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https://github.com/dolphin-emu/dolphin.git
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update zlib to v1.2.8
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68
Externals/zlib/adler32.c
vendored
68
Externals/zlib/adler32.c
vendored
@ -1,5 +1,5 @@
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/* adler32.c -- compute the Adler-32 checksum of a data stream
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* Copyright (C) 1995-2007 Mark Adler
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* Copyright (C) 1995-2011 Mark Adler
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* For conditions of distribution and use, see copyright notice in zlib.h
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*/
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@ -9,9 +9,9 @@
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#define local static
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local uLong adler32_combine_(uLong adler1, uLong adler2, z_off64_t len2);
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local uLong adler32_combine_ OF((uLong adler1, uLong adler2, z_off64_t len2));
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#define BASE 65521UL /* largest prime smaller than 65536 */
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#define BASE 65521 /* largest prime smaller than 65536 */
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#define NMAX 5552
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/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
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@ -21,39 +21,44 @@ local uLong adler32_combine_(uLong adler1, uLong adler2, z_off64_t len2);
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#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);
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#define DO16(buf) DO8(buf,0); DO8(buf,8);
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/* use NO_DIVIDE if your processor does not do division in hardware */
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/* use NO_DIVIDE if your processor does not do division in hardware --
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try it both ways to see which is faster */
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#ifdef NO_DIVIDE
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# define MOD(a) \
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/* note that this assumes BASE is 65521, where 65536 % 65521 == 15
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(thank you to John Reiser for pointing this out) */
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# define CHOP(a) \
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do { \
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if (a >= (BASE << 16)) a -= (BASE << 16); \
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if (a >= (BASE << 15)) a -= (BASE << 15); \
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if (a >= (BASE << 14)) a -= (BASE << 14); \
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if (a >= (BASE << 13)) a -= (BASE << 13); \
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if (a >= (BASE << 12)) a -= (BASE << 12); \
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if (a >= (BASE << 11)) a -= (BASE << 11); \
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if (a >= (BASE << 10)) a -= (BASE << 10); \
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if (a >= (BASE << 9)) a -= (BASE << 9); \
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if (a >= (BASE << 8)) a -= (BASE << 8); \
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if (a >= (BASE << 7)) a -= (BASE << 7); \
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if (a >= (BASE << 6)) a -= (BASE << 6); \
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if (a >= (BASE << 5)) a -= (BASE << 5); \
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if (a >= (BASE << 4)) a -= (BASE << 4); \
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if (a >= (BASE << 3)) a -= (BASE << 3); \
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if (a >= (BASE << 2)) a -= (BASE << 2); \
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if (a >= (BASE << 1)) a -= (BASE << 1); \
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unsigned long tmp = a >> 16; \
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a &= 0xffffUL; \
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a += (tmp << 4) - tmp; \
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} while (0)
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# define MOD28(a) \
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do { \
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CHOP(a); \
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if (a >= BASE) a -= BASE; \
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} while (0)
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# define MOD4(a) \
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# define MOD(a) \
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do { \
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if (a >= (BASE << 4)) a -= (BASE << 4); \
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if (a >= (BASE << 3)) a -= (BASE << 3); \
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if (a >= (BASE << 2)) a -= (BASE << 2); \
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if (a >= (BASE << 1)) a -= (BASE << 1); \
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CHOP(a); \
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MOD28(a); \
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} while (0)
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# define MOD63(a) \
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do { /* this assumes a is not negative */ \
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z_off64_t tmp = a >> 32; \
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a &= 0xffffffffL; \
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a += (tmp << 8) - (tmp << 5) + tmp; \
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tmp = a >> 16; \
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a &= 0xffffL; \
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a += (tmp << 4) - tmp; \
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tmp = a >> 16; \
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a &= 0xffffL; \
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a += (tmp << 4) - tmp; \
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if (a >= BASE) a -= BASE; \
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} while (0)
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#else
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# define MOD(a) a %= BASE
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# define MOD4(a) a %= BASE
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# define MOD28(a) a %= BASE
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# define MOD63(a) a %= BASE
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#endif
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/* ========================================================================= */
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@ -92,7 +97,7 @@ uLong ZEXPORT adler32(adler, buf, len)
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}
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if (adler >= BASE)
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adler -= BASE;
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MOD4(sum2); /* only added so many BASE's */
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MOD28(sum2); /* only added so many BASE's */
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return adler | (sum2 << 16);
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}
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@ -137,8 +142,13 @@ local uLong adler32_combine_(adler1, adler2, len2)
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unsigned long sum2;
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unsigned rem;
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/* for negative len, return invalid adler32 as a clue for debugging */
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if (len2 < 0)
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return 0xffffffffUL;
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/* the derivation of this formula is left as an exercise for the reader */
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rem = (unsigned)(len2 % BASE);
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MOD63(len2); /* assumes len2 >= 0 */
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rem = (unsigned)len2;
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sum1 = adler1 & 0xffff;
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sum2 = rem * sum1;
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MOD(sum2);
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