mzlib.pas

lansd aslda sldasdnaslda sdlandslasd

function Inflate(var Z: TZState; F: Integer): Integer;
function InflateSetDictionary(var Z: TZState; Dictionary: PByte; DictLength: Cardinal): Integer;
function InflateSync(var Z: TZState): Integer;
function IsInflateSyncPoint(var Z: TZState): Integer;

//----------------------------------------------------------------------------------------------------------------------

implementation

uses
  SysUtils;

const
  // Adler checksum
  Base = Cardinal(65521);       // largest prime smaller than 65536 
  NMAX = 3854;                  // Code with signed 32 bit integer
  
type
  LH = record
    L, H: Word;
  end;

//----------------------------------------------------------------------------------------------------------------------

function zError(Error: Integer): String;

begin
  Result := ErrorMessages[Z_NEED_DICT - Error];
end;

//----------------------------------------------------------------------------------------------------------------------

function Adler32(Adler: Cardinal; Buffer: PByte; Len: Cardinal): Cardinal;

var
  s1, s2: Cardinal;
  K: Integer;

begin
  s1 := Adler and $FFFF;
  s2 := (Adler shr 16) and $FFFF;

  if Buffer = nil then Result := 1
                  else
  begin                                             
    while Len > 0 do
    begin
      if Len < NMAX then K := Len
                    else K := NMAX;
      Dec(Len, K);
      while K > 0 do
      begin
        Inc(s1, Buffer^);
        Inc(s2, s1);                      
        Inc(Buffer);
        Dec(K);
      end;
      s1 := s1 mod Base;
      s2 := s2 mod Base;
    end;
    Result := (s2 shl 16) or s1;
  end;
end;

//----------------------------------------------------------------------------------------------------------------------

var
  // used to calculate the running CRC of a bunch of bytes,
  // this table is dynamically created in order to save space if never needed
  CRCTable: array of Cardinal;

procedure MakeCRCTable;

// creates the CRC table when it is needed the first time

var
  C: Cardinal;
  N, K : Integer;
  Poly: Cardinal; // polynomial exclusive-or pattern

const
 // terms of polynomial defining this CRC (except x^32)
 P: array [0..13] of Byte = (0, 1, 2, 4, 5, 7, 8, 10, 11, 12, 16, 22, 23, 26);

begin
  // make exclusive-or pattern from polynomial ($EDB88320)
  SetLength(CRCTable, 256);
  Poly := 0;
  for N := 0 to SizeOf(P) - 1 do
    Poly := Poly or (1 shl (31 - P[N]));

  for N := 0 to 255 do
  begin
    C := N;
    for K := 0 to 7 do
    begin
      if (C and 1) <> 0 then C := Poly xor (C shr 1)
                        else C := C shr 1;
    end;
    CRCTable[N] := C;
  end;
end;

//----------------------------------------------------------------------------------------------------------------------

function CRC32(CRC: Cardinal; Buffer: PByte; Len: Cardinal): Cardinal;

// Generate a table for a byte-wise 32-bit CRC calculation on the polynomial:
// x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1.
//
// Polynomials over GF(2) are represented in binary, one bit per coefficient,
// with the lowest powers in the most significant bit.  Then adding polynomials
// is just exclusive-or, and multiplying a polynomial by x is a right shift by
// one.  If we call the above polynomial p, and represent a byte as the
// polynomial q, also with the lowest power in the most significant bit (so the
// byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
// where a mod b means the remainder after dividing a by b.
//
// This calculation is done using the shift-register method of multiplying and
// taking the remainder.  The register is initialized to zero, and for each
// incoming bit, x^32 is added mod p to the register if the bit is a one (where
// x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
// x (which is shifting right by one and adding x^32 mod p if the bit shifted
// out is a one).  We start with the highest power (least significant bit) of
// q and repeat for all eight bits of q.
//
// The table is simply the CRC of all possible eight bit values.  This is all
// the information needed to generate CRC's on data a byte at a time for all
// combinations of CRC register values and incoming bytes.

begin
  if Buffer = nil then Result := 0
                  else
  begin
    if CRCTable = nil then MakeCRCTable;

    CRC := CRC xor $FFFFFFFF;
    while Len >= 8 do
    begin
      CRC := CRCTable[Byte(CRC) xor Buffer^] xor (CRC shr 8);
      Inc(Buffer);
      CRC := CRCTable[Byte(CRC) xor Buffer^] xor (CRC shr 8);
      Inc(Buffer);
      CRC := CRCTable[Byte(CRC) xor Buffer^] xor (CRC shr 8);
      Inc(Buffer);
      CRC := CRCTable[Byte(CRC) xor Buffer^] xor (CRC shr 8);
      Inc(Buffer);
      CRC := CRCTable[Byte(CRC) xor Buffer^] xor (CRC shr 8);
      Inc(Buffer);
      CRC := CRCTable[Byte(CRC) xor Buffer^] xor (CRC shr 8);
      Inc(Buffer);
      CRC := CRCTable[Byte(CRC) xor Buffer^] xor (CRC shr 8);
      Inc(Buffer);
      CRC := CRCTable[Byte(CRC) xor Buffer^] xor (CRC shr 8);
      Inc(Buffer);

      Dec(Len, 8);
    end;

    while Len > 0 do
    begin
      CRC := CRCTable[(CRC xor Buffer^) and $FF] xor (CRC shr 8);
      Inc(Buffer);
      Dec(Len);
    end;
    Result := CRC xor $FFFFFFFF;
  end;
end;

//----------------- Huffmann trees -------------------------------------------------------------------------------------

const
  DIST_CODE_LEN = 512; // see definition of array dist_code below

  // The static literal tree. Since the bit lengths are imposed, there is no need for the L_CODES Extra codes used
  // during heap construction. However the codes 286 and 287 are needed to build a canonical tree (see TreeInit below).
  StaticLiteralTree: array[0..L_CODES + 1] of TTreeEntry = (
    (fc: (Frequency:  12); dl: (Len: 8)), (fc: (Frequency: 140); dl: (Len: 8)), (fc: (Frequency:  76); dl: (Len: 8)),
    (fc: (Frequency: 204); dl: (Len: 8)), (fc: (Frequency:  44); dl: (Len: 8)), (fc: (Frequency: 172); dl: (Len: 8)),
    (fc: (Frequency: 108); dl: (Len: 8)), (fc: (Frequency: 236); dl: (Len: 8)), (fc: (Frequency:  28); dl: (Len: 8)),
    (fc: (Frequency: 156); dl: (Len: 8)), (fc: (Frequency:  92); dl: (Len: 8)), (fc: (Frequency: 220); dl: (Len: 8)),
    (fc: (Frequency:  60); dl: (Len: 8)), (fc: (Frequency: 188); dl: (Len: 8)), (fc: (Frequency: 124); dl: (Len: 8)),
    (fc: (Frequency: 252); dl: (Len: 8)), (fc: (Frequency:   2); dl: (Len: 8)), (fc: (Frequency: 130); dl: (Len: 8)),
    (fc: (Frequency:  66); dl: (Len: 8)), (fc: (Frequency: 194); dl: (Len: 8)), (fc: (Frequency:  34); dl: (Len: 8)),
    (fc: (Frequency: 162); dl: (Len: 8)), (fc: (Frequency:  98); dl: (Len: 8)), (fc: (Frequency: 226); dl: (Len: 8)),
    (fc: (Frequency:  18); dl: (Len: 8)), (fc: (Frequency: 146); dl: (Len: 8)), (fc: (Frequency:  82); dl: (Len: 8)),
    (fc: (Frequency: 210); dl: (Len: 8)), (fc: (Frequency:  50); dl: (Len: 8)), (fc: (Frequency: 178); dl: (Len: 8)),
    (fc: (Frequency: 114); dl: (Len: 8)), (fc: (Frequency: 242); dl: (Len: 8)), (fc: (Frequency:  10); dl: (Len: 8)),
    (fc: (Frequency: 138); dl: (Len: 8)), (fc: (Frequency:  74); dl: (Len: 8)), (fc: (Frequency: 202); dl: (Len: 8)),
    (fc: (Frequency:  42); dl: (Len: 8)), (fc: (Frequency: 170); dl: (Len: 8)), (fc: (Frequency: 106); dl: (Len: 8)),
    (fc: (Frequency: 234); dl: (Len: 8)), (fc: (Frequency:  26); dl: (Len: 8)), (fc: (Frequency: 154); dl: (Len: 8)),
    (fc: (Frequency:  90); dl: (Len: 8)), (fc: (Frequency: 218); dl: (Len: 8)), (fc: (Frequency:  58); dl: (Len: 8)),
    (fc: (Frequency: 186); dl: (Len: 8)), (fc: (Frequency: 122); dl: (Len: 8)), (fc: (Frequency: 250); dl: (Len: 8)),
    (fc: (Frequency:   6); dl: (Len: 8)), (fc: (Frequency: 134); dl: (Len: 8)), (fc: (Frequency:  70); dl: (Len: 8)),
    (fc: (Frequency: 198); dl: (Len: 8)), (fc: (Frequency:  38); dl: (Len: 8)), (fc: (Frequency: 166); dl: (Len: 8)),
    (fc: (Frequency: 102); dl: (Len: 8)), (fc: (Frequency: 230); dl: (Len: 8)), (fc: (Frequency:  22); dl: (Len: 8)),
    (fc: (Frequency: 150); dl: (Len: 8)), (fc: (Frequency:  86); dl: (Len: 8)), (fc: (Frequency: 214); dl: (Len: 8)),
    (fc: (Frequency:  54); dl: (Len: 8)), (fc: (Frequency: 182); dl: (Len: 8)), (fc: (Frequency: 118); dl: (Len: 8)),
    (fc: (Frequency: 246); dl: (Len: 8)), (fc: (Frequency:  14); dl: (Len: 8)), (fc: (Frequency: 142); dl: (Len: 8)),
    (fc: (Frequency:  78); dl: (Len: 8)), (fc: (Frequency: 206); dl: (Len: 8)), (fc: (Frequency:  46); dl: (Len: 8)),
    (fc: (Frequency: 174); dl: (Len: 8)), (fc: (Frequency: 110); dl: (Len: 8)), (fc: (Frequency: 238); dl: (Len: 8)),
    (fc: (Frequency:  30); dl: (Len: 8)), (fc: (Frequency: 158); dl: (Len: 8)), (fc: (Frequency:  94); dl: (Len: 8)),
    (fc: (Frequency: 222); dl: (Len: 8)), (fc: (Frequency:  62); dl: (Len: 8)), (fc: (Frequency: 190); dl: (Len: 8)),
    (fc: (Frequency: 126); dl: (Len: 8)), (fc: (Frequency: 254); dl: (Len: 8)), (fc: (Frequency:   1); dl: (Len: 8)),
    (fc: (Frequency: 129); dl: (Len: 8)), (fc: (Frequency:  65); dl: (Len: 8)), (fc: (Frequency: 193); dl: (Len: 8)),
    (fc: (Frequency:  33); dl: (Len: 8)), (fc: (Frequency: 161); dl: (Len: 8)), (fc: (Frequency:  97); dl: (Len: 8)),
    (fc: (Frequency: 225); dl: (Len: 8)), (fc: (Frequency:  17); dl: (Len: 8)), (fc: (Frequency: 145); dl: (Len: 8)),
    (fc: (Frequency:  81); dl: (Len: 8)), (fc: (Frequency: 209); dl: (Len: 8)), (fc: (Frequency:  49); dl: (Len: 8)),
    (fc: (Frequency: 177); dl: (Len: 8)), (fc: (Frequency: 113); dl: (Len: 8)), (fc: (Frequency: 241); dl: (Len: 8)),
    (fc: (Frequency:   9); dl: (Len: 8)), (fc: (Frequency: 137); dl: (Len: 8)), (fc: (Frequency:  73); dl: (Len: 8)),
    (fc: (Frequency: 201); dl: (Len: 8)), (fc: (Frequency:  41); dl: (Len: 8)), (fc: (Frequency: 169); dl: (Len: 8)),
    (fc: (Frequency: 105); dl: (Len: 8)), (fc: (Frequency: 233); dl: (Len: 8)), (fc: (Frequency:  25); dl: (Len: 8)),
    (fc: (Frequency: 153); dl: (Len: 8)), (fc: (Frequency:  89); dl: (Len: 8)), (fc: (Frequency: 217); dl: (Len: 8)),
    (fc: (Frequency:  57); dl: (Len: 8)), (fc: (Frequency: 185); dl: (Len: 8)), (fc: (Frequency: 121); dl: (Len: 8)),
    (fc: (Frequency: 249); dl: (Len: 8)), (fc: (Frequency:   5); dl: (Len: 8)), (fc: (Frequency: 133); dl: (Len: 8)),
    (fc: (Frequency:  69); dl: (Len: 8)), (fc: (Frequency: 197); dl: (Len: 8)), (fc: (Frequency:  37); dl: (Len: 8)),
    (fc: (Frequency: 165); dl: (Len: 8)), (fc: (Frequency: 101); dl: (Len: 8)), (fc: (Frequency: 229); dl: (Len: 8)),
    (fc: (Frequency:  21); dl: (Len: 8)), (fc: (Frequency: 149); dl: (Len: 8)), (fc: (Frequency:  85); dl: (Len: 8)),
    (fc: (Frequency: 213); dl: (Len: 8)), (fc: (Frequency:  53); dl: (Len: 8)), (fc: (Frequency: 181); dl: (Len: 8)),
    (fc: (Frequency: 117); dl: (Len: 8)), (fc: (Frequency: 245); dl: (Len: 8)), (fc: (Frequency:  13); dl: (Len: 8)),
    (fc: (Frequency: 141); dl: (Len: 8)), (fc: (Frequency:  77); dl: (Len: 8)), (fc: (Frequency: 205); dl: (Len: 8)),
    (fc: (Frequency:  45); dl: (Len: 8)), (fc: (Frequency: 173); dl: (Len: 8)), (fc: (Frequency: 109); dl: (Len: 8)),
    (fc: (Frequency: 237); dl: (Len: 8)), (fc: (Frequency:  29); dl: (Len: 8)), (fc: (Frequency: 157); dl: (Len: 8)),
    (fc: (Frequency:  93); dl: (Len: 8)), (fc: (Frequency: 221); dl: (Len: 8)), (fc: (Frequency:  61); dl: (Len: 8)),
    (fc: (Frequency: 189); dl: (Len: 8)), (fc: (Frequency: 125); dl: (Len: 8)), (fc: (Frequency: 253); dl: (Len: 8)),
    (fc: (Frequency:  19); dl: (Len: 9)), (fc: (Frequency: 275); dl: (Len: 9)), (fc: (Frequency: 147); dl: (Len: 9)),
    (fc: (Frequency: 403); dl: (Len: 9)), (fc: (Frequency:  83); dl: (Len: 9)), (fc: (Frequency: 339); dl: (Len: 9)),
    (fc: (Frequency: 211); dl: (Len: 9)), (fc: (Frequency: 467); dl: (Len: 9)), (fc: (Frequency:  51); dl: (Len: 9)),
    (fc: (Frequency: 307); dl: (Len: 9)), (fc: (Frequency: 179); dl: (Len: 9)), (fc: (Frequency: 435); dl: (Len: 9)),
    (fc: (Frequency: 115); dl: (Len: 9)), (fc: (Frequency: 371); dl: (Len: 9)), (fc: (Frequency: 243); dl: (Len: 9)),
    (fc: (Frequency: 499); dl: (Len: 9)), (fc: (Frequency:  11); dl: (Len: 9)), (fc: (Frequency: 267); dl: (Len: 9)),
    (fc: (Frequency: 139); dl: (Len: 9)), (fc: (Frequency: 395); dl: (Len: 9)), (fc: (Frequency:  75); dl: (Len: 9)),
    (fc: (Frequency: 331); dl: (Len: 9)), (fc: (Frequency: 203); dl: (Len: 9)), (fc: (Frequency: 459); dl: (Len: 9)),
    (fc: (Frequency:  43); dl: (Len: 9)), (fc: (Frequency: 299); dl: (Len: 9)), (fc: (Frequency: 171); dl: (Len: 9)),
    (fc: (Frequency: 427); dl: (Len: 9)), (fc: (Frequency: 107); dl: (Len: 9)), (fc: (Frequency: 363); dl: (Len: 9)),
    (fc: (Frequency: 235); dl: (Len: 9)), (fc: (Frequency: 491); dl: (Len: 9)), (fc: (Frequency:  27); dl: (Len: 9)),
    (fc: (Frequency: 283); dl: (Len: 9)), (fc: (Frequency: 155); dl: (Len: 9)), (fc: (Frequency: 411); dl: (Len: 9)),
    (fc: (Frequency:  91); dl: (Len: 9)), (fc: (Frequency: 347); dl: (Len: 9)), (fc: (Frequency: 219); dl: (Len: 9)),
    (fc: (Frequency: 475); dl: (Len: 9)), (fc: (Frequency:  59); dl: (Len: 9)), (fc: (Frequency: 315); dl: (Len: 9)),
    (fc: (Frequency: 187); dl: (Len: 9)), (fc: (Frequency: 443); dl: (Len: 9)), (fc: (Frequency: 123); dl: (Len: 9)),
    (fc: (Frequency: 379); dl: (Len: 9)), (fc: (Frequency: 251); dl: (Len: 9)), (fc: (Frequency: 507); dl: (Len: 9)),
    (fc: (Frequency:   7); dl: (Len: 9)), (fc: (Frequency: 263); dl: (Len: 9)), (fc: (Frequency: 135); dl: (Len: 9)),
    (fc: (Frequency: 391); dl: (Len: 9)), (fc: (Frequency:  71); dl: (Len: 9)), (fc: (Frequency: 327); dl: (Len: 9)),
    (fc: (Frequency: 199); dl: (Len: 9)), (fc: (Frequency: 455); dl: (Len: 9)), (fc: (Frequency:  39); dl: (Len: 9)),
    (fc: (Frequency: 295); dl: (Len: 9)), (fc: (Frequency: 167); dl: (Len: 9)), (fc: (Frequency: 423); dl: (Len: 9)),
    (fc: (Frequency: 103); dl: (Len: 9)), (fc: (Frequency: 359); dl: (Len: 9)), (fc: (Frequency: 231); dl: (Len: 9)),
    (fc: (Frequency: 487); dl: (Len: 9)), (fc: (Frequency:  23); dl: (Len: 9)), (fc: (Frequency: 279); dl: (Len: 9)),
    (fc: (Frequency: 151); dl: (Len: 9)), (fc: (Frequency: 407); dl: (Len: 9)), (fc: (Frequency:  87); dl: (Len: 9)),
    (fc: (Frequency: 343); dl: (Len: 9)), (fc: (Frequency: 215); dl: (Len: 9)), (fc: (Frequency: 471); dl: (Len: 9)),
    (fc: (Frequency:  55); dl: (Len: 9)), (fc: (Frequency: 311); dl: (Len: 9)), (fc: (Frequency: 183); dl: (Len: 9)),
    (fc: (Frequency: 439); dl: (Len: 9)), (fc: (Frequency: 119); dl: (Len: 9)), (fc: (Frequency: 375); dl: (Len: 9)),
    (fc: (Frequency: 247); dl: (Len: 9)), (fc: (Frequency: 503); dl: (Len: 9)), (fc: (Frequency:  15); dl: (Len: 9)),
    (fc: (Frequency: 271); dl: (Len: 9)), (fc: (Frequency: 143); dl: (Len: 9)), (fc: (Frequency: 399); dl: (Len: 9)),
    (fc: (Frequency:  79); dl: (Len: 9)), (fc: (Frequency: 335); dl: (Len: 9)), (fc: (Frequency: 207); dl: (Len: 9)),
    (fc: (Frequency: 463); dl: (Len: 9)), (fc: (Frequency:  47); dl: (Len: 9)), (fc: (Frequency: 303); dl: (Len: 9)),
    (fc: (Frequency: 175); dl: (Len: 9)), (fc: (Frequency: 431); dl: (Len: 9)), (fc: (Frequency: 111); dl: (Len: 9)),
    (fc: (Frequency: 367); dl: (Len: 9)), (fc: (Frequency: 239); dl: (Len: 9)), (fc: (Frequency: 495); dl: (Len: 9)),
    (fc: (Frequency:  31); dl: (Len: 9)), (fc: (Frequency: 287); dl: (Len: 9)), (fc: (Frequency: 159); dl: (Len: 9)),
    (fc: (Frequency: 415); dl: (Len: 9)), (fc: (Frequency:  95); dl: (Len: 9)), (fc: (Frequency: 351); dl: (Len: 9)),
    (fc: (Frequency: 223); dl: (Len: 9)), (fc: (Frequency: 479); dl: (Len: 9)), (fc: (Frequency:  63); dl: (Len: 9)),
    (fc: (Frequency: 319); dl: (Len: 9)), (fc: (Frequency: 191); dl: (Len: 9)), (fc: (Frequency: 447); dl: (Len: 9)),
    (fc: (Frequency: 127); dl: (Len: 9)), (fc: (Frequency: 383); dl: (Len: 9)), (fc: (Frequency: 255); dl: (Len: 9)),
    (fc: (Frequency: 511); dl: (Len: 9)), (fc: (Frequency:   0); dl: (Len: 7)), (fc: (Frequency:  64); dl: (Len: 7)),
    (fc: (Frequency:  32); dl: (Len: 7)), (fc: (Frequency:  96); dl: (Len: 7)), (fc: (Frequency:  16); dl: (Len: 7)),
    (fc: (Frequency:  80); dl: (Len: 7)), (fc: (Frequency:  48); dl: (Len: 7)), (fc: (Frequency: 112); dl: (Len: 7)),
    (fc: (Frequency:   8); dl: (Len: 7)), (fc: (Frequency:  72); dl: (Len: 7)), (fc: (Frequency:  40); dl: (Len: 7)),
    (fc: (Frequency: 104); dl: (Len: 7)), (fc: (Frequency:  24); dl: (Len: 7)), (fc: (Frequency:  88); dl: (Len: 7)),
    (fc: (Frequency:  56); dl: (Len: 7)), (fc: (Frequency: 120); dl: (Len: 7)), (fc: (Frequency:   4); dl: (Len: 7)),
    (fc: (Frequency:  68); dl: (Len: 7)), (fc: (Frequency:  36); dl: (Len: 7)), (fc: (Frequency: 100); dl: (Len: 7)),
    (fc: (Frequency:  20); dl: (Len: 7)), (fc: (Frequency:  84); dl: (Len: 7)), (fc: (Frequency:  52); dl: (Len: 7)),
    (fc: (Frequency: 116); dl: (Len: 7)), (fc: (Frequency:   3); dl: (Len: 8)), (fc: (Frequency: 131); dl: (Len: 8)),
    (fc: (Frequency:  67); dl: (Len: 8)), (fc: (Frequency: 195); dl: (Len: 8)), (fc: (Frequency:  35); dl: (Len: 8)),
    (fc: (Frequency: 163); dl: (Len: 8)), (fc: (Frequency:  99); dl: (Len: 8)), (fc: (Frequency: 227); dl: (Len: 8))
  );

  // The static distance tree. (Actually a trivial tree since all lens use 5 Bits.)
  StaticDescriptorTree: array[0..D_CODES - 1] of TTreeEntry = (
    (fc: (Frequency:  0); dl: (Len: 5)), (fc: (Frequency: 16); dl: (Len: 5)), (fc: (Frequency:  8); dl: (Len: 5)),
    (fc: (Frequency: 24); dl: (Len: 5)), (fc: (Frequency:  4); dl: (Len: 5)), (fc: (Frequency: 20); dl: (Len: 5)),
    (fc: (Frequency: 12); dl: (Len: 5)), (fc: (Frequency: 28); dl: (Len: 5)), (fc: (Frequency:  2); dl: (Len: 5)),
    (fc: (Frequency: 18); dl: (Len: 5)), (fc: (Frequency: 10); dl: (Len: 5)), (fc: (Frequency: 26); dl: (Len: 5)),