/*
* $Id:  $
* $Version: $
*
* Copyright (c) Tanel Tammet 2004,2005,2006,2007,2008,2009
*
* Contact: tanel.tammet@gmail.com
*
* This file is part of WhiteDB
*
* WhiteDB 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 3 of the License, or
* (at your option) any later version.
*
* WhiteDB 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 WhiteDB.  If not, see <http://www.gnu.org/licenses/>.
*
*/

 /** @file dbdata.h
 * Datatype encoding defs and public headers for actual data handling procedures.
 */

#ifndef DEFINED_DBDATA_H
#define DEFINED_DBDATA_H

#ifdef _WIN32
#include "../config-w32.h"
#else
#include "../config.h"
#endif
#include "dballoc.h"

// ============= external funs defs ============

#ifndef _WIN32
extern double round(double);
#else
/* round as a macro (no libm equivalent for MSVC) */
#define round(x) ((double) floor((double) x + 0.5))
#endif

// ============= api part starts ================

/* ---  built-in data type numbers ----- */

/* the built-in data types are primarily for api purposes.
   internally, some of these types like int, str etc have several
   different ways to encode along with different bit masks
*/


#define WG_NULLTYPE 1
#define WG_RECORDTYPE 2
#define WG_INTTYPE 3
#define WG_DOUBLETYPE 4
#define WG_STRTYPE 5
#define WG_XMLLITERALTYPE 6
#define WG_URITYPE 7
#define WG_BLOBTYPE 8
#define WG_CHARTYPE 9
#define WG_FIXPOINTTYPE 10
#define WG_DATETYPE 11
#define WG_TIMETYPE 12
#define WG_ANONCONSTTYPE 13  // not implemented yet
#define WG_VARTYPE 14        // not implemented yet

/* Illegal encoded data indicator */
#define WG_ILLEGAL 0xff

/* prototypes of wg database api functions

*/

typedef ptrdiff_t wg_int;
typedef size_t wg_uint; // used in time enc


/* -------- creating and scanning records --------- */

void* wg_create_record(void* db, wg_int length); ///< returns NULL when error, ptr to rec otherwise
void* wg_create_raw_record(void* db, wg_int length); ///< returns NULL when error, ptr to rec otherwise
wg_int wg_delete_record(void* db, void *rec);  ///< returns 0 on success, non-0 on error

void* wg_get_first_record(void* db);              ///< returns NULL when error or no recs
void* wg_get_next_record(void* db, void* record); ///< returns NULL when error or no more recs

void* wg_get_first_raw_record(void* db);
void* wg_get_next_raw_record(void* db, void* record);

/* -------- setting and fetching record field values --------- */

wg_int wg_get_record_len(void* db, void* record); ///< returns negative int when error
wg_int* wg_get_record_dataarray(void* db, void* record); ///< pointer to record data array start

// following field setting functions return negative int when err, 0 when ok
wg_int wg_set_field(void* db, void* record, wg_int fieldnr, wg_int data);
wg_int wg_set_new_field(void* db, void* record, wg_int fieldnr, wg_int data);

wg_int wg_set_int_field(void* db, void* record, wg_int fieldnr, wg_int data);
wg_int wg_set_double_field(void* db, void* record, wg_int fieldnr, double data);
wg_int wg_set_str_field(void* db, void* record, wg_int fieldnr, char* data);

wg_int wg_update_atomic_field(void* db, void* record, wg_int fieldnr, wg_int data, wg_int old_data);
wg_int wg_set_atomic_field(void* db, void* record, wg_int fieldnr, wg_int data);
wg_int wg_add_int_atomic_field(void* db, void* record, wg_int fieldnr, int data);

wg_int wg_get_field(void* db, void* record, wg_int fieldnr);      // returns 0 when error
wg_int wg_get_field_type(void* db, void* record, wg_int fieldnr); // returns 0 when error


/* ---------- general operations on encoded data -------- */

wg_int wg_get_encoded_type(void* db, wg_int data);
char* wg_get_type_name(void* db, wg_int type);
wg_int wg_free_encoded(void* db, wg_int data);

/* -------- encoding and decoding data: records contain encoded data only ---------- */


// null

wg_int wg_encode_null(void* db, char* data);
char* wg_decode_null(void* db, wg_int data);

// int

wg_int wg_encode_int(void* db, wg_int data);
wg_int wg_decode_int(void* db, wg_int data);

// char

wg_int wg_encode_char(void* db, char data);
char wg_decode_char(void* db, wg_int data);


// double

wg_int wg_encode_double(void* db, double data);
double wg_decode_double(void* db, wg_int data);

// fixpoint

wg_int wg_encode_fixpoint(void* db, double data);
double wg_decode_fixpoint(void* db, wg_int data);

// date and time

wg_int wg_encode_date(void* db, int data);
int wg_decode_date(void* db, wg_int data);

wg_int wg_encode_time(void* db, int data);
int wg_decode_time(void* db, wg_int data);

int wg_current_utcdate(void* db);
int wg_current_localdate(void* db);
int wg_current_utctime(void* db);
int wg_current_localtime(void* db);

int wg_strf_iso_datetime(void* db, int date, int time, char* buf);
int wg_strp_iso_date(void* db, char* buf);
int wg_strp_iso_time(void* db, char* inbuf);

int wg_ymd_to_date(void* db, int yr, int mo, int day);
int wg_hms_to_time(void* db, int hr, int min, int sec, int prt);
void wg_date_to_ymd(void* db, int date, int *yr, int *mo, int *day);
void wg_time_to_hms(void* db, int time, int *hr, int *min, int *sec, int *prt);

//record

wg_int wg_encode_record(void* db, void* data);
void* wg_decode_record(void* db, wg_int data);

// str (standard C string: zero-terminated array of chars)
// along with optional attached language indicator str

wg_int wg_encode_str(void* db, char* str, char* lang); ///< let lang==NULL if not used

char* wg_decode_str(void* db, wg_int data);
char* wg_decode_str_lang(void* db, wg_int data);

wg_int wg_decode_str_len(void* db, wg_int data);
wg_int wg_decode_str_lang_len(void* db, wg_int data);
wg_int wg_decode_str_copy(void* db, wg_int data, char* strbuf, wg_int buflen);
wg_int wg_decode_str_lang_copy(void* db, wg_int data, char* langbuf, wg_int buflen);

// xmlliteral (standard C string: zero-terminated array of chars)
// along with obligatory attached xsd:type str

wg_int wg_encode_xmlliteral(void* db, char* str, char* xsdtype);

char* wg_decode_xmlliteral(void* db, wg_int data);
char* wg_decode_xmlliteral_xsdtype(void* db, wg_int data);

wg_int wg_decode_xmlliteral_len(void* db, wg_int data);
wg_int wg_decode_xmlliteral_xsdtype_len(void* db, wg_int data);
wg_int wg_decode_xmlliteral_copy(void* db, wg_int data, char* strbuf, wg_int buflen);
wg_int wg_decode_xmlliteral_xsdtype_copy(void* db, wg_int data, char* strbuf, wg_int buflen);

// uri (standard C string: zero-terminated array of chars)
// along with an optional prefix str


wg_int wg_encode_uri(void* db, char* str, char* prefix);

char* wg_decode_uri(void* db, wg_int data);
char* wg_decode_uri_prefix(void* db, wg_int data);

wg_int wg_decode_uri_len(void* db, wg_int data);
wg_int wg_decode_uri_prefix_len(void* db, wg_int data);
wg_int wg_decode_uri_copy(void* db, wg_int data, char* strbuf, wg_int buflen);
wg_int wg_decode_uri_prefix_copy(void* db, wg_int data, char* strbuf, wg_int buflen);



// blob (binary large object, i.e. any kind of data)
// along with an obligatory length in bytes

wg_int wg_encode_blob(void* db, char* str, char* type, wg_int len);

char* wg_decode_blob(void* db, wg_int data);
char* wg_decode_blob_type(void* db, wg_int data);

wg_int wg_decode_blob_len(void* db, wg_int data);
wg_int wg_decode_blob_copy(void* db, wg_int data, char* strbuf, wg_int buflen);
wg_int wg_decode_blob_type_len(void* db, wg_int data);
wg_int wg_decode_blob_type_copy(void* db, wg_int data, char* langbuf, wg_int buflen);

// anonconst

wg_int wg_encode_anonconst(void* db, char* str);
char* wg_decode_anonconst(void* db, wg_int data);

// var

wg_int wg_encode_var(void* db, wg_int varnr);
wg_int wg_decode_var(void* db, wg_int data);



// ================ api part ends ================

/* Record header structure. Position 0 is always reserved
 * for size.
 */
#define RECORD_HEADER_GINTS 3
#define RECORD_META_POS 1           /** metainfo, reserved for future use */
#define RECORD_BACKLINKS_POS 2      /** backlinks structure offset */

#define LITTLEENDIAN 1  ///< (intel is little-endian) difference in encoding tinystr
//#define USETINYSTR 1    ///< undef to prohibit usage of tinystr

/* Record meta bits. */
#define RECORD_META_NOTDATA 0x1 /** Record is a "special" record (not data) */
#define RECORD_META_MATCH 0x2   /** "match" record (needs NOTDATA as well) */
#define RECORD_META_DOC 0x10    /** schema bits: top-level document */
#define RECORD_META_OBJECT 0x20 /** schema bits: object */
#define RECORD_META_ARRAY 0x40  /** schema bits: array */

#define is_special_record(r) (*((gint *) r + RECORD_META_POS) &\
                            RECORD_META_NOTDATA)
#define is_plain_record(r) (*((gint *) r + RECORD_META_POS) == 0)
#define is_schema_array(r) (*((gint *) r + RECORD_META_POS) &\
                            RECORD_META_ARRAY)
#define is_schema_object(r) (*((gint *) r + RECORD_META_POS) &\
                            RECORD_META_OBJECT)
#define is_schema_document(r) (*((gint *) r + RECORD_META_POS) &\
                            RECORD_META_DOC)

// recognising gint types as gb types: bits, shifts, masks

/*
special value null (unassigned)         integer 0

Pointers to word-len ints end with            ?01  = not eq
Pointers to data records end with             000  = not eq
Pointers to long string records end with      100  = eq
Pointers to doubleword-len doubles end with   010  = not eq
Pointers to 32byte string records end with    110  = not eq


Immediate integers end with                   011  = is eq

(Other immediates                             111 (continued below))
Immediate vars end with                      0111  // not implemented yet
Immediate short fixpoints               0000 1111  = is eq
Immediate chars                         0001 1111  = is eq
Immediate dates                         0010 1111  = is eq
Immediate times                         0011 1111  = is eq
// Immediate tiny strings                  0100 1111  = is eq  // not used yet
Immediate anon constants                0101 1111  = is eq  // not implemented yet
*/


/* --- encoding and decoding basic data ---- */

#define SMALLINTBITS    0x3       ///< int ends with       011
#define SMALLINTSHFT  3
#define SMALLINTMASK  0x7

#define fits_smallint(i)   ((((i)<<SMALLINTSHFT)>>SMALLINTSHFT)==i)
#define encode_smallint(i) (((i)<<SMALLINTSHFT)|SMALLINTBITS)
#define decode_smallint(i) ((i)>>SMALLINTSHFT)

#define FULLINTBITS  0x1      ///< full int ptr ends with       01
#define FULLINTBITSV0  0x1    ///< full int type as 3-bit nr version 0:  001
#define FULLINTBITSV1  0x5    ///< full int type as 3-bit nr version 1:  101
#define FULLINTMASK  0x3

#define encode_fullint_offset(i) ((i)|FULLINTBITS)
#define decode_fullint_offset(i) ((i) & ~FULLINTMASK)

#define DATARECBITS  0x0      ///< datarec ptr ends with       000
#define DATARECMASK  0x7

#define encode_datarec_offset(i) (i)
#define decode_datarec_offset(i) (i)

#define LONGSTRBITS  0x4      ///< longstr ptr ends with       100
#define LONGSTRMASK  0x7

#define encode_longstr_offset(i) ((i)|LONGSTRBITS)
#define decode_longstr_offset(i) ((i) & ~LONGSTRMASK)

#define FULLDOUBLEBITS  0x2      ///< full double ptr ends with       010
#define FULLDOUBLEMASK  0x7

#define encode_fulldouble_offset(i) ((i)|FULLDOUBLEBITS)
#define decode_fulldouble_offset(i) ((i) & ~FULLDOUBLEMASK)

#define SHORTSTRBITS  0x6      ///< short str ptr ends with  110
#define SHORTSTRMASK  0x7

#define encode_shortstr_offset(i) ((i)|SHORTSTRBITS)
#define decode_shortstr_offset(i) ((i) & ~SHORTSTRMASK)

/* --- encoding and decoding other data ---- */

#define VARMASK  0xf
#define VARSHFT  4
#define VARBITS  0x7       ///< var ends with 0111

#define fits_var(i)   ((((i)<<VARSHFT)>>VARSHFT)==i)
#define encode_var(i) (((i)<<VARSHFT)|VARBITS)
#define decode_var(i) ((i)>>VARSHFT)

#define CHARMASK  0xff
#define CHARSHFT  8
#define CHARBITS  0x1f       ///< char ends with 0001 1111

#define encode_char(i) (((i)<<CHARSHFT)|CHARBITS)
#define decode_char(i) ((i)>>CHARSHFT)

#define DATEMASK  0xff
#define DATESHFT  8
#define DATEBITS  0x2f       ///< date ends with 0010 1111

#define MAXDATE  128*255*255
#define MINDATE  -128*255*255

#define fits_date(i)   (((i)<=MAXDATE) && ((i)>=MINDATE))
#define encode_date(i) (((i)<<DATESHFT)|DATEBITS)
#define decode_date(i) ((i)>>DATESHFT)

#define TIMEMASK  0xff
#define TIMESHFT  8
#define TIMEBITS  0x3f       ///< time ends with 0011 1111

#define MAXTIME  24*60*60*100
#define MINTIME  0

#define fits_time(i)   (((i)<=MAXTIME) && ((i)>=MINTIME))
#define encode_time(i) (((i)<<TIMESHFT)|TIMEBITS)
#define decode_time(i) ((int)(((unsigned int)(i))>>TIMESHFT))

#define FIXPOINTMASK  0xff
#define FIXPOINTSHFT  8
#define FIXPOINTBITS  0xf       ///< fixpoint ends with       0000 1111

#define MAXFIXPOINT  800
#define MINFIXPOINT  -800
#define FIXPOINTDIVISOR 10000.0

#define fits_fixpoint(i)   (((i)<=MAXFIXPOINT) && ((i)>=MINFIXPOINT))
#define encode_fixpoint(i) ((((int)(round((i)*(double)FIXPOINTDIVISOR)))<<FIXPOINTSHFT)|FIXPOINTBITS)
#define decode_fixpoint(i) ((double)((double)((i)>>FIXPOINTSHFT)/(double)FIXPOINTDIVISOR))

#define TINYSTRMASK  0xff
#define TINYSTRSHFT  8
#define TINYSTRBITS  0x4f       ///< tiny str ends with 0100 1111

#define ANONCONSTMASK  0xff
#define ANONCONSTSHFT  8
#define ANONCONSTBITS  0x5f       ///< anon const ends with 0101 1111

#define encode_anonconst(i) (((i)<<ANONCONSTSHFT)|ANONCONSTBITS)
#define decode_anonconst(i) ((i)>>ANONCONSTSHFT)

/* --- recognizing data ---- */

#define NORMALPTRMASK 0x7  ///< all pointers except fullint
#define NONPTRBITS 0x3
#define LASTFOURBITSMASK 0xf
#define PRELASTFOURBITSMASK 0xf0
#define LASTBYTEMASK 0xff

#define isptr(i)        ((i) && (((i)&NONPTRBITS)!=NONPTRBITS))

#define isdatarec(i)    (((i)&DATARECMASK)==DATARECBITS)
#define isfullint(i)    (((i)&FULLINTMASK)==FULLINTBITS)
#define isfulldouble(i) (((i)&FULLDOUBLEMASK)==FULLDOUBLEBITS)
#define isshortstr(i)   (((i)&SHORTSTRMASK)==SHORTSTRBITS)
#define islongstr(i)    (((i)&LONGSTRMASK)==LONGSTRBITS)

#define issmallint(i)   (((i)&SMALLINTMASK)==SMALLINTBITS)

#define isvar(i)   (((i)&VARMASK)==VARBITS)
#define ischar(i)   (((i)&CHARMASK)==CHARBITS)
#define isfixpoint(i)   (((i)&FIXPOINTMASK)==FIXPOINTBITS)
#define isdate(i)   (((i)&DATEMASK)==DATEBITS)
#define istime(i)   (((i)&TIMEMASK)==TIMEBITS)
#define istinystr(i)   (((i)&TINYSTRMASK)==TINYSTRBITS)
#define isanonconst(i)   (((i)&ANONCONSTMASK)==ANONCONSTBITS)

#define isimmediatedata(i) ((i)==0 || (!isptr(i) && !isfullint(i)))

/* ------ metainfo and special data items --------- */

#define datarec_size_bytes(i) (getusedobjectwantedbytes(i))
#define datarec_end_ptr(i)


/* --------- record and longstr data object structure ---------- */


/* record data object

gint usage from start:

0:  encodes length in bytes. length is aligned to sizeof gint
1:  pointer to next sibling
2:  pointer to prev sibling or parent
3:  data gints
...



---- conventional database rec ----------

car1:
id: 10
model: ford
licenceplate: 123LGH
owner: 20 (we will have ptr to rec 20)

car2:
id: 11
model: opel
licenceplate: 456RMH
owner: 20 (we will have ptr to rec 20)

person1:
parents: list of pointers to person1?
id: 20
fname: John
lname: Brown


---- xml node -------

<person fname="john" lname="brown">
  <owns>
    <car model="ford">
  </owns>
  <owns>
    <car model="opel">
  </owns>
</person>

xml-corresponding rdf triplets

_10 model ford
_10 licenceplate 123LGH

_11 model opel
_11 licenceplate 456RMH

_20 fname john
_20 lname brown
_20 owns _10
_20 owns _11


(?x fname john) & (?x lname brown) & (?x owns ?y) & (?y model ford) => answer(?y)

solution:

- locate from value index brown
- instantiate ?x with _20
- scan _20 value occurrences with pred lname to find john
- scan _20 subject occurrences with pred owns to find _10
- scan _10 subject occurrences with pred model to find ford

----normal rdf triplets -----

_10 model ford
_10 licenceplate 123LGH
_10 owner _20

_11 model opel
_11 licenceplate 456RMH
_11 owner _20

_20 fname john
_20 lname brown


(?x fname john) & (?x lname brown) & (?y owner ?x) & (?y model ford) => answer(?y)

solution:

- locate from value index brown
- instantiate ?x with _20
- scan _20 value occurrences with pred lname to find john
- scan _20 value occurrences with pred owner to find _10
- scan _10 subject occurrences with pred model to find ford

--------- fromptr structure -------


fld 1 pts to either directly (single) occurrence or rec of occurrences:

single occ case:

- last bit zero indicates direct ptr to rec
- two previous bits indicate position in rec (0-3)

multiple (or far pos) case:

- last bit 1 indicates special pos list array ptr:

pos array:

recsize
position fld nr,
ptr to (single) rec or to corresp list of recs
position fld nr,
ptr to (single) rec or to corresp list o recs
...

where corresp list is made of pairs (list cells):

ptr to rec
ptr to next list cell

alternative:

ptr to rec
ptr to rec
ptr to rec
ptr to rec
ptr to next block


*/

/* record data object

gint usage from start:

0: encodes data obj length in bytes. length is aligned to sizeof gint
1: metainfo, incl object type:
   - last byte object type
   - top-level/dependent bit
   - original/derived bit
2: backlinks
3: actual gints ....
...


*/



/* longstr/xmlliteral/uri/blob data object

gint usage from start:

0:  encodes data obj length in bytes. length is aligned to sizeof gint
1:  metainfo, incl object type (longstr/xmlliteral/uri/blob/datarec etc):
    - last byte object type
    - byte before last: nr to delete from obj length to get real actual-bytes length
2:  refcount
3:  backlinks
4:  pointer to next longstr in the hash bucket, 0 if no following
5:  lang/xsdtype/namespace str (offset):  if 0 not present
6:  actual bytes ....
...


*/


#define LONGSTR_HEADER_GINTS 6 /** including obj length gint */

#define LONGSTR_META_POS 1 /** metainfo, incl object type (longstr/xmlliteral/uri/blob/datarec etc)
   last byte (low 0) object type (WG_STRTYPE,WG_XMLLITERALTYPE, etc)
   byte before last (low 1):
         lendif: nr to delete from obj length to get real actual-bytes length of str
   low 2: unused
   low 3: unused
  */
#define LONGSTR_META_LENDIFMASK 0xFF00 /** second lowest bytes contains lendif*/
#define LONGSTR_META_LENDIFSHFT 8 /** shift 8 bits right to get lendif */
#define LONGSTR_META_TYPEMASK  0xFF /*** lowest byte contains actual subtype: str,uri,xmllliteral */
#define LONGSTR_REFCOUNT_POS 2 /**  reference count, if 0, delete*/
#define LONGSTR_BACKLINKS_POS 3 /**   backlinks structure offset */
#define LONGSTR_HASHCHAIN_POS 4 /**  offset of next longstr in the hash bucket, 0 if no following */
#define LONGSTR_EXTRASTR_POS 5 /**  lang/xsdtype/namespace str (encoded offset):  if 0 not present */


/* --------- error handling ------------ */

#define recordcheck(db,record,fieldnr,opname) { \
  if (!dbcheck(db)) {\
    show_data_error_str(db,"wrong database pointer given to ",opname);\
    return -1;\
  }\
  if (fieldnr<0 || getusedobjectwantedgintsnr(*((gint*)record))<=fieldnr+RECORD_HEADER_GINTS) {\
    show_data_error_str(db,"wrong field number given to ",opname);\
    return -2;\
  }\
}


/* ==== Protos ==== */

//void free_field_data(void* db,gint fielddata, gint fromrecoffset, gint fromrecfield);

gint wg_encode_unistr(void* db, char* str, char* lang, gint type); ///< let lang==NULL if not used
gint wg_encode_uniblob(void* db, char* str, char* lang, gint type, gint len);

char* wg_decode_unistr(void* db, wg_int data, gint type);
char* wg_decode_unistr_lang(void* db, wg_int data, gint type);

gint wg_decode_unistr_len(void* db, wg_int data, gint type);
gint wg_decode_unistr_lang_len(void* db, wg_int data, gint type);
gint wg_decode_unistr_copy(void* db, wg_int data, char* strbuf, wg_int buflen, gint type);
gint wg_decode_unistr_lang_copy(void* db, wg_int data, char* langbuf, wg_int buflen, gint type);

gint wg_encode_external_data(void *db, void *extdb, gint encoded);
#ifdef USE_CHILD_DB
gint wg_translate_hdroffset(void *db, void *exthdr, gint encoded);
void *wg_get_rec_owner(void *db, void *rec);
#endif

#endif /* DEFINED_DBDATA_H */
