//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.

//  This source code is licensed under both the GPLv2 (found in the

//  COPYING file in the root directory) and Apache 2.0 License

//  (found in the LICENSE.Apache file in the root directory).

//

// Copyright (c) 2011 The LevelDB Authors. All rights reserved.

// Use of this source code is governed by a BSD-style license that can be

// found in the LICENSE file. See the AUTHORS file for names of contributors.

//

// A portable implementation of crc32c, optimized to handle

// four bytes at a time.

#include "util/crc32c.h"

#include <array>

#include <cstdint>

#include <utility>

#include "port/lang.h"

#include "util/coding.h"

#include "util/crc32c_arm64.h"

#include "util/math.h"

#ifdef __powerpc64__

#include "util/crc32c_ppc.h"

#include "util/crc32c_ppc_constants.h"

#if __linux__

#ifdef ROCKSDB_AUXV_GETAUXVAL_PRESENT

#include <sys/auxv.h>

#endif

#ifndef PPC_FEATURE2_VEC_CRYPTO

#define PPC_FEATURE2_VEC_CRYPTO 0x02000000

#endif

#ifndef AT_HWCAP2

#define AT_HWCAP2 26

#endif

#elif __FreeBSD__

#include <machine/cpu.h>

#include <sys/auxv.h>

#include <sys/elf_common.h>

#endif /* __linux__ */

#endif

ASSERT_FEATURE_COMPAT_HEADER();

#ifdef __SSE4_2__

#include <nmmintrin.h>

#include <wmmintrin.h>

#endif

#if defined(HAVE_ARM64_CRC)

bool pmull_runtime_flag = false;

#endif

namespace ROCKSDB_NAMESPACE::crc32c {

#if defined(HAVE_POWER8) && defined(HAS_ALTIVEC)

#ifdef __powerpc64__

static int arch_ppc_crc32 = 0;

#endif /* __powerpc64__ */

#endif

static const uint32_t table0_[256] = {

    0x00000000, 0xf26b8303, 0xe13b70f7, 0x1350f3f4, 0xc79a971f, 0x35f1141c,

    0x26a1e7e8, 0xd4ca64eb, 0x8ad958cf, 0x78b2dbcc, 0x6be22838, 0x9989ab3b,

    0x4d43cfd0, 0xbf284cd3, 0xac78bf27, 0x5e133c24, 0x105ec76f, 0xe235446c,

    0xf165b798, 0x030e349b, 0xd7c45070, 0x25afd373, 0x36ff2087, 0xc494a384,

    0x9a879fa0, 0x68ec1ca3, 0x7bbcef57, 0x89d76c54, 0x5d1d08bf, 0xaf768bbc,

    0xbc267848, 0x4e4dfb4b, 0x20bd8ede, 0xd2d60ddd, 0xc186fe29, 0x33ed7d2a,

    0xe72719c1, 0x154c9ac2, 0x061c6936, 0xf477ea35, 0xaa64d611, 0x580f5512,

    0x4b5fa6e6, 0xb93425e5, 0x6dfe410e, 0x9f95c20d, 0x8cc531f9, 0x7eaeb2fa,

    0x30e349b1, 0xc288cab2, 0xd1d83946, 0x23b3ba45, 0xf779deae, 0x05125dad,

    0x1642ae59, 0xe4292d5a, 0xba3a117e, 0x4851927d, 0x5b016189, 0xa96ae28a,

    0x7da08661, 0x8fcb0562, 0x9c9bf696, 0x6ef07595, 0x417b1dbc, 0xb3109ebf,

    0xa0406d4b, 0x522bee48, 0x86e18aa3, 0x748a09a0, 0x67dafa54, 0x95b17957,

    0xcba24573, 0x39c9c670, 0x2a993584, 0xd8f2b687, 0x0c38d26c, 0xfe53516f,

    0xed03a29b, 0x1f682198, 0x5125dad3, 0xa34e59d0, 0xb01eaa24, 0x42752927,

    0x96bf4dcc, 0x64d4cecf, 0x77843d3b, 0x85efbe38, 0xdbfc821c, 0x2997011f,

    0x3ac7f2eb, 0xc8ac71e8, 0x1c661503, 0xee0d9600, 0xfd5d65f4, 0x0f36e6f7,

    0x61c69362, 0x93ad1061, 0x80fde395, 0x72966096, 0xa65c047d, 0x5437877e,

    0x4767748a, 0xb50cf789, 0xeb1fcbad, 0x197448ae, 0x0a24bb5a, 0xf84f3859,

    0x2c855cb2, 0xdeeedfb1, 0xcdbe2c45, 0x3fd5af46, 0x7198540d, 0x83f3d70e,

    0x90a324fa, 0x62c8a7f9, 0xb602c312, 0x44694011, 0x5739b3e5, 0xa55230e6,

    0xfb410cc2, 0x092a8fc1, 0x1a7a7c35, 0xe811ff36, 0x3cdb9bdd, 0xceb018de,

    0xdde0eb2a, 0x2f8b6829, 0x82f63b78, 0x709db87b, 0x63cd4b8f, 0x91a6c88c,

    0x456cac67, 0xb7072f64, 0xa457dc90, 0x563c5f93, 0x082f63b7, 0xfa44e0b4,

    0xe9141340, 0x1b7f9043, 0xcfb5f4a8, 0x3dde77ab, 0x2e8e845f, 0xdce5075c,

    0x92a8fc17, 0x60c37f14, 0x73938ce0, 0x81f80fe3, 0x55326b08, 0xa759e80b,

    0xb4091bff, 0x466298fc, 0x1871a4d8, 0xea1a27db, 0xf94ad42f, 0x0b21572c,

    0xdfeb33c7, 0x2d80b0c4, 0x3ed04330, 0xccbbc033, 0xa24bb5a6, 0x502036a5,

    0x4370c551, 0xb11b4652, 0x65d122b9, 0x97baa1ba, 0x84ea524e, 0x7681d14d,

    0x2892ed69, 0xdaf96e6a, 0xc9a99d9e, 0x3bc21e9d, 0xef087a76, 0x1d63f975,

    0x0e330a81, 0xfc588982, 0xb21572c9, 0x407ef1ca, 0x532e023e, 0xa145813d,

    0x758fe5d6, 0x87e466d5, 0x94b49521, 0x66df1622, 0x38cc2a06, 0xcaa7a905,

    0xd9f75af1, 0x2b9cd9f2, 0xff56bd19, 0x0d3d3e1a, 0x1e6dcdee, 0xec064eed,

    0xc38d26c4, 0x31e6a5c7, 0x22b65633, 0xd0ddd530, 0x0417b1db, 0xf67c32d8,

    0xe52cc12c, 0x1747422f, 0x49547e0b, 0xbb3ffd08, 0xa86f0efc, 0x5a048dff,

    0x8ecee914, 0x7ca56a17, 0x6ff599e3, 0x9d9e1ae0, 0xd3d3e1ab, 0x21b862a8,

    0x32e8915c, 0xc083125f, 0x144976b4, 0xe622f5b7, 0xf5720643, 0x07198540,

    0x590ab964, 0xab613a67, 0xb831c993, 0x4a5a4a90, 0x9e902e7b, 0x6cfbad78,

    0x7fab5e8c, 0x8dc0dd8f, 0xe330a81a, 0x115b2b19, 0x020bd8ed, 0xf0605bee,

    0x24aa3f05, 0xd6c1bc06, 0xc5914ff2, 0x37faccf1, 0x69e9f0d5, 0x9b8273d6,

    0x88d28022, 0x7ab90321, 0xae7367ca, 0x5c18e4c9, 0x4f48173d, 0xbd23943e,

    0xf36e6f75, 0x0105ec76, 0x12551f82, 0xe03e9c81, 0x34f4f86a, 0xc69f7b69,

    0xd5cf889d, 0x27a40b9e, 0x79b737ba, 0x8bdcb4b9, 0x988c474d, 0x6ae7c44e,

    0xbe2da0a5, 0x4c4623a6, 0x5f16d052, 0xad7d5351};

#ifndef __SSE4_2__

static const uint32_t table1_[256] = {

    0x00000000, 0x13a29877, 0x274530ee, 0x34e7a899, 0x4e8a61dc, 0x5d28f9ab,

    0x69cf5132, 0x7a6dc945, 0x9d14c3b8, 0x8eb65bcf, 0xba51f356, 0xa9f36b21,

    0xd39ea264, 0xc03c3a13, 0xf4db928a, 0xe7790afd, 0x3fc5f181, 0x2c6769f6,

    0x1880c16f, 0x0b225918, 0x714f905d, 0x62ed082a, 0x560aa0b3, 0x45a838c4,

    0xa2d13239, 0xb173aa4e, 0x859402d7, 0x96369aa0, 0xec5b53e5, 0xfff9cb92,

    0xcb1e630b, 0xd8bcfb7c, 0x7f8be302, 0x6c297b75, 0x58ced3ec, 0x4b6c4b9b,

    0x310182de, 0x22a31aa9, 0x1644b230, 0x05e62a47, 0xe29f20ba, 0xf13db8cd,

    0xc5da1054, 0xd6788823, 0xac154166, 0xbfb7d911, 0x8b507188, 0x98f2e9ff,

    0x404e1283, 0x53ec8af4, 0x670b226d, 0x74a9ba1a, 0x0ec4735f, 0x1d66eb28,

    0x298143b1, 0x3a23dbc6, 0xdd5ad13b, 0xcef8494c, 0xfa1fe1d5, 0xe9bd79a2,

    0x93d0b0e7, 0x80722890, 0xb4958009, 0xa737187e, 0xff17c604, 0xecb55e73,

    0xd852f6ea, 0xcbf06e9d, 0xb19da7d8, 0xa23f3faf, 0x96d89736, 0x857a0f41,

    0x620305bc, 0x71a19dcb, 0x45463552, 0x56e4ad25, 0x2c896460, 0x3f2bfc17,

    0x0bcc548e, 0x186eccf9, 0xc0d23785, 0xd370aff2, 0xe797076b, 0xf4359f1c,

    0x8e585659, 0x9dface2e, 0xa91d66b7, 0xbabffec0, 0x5dc6f43d, 0x4e646c4a,

    0x7a83c4d3, 0x69215ca4, 0x134c95e1, 0x00ee0d96, 0x3409a50f, 0x27ab3d78,

    0x809c2506, 0x933ebd71, 0xa7d915e8, 0xb47b8d9f, 0xce1644da, 0xddb4dcad,

    0xe9537434, 0xfaf1ec43, 0x1d88e6be, 0x0e2a7ec9, 0x3acdd650, 0x296f4e27,

    0x53028762, 0x40a01f15, 0x7447b78c, 0x67e52ffb, 0xbf59d487, 0xacfb4cf0,

    0x981ce469, 0x8bbe7c1e, 0xf1d3b55b, 0xe2712d2c, 0xd69685b5, 0xc5341dc2,

    0x224d173f, 0x31ef8f48, 0x050827d1, 0x16aabfa6, 0x6cc776e3, 0x7f65ee94,

    0x4b82460d, 0x5820de7a, 0xfbc3faf9, 0xe861628e, 0xdc86ca17, 0xcf245260,

    0xb5499b25, 0xa6eb0352, 0x920cabcb, 0x81ae33bc, 0x66d73941, 0x7575a136,

    0x419209af, 0x523091d8, 0x285d589d, 0x3bffc0ea, 0x0f186873, 0x1cbaf004,

    0xc4060b78, 0xd7a4930f, 0xe3433b96, 0xf0e1a3e1, 0x8a8c6aa4, 0x992ef2d3,

    0xadc95a4a, 0xbe6bc23d, 0x5912c8c0, 0x4ab050b7, 0x7e57f82e, 0x6df56059,

    0x1798a91c, 0x043a316b, 0x30dd99f2, 0x237f0185, 0x844819fb, 0x97ea818c,

    0xa30d2915, 0xb0afb162, 0xcac27827, 0xd960e050, 0xed8748c9, 0xfe25d0be,

    0x195cda43, 0x0afe4234, 0x3e19eaad, 0x2dbb72da, 0x57d6bb9f, 0x447423e8,

    0x70938b71, 0x63311306, 0xbb8de87a, 0xa82f700d, 0x9cc8d894, 0x8f6a40e3,

    0xf50789a6, 0xe6a511d1, 0xd242b948, 0xc1e0213f, 0x26992bc2, 0x353bb3b5,

    0x01dc1b2c, 0x127e835b, 0x68134a1e, 0x7bb1d269, 0x4f567af0, 0x5cf4e287,

    0x04d43cfd, 0x1776a48a, 0x23910c13, 0x30339464, 0x4a5e5d21, 0x59fcc556,

    0x6d1b6dcf, 0x7eb9f5b8, 0x99c0ff45, 0x8a626732, 0xbe85cfab, 0xad2757dc,

    0xd74a9e99, 0xc4e806ee, 0xf00fae77, 0xe3ad3600, 0x3b11cd7c, 0x28b3550b,

    0x1c54fd92, 0x0ff665e5, 0x759baca0, 0x663934d7, 0x52de9c4e, 0x417c0439,

    0xa6050ec4, 0xb5a796b3, 0x81403e2a, 0x92e2a65d, 0xe88f6f18, 0xfb2df76f,

    0xcfca5ff6, 0xdc68c781, 0x7b5fdfff, 0x68fd4788, 0x5c1aef11, 0x4fb87766,

    0x35d5be23, 0x26772654, 0x12908ecd, 0x013216ba, 0xe64b1c47, 0xf5e98430,

    0xc10e2ca9, 0xd2acb4de, 0xa8c17d9b, 0xbb63e5ec, 0x8f844d75, 0x9c26d502,

    0x449a2e7e, 0x5738b609, 0x63df1e90, 0x707d86e7, 0x0a104fa2, 0x19b2d7d5,

    0x2d557f4c, 0x3ef7e73b, 0xd98eedc6, 0xca2c75b1, 0xfecbdd28, 0xed69455f,

    0x97048c1a, 0x84a6146d, 0xb041bcf4, 0xa3e32483};

static const uint32_t table2_[256] = {

    0x00000000, 0xa541927e, 0x4f6f520d, 0xea2ec073, 0x9edea41a, 0x3b9f3664,

    0xd1b1f617, 0x74f06469, 0x38513ec5, 0x9d10acbb, 0x773e6cc8, 0xd27ffeb6,

    0xa68f9adf, 0x03ce08a1, 0xe9e0c8d2, 0x4ca15aac, 0x70a27d8a, 0xd5e3eff4,

    0x3fcd2f87, 0x9a8cbdf9, 0xee7cd990, 0x4b3d4bee, 0xa1138b9d, 0x045219e3,

    0x48f3434f, 0xedb2d131, 0x079c1142, 0xa2dd833c, 0xd62de755, 0x736c752b,

    0x9942b558, 0x3c032726, 0xe144fb14, 0x4405696a, 0xae2ba919, 0x0b6a3b67,

    0x7f9a5f0e, 0xdadbcd70, 0x30f50d03, 0x95b49f7d, 0xd915c5d1, 0x7c5457af,

    0x967a97dc, 0x333b05a2, 0x47cb61cb, 0xe28af3b5, 0x08a433c6, 0xade5a1b8,

    0x91e6869e, 0x34a714e0, 0xde89d493, 0x7bc846ed, 0x0f382284, 0xaa79b0fa,

    0x40577089, 0xe516e2f7, 0xa9b7b85b, 0x0cf62a25, 0xe6d8ea56, 0x43997828,

    0x37691c41, 0x92288e3f, 0x78064e4c, 0xdd47dc32, 0xc76580d9, 0x622412a7,

    0x880ad2d4, 0x2d4b40aa, 0x59bb24c3, 0xfcfab6bd, 0x16d476ce, 0xb395e4b0,

    0xff34be1c, 0x5a752c62, 0xb05bec11, 0x151a7e6f, 0x61ea1a06, 0xc4ab8878,

    0x2e85480b, 0x8bc4da75, 0xb7c7fd53, 0x12866f2d, 0xf8a8af5e, 0x5de93d20,

    0x29195949, 0x8c58cb37, 0x66760b44, 0xc337993a, 0x8f96c396, 0x2ad751e8,

    0xc0f9919b, 0x65b803e5, 0x1148678c, 0xb409f5f2, 0x5e273581, 0xfb66a7ff,

    0x26217bcd, 0x8360e9b3, 0x694e29c0, 0xcc0fbbbe, 0xb8ffdfd7, 0x1dbe4da9,

    0xf7908dda, 0x52d11fa4, 0x1e704508, 0xbb31d776, 0x511f1705, 0xf45e857b,

    0x80aee112, 0x25ef736c, 0xcfc1b31f, 0x6a802161, 0x56830647, 0xf3c29439,

    0x19ec544a, 0xbcadc634, 0xc85da25d, 0x6d1c3023, 0x8732f050, 0x2273622e,

    0x6ed23882, 0xcb93aafc, 0x21bd6a8f, 0x84fcf8f1, 0xf00c9c98, 0x554d0ee6,

    0xbf63ce95, 0x1a225ceb, 0x8b277743, 0x2e66e53d, 0xc448254e, 0x6109b730,

    0x15f9d359, 0xb0b84127, 0x5a968154, 0xffd7132a, 0xb3764986, 0x1637dbf8,

    0xfc191b8b, 0x595889f5, 0x2da8ed9c, 0x88e97fe2, 0x62c7bf91, 0xc7862def,

    0xfb850ac9, 0x5ec498b7, 0xb4ea58c4, 0x11abcaba, 0x655baed3, 0xc01a3cad,

    0x2a34fcde, 0x8f756ea0, 0xc3d4340c, 0x6695a672, 0x8cbb6601, 0x29faf47f,

    0x5d0a9016, 0xf84b0268, 0x1265c21b, 0xb7245065, 0x6a638c57, 0xcf221e29,

    0x250cde5a, 0x804d4c24, 0xf4bd284d, 0x51fcba33, 0xbbd27a40, 0x1e93e83e,

    0x5232b292, 0xf77320ec, 0x1d5de09f, 0xb81c72e1, 0xccec1688, 0x69ad84f6,

    0x83834485, 0x26c2d6fb, 0x1ac1f1dd, 0xbf8063a3, 0x55aea3d0, 0xf0ef31ae,

    0x841f55c7, 0x215ec7b9, 0xcb7007ca, 0x6e3195b4, 0x2290cf18, 0x87d15d66,

    0x6dff9d15, 0xc8be0f6b, 0xbc4e6b02, 0x190ff97c, 0xf321390f, 0x5660ab71,

    0x4c42f79a, 0xe90365e4, 0x032da597, 0xa66c37e9, 0xd29c5380, 0x77ddc1fe,

    0x9df3018d, 0x38b293f3, 0x7413c95f, 0xd1525b21, 0x3b7c9b52, 0x9e3d092c,

    0xeacd6d45, 0x4f8cff3b, 0xa5a23f48, 0x00e3ad36, 0x3ce08a10, 0x99a1186e,

    0x738fd81d, 0xd6ce4a63, 0xa23e2e0a, 0x077fbc74, 0xed517c07, 0x4810ee79,

    0x04b1b4d5, 0xa1f026ab, 0x4bdee6d8, 0xee9f74a6, 0x9a6f10cf, 0x3f2e82b1,

    0xd50042c2, 0x7041d0bc, 0xad060c8e, 0x08479ef0, 0xe2695e83, 0x4728ccfd,

    0x33d8a894, 0x96993aea, 0x7cb7fa99, 0xd9f668e7, 0x9557324b, 0x3016a035,

    0xda386046, 0x7f79f238, 0x0b899651, 0xaec8042f, 0x44e6c45c, 0xe1a75622,

    0xdda47104, 0x78e5e37a, 0x92cb2309, 0x378ab177, 0x437ad51e, 0xe63b4760,

    0x0c158713, 0xa954156d, 0xe5f54fc1, 0x40b4ddbf, 0xaa9a1dcc, 0x0fdb8fb2,

    0x7b2bebdb, 0xde6a79a5, 0x3444b9d6, 0x91052ba8};

static const uint32_t table3_[256] = {

    0x00000000, 0xdd45aab8, 0xbf672381, 0x62228939, 0x7b2231f3, 0xa6679b4b,

    0xc4451272, 0x1900b8ca, 0xf64463e6, 0x2b01c95e, 0x49234067, 0x9466eadf,

    0x8d665215, 0x5023f8ad, 0x32017194, 0xef44db2c, 0xe964b13d, 0x34211b85,

    0x560392bc, 0x8b463804, 0x924680ce, 0x4f032a76, 0x2d21a34f, 0xf06409f7,

    0x1f20d2db, 0xc2657863, 0xa047f15a, 0x7d025be2, 0x6402e328, 0xb9474990,

    0xdb65c0a9, 0x06206a11, 0xd725148b, 0x0a60be33, 0x6842370a, 0xb5079db2,

    0xac072578, 0x71428fc0, 0x136006f9, 0xce25ac41, 0x2161776d, 0xfc24ddd5,

    0x9e0654ec, 0x4343fe54, 0x5a43469e, 0x8706ec26, 0xe524651f, 0x3861cfa7,

    0x3e41a5b6, 0xe3040f0e, 0x81268637, 0x5c632c8f, 0x45639445, 0x98263efd,

    0xfa04b7c4, 0x27411d7c, 0xc805c650, 0x15406ce8, 0x7762e5d1, 0xaa274f69,

    0xb327f7a3, 0x6e625d1b, 0x0c40d422, 0xd1057e9a, 0xaba65fe7, 0x76e3f55f,

    0x14c17c66, 0xc984d6de, 0xd0846e14, 0x0dc1c4ac, 0x6fe34d95, 0xb2a6e72d,

    0x5de23c01, 0x80a796b9, 0xe2851f80, 0x3fc0b538, 0x26c00df2, 0xfb85a74a,

    0x99a72e73, 0x44e284cb, 0x42c2eeda, 0x9f874462, 0xfda5cd5b, 0x20e067e3,

    0x39e0df29, 0xe4a57591, 0x8687fca8, 0x5bc25610, 0xb4868d3c, 0x69c32784,

    0x0be1aebd, 0xd6a40405, 0xcfa4bccf, 0x12e11677, 0x70c39f4e, 0xad8635f6,

    0x7c834b6c, 0xa1c6e1d4, 0xc3e468ed, 0x1ea1c255, 0x07a17a9f, 0xdae4d027,

    0xb8c6591e, 0x6583f3a6, 0x8ac7288a, 0x57828232, 0x35a00b0b, 0xe8e5a1b3,

    0xf1e51979, 0x2ca0b3c1, 0x4e823af8, 0x93c79040, 0x95e7fa51, 0x48a250e9,

    0x2a80d9d0, 0xf7c57368, 0xeec5cba2, 0x3380611a, 0x51a2e823, 0x8ce7429b,

    0x63a399b7, 0xbee6330f, 0xdcc4ba36, 0x0181108e, 0x1881a844, 0xc5c402fc,

    0xa7e68bc5, 0x7aa3217d, 0x52a0c93f, 0x8fe56387, 0xedc7eabe, 0x30824006,

    0x2982f8cc, 0xf4c75274, 0x96e5db4d, 0x4ba071f5, 0xa4e4aad9, 0x79a10061,

    0x1b838958, 0xc6c623e0, 0xdfc69b2a, 0x02833192, 0x60a1b8ab, 0xbde41213,

    0xbbc47802, 0x6681d2ba, 0x04a35b83, 0xd9e6f13b, 0xc0e649f1, 0x1da3e349,

    0x7f816a70, 0xa2c4c0c8, 0x4d801be4, 0x90c5b15c, 0xf2e73865, 0x2fa292dd,

    0x36a22a17, 0xebe780af, 0x89c50996, 0x5480a32e, 0x8585ddb4, 0x58c0770c,

    0x3ae2fe35, 0xe7a7548d, 0xfea7ec47, 0x23e246ff, 0x41c0cfc6, 0x9c85657e,

    0x73c1be52, 0xae8414ea, 0xcca69dd3, 0x11e3376b, 0x08e38fa1, 0xd5a62519,

    0xb784ac20, 0x6ac10698, 0x6ce16c89, 0xb1a4c631, 0xd3864f08, 0x0ec3e5b0,

    0x17c35d7a, 0xca86f7c2, 0xa8a47efb, 0x75e1d443, 0x9aa50f6f, 0x47e0a5d7,

    0x25c22cee, 0xf8878656, 0xe1873e9c, 0x3cc29424, 0x5ee01d1d, 0x83a5b7a5,

    0xf90696d8, 0x24433c60, 0x4661b559, 0x9b241fe1, 0x8224a72b, 0x5f610d93,

    0x3d4384aa, 0xe0062e12, 0x0f42f53e, 0xd2075f86, 0xb025d6bf, 0x6d607c07,

    0x7460c4cd, 0xa9256e75, 0xcb07e74c, 0x16424df4, 0x106227e5, 0xcd278d5d,

    0xaf050464, 0x7240aedc, 0x6b401616, 0xb605bcae, 0xd4273597, 0x09629f2f,

    0xe6264403, 0x3b63eebb, 0x59416782, 0x8404cd3a, 0x9d0475f0, 0x4041df48,

    0x22635671, 0xff26fcc9, 0x2e238253, 0xf36628eb, 0x9144a1d2, 0x4c010b6a,

    0x5501b3a0, 0x88441918, 0xea669021, 0x37233a99, 0xd867e1b5, 0x05224b0d,

    0x6700c234, 0xba45688c, 0xa345d046, 0x7e007afe, 0x1c22f3c7, 0xc167597f,

    0xc747336e, 0x1a0299d6, 0x782010ef, 0xa565ba57, 0xbc65029d, 0x6120a825,

    0x0302211c, 0xde478ba4, 0x31035088, 0xec46fa30, 0x8e647309, 0x5321d9b1,

    0x4a21617b, 0x9764cbc3, 0xf54642fa, 0x2803e842};

// Used to fetch a naturally-aligned 32-bit word in little endian byte-order

static inline uint32_t LE_LOAD32(const uint8_t* p) {

  return DecodeFixed32(reinterpret_cast<const char*>(p));

}

#endif  // !__SSE4_2__

static inline void DefaultCRC32(uint64_t* l, uint8_t const** p) {

#ifndef __SSE4_2__

  uint32_t c = static_cast<uint32_t>(*l ^ LE_LOAD32(*p));

  *p += 4;

  *l = table3_[c & 0xff] ^ table2_[(c >> 8) & 0xff] ^

       table1_[(c >> 16) & 0xff] ^ table0_[c >> 24];

  // DO it twice.

  c = static_cast<uint32_t>(*l ^ LE_LOAD32(*p));

  *p += 4;

  *l = table3_[c & 0xff] ^ table2_[(c >> 8) & 0xff] ^

       table1_[(c >> 16) & 0xff] ^ table0_[c >> 24];

#elif defined(__LP64__) || defined(_WIN64)

  *l = _mm_crc32_u64(*l, DecodeFixed64(reinterpret_cast<const char*>(*p)));

  *p += 8;

#else

  *l = _mm_crc32_u32(static_cast<unsigned int>(*l), LE_LOAD32(*p));

  *p += 4;

  *l = _mm_crc32_u32(static_cast<unsigned int>(*l), LE_LOAD32(*p));

  *p += 4;

#endif

}

template <void (*CRC32)(uint64_t*, uint8_t const**)>

uint32_t ExtendImpl(uint32_t crc, const char* buf, size_t size) {

  const uint8_t* p = reinterpret_cast<const uint8_t*>(buf);

  const uint8_t* e = p + size;

  uint64_t l = crc ^ 0xffffffffu;

// Align n to (1 << m) byte boundary

#define ALIGN(n, m) ((n + ((1 << m) - 1)) & ~((1 << m) - 1))

#define STEP1                  \

  do {                         \

    int c = (l & 0xff) ^ *p++; \

    l = table0_[c] ^ (l >> 8); \

  } while (0)

  // Point x at first 16-byte aligned byte in string.  This might be

  // just past the end of the string.

  const uintptr_t pval = reinterpret_cast<uintptr_t>(p);

  const uint8_t* x = reinterpret_cast<const uint8_t*>(ALIGN(pval, 4));

  if (x <= e) {

    // Process bytes until finished or p is 16-byte aligned

    while (p != x) {

      STEP1;

    }

  }

  // Process bytes 16 at a time

  while ((e - p) >= 16) {

    CRC32(&l, &p);

    CRC32(&l, &p);

  }

  // Process bytes 8 at a time

  while ((e - p) >= 8) {

    CRC32(&l, &p);

  }

  // Process the last few bytes

  while (p != e) {

    STEP1;

  }

#undef STEP1

#undef ALIGN

  return static_cast<uint32_t>(l ^ 0xffffffffu);

}

using Function = uint32_t (*)(uint32_t, const char*, size_t);

#if defined(HAVE_POWER8) && defined(HAS_ALTIVEC)

uint32_t ExtendPPCImpl(uint32_t crc, const char* buf, size_t size) {

  return crc32c_ppc(crc, (const unsigned char*)buf, size);

}

#if __linux__

static int arch_ppc_probe(void) {

  arch_ppc_crc32 = 0;

#if defined(__powerpc64__) && defined(ROCKSDB_AUXV_GETAUXVAL_PRESENT)

  if (getauxval(AT_HWCAP2) & PPC_FEATURE2_VEC_CRYPTO) arch_ppc_crc32 = 1;

#endif /* __powerpc64__ */

  return arch_ppc_crc32;

}

#elif __FreeBSD__

static int arch_ppc_probe(void) {

  unsigned long cpufeatures;

  arch_ppc_crc32 = 0;

#if defined(__powerpc64__)

  elf_aux_info(AT_HWCAP2, &cpufeatures, sizeof(cpufeatures));

  if (cpufeatures & PPC_FEATURE2_HAS_VEC_CRYPTO) arch_ppc_crc32 = 1;

#endif  /* __powerpc64__ */

  return arch_ppc_crc32;

}

#endif  // __linux__

static bool isAltiVec() {

  if (arch_ppc_probe()) {

    return true;

  } else {

    return false;

  }

}

#endif

#if defined(HAVE_ARM64_CRC)

uint32_t ExtendARMImpl(uint32_t crc, const char* buf, size_t size) {

  return crc32c_arm64(crc, (const unsigned char*)buf, size);

}

#endif

std::string IsFastCrc32Supported() {

  bool has_fast_crc = false;

  std::string fast_zero_msg;

  std::string arch;

#ifdef HAVE_POWER8

#ifdef HAS_ALTIVEC

  if (arch_ppc_probe()) {

    has_fast_crc = true;

    arch = "PPC";

  }

#else

  has_fast_crc = false;

  arch = "PPC";

#endif

#elif defined(HAVE_ARM64_CRC)

  if (crc32c_runtime_check()) {

    has_fast_crc = true;

    arch = "Arm64";

    pmull_runtime_flag = crc32c_pmull_runtime_check();

  } else {

    has_fast_crc = false;

    arch = "Arm64";

  }

#else

#ifdef __SSE4_2__

  has_fast_crc = true;

#endif  // __SSE4_2__

  arch = "x86";

#endif

  if (has_fast_crc) {

    fast_zero_msg.append("Supported on " + arch);

  } else {

    fast_zero_msg.append("Not supported on " + arch);

  }

  return fast_zero_msg;

}

/*

 * Copyright 2016 Ferry Toth, Exalon Delft BV, The Netherlands

 *  This software is provided 'as-is', without any express or implied

 * warranty.  In no event will the author be held liable for any damages

 * arising from the use of this software.

 *  Permission is granted to anyone to use this software for any purpose,

 * including commercial applications, and to alter it and redistribute it

 * freely, subject to the following restrictions:

 *  1. The origin of this software must not be misrepresented; you must not

 *   claim that you wrote the original software. If you use this software

 *   in a product, an acknowledgment in the product documentation would be

 *   appreciated but is not required.

 * 2. Altered source versions must be plainly marked as such, and must not be

 *   misrepresented as being the original software.

 * 3. This notice may not be removed or altered from any source distribution.

 *  Ferry Toth

 * ftoth@exalondelft.nl

 *

 * https://github.com/htot/crc32c

 *

 * Modified by Facebook

 *

 * Original intel whitepaper:

 * "Fast CRC Computation for iSCSI Polynomial Using CRC32 Instruction"

 * https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/crc-iscsi-polynomial-crc32-instruction-paper.pdf

 *

 * This version is from the folly library, created by Dave Watson

 * <davejwatson@fb.com>

 *

 */

#if defined(__SSE4_2__) && defined(__PCLMUL__)

#define CRCtriplet(crc, buf, offset)                  \

  crc##0 = _mm_crc32_u64(crc##0, *(buf##0 + offset)); \

  crc##1 = _mm_crc32_u64(crc##1, *(buf##1 + offset)); \

  crc##2 = _mm_crc32_u64(crc##2, *(buf##2 + offset));

#define CRCduplet(crc, buf, offset)                   \

  crc##0 = _mm_crc32_u64(crc##0, *(buf##0 + offset)); \

  crc##1 = _mm_crc32_u64(crc##1, *(buf##1 + offset));

#define CRCsinglet(crc, buf, offset) \

  crc = _mm_crc32_u64(crc, *(uint64_t*)(buf + offset));

// Numbers taken directly from intel whitepaper.

// clang-format off

const uint64_t clmul_constants[] = {

    0x14cd00bd6, 0x105ec76f0, 0x0ba4fc28e, 0x14cd00bd6,

    0x1d82c63da, 0x0f20c0dfe, 0x09e4addf8, 0x0ba4fc28e,

    0x039d3b296, 0x1384aa63a, 0x102f9b8a2, 0x1d82c63da,

    0x14237f5e6, 0x01c291d04, 0x00d3b6092, 0x09e4addf8,

    0x0c96cfdc0, 0x0740eef02, 0x18266e456, 0x039d3b296,

    0x0daece73e, 0x0083a6eec, 0x0ab7aff2a, 0x102f9b8a2,

    0x1248ea574, 0x1c1733996, 0x083348832, 0x14237f5e6,

    0x12c743124, 0x02ad91c30, 0x0b9e02b86, 0x00d3b6092,

    0x018b33a4e, 0x06992cea2, 0x1b331e26a, 0x0c96cfdc0,

    0x17d35ba46, 0x07e908048, 0x1bf2e8b8a, 0x18266e456,

    0x1a3e0968a, 0x11ed1f9d8, 0x0ce7f39f4, 0x0daece73e,

    0x061d82e56, 0x0f1d0f55e, 0x0d270f1a2, 0x0ab7aff2a,

    0x1c3f5f66c, 0x0a87ab8a8, 0x12ed0daac, 0x1248ea574,

    0x065863b64, 0x08462d800, 0x11eef4f8e, 0x083348832,

    0x1ee54f54c, 0x071d111a8, 0x0b3e32c28, 0x12c743124,

    0x0064f7f26, 0x0ffd852c6, 0x0dd7e3b0c, 0x0b9e02b86,

    0x0f285651c, 0x0dcb17aa4, 0x010746f3c, 0x018b33a4e,

    0x1c24afea4, 0x0f37c5aee, 0x0271d9844, 0x1b331e26a,

    0x08e766a0c, 0x06051d5a2, 0x093a5f730, 0x17d35ba46,

    0x06cb08e5c, 0x11d5ca20e, 0x06b749fb2, 0x1bf2e8b8a,

    0x1167f94f2, 0x021f3d99c, 0x0cec3662e, 0x1a3e0968a,

    0x19329634a, 0x08f158014, 0x0e6fc4e6a, 0x0ce7f39f4,

    0x08227bb8a, 0x1a5e82106, 0x0b0cd4768, 0x061d82e56,

    0x13c2b89c4, 0x188815ab2, 0x0d7a4825c, 0x0d270f1a2,

    0x10f5ff2ba, 0x105405f3e, 0x00167d312, 0x1c3f5f66c,

    0x0f6076544, 0x0e9adf796, 0x026f6a60a, 0x12ed0daac,

    0x1a2adb74e, 0x096638b34, 0x19d34af3a, 0x065863b64,

    0x049c3cc9c, 0x1e50585a0, 0x068bce87a, 0x11eef4f8e,

    0x1524fa6c6, 0x19f1c69dc, 0x16cba8aca, 0x1ee54f54c,

    0x042d98888, 0x12913343e, 0x1329d9f7e, 0x0b3e32c28,

    0x1b1c69528, 0x088f25a3a, 0x02178513a, 0x0064f7f26,

    0x0e0ac139e, 0x04e36f0b0, 0x0170076fa, 0x0dd7e3b0c,

    0x141a1a2e2, 0x0bd6f81f8, 0x16ad828b4, 0x0f285651c,

    0x041d17b64, 0x19425cbba, 0x1fae1cc66, 0x010746f3c,

    0x1a75b4b00, 0x18db37e8a, 0x0f872e54c, 0x1c24afea4,

    0x01e41e9fc, 0x04c144932, 0x086d8e4d2, 0x0271d9844,

    0x160f7af7a, 0x052148f02, 0x05bb8f1bc, 0x08e766a0c,

    0x0a90fd27a, 0x0a3c6f37a, 0x0b3af077a, 0x093a5f730,

    0x04984d782, 0x1d22c238e, 0x0ca6ef3ac, 0x06cb08e5c,

    0x0234e0b26, 0x063ded06a, 0x1d88abd4a, 0x06b749fb2,

    0x04597456a, 0x04d56973c, 0x0e9e28eb4, 0x1167f94f2,

    0x07b3ff57a, 0x19385bf2e, 0x0c9c8b782, 0x0cec3662e,

    0x13a9cba9e, 0x0e417f38a, 0x093e106a4, 0x19329634a,

    0x167001a9c, 0x14e727980, 0x1ddffc5d4, 0x0e6fc4e6a,

    0x00df04680, 0x0d104b8fc, 0x02342001e, 0x08227bb8a,

    0x00a2a8d7e, 0x05b397730, 0x168763fa6, 0x0b0cd4768,

    0x1ed5a407a, 0x0e78eb416, 0x0d2c3ed1a, 0x13c2b89c4,

    0x0995a5724, 0x1641378f0, 0x19b1afbc4, 0x0d7a4825c,

    0x109ffedc0, 0x08d96551c, 0x0f2271e60, 0x10f5ff2ba,

    0x00b0bf8ca, 0x00bf80dd2, 0x123888b7a, 0x00167d312,

    0x1e888f7dc, 0x18dcddd1c, 0x002ee03b2, 0x0f6076544,

    0x183e8d8fe, 0x06a45d2b2, 0x133d7a042, 0x026f6a60a,

    0x116b0f50c, 0x1dd3e10e8, 0x05fabe670, 0x1a2adb74e,

    0x130004488, 0x0de87806c, 0x000bcf5f6, 0x19d34af3a,

    0x18f0c7078, 0x014338754, 0x017f27698, 0x049c3cc9c,

    0x058ca5f00, 0x15e3e77ee, 0x1af900c24, 0x068bce87a,

    0x0b5cfca28, 0x0dd07448e, 0x0ded288f8, 0x1524fa6c6,

    0x059f229bc, 0x1d8048348, 0x06d390dec, 0x16cba8aca,

    0x037170390, 0x0a3e3e02c, 0x06353c1cc, 0x042d98888,

    0x0c4584f5c, 0x0d73c7bea, 0x1f16a3418, 0x1329d9f7e,

    0x0531377e2, 0x185137662, 0x1d8d9ca7c, 0x1b1c69528,

    0x0b25b29f2, 0x18a08b5bc, 0x19fb2a8b0, 0x02178513a,

    0x1a08fe6ac, 0x1da758ae0, 0x045cddf4e, 0x0e0ac139e,

    0x1a91647f2, 0x169cf9eb0, 0x1a0f717c4, 0x0170076fa,

};

// Compute the crc32c value for buffer smaller than 8

#ifdef ROCKSDB_UBSAN_RUN

#if defined(__clang__)

__attribute__((__no_sanitize__("alignment")))

#elif defined(__GNUC__)

__attribute__((__no_sanitize_undefined__))

#endif

#endif

inline void align_to_8(

    size_t len,

    uint64_t& crc0, // crc so far, updated on return

    const unsigned char*& next) { // next data pointer, updated on return

  uint32_t crc32bit = static_cast<uint32_t>(crc0);

  if (len & 0x04) {

    crc32bit = _mm_crc32_u32(crc32bit, *(uint32_t*)next);

    next += sizeof(uint32_t);

  }

  if (len & 0x02) {

    crc32bit = _mm_crc32_u16(crc32bit, *(uint16_t*)next);

    next += sizeof(uint16_t);

  }

  if (len & 0x01) {

    crc32bit = _mm_crc32_u8(crc32bit, *(next));

    next++;

  }

  crc0 = crc32bit;

}

//

// CombineCRC performs pclmulqdq multiplication of 2 partial CRC's and a well

// chosen constant and xor's these with the remaining CRC.

//

inline uint64_t CombineCRC(

    size_t block_size,

    uint64_t crc0,

    uint64_t crc1,

    uint64_t crc2,

    const uint64_t* next2) {

  const auto multiplier =

      *(reinterpret_cast<const __m128i*>(clmul_constants) + block_size - 1);

  const auto crc0_xmm = _mm_set_epi64x(0, crc0);

  const auto res0 = _mm_clmulepi64_si128(crc0_xmm, multiplier, 0x00);

  const auto crc1_xmm = _mm_set_epi64x(0, crc1);

  const auto res1 = _mm_clmulepi64_si128(crc1_xmm, multiplier, 0x10);

  const auto res = _mm_xor_si128(res0, res1);

  crc0 = _mm_cvtsi128_si64(res);

  crc0 = crc0 ^ *((uint64_t*)next2 - 1);

  crc2 = _mm_crc32_u64(crc2, crc0);

  return crc2;

}

// Compute CRC-32C using the Intel hardware instruction.

#ifdef ROCKSDB_UBSAN_RUN

#if defined(__clang__)

__attribute__((__no_sanitize__("alignment")))

#elif defined(__GNUC__)

__attribute__((__no_sanitize_undefined__))

#endif

#endif

uint32_t crc32c_3way(uint32_t crc, const char* buf, size_t len) {

  const unsigned char* next = (const unsigned char*)buf;

  uint64_t count;

  uint64_t crc0, crc1, crc2;

  crc0 = crc ^ 0xffffffffu;

  if (len >= 8) {

    // if len > 216 then align and use triplets

    if (len > 216) {

      {

        // Work on the bytes (< 8) before the first 8-byte alignment addr starts

        uint64_t align_bytes = (8 - (uintptr_t)next) & 7;

        len -= align_bytes;

        align_to_8(align_bytes, crc0, next);

      }

      // Now work on the remaining blocks

      count = len / 24; // number of triplets

      len %= 24; // bytes remaining

      uint64_t n = count >> 7; // #blocks = first block + full blocks

      uint64_t block_size = count & 127;

      if (block_size == 0) {

        block_size = 128;

      } else {

        n++;

      }

      // points to the first byte of the next block

      const uint64_t* next0 = (uint64_t*)next + block_size;

      const uint64_t* next1 = next0 + block_size;

      const uint64_t* next2 = next1 + block_size;

      crc1 = crc2 = 0;

      // Use Duff's device, a for() loop inside a switch()

      // statement. This needs to execute at least once, round len

      // down to nearest triplet multiple

      switch (block_size) {

        case 128:

          do {

            // jumps here for a full block of len 128

            CRCtriplet(crc, next, -128);

            FALLTHROUGH_INTENDED;

            case 127:

              // jumps here or below for the first block smaller

              CRCtriplet(crc, next, -127);

              FALLTHROUGH_INTENDED;

            case 126:

              CRCtriplet(crc, next, -126); // than 128

              FALLTHROUGH_INTENDED;

            case 125:

              CRCtriplet(crc, next, -125);

              FALLTHROUGH_INTENDED;

            case 124:

              CRCtriplet(crc, next, -124);

              FALLTHROUGH_INTENDED;

            case 123:

              CRCtriplet(crc, next, -123);

              FALLTHROUGH_INTENDED;

            case 122:

              CRCtriplet(crc, next, -122);

              FALLTHROUGH_INTENDED;

            case 121:

              CRCtriplet(crc, next, -121);

              FALLTHROUGH_INTENDED;

            case 120:

              CRCtriplet(crc, next, -120);

              FALLTHROUGH_INTENDED;

            case 119:

              CRCtriplet(crc, next, -119);

              FALLTHROUGH_INTENDED;

            case 118:

              CRCtriplet(crc, next, -118);

              FALLTHROUGH_INTENDED;

            case 117:

              CRCtriplet(crc, next, -117);

              FALLTHROUGH_INTENDED;

            case 116:

              CRCtriplet(crc, next, -116);

              FALLTHROUGH_INTENDED;

            case 115:

              CRCtriplet(crc, next, -115);

              FALLTHROUGH_INTENDED;

            case 114:

              CRCtriplet(crc, next, -114);

              FALLTHROUGH_INTENDED;

            case 113:

              CRCtriplet(crc, next, -113);

              FALLTHROUGH_INTENDED;

            case 112:

              CRCtriplet(crc, next, -112);

              FALLTHROUGH_INTENDED;

            case 111:

              CRCtriplet(crc, next, -111);

              FALLTHROUGH_INTENDED;

            case 110:

              CRCtriplet(crc, next, -110);

              FALLTHROUGH_INTENDED;

            case 109:

              CRCtriplet(crc, next, -109);

              FALLTHROUGH_INTENDED;

            case 108:

              CRCtriplet(crc, next, -108);

              FALLTHROUGH_INTENDED;

            case 107:

              CRCtriplet(crc, next, -107);

              FALLTHROUGH_INTENDED;

            case 106:

              CRCtriplet(crc, next, -106);

              FALLTHROUGH_INTENDED;

            case 105:

              CRCtriplet(crc, next, -105);

              FALLTHROUGH_INTENDED;

            case 104:

              CRCtriplet(crc, next, -104);

              FALLTHROUGH_INTENDED;

            case 103:

              CRCtriplet(crc, next, -103);

              FALLTHROUGH_INTENDED;

            case 102:

              CRCtriplet(crc, next, -102);

              FALLTHROUGH_INTENDED;

            case 101:

              CRCtriplet(crc, next, -101);

              FALLTHROUGH_INTENDED;

            case 100:

              CRCtriplet(crc, next, -100);

              FALLTHROUGH_INTENDED;

            case 99:

              CRCtriplet(crc, next, -99);

              FALLTHROUGH_INTENDED;

            case 98:

              CRCtriplet(crc, next, -98);

              FALLTHROUGH_INTENDED;

            case 97:

              CRCtriplet(crc, next, -97);

              FALLTHROUGH_INTENDED;

            case 96:

              CRCtriplet(crc, next, -96);

              FALLTHROUGH_INTENDED;

            case 95:

              CRCtriplet(crc, next, -95);

              FALLTHROUGH_INTENDED;

            case 94:

              CRCtriplet(crc, next, -94);

              FALLTHROUGH_INTENDED;

            case 93:

              CRCtriplet(crc, next, -93);

              FALLTHROUGH_INTENDED;

            case 92:

              CRCtriplet(crc, next, -92);

              FALLTHROUGH_INTENDED;

            case 91:

              CRCtriplet(crc, next, -91);

              FALLTHROUGH_INTENDED;

            case 90:

              CRCtriplet(crc, next, -90);

              FALLTHROUGH_INTENDED;

            case 89:

              CRCtriplet(crc, next, -89);

              FALLTHROUGH_INTENDED;

            case 88:

              CRCtriplet(crc, next, -88);

              FALLTHROUGH_INTENDED;

            case 87:

              CRCtriplet(crc, next, -87);

              FALLTHROUGH_INTENDED;

            case 86:

              CRCtriplet(crc, next, -86);

              FALLTHROUGH_INTENDED;

            case 85:

              CRCtriplet(crc, next, -85);

              FALLTHROUGH_INTENDED;

            case 84:

              CRCtriplet(crc, next, -84);

              FALLTHROUGH_INTENDED;

            case 83:

              CRCtriplet(crc, next, -83);

              FALLTHROUGH_INTENDED;

            case 82:

              CRCtriplet(crc, next, -82);

              FALLTHROUGH_INTENDED;

            case 81:

              CRCtriplet(crc, next, -81);

              FALLTHROUGH_INTENDED;

            case 80:

              CRCtriplet(crc, next, -80);

              FALLTHROUGH_INTENDED;

            case 79:

              CRCtriplet(crc, next, -79);

              FALLTHROUGH_INTENDED;

            case 78:

              CRCtriplet(crc, next, -78);

              FALLTHROUGH_INTENDED;

            case 77:

              CRCtriplet(crc, next, -77);

              FALLTHROUGH_INTENDED;

            case 76:

              CRCtriplet(crc, next, -76);

              FALLTHROUGH_INTENDED;

            case 75:

              CRCtriplet(crc, next, -75);

              FALLTHROUGH_INTENDED;

            case 74:

              CRCtriplet(crc, next, -74);

              FALLTHROUGH_INTENDED;

            case 73:

              CRCtriplet(crc, next, -73);

              FALLTHROUGH_INTENDED;

            case 72:

              CRCtriplet(crc, next, -72);

              FALLTHROUGH_INTENDED;

            case 71:

              CRCtriplet(crc, next, -71);

              FALLTHROUGH_INTENDED;

            case 70:

              CRCtriplet(crc, next, -70);

              FALLTHROUGH_INTENDED;

            case 69:

              CRCtriplet(crc, next, -69);

              FALLTHROUGH_INTENDED;

            case 68:

              CRCtriplet(crc, next, -68);

              FALLTHROUGH_INTENDED;

            case 67:

              CRCtriplet(crc, next, -67);

              FALLTHROUGH_INTENDED;

            case 66:

              CRCtriplet(crc, next, -66);

              FALLTHROUGH_INTENDED;

            case 65:

              CRCtriplet(crc, next, -65);

              FALLTHROUGH_INTENDED;

            case 64:

              CRCtriplet(crc, next, -64);

              FALLTHROUGH_INTENDED;

            case 63:

              CRCtriplet(crc, next, -63);

              FALLTHROUGH_INTENDED;

            case 62:

              CRCtriplet(crc, next, -62);

              FALLTHROUGH_INTENDED;

            case 61:

              CRCtriplet(crc, next, -61);

              FALLTHROUGH_INTENDED;

            case 60:

              CRCtriplet(crc, next, -60);

              FALLTHROUGH_INTENDED;

            case 59:

              CRCtriplet(crc, next, -59);

              FALLTHROUGH_INTENDED;

            case 58:

              CRCtriplet(crc, next, -58);

              FALLTHROUGH_INTENDED;

            case 57:

              CRCtriplet(crc, next, -57);

              FALLTHROUGH_INTENDED;

            case 56:

              CRCtriplet(crc, next, -56);

              FALLTHROUGH_INTENDED;

            case 55:

              CRCtriplet(crc, next, -55);

              FALLTHROUGH_INTENDED;

            case 54:

              CRCtriplet(crc, next, -54);

              FALLTHROUGH_INTENDED;

            case 53:

              CRCtriplet(crc, next, -53);

              FALLTHROUGH_INTENDED;

            case 52:

              CRCtriplet(crc, next, -52);

              FALLTHROUGH_INTENDED;

            case 51:

              CRCtriplet(crc, next, -51);

              FALLTHROUGH_INTENDED;

            case 50:

              CRCtriplet(crc, next, -50);

              FALLTHROUGH_INTENDED;

            case 49:

              CRCtriplet(crc, next, -49);

              FALLTHROUGH_INTENDED;

            case 48:

              CRCtriplet(crc, next, -48);

              FALLTHROUGH_INTENDED;

            case 47:

              CRCtriplet(crc, next, -47);

              FALLTHROUGH_INTENDED;

            case 46:

              CRCtriplet(crc, next, -46);

              FALLTHROUGH_INTENDED;

            case 45:

              CRCtriplet(crc, next, -45);

              FALLTHROUGH_INTENDED;

            case 44:

              CRCtriplet(crc, next, -44);

              FALLTHROUGH_INTENDED;

            case 43:

              CRCtriplet(crc, next, -43);

              FALLTHROUGH_INTENDED;

            case 42:

              CRCtriplet(crc, next, -42);

              FALLTHROUGH_INTENDED;

            case 41:

              CRCtriplet(crc, next, -41);

              FALLTHROUGH_INTENDED;

            case 40:

              CRCtriplet(crc, next, -40);

              FALLTHROUGH_INTENDED;

            case 39:

              CRCtriplet(crc, next, -39);

              FALLTHROUGH_INTENDED;

            case 38:

              CRCtriplet(crc, next, -38);

              FALLTHROUGH_INTENDED;

            case 37:

              CRCtriplet(crc, next, -37);

              FALLTHROUGH_INTENDED;

            case 36:

              CRCtriplet(crc, next, -36);

              FALLTHROUGH_INTENDED;

            case 35:

              CRCtriplet(crc, next, -35);

              FALLTHROUGH_INTENDED;

            case 34:

              CRCtriplet(crc, next, -34);

              FALLTHROUGH_INTENDED;

            case 33:

              CRCtriplet(crc, next, -33);

              FALLTHROUGH_INTENDED;

            case 32:

              CRCtriplet(crc, next, -32);

              FALLTHROUGH_INTENDED;

            case 31:

              CRCtriplet(crc, next, -31);

              FALLTHROUGH_INTENDED;

            case 30:

              CRCtriplet(crc, next, -30);

              FALLTHROUGH_INTENDED;

            case 29:

              CRCtriplet(crc, next, -29);

              FALLTHROUGH_INTENDED;

            case 28:

              CRCtriplet(crc, next, -28);

              FALLTHROUGH_INTENDED;

            case 27:

              CRCtriplet(crc, next, -27);

              FALLTHROUGH_INTENDED;

            case 26:

              CRCtriplet(crc, next, -26);

              FALLTHROUGH_INTENDED;

            case 25:

              CRCtriplet(crc, next, -25);

              FALLTHROUGH_INTENDED;

            case 24:

              CRCtriplet(crc, next, -24);

              FALLTHROUGH_INTENDED;

            case 23:

              CRCtriplet(crc, next, -23);

              FALLTHROUGH_INTENDED;

            case 22:

              CRCtriplet(crc, next, -22);

              FALLTHROUGH_INTENDED;

            case 21:

              CRCtriplet(crc, next, -21);

              FALLTHROUGH_INTENDED;

            case 20:

              CRCtriplet(crc, next, -20);

              FALLTHROUGH_INTENDED;

            case 19:

              CRCtriplet(crc, next, -19);

              FALLTHROUGH_INTENDED;

            case 18:

              CRCtriplet(crc, next, -18);

              FALLTHROUGH_INTENDED;

            case 17:

              CRCtriplet(crc, next, -17);

              FALLTHROUGH_INTENDED;

            case 16:

              CRCtriplet(crc, next, -16);

              FALLTHROUGH_INTENDED;

            case 15:

              CRCtriplet(crc, next, -15);

              FALLTHROUGH_INTENDED;

            case 14:

              CRCtriplet(crc, next, -14);

              FALLTHROUGH_INTENDED;

            case 13:

              CRCtriplet(crc, next, -13);

              FALLTHROUGH_INTENDED;

            case 12:

              CRCtriplet(crc, next, -12);

              FALLTHROUGH_INTENDED;

            case 11:

              CRCtriplet(crc, next, -11);

              FALLTHROUGH_INTENDED;

            case 10:

              CRCtriplet(crc, next, -10);

              FALLTHROUGH_INTENDED;

            case 9:

              CRCtriplet(crc, next, -9);

              FALLTHROUGH_INTENDED;

            case 8:

              CRCtriplet(crc, next, -8);

              FALLTHROUGH_INTENDED;

            case 7:

              CRCtriplet(crc, next, -7);

              FALLTHROUGH_INTENDED;

            case 6:

              CRCtriplet(crc, next, -6);

              FALLTHROUGH_INTENDED;

            case 5:

              CRCtriplet(crc, next, -5);

              FALLTHROUGH_INTENDED;

            case 4:

              CRCtriplet(crc, next, -4);

              FALLTHROUGH_INTENDED;

            case 3:

              CRCtriplet(crc, next, -3);

              FALLTHROUGH_INTENDED;

            case 2:

              CRCtriplet(crc, next, -2);

              FALLTHROUGH_INTENDED;

            case 1:

              CRCduplet(crc, next, -1); // the final triplet is actually only 2

              //{ CombineCRC(); }

              crc0 = CombineCRC(block_size, crc0, crc1, crc2, next2);

              if (--n > 0) {

                crc1 = crc2 = 0;

                block_size = 128;

                // points to the first byte of the next block

                next0 = next2 + 128;

                next1 = next0 + 128; // from here on all blocks are 128 long

                next2 = next1 + 128;

              }

              FALLTHROUGH_INTENDED;

            case 0:;

          } while (n > 0);

      }

      next = (const unsigned char*)next2;

    }

    uint64_t count2 = len >> 3; // 216 of less bytes is 27 or less singlets

    len = len & 7;

    next += (count2 * 8);

    switch (count2) {

      case 27:

        CRCsinglet(crc0, next, -27 * 8);

        FALLTHROUGH_INTENDED;

      case 26:

        CRCsinglet(crc0, next, -26 * 8);

        FALLTHROUGH_INTENDED;

      case 25:

        CRCsinglet(crc0, next, -25 * 8);

        FALLTHROUGH_INTENDED;

      case 24:

        CRCsinglet(crc0, next, -24 * 8);

        FALLTHROUGH_INTENDED;

      case 23:

        CRCsinglet(crc0, next, -23 * 8);

        FALLTHROUGH_INTENDED;

      case 22:

        CRCsinglet(crc0, next, -22 * 8);

        FALLTHROUGH_INTENDED;

      case 21:

        CRCsinglet(crc0, next, -21 * 8);

        FALLTHROUGH_INTENDED;

      case 20:

        CRCsinglet(crc0, next, -20 * 8);

        FALLTHROUGH_INTENDED;

      case 19:

        CRCsinglet(crc0, next, -19 * 8);

        FALLTHROUGH_INTENDED;

      case 18:

        CRCsinglet(crc0, next, -18 * 8);

        FALLTHROUGH_INTENDED;

      case 17:

        CRCsinglet(crc0, next, -17 * 8);

        FALLTHROUGH_INTENDED;

      case 16:

        CRCsinglet(crc0, next, -16 * 8);

        FALLTHROUGH_INTENDED;

      case 15:

        CRCsinglet(crc0, next, -15 * 8);