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- /*
- * This file is part of the UCB release of Plan 9. It is subject to the license
- * terms in the LICENSE file found in the top-level directory of this
- * distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
- * part of the UCB release of Plan 9, including this file, may be copied,
- * modified, propagated, or distributed except according to the terms contained
- * in the LICENSE file.
- */
- #include <u.h>
- #include <libc.h>
- #include <flate.h>
- #include "zlib.h"
- int
- deflatezlibblock(uint8_t *dst, int dsize, uint8_t *src, int ssize,
- int level, int debug)
- {
- uint32_t adler;
- int n;
- if(dsize < 6)
- return FlateOutputFail;
- n = deflateblock(dst + 2, dsize - 6, src, ssize, level, debug);
- if(n < 0)
- return n;
- dst[0] = ZlibDeflate | ZlibWin32k;
- /* bogus zlib encoding of compression level */
- dst[1] = ((level > 2) + (level > 5) + (level > 8)) << 6;
- /* header check field */
- dst[1] |= 31 - ((dst[0] << 8) | dst[1]) % 31;
- adler = adler32(1, src, ssize);
- dst[n + 2] = adler >> 24;
- dst[n + 3] = adler >> 16;
- dst[n + 4] = adler >> 8;
- dst[n + 5] = adler;
- return n + 6;
- }
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