david
ef415fa856
git-svn-id: https://192.168.0.254/svn/Componentes.Terceros.FastReport@9 475b051d-3a53-6940-addd-820bf0cfe0d7
302 lines
9.2 KiB
ObjectPascal
302 lines
9.2 KiB
ObjectPascal
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{******************************************}
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{ }
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{ FastReport v3.0 }
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{ GZIP compress/decompress }
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{ }
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{ Copyright (c) 2004 }
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{ by Alexander Fediachov, }
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{ Fast Reports, Inc. }
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{ }
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{******************************************}
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unit frxGZip;
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interface
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{$I frx.inc}
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uses Windows, Classes, SysUtils, frxZLib, frxClass;
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type
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TfrxCompressionLevel = (gzNone, gzFastest, gzDefault, gzMax);
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TfrxGZipCompressor = class(TfrxCustomCompressor)
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public
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procedure Compress(Dest: TStream); override;
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procedure Decompress(Source: TStream); override;
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end;
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procedure frxCompressStream(Source, Dest: TStream;
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Compression: TfrxCompressionLevel = gzDefault; FileName: String = '');
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function frxDecompressStream(Source, Dest: TStream): String;
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function frxStreamCRC32(Stream: TStream): Cardinal;
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procedure frxDeflateStream(Source, Dest: TStream;
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Compression: TfrxCompressionLevel = gzDefault);
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procedure frxInflateStream(Source, Dest: TStream);
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implementation
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const
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CRCTable: array [0..255] of Cardinal = (
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0000000000, 1996959894, 3993919788, 2567524794,
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0124634137, 1886057615, 3915621685, 2657392035,
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0249268274, 2044508324, 3772115230, 2547177864,
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0162941995, 2125561021, 3887607047, 2428444049,
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0498536548, 1789927666, 4089016648, 2227061214,
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0450548861, 1843258603, 4107580753, 2211677639,
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0325883990, 1684777152, 4251122042, 2321926636,
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0335633487, 1661365465, 4195302755, 2366115317,
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0997073096, 1281953886, 3579855332, 2724688242,
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1006888145, 1258607687, 3524101629, 2768942443,
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0901097722, 1119000684, 3686517206, 2898065728,
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0853044451, 1172266101, 3705015759, 2882616665,
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0651767980, 1373503546, 3369554304, 3218104598,
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0565507253, 1454621731, 3485111705, 3099436303,
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0671266974, 1594198024, 3322730930, 2970347812,
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0795835527, 1483230225, 3244367275, 3060149565,
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1994146192, 0031158534, 2563907772, 4023717930,
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1907459465, 0112637215, 2680153253, 3904427059,
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2013776290, 0251722036, 2517215374, 3775830040,
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2137656763, 0141376813, 2439277719, 3865271297,
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1802195444, 0476864866, 2238001368, 4066508878,
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1812370925, 0453092731, 2181625025, 4111451223,
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1706088902, 0314042704, 2344532202, 4240017532,
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1658658271, 0366619977, 2362670323, 4224994405,
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1303535960, 0984961486, 2747007092, 3569037538,
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1256170817, 1037604311, 2765210733, 3554079995,
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1131014506, 0879679996, 2909243462, 3663771856,
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1141124467, 0855842277, 2852801631, 3708648649,
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1342533948, 0654459306, 3188396048, 3373015174,
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1466479909, 0544179635, 3110523913, 3462522015,
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1591671054, 0702138776, 2966460450, 3352799412,
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1504918807, 0783551873, 3082640443, 3233442989,
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3988292384, 2596254646, 0062317068, 1957810842,
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3939845945, 2647816111, 0081470997, 1943803523,
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3814918930, 2489596804, 0225274430, 2053790376,
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3826175755, 2466906013, 0167816743, 2097651377,
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4027552580, 2265490386, 0503444072, 1762050814,
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4150417245, 2154129355, 0426522225, 1852507879,
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4275313526, 2312317920, 0282753626, 1742555852,
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4189708143, 2394877945, 0397917763, 1622183637,
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3604390888, 2714866558, 0953729732, 1340076626,
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3518719985, 2797360999, 1068828381, 1219638859,
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3624741850, 2936675148, 0906185462, 1090812512,
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3747672003, 2825379669, 0829329135, 1181335161,
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3412177804, 3160834842, 0628085408, 1382605366,
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3423369109, 3138078467, 0570562233, 1426400815,
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3317316542, 2998733608, 0733239954, 1555261956,
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3268935591, 3050360625, 0752459403, 1541320221,
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2607071920, 3965973030, 1969922972, 0040735498,
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2617837225, 3943577151, 1913087877, 0083908371,
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2512341634, 3803740692, 2075208622, 0213261112,
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2463272603, 3855990285, 2094854071, 0198958881,
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2262029012, 4057260610, 1759359992, 0534414190,
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2176718541, 4139329115, 1873836001, 0414664567,
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2282248934, 4279200368, 1711684554, 0285281116,
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2405801727, 4167216745, 1634467795, 0376229701,
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2685067896, 3608007406, 1308918612, 0956543938,
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2808555105, 3495958263, 1231636301, 1047427035,
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2932959818, 3654703836, 1088359270, 0936918000,
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2847714899, 3736837829, 1202900863, 0817233897,
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3183342108, 3401237130, 1404277552, 0615818150,
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3134207493, 3453421203, 1423857449, 0601450431,
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3009837614, 3294710456, 1567103746, 0711928724,
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3020668471, 3272380065, 1510334235, 0755167117);
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function frxStreamCRC32(Stream: TStream): Cardinal;
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var
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OldPos: Integer;
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b: Byte;
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c: Cardinal;
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begin
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OldPos := Stream.Position;
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Stream.Position := 0;
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c := $ffffffff;
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while Stream.Position < Stream.Size do
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begin
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Stream.Read(b,1);
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c := CrcTable[(c xor Cardinal(b)) and $ff] xor (c shr 8);
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end;
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Stream.Position := OldPos;
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Result := c xor $ffffffff;
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end;
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procedure frxCompressStream(Source, Dest: TStream;
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Compression: TfrxCompressionLevel = gzDefault; FileName: String = '');
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var
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header: array [0..3] of Byte;
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Compressor: TZCompressionStream;
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Size: Cardinal;
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CRC: Cardinal;
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begin
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CRC := frxStreamCRC32(Source);
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Size := Source.Size;
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if FileName = '' then
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FileName := '1';
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FileName := FileName + #0;
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// put gzip header
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header[0] := $1f; // ID1 (IDentification 1)
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header[1] := $8b; // ID2 (IDentification 2)
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header[2] := $8; // CM (Compression Method) CM = 8 denotes the "deflate"
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header[3] := $8; // FLG (FLaGs) bit 3 FNAME
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Dest.Write(header, 4);
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// reserve 4 bytes in MTIME field
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Dest.Write(header, 4);
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header[0] := 0; // XFL (eXtra FLags) XFL = 2 - compressor used maximum compression
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header[1] := 0; // OS (Operating System) 0 - FAT filesystem (MS-DOS, OS/2, NT/Win32)
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Dest.Write(header, 2);
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// original file name, zero-terminated
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Dest.Write(FileName[1], Length(FileName));
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// seek back to skip 2 bytes zlib header
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Dest.Seek(-2, soFromCurrent);
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// put compressed data
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Compressor := TZCompressionStream.Create(Dest, TZCompressionLevel(Compression));
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try
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Compressor.CopyFrom(Source, 0);
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finally
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Compressor.Free;
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end;
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// get adler32 checksum
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Dest.Seek(-4, soFromEnd);
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Dest.Read(header, 4);
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// write it to the header (to MTIME field)
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Dest.Position := 4;
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Dest.Write(header, 4);
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// restore original file name (it was corrupted by zlib header)
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Dest.Seek(2, soFromCurrent);
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Dest.Write(FileName[1], Length(FileName));
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// put crc32 and length
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Dest.Seek(-4, soFromEnd);
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Dest.Write(CRC, 4);
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Dest.Write(Size, 4);
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end;
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function frxDecompressStream(Source, Dest: TStream): String;
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var
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s: String;
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header: array [0..3] of byte;
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adler32: Integer;
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FTempStream: TMemoryStream;
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UnknownPtr: Pointer;
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NewSize: Integer;
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begin
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s := '';
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// read gzip header
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Source.Read(header, 4);
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if (header[0] = $1f) and (header[1] = $8b) and (header[2] = $8) then
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begin
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Source.Read(adler32, 4);
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Source.Read(header, 2);
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if (header[3] and $8) <> 0 then
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begin
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Source.Read(header, 1);
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while header[0] <> 0 do
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begin
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s := s + Char(header[0]);
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Source.Read(header, 1);
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end;
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end;
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end;
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FTempStream := TMemoryStream.Create;
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try
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// put zlib header
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s := #$78#$DA;
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FTempStream.Write(s[1], 2);
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// put compressed data, skip gzip's crc32 and filelength
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FTempStream.CopyFrom(Source, Source.Size - Source.Position - 8);
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// put adler32
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FTempStream.Write(adler32, 4);
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// uncompress data and save it to the Dest
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ZDeCompress(FTempStream.Memory, FTempStream.Size, UnknownPtr, NewSize);
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Dest.Write(UnknownPtr^, NewSize);
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FreeMem(UnknownPtr, NewSize);
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finally
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FTempStream.Free;
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end;
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Result := s;
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end;
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procedure frxDeflateStream(Source, Dest: TStream;
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Compression: TfrxCompressionLevel = gzDefault);
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var
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Compressor: TZCompressionStream;
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begin
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Compressor := TZCompressionStream.Create(Dest, TZCompressionLevel(Compression));
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try
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Compressor.CopyFrom(Source, 0);
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finally
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Compressor.Free;
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end;
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end;
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procedure frxInflateStream(Source, Dest: TStream);
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var
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FTempStream: TMemoryStream;
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UnknownPtr: Pointer;
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NewSize: Integer;
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begin
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FTempStream := TMemoryStream.Create;
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try
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FTempStream.CopyFrom(Source, 0);
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// uncompress data and save it to the Dest
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ZDeCompress(FTempStream.Memory, FTempStream.Size, UnknownPtr, NewSize);
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Dest.Write(UnknownPtr^, NewSize);
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FreeMem(UnknownPtr, NewSize);
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finally
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FTempStream.Free;
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end;
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end;
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{ TfrxGZipCompressor }
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procedure TfrxGZipCompressor.Compress(Dest: TStream);
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var
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Compression: TfrxCompressionLevel;
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FileName: String;
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begin
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if IsFR3File then
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begin
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Compression := gzMax;
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FileName := '1.fr3';
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end
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else
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begin
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Compression := gzDefault;
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FileName := '1.fp3';
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end;
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frxCompressStream(Stream, Dest, Compression, FileName);
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end;
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procedure TfrxGZipCompressor.Decompress(Source: TStream);
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var
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Signature: array[0..1] of Byte;
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begin
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Source.Read(Signature, 2);
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Source.Seek(-2, soFromCurrent);
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if (Signature[0] = $1F) and (Signature[1] = $8B) then
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frxDecompressStream(Source, Stream) else
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Stream.CopyFrom(Source, 0);
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Stream.Position := 0;
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end;
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end.
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//<censored> |