static uint32_t adler32(uint32_t adler, const uint8_t *buf, unsigned int len) { unsigned long s1 = adler & 0xffff; unsigned long s2 = (adler >> 16) & 0xffff; int k; if (buf == NULL) return 1L; while (len > 0) { k = len < NMAX ? len : NMAX; len -= k; while (k >= 16) { DO16(buf); k -= 16; } if (k != 0) do { DO1(buf); } while (--k); s1 %= BASE; s2 %= BASE; } return (s2 << 16) | s1; }