/*
 * 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__

#ifdef __cplusplus
extern "C" {
#endif

#include "tarray.h"
#include "index_fst_common.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 version 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 FstString {
  uint8_t *data; 
  uint32_t len;
  int32_t ref;
} FstString;

typedef struct FstSlice {
  FstString   *str;     
  int32_t start; 
  int32_t end; 
} FstSlice;

FstSlice fstSliceCreate(uint8_t *data, uint64_t len);
FstSlice fstSliceCopy(FstSlice *s, int32_t start, int32_t end);
FstSlice fstSliceDeepCopy(FstSlice *s, int32_t start, int32_t end);
bool fstSliceIsEmpty(FstSlice *s);
int  fstSliceCompare(FstSlice *s1, FstSlice *s2);
void fstSliceDestroy(FstSlice *s); 
uint8_t *fstSliceData(FstSlice *s, int32_t *sz); 

#define FST_SLICE_LEN(s) (s->end - s->start + 1)

//// stack 
//
//typedef (*StackFreeElemFn)(void *elem);
//
//typedef struct FstStack {
//  void   *first;    
//  void   *end;  
//  size_t elemSize; 
//  size_t nElem;
//  StackFreeElemFn fn;
//} FstStack;
//
//
//FstStack* fstStackCreate(size_t elemSize, stackFreeElem); 
//void  *fstStackPush(FstStack *s, void *elem);
//void  *fstStackTop(FstStack *s);
//size_t fstStackLen(FstStack *s); 
//void  fstStackDestory(FstStack *); 
//


  
#ifdef __cplusplus
}
#endif

#endif
