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9198133711
other zlib package
* paszlib unit added as generic interface for all other units, this
unit is partly compatible with the other zlib pacakge
122 lines
3.4 KiB
ObjectPascal
122 lines
3.4 KiB
ObjectPascal
Unit zCompres;
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{ compress.c -- compress a memory buffer
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Copyright (C) 1995-1998 Jean-loup Gailly.
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Pascal tranlastion
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Copyright (C) 1998 by Jacques Nomssi Nzali
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For conditions of distribution and use, see copyright notice in readme.txt
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}
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interface
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{$I zconf.inc}
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uses
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zutil, zbase, zDeflate;
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{ utility functions }
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{EXPORT}
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function compress (dest : pBytef;
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var destLen : uLong;
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source : pBytef;
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sourceLen : uLong) : int;
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{ Compresses the source buffer into the destination buffer. sourceLen is
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the byte length of the source buffer. Upon entry, destLen is the total
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size of the destination buffer, which must be at least 0.1% larger than
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sourceLen plus 12 bytes. Upon exit, destLen is the actual size of the
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compressed buffer.
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This function can be used to compress a whole file at once if the
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input file is mmap'ed.
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compress returns Z_OK if success, Z_MEM_ERROR if there was not
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enough memory, Z_BUF_ERROR if there was not enough room in the output
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buffer. }
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{EXPORT}
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function compress2 (dest : pBytef;
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var destLen : uLong;
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source : pBytef;
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sourceLen : uLong;
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level : int) : int;
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{ Compresses the source buffer into the destination buffer. The level
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parameter has the same meaning as in deflateInit. sourceLen is the byte
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length of the source buffer. Upon entry, destLen is the total size of the
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destination buffer, which must be at least 0.1% larger than sourceLen plus
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12 bytes. Upon exit, destLen is the actual size of the compressed buffer.
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compress2 returns Z_OK if success, Z_MEM_ERROR if there was not enough
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memory, Z_BUF_ERROR if there was not enough room in the output buffer,
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Z_STREAM_ERROR if the level parameter is invalid. }
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implementation
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{ ===========================================================================
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}
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function compress2 (dest : pBytef;
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var destLen : uLong;
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source : pbytef;
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sourceLen : uLong;
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level : int) : int;
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var
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stream : z_stream;
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err : int;
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begin
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stream.next_in := source;
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stream.avail_in := uInt(sourceLen);
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{$ifdef MAXSEG_64K}
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{ Check for source > 64K on 16-bit machine: }
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if (uLong(stream.avail_in) <> sourceLen) then
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begin
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compress2 := Z_BUF_ERROR;
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exit;
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end;
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{$endif}
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stream.next_out := dest;
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stream.avail_out := uInt(destLen);
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if (uLong(stream.avail_out) <> destLen) then
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begin
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compress2 := Z_BUF_ERROR;
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exit;
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end;
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stream.zalloc := NIL; { alloc_func(0); }
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stream.zfree := NIL; { free_func(0); }
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stream.opaque := NIL; { voidpf(0); }
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err := deflateInit(stream, level);
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if (err <> Z_OK) then
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begin
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compress2 := err;
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exit;
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end;
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err := deflate(stream, Z_FINISH);
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if (err <> Z_STREAM_END) then
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begin
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deflateEnd(stream);
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if err = Z_OK then
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compress2 := Z_BUF_ERROR
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else
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compress2 := err;
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exit;
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end;
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destLen := stream.total_out;
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err := deflateEnd(stream);
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compress2 := err;
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end;
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{ ===========================================================================
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}
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function compress (dest : pBytef;
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var destLen : uLong;
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source : pBytef;
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sourceLen : uLong) : int;
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begin
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compress := compress2(dest, destLen, source, sourceLen, Z_DEFAULT_COMPRESSION);
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end;
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end. |