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123 lines
3.4 KiB
ObjectPascal
123 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.
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