📄 zlibex.pas
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{*****************************************************************************
* ZLibEx.pas *
* *
* copyright (c) 2000-2005 base2 technologies *
* copyright (c) 1997 Borland International *
* *
* revision history *
* 2005.07.25 updated to zlib version 1.2.3 *
* 2005.03.04 modified ZInternalCompressStream loops *
* modified ZInternalDecompressStream loops *
* 2005.02.07 fixed ZInternalCompressStream loop conditions *
* fixed ZInternalDecompressStream loop conditions *
* 2005.01.11 updated to zlib version 1.2.2 *
* added ZCompressStrWeb *
* 2004.01.06 updated to zlib version 1.2.1 *
* 2003.04.14 added ZCompress2 and ZDecompress2 *
* added ZCompressStr2 and ZDecompressStr2 *
* added ZCompressStream2 and ZDecompressStream2 *
* added overloaded T*Stream constructors to support *
* InflateInit2 and DeflateInit2 *
* fixed ZDecompressStream to use ZDecompressCheck instead of *
* ZCompressCheck *
* 2002.03.15 updated to zlib version 1.1.4 *
* 2001.11.27 enhanced TZDecompressionStream.Read to adjust source *
* stream position upon end of compression data *
* fixed endless loop in TZDecompressionStream.Read when *
* destination count was greater than uncompressed data *
* 2001.10.26 renamed unit to integrate "nicely" with delphi 6 *
* 2000.11.24 added soFromEnd condition to TZDecompressionStream.Seek *
* added ZCompressStream and ZDecompressStream *
* 2000.06.13 optimized, fixed, rewrote, and enhanced the zlib.pas unit *
* included on the delphi cd (zlib version 1.1.3) *
* *
* acknowledgements *
* erik turner *
* Z*Stream routines *
* *
* david bennion *
* finding the nastly little endless loop quirk with the *
* TZDecompressionStream.Read method *
* *
* burak kalayci *
* informing me about the zlib 1.1.4 update and the 1.2.1 update *
* *
* vicente s醤chez-alarcos *
* informing me about the zlib 1.2.2 update *
* *
* luigi sandon *
* pointing out the missing loop condition (Z_STREAM_END) in *
* ZInternalCompressStream and ZInternalDecompressStream *
* *
* ferry van genderen *
* assiting me fine tune and beta test ZInternalCompressStream and *
* ZInternalDecompressStream *
* *
* mathijs van veluw *
* informing me about the zlib 1.2.3 update *
*****************************************************************************}
unit ZLibEx;
interface
uses
Sysutils, Classes;
const
ZLIB_VERSION = '1.2.3';
ZLIB_VERNUM = $1230;
type
TZAlloc = function (opaque: Pointer; items, size: Integer): Pointer;
TZFree = procedure (opaque, block: Pointer);
TZCompressionLevel = (zcNone, zcFastest, zcDefault, zcMax);
TZStrategy = (zsDefault, zsFiltered, zsHuffman, zsRLE, zsFixed);
{** TZStreamRec ***********************************************************}
TZStreamRec = packed record
next_in : PChar; // next input byte
avail_in : Longint; // number of bytes available at next_in
total_in : Longint; // total nb of input bytes read so far
next_out : PChar; // next output byte should be put here
avail_out: Longint; // remaining free space at next_out
total_out: Longint; // total nb of bytes output so far
msg : PChar; // last error message, NULL if no error
state : Pointer; // not visible by applications
zalloc : TZAlloc; // used to allocate the internal state
zfree : TZFree; // used to free the internal state
opaque : Pointer; // private data object passed to zalloc and zfree
data_type: Integer; // best guess about the data type: ascii or binary
adler : Longint; // adler32 value of the uncompressed data
reserved : Longint; // reserved for future use
end;
{** TCustomZStream ********************************************************}
TCustomZStream = class(TStream)
private
FStream : TStream;
FStreamPos : Integer;
FOnProgress: TNotifyEvent;
FZStream : TZStreamRec;
FBuffer : Array [Word] of Char;
protected
constructor Create(stream: TStream);
procedure DoProgress; dynamic;
property OnProgress: TNotifyEvent read FOnProgress write FOnProgress;
end;
{** TZCompressionStream ***************************************************}
TZCompressionStream = class(TCustomZStream)
private
function GetCompressionRate: Single;
public
constructor Create(dest: TStream;
compressionLevel: TZCompressionLevel = zcDefault); overload;
constructor Create(dest: TStream; compressionLevel: TZCompressionLevel;
windowBits, memLevel: Integer; strategy: TZStrategy); overload;
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;
{** TZDecompressionStream *************************************************}
TZDecompressionStream = class(TCustomZStream)
public
constructor Create(source: TStream); overload;
constructor Create(source: TStream; windowBits: Integer); overload;
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;
{** zlib public routines ****************************************************}
{*****************************************************************************
* ZCompress *
* *
* pre-conditions *
* inBuffer = pointer to uncompressed data *
* inSize = size of inBuffer (bytes) *
* outBuffer = pointer (unallocated) *
* level = compression level *
* *
* post-conditions *
* outBuffer = pointer to compressed data (allocated) *
* outSize = size of outBuffer (bytes) *
*****************************************************************************}
procedure ZCompress(const inBuffer: Pointer; inSize: Integer;
out outBuffer: Pointer; out outSize: Integer;
level: TZCompressionLevel = zcDefault);
{*****************************************************************************
* ZCompress2 *
* *
* pre-conditions *
* inBuffer = pointer to uncompressed data *
* inSize = size of inBuffer (bytes) *
* outBuffer = pointer (unallocated) *
* level = compression level *
* method = compression method *
* windowBits = window bits *
* memLevel = memory level *
* strategy = strategy *
* *
* post-conditions *
* outBuffer = pointer to compressed data (allocated) *
* outSize = size of outBuffer (bytes) *
*****************************************************************************}
procedure ZCompress2(const inBuffer: Pointer; inSize: Integer;
out outBuffer: Pointer; out outSize: Integer; level: TZCompressionLevel;
windowBits, memLevel: Integer; strategy: TZStrategy);
{*****************************************************************************
* ZDecompress *
* *
* pre-conditions *
* inBuffer = pointer to compressed data *
* inSize = size of inBuffer (bytes) *
* outBuffer = pointer (unallocated) *
* outEstimate = estimated size of uncompressed data (bytes) *
* *
* post-conditions *
* outBuffer = pointer to decompressed data (allocated) *
* outSize = size of outBuffer (bytes) *
*****************************************************************************}
procedure ZDecompress(const inBuffer: Pointer; inSize: Integer;
out outBuffer: Pointer; out outSize: Integer; outEstimate: Integer = 0);
{*****************************************************************************
* ZDecompress2 *
* *
* pre-conditions *
* inBuffer = pointer to compressed data *
* inSize = size of inBuffer (bytes) *
* outBuffer = pointer (unallocated) *
* windowBits = window bits *
* outEstimate = estimated size of uncompressed data (bytes) *
* *
* post-conditions *
* outBuffer = pointer to decompressed data (allocated) *
* outSize = size of outBuffer (bytes) *
*****************************************************************************}
procedure ZDecompress2(const inBuffer: Pointer; inSize: Integer;
out outBuffer: Pointer; out outSize: Integer; windowBits: Integer;
outEstimate: Integer = 0);
{** string routines *********************************************************}
function ZCompressStr(const s: String;
level: TZCompressionLevel = zcDefault): String;
function ZCompressStrEx(const s: String;
level: TZCompressionLevel = zcDefault): String;
function ZCompressStr2(const s: String; level: TZCompressionLevel;
windowBits, memLevel: Integer; strategy: TZStrategy): String;
function ZCompressStrWeb(const s: String): String;
function ZDecompressStr(const s: String): String;
function ZDecompressStrEx(const s: String): String;
function ZDecompressStr2(const s: String; windowBits: Integer): String;
{** stream routines *********************************************************}
procedure ZCompressStream(inStream, outStream: TStream;
level: TZCompressionLevel = zcDefault);
procedure ZCompressStream2(inStream, outStream: TStream;
level: TZCompressionLevel; windowBits, memLevel: Integer;
strategy: TZStrategy);
procedure ZDecompressStream(inStream, outStream: TStream);
procedure ZDecompressStream2(inStream, outStream: TStream;
windowBits: Integer);
{****************************************************************************}
type
EZLibError = class(Exception)
private
FErrorCode: Integer;
public
constructor Create(code: Integer); overload;
property ErrorCode: Integer read FErrorCode write FErrorCode;
end;
EZCompressionError = class(EZLibError);
EZDecompressionError = class(EZLibError);
implementation
{** link zlib code **********************************************************}
{$L deflate.obj}
{$L inflate.obj}
{$L inftrees.obj}
{$L infback.obj}
{$L inffast.obj}
{$L trees.obj}
{$L compress.obj}
{$L adler32.obj}
{$L crc32.obj}
{*****************************************************************************
* note: do not reorder the above -- doing so will result in external *
* functions being undefined *
*****************************************************************************}
const
{** flush constants *******************************************************}
Z_NO_FLUSH = 0;
Z_PARTIAL_FLUSH = 1;
Z_SYNC_FLUSH = 2;
Z_FULL_FLUSH = 3;
Z_FINISH = 4;
Z_BLOCK = 5;
{** return codes **********************************************************}
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);
{** compression levels ****************************************************}
Z_NO_COMPRESSION = 0;
Z_BEST_SPEED = 1;
Z_BEST_COMPRESSION = 9;
Z_DEFAULT_COMPRESSION = (-1);
{** compression strategies ************************************************}
Z_FILTERED = 1;
Z_HUFFMAN_ONLY = 2;
Z_RLE = 3;
Z_FIXED = 4;
Z_DEFAULT_STRATEGY = 0;
{** data types ************************************************************}
Z_BINARY = 0;
Z_ASCII = 1;
Z_TEXT = Z_ASCII;
Z_UNKNOWN = 2;
{** compression methods ***************************************************}
Z_DEFLATED = 8;
{** return code messages **************************************************}
_z_errmsg: array[0..9] of PChar = (
'need dictionary', // Z_NEED_DICT (2)
'stream end', // Z_STREAM_END (1)
'ok', // 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)
''
);
ZLevels: Array [TZCompressionLevel] of Shortint = (
Z_NO_COMPRESSION,
Z_BEST_SPEED,
Z_DEFAULT_COMPRESSION,
Z_BEST_COMPRESSION
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