61 lines
1.1 KiB
C
61 lines
1.1 KiB
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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typedef struct ZRead ZRead;
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struct ZRead
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{
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uint32_t adler;
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void *rr;
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int (*r)(void*, void*, int);
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};
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static int
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zlread(void *vzr, void *buf, int n)
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{
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ZRead *zr;
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zr = vzr;
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n = (*zr->r)(zr->rr, buf, n);
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if(n <= 0)
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return n;
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zr->adler = adler32(zr->adler, buf, n);
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return n;
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}
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int
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deflatezlib(void *wr, int (*w)(void*, void*, int), void *rr, int (*r)(void*, void*, int), int level, int debug)
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{
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ZRead zr;
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uint8_t buf[4];
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int ok;
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buf[0] = ZlibDeflate | ZlibWin32k;
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/* bogus zlib encoding of compression level */
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buf[1] = ((level > 2) + (level > 5) + (level > 8)) << 6;
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/* header check field */
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buf[1] |= 31 - ((buf[0] << 8) | buf[1]) % 31;
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if((*w)(wr, buf, 2) != 2)
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return FlateOutputFail;
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zr.rr = rr;
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zr.r = r;
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zr.adler = 1;
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ok = deflate(wr, w, &zr, zlread, level, debug);
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if(ok != FlateOk)
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return ok;
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buf[0] = zr.adler >> 24;
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buf[1] = zr.adler >> 16;
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buf[2] = zr.adler >> 8;
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buf[3] = zr.adler;
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if((*w)(wr, buf, 4) != 4)
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return FlateOutputFail;
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return FlateOk;
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}
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