test should take that into account
 * by using the CCN_FINAL_DSTATE macro instead of testing for state 0.
 */
#define CCN_DSTATE_PAUSE (1 << 15)
#define CCN_GET_TT_FROM_DSTATE(state) (CCN_TT_MASK & ((state) >> 16))
#define CCN_FINAL_DSTATE(state) (((state) & (CCN_DSTATE_PAUSE-1)) == 0)

ssize_t ccn_skeleton_decode(struct ccn_skeleton_decoder *d,
                            const unsigned char *p,
                            size_t n);

#endif