(*
    BSD 2-Clause License

    Copyright (c) 2018, Anton Krotov
    All rights reserved.
*)

MODULE CHUNKLISTS;

IMPORT LISTS, WR := WRITER;


CONST

    LENOFBYTECHUNK = 64000;
    LENOFINTCHUNK  = 16000;


TYPE

    ANYLIST = POINTER TO RECORD (LISTS.LIST)

        length: INTEGER

    END;

    BYTELIST* = POINTER TO RECORD (ANYLIST) END;

    BYTECHUNK = POINTER TO RECORD (LISTS.ITEM)

        data:   ARRAY LENOFBYTECHUNK OF BYTE;
        count:  INTEGER

    END;


    INTLIST* = POINTER TO RECORD (ANYLIST) END;

    INTCHUNK = POINTER TO RECORD (LISTS.ITEM)

        data:   ARRAY LENOFINTCHUNK OF INTEGER;
        count:  INTEGER

    END;


PROCEDURE SetByte* (list: BYTELIST; idx: INTEGER; byte: BYTE);
VAR
    ChunkNum: INTEGER;
    chunk:    BYTECHUNK;

BEGIN
    ASSERT(idx >= 0);
    ASSERT(list # NIL);

    ChunkNum := idx DIV LENOFBYTECHUNK;
    idx      := idx MOD LENOFBYTECHUNK;

    chunk := list.first(BYTECHUNK);

    WHILE (chunk # NIL) & (ChunkNum > 0) DO
        chunk := chunk.next(BYTECHUNK);
        DEC(ChunkNum)
    END;

    ASSERT(chunk # NIL);
    ASSERT(idx < chunk.count);

    chunk.data[idx] := byte
END SetByte;


PROCEDURE GetByte* (list: BYTELIST; idx: INTEGER): BYTE;
VAR
    ChunkNum: INTEGER;
    chunk:    BYTECHUNK;

BEGIN
    ASSERT(idx >= 0);
    ASSERT(list # NIL);

    ChunkNum := idx DIV LENOFBYTECHUNK;
    idx      := idx MOD LENOFBYTECHUNK;

    chunk := list.first(BYTECHUNK);

    WHILE (chunk # NIL) & (ChunkNum > 0) DO
        chunk := chunk.next(BYTECHUNK);
        DEC(ChunkNum)
    END;

    ASSERT(chunk # NIL);
    ASSERT(idx < chunk.count)

    RETURN chunk.data[idx]
END GetByte;


PROCEDURE PushByte* (list: BYTELIST; byte: BYTE);
VAR
    chunk: BYTECHUNK;

BEGIN
    ASSERT(list # NIL);

    chunk := list.last(BYTECHUNK);

    IF chunk.count = LENOFBYTECHUNK THEN
        NEW(chunk);
        chunk.count := 0;
        LISTS.push(list, chunk)
    END;

    chunk.data[chunk.count] := byte;
    INC(chunk.count);

    INC(list.length)
END PushByte;


PROCEDURE WriteToFile* (file: WR.FILE; list: BYTELIST);
VAR
    chunk: BYTECHUNK;

BEGIN              
    chunk := list.first(BYTECHUNK);
    WHILE chunk # NIL DO
        WR.Write(file, chunk.data, chunk.count);
        chunk := chunk.next(BYTECHUNK)
    END
END WriteToFile;


PROCEDURE CreateByteList* (): BYTELIST;
VAR
    bytelist: BYTELIST;
    list:     LISTS.LIST;
    chunk:    BYTECHUNK;

BEGIN
    NEW(bytelist);
    list := LISTS.create(bytelist);
    bytelist.length := 0;

    NEW(chunk);
    chunk.count := 0;
    LISTS.push(list, chunk)

    RETURN list(BYTELIST)
END CreateByteList;


PROCEDURE SetInt* (list: INTLIST; idx: INTEGER; int: INTEGER);
VAR
    ChunkNum: INTEGER;
    chunk:    INTCHUNK;

BEGIN
    ASSERT(idx >= 0);
    ASSERT(list # NIL);

    ChunkNum := idx DIV LENOFINTCHUNK;
    idx      := idx MOD LENOFINTCHUNK;

    chunk := list.first(INTCHUNK);

    WHILE (chunk # NIL) & (ChunkNum > 0) DO
        chunk := chunk.next(INTCHUNK);
        DEC(ChunkNum)
    END;

    ASSERT(chunk # NIL);
    ASSERT(idx < chunk.count);

    chunk.data[idx] := int
END SetInt;


PROCEDURE GetInt* (list: INTLIST; idx: INTEGER): INTEGER;
VAR
    ChunkNum: INTEGER;
    chunk:    INTCHUNK;

BEGIN
    ASSERT(idx >= 0);
    ASSERT(list # NIL);

    ChunkNum := idx DIV LENOFINTCHUNK;
    idx      := idx MOD LENOFINTCHUNK;

    chunk := list.first(INTCHUNK);

    WHILE (chunk # NIL) & (ChunkNum > 0) DO
        chunk := chunk.next(INTCHUNK);
        DEC(ChunkNum)
    END;

    ASSERT(chunk # NIL);
    ASSERT(idx < chunk.count)

    RETURN chunk.data[idx]
END GetInt;


PROCEDURE PushInt* (list: INTLIST; int: INTEGER);
VAR
    chunk: INTCHUNK;

BEGIN
    ASSERT(list # NIL);

    chunk := list.last(INTCHUNK);

    IF chunk.count = LENOFINTCHUNK THEN
        NEW(chunk);
        chunk.count := 0;
        LISTS.push(list, chunk)
    END;

    chunk.data[chunk.count] := int;
    INC(chunk.count);

    INC(list.length)
END PushInt;


PROCEDURE CreateIntList* (): INTLIST;
VAR
    intlist:  INTLIST;
    list:     LISTS.LIST;
    chunk:    INTCHUNK;

BEGIN
    NEW(intlist);
    list := LISTS.create(intlist);
    intlist.length := 0;

    NEW(chunk);
    chunk.count := 0;
    LISTS.push(list, chunk)

    RETURN list(INTLIST)
END CreateIntList;


PROCEDURE Length* (list: ANYLIST): INTEGER;
    RETURN list.length
END Length;


END CHUNKLISTS.