unit zlib;
interface
uses Sysutils, Classes;
type
TAlloc = function (AppData: Pointer; Items, Size: Integer): Pointer;
TFree = procedure (AppData, Block: Pointer);
// Internal structure. Ignore.
TZStreamRec = packed record
next_in: PChar; // next input byte
avail_in: Integer; // number of bytes available at next_in
total_in: Integer; // total nb of input bytes read so far
next_out: PChar; // next output byte should be put here
avail_out: Integer; // remaining free space at next_out
total_out: Integer; // total nb of bytes output so far
msg: PChar; // last error message, NULL if no error
internal: Pointer; // not visible by applications
zalloc: TAlloc; // used to allocate the internal state
zfree: TFree; // used to free the internal state
AppData: Pointer; // private data object passed to zalloc and zfree
data_type: Integer; // best guess about the data type: ascii or binary
adler: Integer; // adler32 value of the uncompressed data
reserved: Integer; // reserved for future use
end;
// Abstract ancestor class
TCustomZlibStream = class(TStream)
private
FStrm: TStream;
FStrmPos: Integer;
FOnProgress: TNotifyEvent;
FZRec: TZStreamRec;
FBuffer: array [Word] of Char;
protected
procedure Progress(Sender: TObject); dynamic;
property OnProgress: TNotifyEvent read FOnProgress write FOnProgress;
constructor Create(Strm: TStream);
end;
TCompressionLevel = (clNone, clFastest, clDefault, clMax);
TCompressionStream = class(TCustomZlibStream)
private
function GetCompressionRate: Single;
public
constructor Create(CompressionLevel: TCompressionLevel; Dest: TStream);
destructor Destroy; override;
function Read(var Buffer; Count: Longint): Longint; override;
function Write(const Buffer; Count: Longint): Longint; override;
function Seek(Offset: Longint; Origin: Word): Longint; override;
property CompressionRate: Single read GetCompressionRate;
property OnProgress;
end;
TDecompressionStream = class(TCustomZlibStream)
public
constructor Create(Source: TStream);
destructor Destroy; override;
function Read(var Buffer; Count: Longint): Longint; override;
function Write(const Buffer; Count: Longint): Longint; override;
function Seek(Offset: Longint; Origin: Word): Longint; override;
property OnProgress;
end;
procedure CompressBuf(const InBuf: Pointer; InBytes: Integer;
out OutBuf: Pointer; out OutBytes: Integer);
procedure DecompressBuf(const InBuf: Pointer; InBytes: Integer;
OutEstimate: Integer; out OutBuf: Pointer; out OutBytes: Integer);
const
zlib_version = '1.1.3';
type
EZlibError = class(Exception);
ECompressionError = class(EZlibError);
EDecompressionError = class(EZlibError);
function adler32(adler: Integer; buf: PChar; len: Integer): Integer;
implementation
const
Z_NO_FLUSH = 0;
Z_PARTIAL_FLUSH = 1;
Z_SYNC_FLUSH = 2;
Z_FULL_FLUSH = 3;
Z_FINISH = 4;
Z_OK = 0;
Z_STREAM_END = 1;
Z_NEED_DICT = 2;
Z_ERRNO = (-1);
Z_STREAM_ERROR = (-2);
Z_DATA_ERROR = (-3);
Z_MEM_ERROR = (-4);
Z_BUF_ERROR = (-5);
Z_VERSION_ERROR = (-6);
Z_NO_COMPRESSION = 0;
Z_BEST_SPEED = 1;
Z_BEST_COMPRESSION = 9;
Z_DEFAULT_COMPRESSION = (-1);
Z_FILTERED = 1;
Z_HUFFMAN_ONLY = 2;
Z_DEFAULT_STRATEGY = 0;
Z_BINARY = 0;
Z_ASCII = 1;
Z_UNKNOWN = 2;
Z_DEFLATED = 8;
_z_errmsg: array[0..9] of PChar = (
'need dictionary', // Z_NEED_DICT (2)
'stream end', // Z_STREAM_END (1)
'', // Z_OK (0)
'file error', // Z_ERRNO (-1)
'stream error', // Z_STREAM_ERROR (-2)
'data error', // Z_DATA_ERROR (-3)
'insufficient memory', // Z_MEM_ERROR (-4)
'buffer error', // Z_BUF_ERROR (-5)
'incompatible version', // Z_VERSION_ERROR (-6)
''
);
procedure _tr_init; external;
procedure _tr_tally; external;
procedure _tr_flush_block; external;
procedure _tr_align; external;
procedure _tr_stored_block; external;
function adler32; external;
procedure inflate_blocks_new; external;
procedure inflate_blocks; external;
procedure inflate_blocks_reset; external;
procedure inflate_blocks_free; external;
procedure inflate_set_dictionary; external;
procedure inflate_trees_bits; external;
procedure inflate_trees_dynamic; external;
procedure inflate_trees_fixed; external;
procedure inflate_codes_new; external;
procedure inflate_codes; external;
procedure inflate_codes_free; external;
procedure _inflate_mask; external;
procedure inflate_flush; external;
procedure inflate_fast; external;
procedure _memset(P: Pointer; B: Byte; count: Integer);cdecl;
begin
FillChar(P^, count, B);
end;
procedure _memcpy(dest, source: Pointer; count: Integer);cdecl;
begin
Move(source^, dest^, count);
end;
// deflate compresses data
function deflateInit_(var strm: TZStreamRec; level: Integer; version: PChar;
recsize: Integer): Integer; external;
function deflate(var strm: TZStreamRec; flush: Integer): Integer; external;
function deflateEnd(var strm: TZStreamRec): Integer; external;
// inflate decompresses data
function inflateInit_(var strm: TZStreamRec; version: PChar;
recsize: Integer): Integer; external;
function inflate(var strm: TZStreamRec; flush: Integer): Integer; external;
function inflateEnd(var strm: TZStreamRec): Integer; external;
function inflateReset(var strm: TZStreamRec): Integer; external;
function zcalloc(AppData: Pointer; Items, Size: Integer): Pointer;
begin
GetMem(Result, Items*Size);
end;
procedure zcfree(AppData, Block: Pointer);
begin
FreeMem(Block);
end;
function zlibCheck(code: Integer): Integer;
begin
Result := code;
if code < 0 then
raise EZlibError.Create('error'); //!!
end;
function CCheck(code: Integer): Integer;
begin
Result := code;
if code < 0 then
raise ECompressionError.Create('error'); //!!
end;
function DCheck(code: Integer): Integer;
begin
Result := code;
if code < 0 then
raise EDecompressionError.Create('error'); //!!
end;
procedure CompressBuf(const InBuf: Pointer; InBytes: Integer;
out OutBuf: Pointer; out OutBytes: Integer);
var
strm: TZStreamRec;
P: Pointer;
begin
FillChar(strm, sizeof(strm), 0);
OutBytes := ((InBytes + (InBytes div 10) + 12) + 255) and not 255;
GetMem(OutBuf, OutBytes);
try
strm.next_in := InBuf;
strm.avail_in := InBytes;
strm.next_out := OutBuf;
strm.avail_out := OutBytes;
CCheck(deflateInit_(strm, Z_BEST_COMPRESSION, zlib_version, sizeof(strm)));
try
while CCheck(deflate(strm, Z_FINISH)) <> Z_STREAM_END do
begin
P := OutBuf;
Inc(OutBytes, 256);
ReallocMem(OutBuf, OutBytes);
strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P)));
strm.avail_out := 256;
end;
finally
CCheck(deflateEnd(strm));
end;
ReallocMem(OutBuf, strm.total_out);
OutBytes := strm.total_out;
except
FreeMem(OutBuf);
raise
end;
end;
procedure DecompressBuf(const InBuf: Pointer; InBytes: Integer;
OutEstimate: Integer; out OutBuf: Pointer; out OutBytes: Integer);
var
strm: TZStreamRec;
P: Pointer;
BufInc: Integer;
begin
FillChar(strm, sizeof(strm), 0);
BufInc := (InBytes + 255) and not 255;
if OutEstimate = 0 then
OutBytes := BufInc
else
OutBytes := OutEstimate;
GetMem(OutBuf, OutBytes);
try
strm.next_in := InBuf;
strm.avail_in := InBytes;
strm.next_out := OutBuf;
strm.avail_out := OutBytes;
DCheck(inflateInit_(strm, zlib_version, sizeof(strm)));
try
while DCheck(inflate(strm, Z_FINISH)) <> Z_STREAM_END do
begin
P := OutBuf;
Inc(OutBytes, BufInc);
ReallocMem(OutBuf, OutBytes);
strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P)));
strm.avail_out := BufInc;
end;
finally
DCheck(inflateEnd(strm));
end;
ReallocMem(OutBuf, strm.total_out);
OutBytes := strm.total_out;
except
FreeMem(OutBuf);
raise
end;
end;
// TCustomZlibStream
constructor TCustomZLibStream.Create(Strm: TStream);
begin
inherited Create;
FStrm := Strm;
FStrmPos := Strm.Position;
end;
procedure TCustomZLibStream.Progress(Sender: TObject);
begin
if Assigned(FOnProgress) then FOnProgress(Sender);
end;
// TCompressionStream
constructor TCompressionStream.Create(CompressionLevel: TCompressionLevel;
Dest: TStream);
const
Levels: array [TCompressionLevel] of ShortInt =
(Z_NO_COMPRESSION, Z_BEST_SPEED, Z_DEFAULT_COMPRESSION, Z_BEST_COMPRESSION);
begin
inherited Create(Dest);
FZRec.next_out := FBuffer;
FZRec.avail_out := sizeof(FBuffer);
CCheck(deflateInit_(FZRec, Levels[CompressionLevel], zlib_version, sizeof(FZRec)));
end;
destructor TCompressionStream.Destroy;
begin
FZRec.next_in := nil;
FZRec.avail_in := 0;
try
if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
while (CCheck(deflate(FZRec, Z_FINISH)) <> Z_STREAM_END)
and (FZRec.avail_out = 0) do
begin
FStrm.WriteBuffer(FBuffer, sizeof(FBuffer));
FZRec.next_out := FBuffer;
FZRec.avail_out := sizeof(FBuffer);
end;
if FZRec.avail_out < sizeof(FBuffer) then
FStrm.WriteBuffer(FBuffer, sizeof(FBuffer) - FZRec.avail_out);
finally
deflateEnd(FZRec);
end;
inherited Destroy;
end;
function TCompressionStream.Read(var Buffer; Count: Longint): Longint;
begin
raise ECompressionError.Create('Invalid stream operation');
end;
function TCompressionStream.Write(const Buffer; Count: Longint): Longint;
begin
FZRec.next_in := @Buffer;
FZRec.avail_in := Count;
if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
while (FZRec.avail_in > 0) do
begin
CCheck(deflate(FZRec, 0));
if FZRec.avail_out = 0 then
begin
FStrm.WriteBuffer(FBuffer, sizeof(FBuffer));
FZRec.next_out := FBuffer;
FZRec.avail_out := sizeof(FBuffer);
FStrmPos := FStrm.Position;
Progress(Self);
end;
end;
Result := Count;
end;
function TCompressionStream.Seek(Offset: Longint; Origin: Word): Longint;
begin
if (Offset = 0) and (Origin = soFromCurrent) then
Result := FZRec.total_in
else
raise ECompressionError.Create('Invalid stream operation');
end;
function TCompressionStream.GetCompressionRate: Single;
begin
if FZRec.total_in = 0 then
Result := 0
else
Result := (1.0 - (FZRec.total_out / FZRec.total_in)) * 100.0;
end;
// TDecompressionStream
constructor TDecompressionStream.Create(Source: TStream);
begin
inherited Create(Source);
FZRec.next_in := FBuffer;
FZRec.avail_in := 0;
DCheck(inflateInit_(FZRec, zlib_version, sizeof(FZRec)));
end;
destructor TDecompressionStream.Destroy;
begin
inflateEnd(FZRec);
inherited Destroy;
end;
function TDecompressionStream.Read(var Buffer; Count: Longint): Longint;
begin
FZRec.next_out := @Buffer;
FZRec.avail_out := Count;
if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
while (FZRec.avail_out > 0) do
begin
if FZRec.avail_in = 0 then
begin
FZRec.avail_in := FStrm.Read(FBuffer, sizeof(FBuffer));
if FZRec.avail_in = 0 then
begin
Result := Count - FZRec.avail_out;
Exit;
end;
FZRec.next_in := FBuffer;
FStrmPos := FStrm.Position;
Progress(Self);
end;
DCheck(inflate(FZRec, 0));
end;
Result := Count;
end;
function TDecompressionStream.Write(const Buffer; Count: Longint): Longint;
begin
raise EDecompressionError.Create('Invalid stream operation');
end;
function TDecompressionStream.Seek(Offset: Longint; Origin: Word): Longint;
var
I: Integer;
Buf: array [0..4095] of Char;
begin
if (Offset = 0) and (Origin = soFromBeginning) then
begin
DCheck(inflateReset(FZRec));
FZRec.next_in := FBuffer;
FZRec.avail_in := 0;
FStrm.Position := 0;
FStrmPos := 0;
end
else if ( (Offset >= 0) and (Origin = soFromCurrent)) or
( ((Offset - FZRec.total_out) > 0) and (Origin = soFromBeginning)) then
begin
if Origin = soFromBeginning then Dec(Offset, FZRec.total_out);
if Offset > 0 then
begin
for I := 1 to Offset div sizeof(Buf) do
ReadBuffer(Buf, sizeof(Buf));
ReadBuffer(Buf, Offset mod sizeof(Buf));
end;
end
else
raise EDecompressionError.Create('Invalid stream operation');
Result := FZRec.total_out;
end;
end.