index_fst_util.h

/*
 * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), 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.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */


#ifndef __INDEX_FST_UTIL_H__
#define __INDEX_FST_UTIL_H__

#include "tarray.h"


typedef uint64_t FstType;
typedef uint64_t CompiledAddr; 
typedef uint64_t Output;  
typedef uint8_t PackSizes;


//A sentinel value used to indicate an empty final state
extern const CompiledAddr EMPTY_ADDRESS;
/// A sentinel value used to indicate an invalid state.
extern const CompiledAddr NONE_ADDRESS;

// This version number is written to every finite state transducer created by
// this crate. When a finite state transducer is read, its version number is
// checked against this value.
extern const uint64_t    version;
// The threshold (in number of transitions) at which an index is created for                                   
// a node's transitions. This speeds up lookup time at the expense of FST size 

extern const uint64_t TRANS_INDEX_THRESHOLD;
// high 4 bits is transition address packed size.
// low 4 bits is output value packed size.
//
// `0` is a legal value which means there are no transitions/outputs

#define FST_SET_TRANSITION_PACK_SIZE(v, sz) do {v = (v & 0b00001111) | (sz << 4} while(0)
#define FST_GET_TRANSITION_PACK_SIZE(v) (((v) & 0b11110000) >> 4) 
#define FST_SET_OUTPUT_PACK_SIZE(v, sz) do { v =  (v & 0b11110000) | sz } while(0)
#define FST_GET_OUTPUT_PACK_SIZE(v) ((v) & 0b00001111)   

#define COMMON_INPUT(idx) COMMON_INPUTS_INV[(idx) - 1]

#define COMMON_INDEX(v, max, val) do {         \
  val = ((uint16_t)COMMON_INPUTS[v] + 1)%256;  \
  val = val > max ? 0: val;                    \
} while(0) 


//uint8_t commonInput(uint8_t idx);
//uint8_t commonIdx(uint8_t v, uint8_t max);

uint8_t      packSize(uint64_t n); 
uint64_t     unpackUint64(uint8_t *ch, uint8_t sz);
uint8_t      packDeltaSize(CompiledAddr nodeAddr, CompiledAddr transAddr);
CompiledAddr unpackDelta(char *data, uint64_t len, uint64_t nodeAddr);



typedef struct FstSlice {
  uint8_t *data; 
  uint64_t dLen;
  uint32_t start;
  uint32_t end;
} FstSlice;

FstSlice fstSliceCopy(FstSlice *slice, uint32_t start, uint32_t end);
FstSlice fstSliceCreate(uint8_t *data, uint64_t dLen);
bool fstSliceEmpty(FstSlice *slice);

int fstSliceCompare(FstSlice *a, FstSlice *b);


#endif