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/* adler32_p.h -- Private inline functions and macros shared with
* different computation of the Adler-32 checksum
* of a data stream.
* Copyright (C) 1995-2011, 2016 Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
#ifndef ADLER32_P_H
#define ADLER32_P_H
#define BASE 65521U /* 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 NMAX_ALIGNED32 (NMAX & ~31)
/* NMAX rounded down to a multiple of 32 is 5536 */
#define ADLER_DO1(sum1, sum2, buf, i) {(sum1) += buf[(i)]; (sum2) += (sum1);}
#define ADLER_DO2(sum1, sum2, buf, i) {ADLER_DO1(sum1, sum2, buf, i); ADLER_DO1(sum1, sum2, buf, i+1);}
#define ADLER_DO4(sum1, sum2, buf, i) {ADLER_DO2(sum1, sum2, buf, i); ADLER_DO2(sum1, sum2, buf, i+2);}
#define ADLER_DO8(sum1, sum2, buf, i) {ADLER_DO4(sum1, sum2, buf, i); ADLER_DO4(sum1, sum2, buf, i+4);}
#define ADLER_DO16(sum1, sum2, buf) {ADLER_DO8(sum1, sum2, buf, 0); ADLER_DO8(sum1, sum2, buf, 8);}
Z_FORCEINLINE static void adler32_copy_align(uint32_t *Z_RESTRICT adler, uint8_t *dst, const uint8_t *buf, size_t len,
uint32_t *Z_RESTRICT sum2, const int MAX_LEN, const int COPY) {
Z_UNUSED(MAX_LEN);
if (len & 1) {
if (COPY) {
*dst = *buf;
dst += 1;
}
ADLER_DO1(*adler, *sum2, buf, 0);
buf += 1;
}
if (len & 2) {
if (COPY) {
memcpy(dst, buf, 2);
dst += 2;
}
ADLER_DO2(*adler, *sum2, buf, 0);
buf += 2;
}
while (len >= 4) {
if (COPY) {
memcpy(dst, buf, 4);
dst += 4;
}
len -= 4;
ADLER_DO4(*adler, *sum2, buf, 0);
buf += 4;
}
}
Z_FORCEINLINE static uint32_t adler32_copy_tail(uint32_t adler, uint8_t *dst, const uint8_t *buf, size_t len,
uint32_t sum2, const int REBASE, const int MAX_LEN, const int COPY) {
if (len) {
/* DO16 loop for large remainders only (scalar, risc-v). */
if (MAX_LEN >= 32) {
while (len >= 16) {
if (COPY) {
memcpy(dst, buf, 16);
dst += 16;
}
len -= 16;
ADLER_DO16(adler, sum2, buf);
buf += 16;
}
}
/* DO4 loop avoids GCC x86 register pressure from hoisted DO8/DO16 loads. */
while (len >= 4) {
if (COPY) {
memcpy(dst, buf, 4);
dst += 4;
}
len -= 4;
ADLER_DO4(adler, sum2, buf, 0);
buf += 4;
}
if (len & 2) {
if (COPY) {
memcpy(dst, buf, 2);
dst += 2;
}
ADLER_DO2(adler, sum2, buf, 0);
buf += 2;
}
if (len & 1) {
if (COPY)
*dst = *buf;
ADLER_DO1(adler, sum2, buf, 0);
}
}
if (REBASE) {
adler %= BASE;
sum2 %= BASE;
}
/* D = B * 65536 + A, see: https://en.wikipedia.org/wiki/Adler-32. */
return adler | (sum2 << 16);
}
#endif /* ADLER32_P_H */
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