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https://gitlab.com/freepascal.org/fpc/source.git
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* Add gzStream routines, patch by Dokkie8844. Fix issue #39654
This commit is contained in:
Michaël Van Canneyt
parent
bbece3e668
commit
3827889e61
41
packages/paszlib/examples/testgzstream.pp
Normal file
41
packages/paszlib/examples/testgzstream.pp
Normal file
@ -0,0 +1,41 @@
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program example;
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uses
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SysUtils, ZStream, Classes;
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procedure TestGZip;
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var
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SS: TStringStream;
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CS: TGZipCompressionStream;
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FS: TFileStream;
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begin
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SS := TStringStream.Create('hello, hello!');
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FS := TFileStream.Create(GetTempDir+'test.gz', fmCreate);
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CS := TGZipCompressionStream.Create(FS);
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CS.CopyFrom(SS, 0);
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CS.Free;
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FS.Free;
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SS.Free;
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end;
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procedure TestGUnzip;
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var
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FS: TFileStream;
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DS: TGZipDecompressionStream;
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SS: TStringStream;
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begin
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FS := TFileStream.Create(GetTempDir+'test.gz', fmOpenRead);
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DS := TGZipDecompressionStream.Create(FS);
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SS := TStringStream.Create('');
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SS.CopyFrom(DS, 0);
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DS.Free;
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FS.Free;
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WriteLn(SS.DataString);
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SS.Free;
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end;
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begin
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TestGZip;
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TestGUnZip;
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end.
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@ -19,6 +19,8 @@ unit ZStream;
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**********************************************************************}
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{ GZip specs: https://datatracker.ietf.org/doc/html/rfc1952 }
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{$mode objfpc}
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{***************************************************************************}
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@ -97,6 +99,38 @@ type
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destructor destroy;override;
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end;
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TGZipCompressionStream = class(TStream)
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private
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FLevel: TCompressionLevel;
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FCrc32Val: Longword;
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FUncompressedSize: Cardinal;
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FDest: TStream;
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FCompressionStream: TCompressionStream;
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procedure WriteHeader;
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procedure WriteFooter;
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public
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constructor Create(ADest: TStream); overload;
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constructor Create(ALevel: TCompressionLevel; ADest: TStream); overload;
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destructor Destroy; override;
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function Write(const Buffer; Count: Longint): Longint; override;
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end;
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TGZipDecompressionStream = class(TStream)
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private
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FCrc32Val: Longword;
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FUncompressedSize: Cardinal;
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FSource: TStream;
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FDecompressionStream: TDecompressionStream;
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procedure Assert(ACond: Boolean; AMsg: string = '');
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procedure ReadHeader;
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procedure ReadFooter;
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public
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constructor Create(ASource: 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 Seek(const Offset: Int64; Origin: TSeekOrigin): Int64; override;
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end;
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Ezliberror=class(Estreamerror)
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end;
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@ -117,12 +151,66 @@ uses zdeflate,zinflate;
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const bufsize=16384; {Size of the buffer used for temporarily storing
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data from the child stream.}
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Crc_32_Tab : Array[0..255] of LongWord = (
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$00000000, $77073096, $ee0e612c, $990951ba, $076dc419, $706af48f, $e963a535, $9e6495a3,
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$0edb8832, $79dcb8a4, $e0d5e91e, $97d2d988, $09b64c2b, $7eb17cbd, $e7b82d07, $90bf1d91,
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$1db71064, $6ab020f2, $f3b97148, $84be41de, $1adad47d, $6ddde4eb, $f4d4b551, $83d385c7,
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$136c9856, $646ba8c0, $fd62f97a, $8a65c9ec, $14015c4f, $63066cd9, $fa0f3d63, $8d080df5,
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$3b6e20c8, $4c69105e, $d56041e4, $a2677172, $3c03e4d1, $4b04d447, $d20d85fd, $a50ab56b,
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$35b5a8fa, $42b2986c, $dbbbc9d6, $acbcf940, $32d86ce3, $45df5c75, $dcd60dcf, $abd13d59,
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$26d930ac, $51de003a, $c8d75180, $bfd06116, $21b4f4b5, $56b3c423, $cfba9599, $b8bda50f,
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$2802b89e, $5f058808, $c60cd9b2, $b10be924, $2f6f7c87, $58684c11, $c1611dab, $b6662d3d,
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$76dc4190, $01db7106, $98d220bc, $efd5102a, $71b18589, $06b6b51f, $9fbfe4a5, $e8b8d433,
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$7807c9a2, $0f00f934, $9609a88e, $e10e9818, $7f6a0dbb, $086d3d2d, $91646c97, $e6635c01,
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$6b6b51f4, $1c6c6162, $856530d8, $f262004e, $6c0695ed, $1b01a57b, $8208f4c1, $f50fc457,
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$65b0d9c6, $12b7e950, $8bbeb8ea, $fcb9887c, $62dd1ddf, $15da2d49, $8cd37cf3, $fbd44c65,
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$4db26158, $3ab551ce, $a3bc0074, $d4bb30e2, $4adfa541, $3dd895d7, $a4d1c46d, $d3d6f4fb,
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$4369e96a, $346ed9fc, $ad678846, $da60b8d0, $44042d73, $33031de5, $aa0a4c5f, $dd0d7cc9,
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$5005713c, $270241aa, $be0b1010, $c90c2086, $5768b525, $206f85b3, $b966d409, $ce61e49f,
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$5edef90e, $29d9c998, $b0d09822, $c7d7a8b4, $59b33d17, $2eb40d81, $b7bd5c3b, $c0ba6cad,
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$edb88320, $9abfb3b6, $03b6e20c, $74b1d29a, $ead54739, $9dd277af, $04db2615, $73dc1683,
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$e3630b12, $94643b84, $0d6d6a3e, $7a6a5aa8, $e40ecf0b, $9309ff9d, $0a00ae27, $7d079eb1,
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$f00f9344, $8708a3d2, $1e01f268, $6906c2fe, $f762575d, $806567cb, $196c3671, $6e6b06e7,
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$fed41b76, $89d32be0, $10da7a5a, $67dd4acc, $f9b9df6f, $8ebeeff9, $17b7be43, $60b08ed5,
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$d6d6a3e8, $a1d1937e, $38d8c2c4, $4fdff252, $d1bb67f1, $a6bc5767, $3fb506dd, $48b2364b,
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$d80d2bda, $af0a1b4c, $36034af6, $41047a60, $df60efc3, $a867df55, $316e8eef, $4669be79,
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$cb61b38c, $bc66831a, $256fd2a0, $5268e236, $cc0c7795, $bb0b4703, $220216b9, $5505262f,
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$c5ba3bbe, $b2bd0b28, $2bb45a92, $5cb36a04, $c2d7ffa7, $b5d0cf31, $2cd99e8b, $5bdeae1d,
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$9b64c2b0, $ec63f226, $756aa39c, $026d930a, $9c0906a9, $eb0e363f, $72076785, $05005713,
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$95bf4a82, $e2b87a14, $7bb12bae, $0cb61b38, $92d28e9b, $e5d5be0d, $7cdcefb7, $0bdbdf21,
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$86d3d2d4, $f1d4e242, $68ddb3f8, $1fda836e, $81be16cd, $f6b9265b, $6fb077e1, $18b74777,
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$88085ae6, $ff0f6a70, $66063bca, $11010b5c, $8f659eff, $f862ae69, $616bffd3, $166ccf45,
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$a00ae278, $d70dd2ee, $4e048354, $3903b3c2, $a7672661, $d06016f7, $4969474d, $3e6e77db,
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$aed16a4a, $d9d65adc, $40df0b66, $37d83bf0, $a9bcae53, $debb9ec5, $47b2cf7f, $30b5ffe9,
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$bdbdf21c, $cabac28a, $53b39330, $24b4a3a6, $bad03605, $cdd70693, $54de5729, $23d967bf,
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$b3667a2e, $c4614ab8, $5d681b02, $2a6f2b94, $b40bbe37, $c30c8ea1, $5a05df1b, $2d02ef8d
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);
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resourcestring Sgz_open_error='Could not open gzip compressed file %s.';
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Sgz_read_only='Gzip compressed file was opened for reading.';
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Sgz_write_only='Gzip compressed file was opened for writing.';
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Sgz_invalid_header='Invalid GZip header';
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Sgz_invalid_algorithm='Invalid compression algorithm';
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Sgz_invalid_crc32='Invalid crc32 checksum';
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Sgz_invalid_output_size='Invalid output size';
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Sseek_failed='Seek in deflate compressed stream failed.';
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function UpdateCrc32(Crc: Longword; const Buffer; Count: Longint): Longword;
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var
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PBuf: PByte;
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i: Longint;
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begin
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PBuf := @Buffer;
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Result := Crc xor $FFFFFFFF;
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for i := 1 to Count do
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begin
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Result := Crc_32_Tab[(Result xor PBuf^) and $ff] xor (Result shr 8);
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Inc(PBuf);
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end;
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Result := Result xor $FFFFFFFF;
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end;
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constructor Tcustomzlibstream.create(stream:Tstream);
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begin
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@ -413,4 +501,175 @@ begin
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inherited destroy;
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end;
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{ TGZipCompressionStream }
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constructor TGZipCompressionStream.Create(ADest: TStream);
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begin
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Create(clDefault, ADest);
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end;
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constructor TGZipCompressionStream.Create(ALevel: TCompressionLevel; ADest: TStream);
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begin
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inherited Create;
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FLevel := ALevel;
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FCrc32Val := 0;
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FUncompressedSize := 0;
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FDest := ADest;
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WriteHeader;
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FCompressionStream := TCompressionStream.Create(FLevel, FDest, True);
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end;
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destructor TGZipCompressionStream.Destroy;
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begin
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FCompressionStream.Flush;
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FCompressionStream.Free;
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WriteFooter;
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inherited;
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end;
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procedure TGZipCompressionStream.WriteHeader;
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begin
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FDest.WriteByte($1f); // signature 1 of 2
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FDest.WriteByte($8b); // signature 2 of 2
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FDest.WriteByte($08); // deflate algorithm
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FDest.WriteByte($00); // no flags
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FDest.WriteDWord($00); // modification time unknown. Source is stream, not a file
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if FLevel = clmax then // XFL = extra flags = compression level
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FDest.WriteByte($02)
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else if FLevel = clfastest then
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FDest.WriteByte($04)
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else
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FDest.WriteByte($00);
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FDest.WriteByte($ff); // OS file system unknown. Source is stream, not a file
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end;
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procedure TGZipCompressionStream.WriteFooter;
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var
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i: Integer;
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begin
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// write crc32 in 4 bytes, least significant byte first
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for i := 1 to 4 do
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begin
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FDest.WriteByte(FCrc32Val and $ff);
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FCrc32Val := FCrc32Val shr 8;
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end;
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// write uncompressed size in 4 bytes, least significant byte first
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for i := 1 to 4 do
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begin
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FDest.WriteByte(FUncompressedSize and $ff);
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FUncompressedSize := FUncompressedSize shr 8;
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end;
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end;
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function TGZipCompressionStream.Write(const Buffer; Count: Longint): Longint;
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begin
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FCrc32Val := UpdateCrc32(FCrc32Val, Buffer, Count);
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Inc(FUncompressedSize, Count);
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Result := FCompressionStream.Write(Buffer, Count);
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end;
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{ TGZipDecompressionStream }
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constructor TGZipDecompressionStream.Create(ASource: TStream);
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begin
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inherited Create;
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FSource := ASource;
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FCrc32Val := 0;
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FUncompressedSize := 0;
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ReadHeader;
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FDecompressionStream := TDecompressionStream.Create(FSource, True);
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end;
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destructor TGZipDecompressionStream.Destroy;
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begin
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FDecompressionStream.Free;
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inherited;
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end;
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procedure TGZipDecompressionStream.Assert(ACond: Boolean; AMsg: string = '');
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begin
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if not ACond then
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raise EDecompressionError.Create(AMsg);
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end;
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procedure TGZipDecompressionStream.ReadHeader;
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var
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Flags: Byte;
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XLEN: Cardinal;
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begin
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Assert(FSource.ReadByte = $1f, Sgz_invalid_header);
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Assert(FSource.ReadByte = $8b, Sgz_invalid_header);
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Assert(FSource.ReadByte = $08, Sgz_invalid_algorithm);
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Flags := FSource.ReadByte;
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FSource.ReadDWord; // skip modification time. Dest is stream, not a file
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FSource.ReadByte; // skip compression level, is not needed
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FSource.ReadByte; // skip OS file system. Dest is stream, not a file
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if (Flags and $4) <> 0 then // FLG.FEXTRA
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begin
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XLEN := FSource.ReadByte + FSource.ReadByte shl 8; // least significant byte first
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while XLEN > 0 do
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begin
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FSource.ReadByte;
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Dec(XLEN);
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end;
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end;
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if (Flags and $8) <> 0 then // FLG.FNAME
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begin
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repeat
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until FSource.ReadByte = 0; // zero-terminated file name
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end;
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if (Flags and $10) <> 0 then // FLG.FCOMMENT
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begin
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repeat
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until FSource.ReadByte = 0; // zero-terminated file comment
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end;
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if (Flags and $2) <> 0 then // FLG.FHCRC
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FSource.ReadWord; // skip CRC16, check not implemented
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end;
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procedure TGZipDecompressionStream.ReadFooter;
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var
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Crc32: Longword;
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OrigSize: Longword;
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begin
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// The TDecompressionStream reads in buffers, so the footer
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// may already be skipped. Therefore, we need to Seek to the footer.
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// If FSource is non-seekable, we skip checking Crc32 and OrigSize.
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try
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FSource.Seek(-8, soEnd);
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except
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Exit; // skip Crc32 and OrigSize checking
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end;
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Crc32 := FSource.ReadByte + FSource.ReadByte shl 8 + FSource.ReadByte shl 16 + FSource.ReadByte shl 24;
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Assert(FCrc32Val = Crc32, Sgz_invalid_crc32);
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OrigSize := FSource.ReadByte + FSource.ReadByte shl 8 + FSource.ReadByte shl 16 + FSource.ReadByte shl 24;
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Assert(FUncompressedSize = OrigSize, Sgz_invalid_output_size);
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end;
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function TGZipDecompressionStream.Read(var Buffer; Count: Longint): Longint;
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begin
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Result := FDecompressionStream.Read(Buffer, Count);
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Inc(FUncompressedSize, Result);
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FCrc32Val := UpdateCrc32(FCrc32Val, Buffer, Result);
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if Result < Count then
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ReadFooter;
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end;
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function TGZipDecompressionStream.Seek(const Offset: Int64; Origin: TSeekOrigin): Int64;
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begin
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// accept Seek(0, soBeginning) if nothing read yet
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// this is needed for the TStream.CopyFrom() method
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if (Offset = 0) and (Origin = TSeekOrigin.soBeginning) and (FUncompressedSize = 0) then
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Result := 0
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else
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Result := inherited Seek(Offset, Origin);
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end;
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end.
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