diff --git a/deps/rzlib/adler32.c b/deps/rzlib/adler32.c index 328449d5e1..71000d1cd9 100644 --- a/deps/rzlib/adler32.c +++ b/deps/rzlib/adler32.c @@ -1,167 +1,75 @@ /* adler32.c -- compute the Adler-32 checksum of a data stream - * Copyright (C) 1995-2011 Mark Adler + * Copyright (C) 1995-2003 Mark Adler * For conditions of distribution and use, see copyright notice in zlib.h */ /* @(#) $Id$ */ +#define ZLIB_INTERNAL +#include +#include #include "zutil.h" -#define local static - -local uLong adler32_combine_ OF((uLong adler1, uLong adler2, z_off64_t len2)); - -#define BASE 65521 /* largest prime smaller than 65536 */ +#define BASE 65521UL /* largest prime smaller than 65536 */ #define NMAX 5552 /* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */ -#define DO1(buf,i) {adler += (buf)[i]; sum2 += adler;} +#define DO1(buf,i) {s1 += buf[i]; s2 += s1;} #define DO2(buf,i) DO1(buf,i); DO1(buf,i+1); #define DO4(buf,i) DO2(buf,i); DO2(buf,i+2); #define DO8(buf,i) DO4(buf,i); DO4(buf,i+4); #define DO16(buf) DO8(buf,0); DO8(buf,8); -/* use NO_DIVIDE if your processor does not do division in hardware -- - try it both ways to see which is faster */ #ifdef NO_DIVIDE -/* note that this assumes BASE is 65521, where 65536 % 65521 == 15 - (thank you to John Reiser for pointing this out) */ -# define CHOP(a) \ - do { \ - unsigned long tmp = a >> 16; \ - a &= 0xffffUL; \ - a += (tmp << 4) - tmp; \ - } while (0) -# define MOD28(a) \ - do { \ - CHOP(a); \ - if (a >= BASE) a -= BASE; \ - } while (0) # define MOD(a) \ - do { \ - CHOP(a); \ - MOD28(a); \ - } while (0) -# define MOD63(a) \ - do { /* this assumes a is not negative */ \ - z_off64_t tmp = a >> 32; \ - a &= 0xffffffffL; \ - a += (tmp << 8) - (tmp << 5) + tmp; \ - tmp = a >> 16; \ - a &= 0xffffL; \ - a += (tmp << 4) - tmp; \ - tmp = a >> 16; \ - a &= 0xffffL; \ - a += (tmp << 4) - tmp; \ - if (a >= BASE) a -= BASE; \ - } while (0) +do { \ +if (a >= (BASE << 16)) a -= (BASE << 16); \ +if (a >= (BASE << 15)) a -= (BASE << 15); \ +if (a >= (BASE << 14)) a -= (BASE << 14); \ +if (a >= (BASE << 13)) a -= (BASE << 13); \ +if (a >= (BASE << 12)) a -= (BASE << 12); \ +if (a >= (BASE << 11)) a -= (BASE << 11); \ +if (a >= (BASE << 10)) a -= (BASE << 10); \ +if (a >= (BASE << 9)) a -= (BASE << 9); \ +if (a >= (BASE << 8)) a -= (BASE << 8); \ +if (a >= (BASE << 7)) a -= (BASE << 7); \ +if (a >= (BASE << 6)) a -= (BASE << 6); \ +if (a >= (BASE << 5)) a -= (BASE << 5); \ +if (a >= (BASE << 4)) a -= (BASE << 4); \ +if (a >= (BASE << 3)) a -= (BASE << 3); \ +if (a >= (BASE << 2)) a -= (BASE << 2); \ +if (a >= (BASE << 1)) a -= (BASE << 1); \ +if (a >= BASE) a -= BASE; \ +} while (0) #else # define MOD(a) a %= BASE -# define MOD28(a) a %= BASE -# define MOD63(a) a %= BASE #endif /* ========================================================================= */ -uLong ZEXPORT adler32(uLong adler, const Bytef *buf, uInt len) +uLong adler32(uLong adler, const Bytef *buf, uInt len) { - unsigned long sum2; - unsigned n; - - /* split Adler-32 into component sums */ - sum2 = (adler >> 16) & 0xffff; - adler &= 0xffff; - - /* in case user likes doing a byte at a time, keep it fast */ - if (len == 1) { - adler += buf[0]; - if (adler >= BASE) - adler -= BASE; - sum2 += adler; - if (sum2 >= BASE) - sum2 -= BASE; - return adler | (sum2 << 16); - } - - /* initial Adler-32 value (deferred check for len == 1 speed) */ - if (buf == Z_NULL) + uint32_t s1 = adler & 0xffff; + uint32_t s2 = (adler >> 16) & 0xffff; + int k; + + if (buf == NULL) return 1L; - - /* in case short lengths are provided, keep it somewhat fast */ - if (len < 16) { - while (len--) { - adler += *buf++; - sum2 += adler; - } - if (adler >= BASE) - adler -= BASE; - MOD28(sum2); /* only added so many BASE's */ - return adler | (sum2 << 16); - } - - /* do length NMAX blocks -- requires just one modulo operation */ - while (len >= NMAX) { - len -= NMAX; - n = NMAX / 16; /* NMAX is divisible by 16 */ - do { - DO16(buf); /* 16 sums unrolled */ - buf += 16; - } while (--n); - MOD(adler); - MOD(sum2); - } - - /* do remaining bytes (less than NMAX, still just one modulo) */ - if (len) { /* avoid modulos if none remaining */ - while (len >= 16) { - len -= 16; + + while (len > 0) { + k = len < NMAX ? (int)len : NMAX; + len -= k; + while (k >= 16) { DO16(buf); buf += 16; + k -= 16; } - while (len--) { - adler += *buf++; - sum2 += adler; - } - MOD(adler); - MOD(sum2); + if (k != 0) do { + s1 += *buf++; + s2 += s1; + } while (--k); + MOD(s1); + MOD(s2); } - - /* return recombined sums */ - return adler | (sum2 << 16); + return (s2 << 16) | s1; } -/* ========================================================================= */ -local uLong adler32_combine_(uLong adler1, uLong adler2, z_off64_t len2) -{ - unsigned long sum1; - unsigned long sum2; - unsigned rem; - - /* for negative len, return invalid adler32 as a clue for debugging */ - if (len2 < 0) - return 0xffffffffUL; - - /* the derivation of this formula is left as an exercise for the reader */ - MOD63(len2); /* assumes len2 >= 0 */ - rem = (unsigned)len2; - sum1 = adler1 & 0xffff; - sum2 = rem * sum1; - MOD(sum2); - sum1 += (adler2 & 0xffff) + BASE - 1; - sum2 += ((adler1 >> 16) & 0xffff) + ((adler2 >> 16) & 0xffff) + BASE - rem; - if (sum1 >= BASE) sum1 -= BASE; - if (sum1 >= BASE) sum1 -= BASE; - if (sum2 >= (BASE << 1)) sum2 -= (BASE << 1); - if (sum2 >= BASE) sum2 -= BASE; - return sum1 | (sum2 << 16); -} - -/* ========================================================================= */ -uLong adler32_combine(uLong adler1, uLong adler2, z_off_t len2) -{ - return adler32_combine_(adler1, adler2, len2); -} - -uLong adler32_combine64(uLong adler1, uLong adler2, z_off64_t len2) -{ - return adler32_combine_(adler1, adler2, len2); -}