35 lines
693 B
C
35 lines
693 B
C
#include <u.h>
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#include <lib9.h>
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#include <flate.h>
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#include "zlib.h"
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int
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deflatezlibblock(uint8_t *dst, int dsize, uint8_t *src, int ssize, int level, int debug)
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{
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uint32_t adler;
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int n;
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if(dsize < 6)
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return FlateOutputFail;
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n = deflateblock(dst + 2, dsize - 6, src, ssize, level, debug);
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if(n < 0)
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return n;
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dst[0] = ZlibDeflate | ZlibWin32k;
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/* bogus zlib encoding of compression level */
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dst[1] = ((level > 2) + (level > 5) + (level > 8)) << 6;
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/* header check field */
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dst[1] |= 31 - ((dst[0] << 8) | dst[1]) % 31;
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adler = adler32(1, src, ssize);
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dst[n + 2] = adler >> 24;
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dst[n + 3] = adler >> 16;
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dst[n + 4] = adler >> 8;
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dst[n + 5] = adler;
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return n + 6;
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}
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