| /* 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 DO1(sum1, sum2, buf, i) {(sum1) += buf[(i)]; (sum2) += (sum1);} |
| #define DO2(sum1, sum2, buf, i) {DO1(sum1, sum2, buf, i); DO1(sum1, sum2, buf, i+1);} |
| #define DO4(sum1, sum2, buf, i) {DO2(sum1, sum2, buf, i); DO2(sum1, sum2, buf, i+2);} |
| #define DO8(sum1, sum2, buf, i) {DO4(sum1, sum2, buf, i); DO4(sum1, sum2, buf, i+4);} |
| #define DO16(sum1, sum2, buf) {DO8(sum1, sum2, buf, 0); DO8(sum1, sum2, buf, 8);} |
| |
| static inline uint32_t adler32_len_1(uint32_t adler, const uint8_t *buf, uint32_t sum2) { |
| adler += buf[0]; |
| adler %= BASE; |
| sum2 += adler; |
| sum2 %= BASE; |
| return adler | (sum2 << 16); |
| } |
| |
| static inline uint32_t adler32_len_16(uint32_t adler, const uint8_t *buf, size_t len, uint32_t sum2) { |
| while (len) { |
| --len; |
| adler += *buf++; |
| sum2 += adler; |
| } |
| adler %= BASE; |
| sum2 %= BASE; /* only added so many BASE's */ |
| /* return recombined sums */ |
| return adler | (sum2 << 16); |
| } |
| |
| static inline uint32_t adler32_copy_len_16(uint32_t adler, const uint8_t *buf, uint8_t *dst, size_t len, uint32_t sum2) { |
| while (len--) { |
| *dst = *buf++; |
| adler += *dst++; |
| sum2 += adler; |
| } |
| adler %= BASE; |
| sum2 %= BASE; /* only added so many BASE's */ |
| /* return recombined sums */ |
| return adler | (sum2 << 16); |
| } |
| |
| static inline uint32_t adler32_len_64(uint32_t adler, const uint8_t *buf, size_t len, uint32_t sum2) { |
| #ifdef UNROLL_MORE |
| while (len >= 16) { |
| len -= 16; |
| DO16(adler, sum2, buf); |
| buf += 16; |
| #else |
| while (len >= 8) { |
| len -= 8; |
| DO8(adler, sum2, buf, 0); |
| buf += 8; |
| #endif |
| } |
| /* Process tail (len < 16). */ |
| return adler32_len_16(adler, buf, len, sum2); |
| } |
| |
| #endif /* ADLER32_P_H */ |