558 lines
16 KiB
ObjectPascal
558 lines
16 KiB
ObjectPascal
{*******************************************************}
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{ }
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{ Borland Delphi Supplemental Components }
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{ ZLIB Data Compression Interface Unit }
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{ }
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{ Copyright (c) 1997,99 Borland Corporation }
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{ }
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{*******************************************************}
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{ Updated for zlib 1.2.x by Cosmin Truta <cosmint@cs.ubbcluj.ro> }
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unit ZLib;
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interface
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uses SysUtils, Classes;
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type
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TAlloc = function (AppData: Pointer; Items, Size: Integer): Pointer; cdecl;
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TFree = procedure (AppData, Block: Pointer); cdecl;
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// Internal structure. Ignore.
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TZStreamRec = packed record
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next_in: PChar; // next input byte
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avail_in: Integer; // number of bytes available at next_in
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total_in: Longint; // total nb of input bytes read so far
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next_out: PChar; // next output byte should be put here
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avail_out: Integer; // remaining free space at next_out
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total_out: Longint; // total nb of bytes output so far
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msg: PChar; // last error message, NULL if no error
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internal: Pointer; // not visible by applications
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zalloc: TAlloc; // used to allocate the internal state
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zfree: TFree; // used to free the internal state
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AppData: Pointer; // private data object passed to zalloc and zfree
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data_type: Integer; // best guess about the data type: ascii or binary
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adler: Longint; // adler32 value of the uncompressed data
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reserved: Longint; // reserved for future use
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end;
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// Abstract ancestor class
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TCustomZlibStream = class(TStream)
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private
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FStrm: TStream;
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FStrmPos: Integer;
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FOnProgress: TNotifyEvent;
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FZRec: TZStreamRec;
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FBuffer: array [Word] of Char;
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protected
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procedure Progress(Sender: TObject); dynamic;
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property OnProgress: TNotifyEvent read FOnProgress write FOnProgress;
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constructor Create(Strm: TStream);
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end;
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{ TCompressionStream compresses data on the fly as data is written to it, and
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stores the compressed data to another stream.
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TCompressionStream is write-only and strictly sequential. Reading from the
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stream will raise an exception. Using Seek to move the stream pointer
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will raise an exception.
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Output data is cached internally, written to the output stream only when
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the internal output buffer is full. All pending output data is flushed
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when the stream is destroyed.
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The Position property returns the number of uncompressed bytes of
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data that have been written to the stream so far.
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CompressionRate returns the on-the-fly percentage by which the original
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data has been compressed: (1 - (CompressedBytes / UncompressedBytes)) * 100
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If raw data size = 100 and compressed data size = 25, the CompressionRate
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is 75%
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The OnProgress event is called each time the output buffer is filled and
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written to the output stream. This is useful for updating a progress
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indicator when you are writing a large chunk of data to the compression
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stream in a single call.}
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TCompressionLevel = (clNone, clFastest, clDefault, clMax);
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TCompressionStream = class(TCustomZlibStream)
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private
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function GetCompressionRate: Single;
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public
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constructor Create(CompressionLevel: TCompressionLevel; Dest: TStream);
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destructor Destroy; override;
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function Read(var Buffer; Count: Longint): Longint; override;
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function Write(const Buffer; Count: Longint): Longint; override;
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function Seek(Offset: Longint; Origin: Word): Longint; override;
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property CompressionRate: Single read GetCompressionRate;
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property OnProgress;
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end;
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{ TDecompressionStream decompresses data on the fly as data is read from it.
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Compressed data comes from a separate source stream. TDecompressionStream
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is read-only and unidirectional; you can seek forward in the stream, but not
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backwards. The special case of setting the stream position to zero is
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allowed. Seeking forward decompresses data until the requested position in
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the uncompressed data has been reached. Seeking backwards, seeking relative
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to the end of the stream, requesting the size of the stream, and writing to
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the stream will raise an exception.
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The Position property returns the number of bytes of uncompressed data that
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have been read from the stream so far.
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The OnProgress event is called each time the internal input buffer of
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compressed data is exhausted and the next block is read from the input stream.
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This is useful for updating a progress indicator when you are reading a
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large chunk of data from the decompression stream in a single call.}
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TDecompressionStream = class(TCustomZlibStream)
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public
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constructor Create(Source: TStream);
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destructor Destroy; override;
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function Read(var Buffer; Count: Longint): Longint; override;
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function Write(const Buffer; Count: Longint): Longint; override;
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function Seek(Offset: Longint; Origin: Word): Longint; override;
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property OnProgress;
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end;
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{ CompressBuf compresses data, buffer to buffer, in one call.
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In: InBuf = ptr to compressed data
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InBytes = number of bytes in InBuf
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Out: OutBuf = ptr to newly allocated buffer containing decompressed data
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OutBytes = number of bytes in OutBuf }
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procedure CompressBuf(const InBuf: Pointer; InBytes: Integer;
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out OutBuf: Pointer; out OutBytes: Integer);
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{ DecompressBuf decompresses data, buffer to buffer, in one call.
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In: InBuf = ptr to compressed data
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InBytes = number of bytes in InBuf
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OutEstimate = zero, or est. size of the decompressed data
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Out: OutBuf = ptr to newly allocated buffer containing decompressed data
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OutBytes = number of bytes in OutBuf }
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procedure DecompressBuf(const InBuf: Pointer; InBytes: Integer;
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OutEstimate: Integer; out OutBuf: Pointer; out OutBytes: Integer);
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{ DecompressToUserBuf decompresses data, buffer to buffer, in one call.
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In: InBuf = ptr to compressed data
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InBytes = number of bytes in InBuf
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Out: OutBuf = ptr to user-allocated buffer to contain decompressed data
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BufSize = number of bytes in OutBuf }
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procedure DecompressToUserBuf(const InBuf: Pointer; InBytes: Integer;
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const OutBuf: Pointer; BufSize: Integer);
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const
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zlib_version = '1.3.1.1';
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type
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EZlibError = class(Exception);
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ECompressionError = class(EZlibError);
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EDecompressionError = class(EZlibError);
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implementation
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uses ZLibConst;
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const
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Z_NO_FLUSH = 0;
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Z_PARTIAL_FLUSH = 1;
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Z_SYNC_FLUSH = 2;
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Z_FULL_FLUSH = 3;
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Z_FINISH = 4;
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Z_OK = 0;
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Z_STREAM_END = 1;
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Z_NEED_DICT = 2;
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Z_ERRNO = (-1);
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Z_STREAM_ERROR = (-2);
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Z_DATA_ERROR = (-3);
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Z_MEM_ERROR = (-4);
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Z_BUF_ERROR = (-5);
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Z_VERSION_ERROR = (-6);
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Z_NO_COMPRESSION = 0;
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Z_BEST_SPEED = 1;
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Z_BEST_COMPRESSION = 9;
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Z_DEFAULT_COMPRESSION = (-1);
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Z_FILTERED = 1;
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Z_HUFFMAN_ONLY = 2;
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Z_RLE = 3;
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Z_DEFAULT_STRATEGY = 0;
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Z_BINARY = 0;
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Z_ASCII = 1;
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Z_UNKNOWN = 2;
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Z_DEFLATED = 8;
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{$L adler32.obj}
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{$L compress.obj}
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{$L crc32.obj}
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{$L deflate.obj}
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{$L infback.obj}
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{$L inffast.obj}
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{$L inflate.obj}
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{$L inftrees.obj}
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{$L trees.obj}
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{$L uncompr.obj}
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{$L zutil.obj}
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procedure adler32; external;
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procedure compressBound; external;
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procedure crc32; external;
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procedure deflateInit2_; external;
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procedure deflateParams; external;
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function _malloc(Size: Integer): Pointer; cdecl;
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begin
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Result := AllocMem(Size);
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end;
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procedure _free(Block: Pointer); cdecl;
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begin
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FreeMem(Block);
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end;
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procedure _memset(P: Pointer; B: Byte; count: Integer); cdecl;
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begin
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FillChar(P^, count, B);
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end;
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procedure _memcpy(dest, source: Pointer; count: Integer); cdecl;
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begin
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Move(source^, dest^, count);
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end;
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// deflate compresses data
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function deflateInit_(var strm: TZStreamRec; level: Integer; version: PChar;
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recsize: Integer): Integer; external;
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function deflate(var strm: TZStreamRec; flush: Integer): Integer; external;
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function deflateEnd(var strm: TZStreamRec): Integer; external;
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// inflate decompresses data
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function inflateInit_(var strm: TZStreamRec; version: PChar;
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recsize: Integer): Integer; external;
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function inflate(var strm: TZStreamRec; flush: Integer): Integer; external;
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function inflateEnd(var strm: TZStreamRec): Integer; external;
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function inflateReset(var strm: TZStreamRec): Integer; external;
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function zlibAllocMem(AppData: Pointer; Items, Size: Integer): Pointer; cdecl;
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begin
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// GetMem(Result, Items*Size);
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Result := AllocMem(Items * Size);
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end;
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procedure zlibFreeMem(AppData, Block: Pointer); cdecl;
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begin
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FreeMem(Block);
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end;
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{function zlibCheck(code: Integer): Integer;
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begin
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Result := code;
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if code < 0 then
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raise EZlibError.Create('error'); //!!
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end;}
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function CCheck(code: Integer): Integer;
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begin
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Result := code;
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if code < 0 then
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raise ECompressionError.Create('error'); //!!
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end;
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function DCheck(code: Integer): Integer;
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begin
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Result := code;
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if code < 0 then
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raise EDecompressionError.Create('error'); //!!
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end;
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procedure CompressBuf(const InBuf: Pointer; InBytes: Integer;
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out OutBuf: Pointer; out OutBytes: Integer);
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var
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strm: TZStreamRec;
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P: Pointer;
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begin
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FillChar(strm, sizeof(strm), 0);
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strm.zalloc := zlibAllocMem;
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strm.zfree := zlibFreeMem;
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OutBytes := ((InBytes + (InBytes div 10) + 12) + 255) and not 255;
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GetMem(OutBuf, OutBytes);
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try
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strm.next_in := InBuf;
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strm.avail_in := InBytes;
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strm.next_out := OutBuf;
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strm.avail_out := OutBytes;
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CCheck(deflateInit_(strm, Z_BEST_COMPRESSION, zlib_version, sizeof(strm)));
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try
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while CCheck(deflate(strm, Z_FINISH)) <> Z_STREAM_END do
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begin
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P := OutBuf;
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Inc(OutBytes, 256);
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ReallocMem(OutBuf, OutBytes);
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strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P)));
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strm.avail_out := 256;
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end;
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finally
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CCheck(deflateEnd(strm));
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end;
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ReallocMem(OutBuf, strm.total_out);
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OutBytes := strm.total_out;
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except
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FreeMem(OutBuf);
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raise
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end;
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end;
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procedure DecompressBuf(const InBuf: Pointer; InBytes: Integer;
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OutEstimate: Integer; out OutBuf: Pointer; out OutBytes: Integer);
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var
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strm: TZStreamRec;
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P: Pointer;
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BufInc: Integer;
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begin
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FillChar(strm, sizeof(strm), 0);
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strm.zalloc := zlibAllocMem;
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strm.zfree := zlibFreeMem;
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BufInc := (InBytes + 255) and not 255;
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if OutEstimate = 0 then
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OutBytes := BufInc
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else
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OutBytes := OutEstimate;
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GetMem(OutBuf, OutBytes);
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try
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strm.next_in := InBuf;
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strm.avail_in := InBytes;
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strm.next_out := OutBuf;
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strm.avail_out := OutBytes;
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DCheck(inflateInit_(strm, zlib_version, sizeof(strm)));
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try
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while DCheck(inflate(strm, Z_NO_FLUSH)) <> Z_STREAM_END do
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begin
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P := OutBuf;
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Inc(OutBytes, BufInc);
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ReallocMem(OutBuf, OutBytes);
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strm.next_out := PChar(Integer(OutBuf) + (Integer(strm.next_out) - Integer(P)));
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strm.avail_out := BufInc;
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end;
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finally
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DCheck(inflateEnd(strm));
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end;
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ReallocMem(OutBuf, strm.total_out);
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OutBytes := strm.total_out;
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except
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FreeMem(OutBuf);
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raise
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end;
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end;
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procedure DecompressToUserBuf(const InBuf: Pointer; InBytes: Integer;
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const OutBuf: Pointer; BufSize: Integer);
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var
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strm: TZStreamRec;
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begin
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FillChar(strm, sizeof(strm), 0);
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strm.zalloc := zlibAllocMem;
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strm.zfree := zlibFreeMem;
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strm.next_in := InBuf;
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strm.avail_in := InBytes;
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strm.next_out := OutBuf;
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strm.avail_out := BufSize;
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DCheck(inflateInit_(strm, zlib_version, sizeof(strm)));
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try
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if DCheck(inflate(strm, Z_FINISH)) <> Z_STREAM_END then
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raise EZlibError.CreateRes(@sTargetBufferTooSmall);
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finally
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DCheck(inflateEnd(strm));
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end;
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end;
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// TCustomZlibStream
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constructor TCustomZLibStream.Create(Strm: TStream);
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begin
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inherited Create;
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FStrm := Strm;
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FStrmPos := Strm.Position;
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FZRec.zalloc := zlibAllocMem;
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FZRec.zfree := zlibFreeMem;
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end;
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procedure TCustomZLibStream.Progress(Sender: TObject);
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begin
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if Assigned(FOnProgress) then FOnProgress(Sender);
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end;
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// TCompressionStream
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constructor TCompressionStream.Create(CompressionLevel: TCompressionLevel;
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Dest: TStream);
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const
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Levels: array [TCompressionLevel] of ShortInt =
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(Z_NO_COMPRESSION, Z_BEST_SPEED, Z_DEFAULT_COMPRESSION, Z_BEST_COMPRESSION);
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begin
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inherited Create(Dest);
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FZRec.next_out := FBuffer;
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FZRec.avail_out := sizeof(FBuffer);
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CCheck(deflateInit_(FZRec, Levels[CompressionLevel], zlib_version, sizeof(FZRec)));
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end;
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destructor TCompressionStream.Destroy;
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begin
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FZRec.next_in := nil;
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FZRec.avail_in := 0;
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try
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if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
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while (CCheck(deflate(FZRec, Z_FINISH)) <> Z_STREAM_END)
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and (FZRec.avail_out = 0) do
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begin
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FStrm.WriteBuffer(FBuffer, sizeof(FBuffer));
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FZRec.next_out := FBuffer;
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FZRec.avail_out := sizeof(FBuffer);
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end;
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if FZRec.avail_out < sizeof(FBuffer) then
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FStrm.WriteBuffer(FBuffer, sizeof(FBuffer) - FZRec.avail_out);
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finally
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deflateEnd(FZRec);
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end;
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inherited Destroy;
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end;
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function TCompressionStream.Read(var Buffer; Count: Longint): Longint;
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begin
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raise ECompressionError.CreateRes(@sInvalidStreamOp);
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end;
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function TCompressionStream.Write(const Buffer; Count: Longint): Longint;
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begin
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FZRec.next_in := @Buffer;
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FZRec.avail_in := Count;
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if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
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while (FZRec.avail_in > 0) do
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begin
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CCheck(deflate(FZRec, 0));
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if FZRec.avail_out = 0 then
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begin
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FStrm.WriteBuffer(FBuffer, sizeof(FBuffer));
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FZRec.next_out := FBuffer;
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FZRec.avail_out := sizeof(FBuffer);
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FStrmPos := FStrm.Position;
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Progress(Self);
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end;
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end;
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Result := Count;
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end;
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function TCompressionStream.Seek(Offset: Longint; Origin: Word): Longint;
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begin
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if (Offset = 0) and (Origin = soFromCurrent) then
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Result := FZRec.total_in
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else
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raise ECompressionError.CreateRes(@sInvalidStreamOp);
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end;
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function TCompressionStream.GetCompressionRate: Single;
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begin
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if FZRec.total_in = 0 then
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Result := 0
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else
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Result := (1.0 - (FZRec.total_out / FZRec.total_in)) * 100.0;
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end;
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// TDecompressionStream
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constructor TDecompressionStream.Create(Source: TStream);
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begin
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inherited Create(Source);
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FZRec.next_in := FBuffer;
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FZRec.avail_in := 0;
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DCheck(inflateInit_(FZRec, zlib_version, sizeof(FZRec)));
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end;
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destructor TDecompressionStream.Destroy;
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begin
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FStrm.Seek(-FZRec.avail_in, 1);
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inflateEnd(FZRec);
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inherited Destroy;
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end;
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function TDecompressionStream.Read(var Buffer; Count: Longint): Longint;
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begin
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FZRec.next_out := @Buffer;
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FZRec.avail_out := Count;
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if FStrm.Position <> FStrmPos then FStrm.Position := FStrmPos;
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while (FZRec.avail_out > 0) do
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begin
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if FZRec.avail_in = 0 then
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begin
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FZRec.avail_in := FStrm.Read(FBuffer, sizeof(FBuffer));
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if FZRec.avail_in = 0 then
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begin
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Result := Count - FZRec.avail_out;
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Exit;
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end;
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FZRec.next_in := FBuffer;
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FStrmPos := FStrm.Position;
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Progress(Self);
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end;
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CCheck(inflate(FZRec, 0));
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end;
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Result := Count;
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end;
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function TDecompressionStream.Write(const Buffer; Count: Longint): Longint;
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|
begin
|
|
raise EDecompressionError.CreateRes(@sInvalidStreamOp);
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|
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.CreateRes(@sInvalidStreamOp);
|
|
Result := FZRec.total_out;
|
|
end;
|
|
|
|
|
|
end.
|