mirror of
https://github.com/jart/cosmopolitan.git
synced 2024-05-18 11:32:41 +00:00
e16a7d8f3b
`et` means `expandtab`. ```sh rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\) et\(.*\) :vi/vi: \1 xoet\2:vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)noet\(.*\):vi/vi: \1et\2 :vi/' rg 'vi: .* :vi' -l -0 | \ xargs -0 sed -i '' 's/vi: \(.*\)xoet\(.*\):vi/vi: \1noet\2:vi/' ```
63 lines
2.9 KiB
C
63 lines
2.9 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
|
|
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
|
|
╞══════════════════════════════════════════════════════════════════════════════╡
|
|
│ Copyright 2021 Justine Alexandra Roberts Tunney │
|
|
│ │
|
|
│ Permission to use, copy, modify, and/or distribute this software for │
|
|
│ any purpose with or without fee is hereby granted, provided that the │
|
|
│ above copyright notice and this permission notice appear in all copies. │
|
|
│ │
|
|
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
|
|
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
|
|
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
|
|
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
|
|
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
|
|
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
|
|
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
|
|
│ PERFORMANCE OF THIS SOFTWARE. │
|
|
╚─────────────────────────────────────────────────────────────────────────────*/
|
|
#include "libc/nexgen32e/crc32.h"
|
|
#include "libc/nexgen32e/x86feature.h"
|
|
|
|
/**
|
|
* Computes 32-bit Castagnoli Cyclic Redundancy Check.
|
|
*
|
|
* x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1
|
|
* 0b00011110110111000110111101000001
|
|
*
|
|
* @param init is the initial hash value
|
|
* @param data points to the data
|
|
* @param size is the byte size of data
|
|
* @return eax is the new hash value
|
|
* @note Used by ISCSI, TensorFlow, etc.
|
|
*/
|
|
uint32_t crc32c(uint32_t init, const void *data, size_t size) {
|
|
uint64_t h;
|
|
static bool once;
|
|
const unsigned char *p, *pe;
|
|
static uint32_t kCrc32cTab[256];
|
|
if (!once) {
|
|
crc32init(kCrc32cTab, 0x82f63b78);
|
|
once = 1;
|
|
}
|
|
p = data;
|
|
pe = p + size;
|
|
h = init ^ 0xffffffff;
|
|
if (X86_HAVE(SSE4_2)) {
|
|
while (p < pe && ((intptr_t)p & 7)) {
|
|
h = h >> 8 ^ kCrc32cTab[(h & 0xff) ^ *p++];
|
|
}
|
|
for (; p + 8 <= pe; p += 8) {
|
|
asm("crc32q\t%1,%0" : "+r"(h) : "rm"(*(const uint64_t *)p));
|
|
}
|
|
while (p < pe) {
|
|
asm("crc32b\t%1,%0" : "+r"(h) : "rm"(*p++));
|
|
}
|
|
} else {
|
|
while (p < pe) {
|
|
h = h >> 8 ^ kCrc32cTab[(h & 0xff) ^ *p++];
|
|
}
|
|
}
|
|
return h ^ 0xffffffff;
|
|
}
|