223 lines
6.8 KiB
C
223 lines
6.8 KiB
C
/*
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* Copied from the kernel source code, lib/libcrc32c.c.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include "kerncompat.h"
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#include "crc32c.h"
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#include <inttypes.h>
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#include <string.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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u32 __crc32c_le(u32 crc, unsigned char const *data, size_t length);
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static u32 (*crc_function)(u32 crc, unsigned char const *data, size_t length) = __crc32c_le;
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#ifdef __x86_64__
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/*
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* Based on a posting to lkml by Austin Zhang <austin.zhang@intel.com>
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*
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* Using hardware provided CRC32 instruction to accelerate the CRC32 disposal.
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* CRC32C polynomial:0x1EDC6F41(BE)/0x82F63B78(LE)
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* CRC32 is a new instruction in Intel SSE4.2, the reference can be found at:
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* http://www.intel.com/products/processor/manuals/
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* Intel(R) 64 and IA-32 Architectures Software Developer's Manual
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* Volume 2A: Instruction Set Reference, A-M
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*/
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#if __SIZEOF_LONG__ == 8
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#define REX_PRE "0x48, "
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#define SCALE_F 8
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#else
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#define REX_PRE
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#define SCALE_F 4
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#endif
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static int crc32c_probed = 0;
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static int crc32c_intel_available = 0;
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static uint32_t crc32c_intel_le_hw_byte(uint32_t crc, unsigned char const *data,
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unsigned long length)
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{
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while (length--) {
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__asm__ __volatile__(
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".byte 0xf2, 0xf, 0x38, 0xf0, 0xf1"
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:"=S"(crc)
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:"0"(crc), "c"(*data)
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);
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data++;
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}
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return crc;
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}
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/*
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* Steps through buffer one byte at at time, calculates reflected
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* crc using table.
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*/
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static uint32_t crc32c_intel(u32 crc, unsigned char const *data, unsigned long length)
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{
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unsigned int iquotient = length / SCALE_F;
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unsigned int iremainder = length % SCALE_F;
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unsigned long *ptmp = (unsigned long *)data;
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while (iquotient--) {
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__asm__ __volatile__(
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".byte 0xf2, " REX_PRE "0xf, 0x38, 0xf1, 0xf1;"
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:"=S"(crc)
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:"0"(crc), "c"(*ptmp)
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);
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ptmp++;
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}
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if (iremainder)
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crc = crc32c_intel_le_hw_byte(crc, (unsigned char *)ptmp,
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iremainder);
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return crc;
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}
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static void do_cpuid(unsigned int *eax, unsigned int *ebx, unsigned int *ecx,
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unsigned int *edx)
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{
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int id = *eax;
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asm("movl %4, %%eax;"
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"cpuid;"
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"movl %%eax, %0;"
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"movl %%ebx, %1;"
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"movl %%ecx, %2;"
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"movl %%edx, %3;"
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: "=r" (*eax), "=r" (*ebx), "=r" (*ecx), "=r" (*edx)
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: "r" (id)
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: "eax", "ebx", "ecx", "edx");
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}
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static void crc32c_intel_probe(void)
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{
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if (!crc32c_probed) {
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unsigned int eax, ebx, ecx, edx;
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eax = 1;
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do_cpuid(&eax, &ebx, &ecx, &edx);
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crc32c_intel_available = (ecx & (1 << 20)) != 0;
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crc32c_probed = 1;
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}
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}
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void crc32c_optimization_init(void)
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{
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crc32c_intel_probe();
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if (crc32c_intel_available)
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crc_function = crc32c_intel;
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}
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#else
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void crc32c_optimization_init(void)
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{
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}
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#endif /* __x86_64__ */
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/*
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* This is the CRC-32C table
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* Generated with:
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* width = 32 bits
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* poly = 0x1EDC6F41
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* reflect input bytes = true
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* reflect output bytes = true
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*/
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static const u32 crc32c_table[256] = {
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0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
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0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
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0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
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0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
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0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
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0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
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0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
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0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
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0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
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0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
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0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
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0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
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0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
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0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
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0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
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0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
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0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
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0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
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0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
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0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
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0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
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0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
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0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
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0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
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0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
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0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
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0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
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0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
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0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
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0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
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0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
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0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
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0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
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0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
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0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
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0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
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0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
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0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
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0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
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0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
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0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
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0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
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0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
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0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
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0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
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0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
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0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
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0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
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0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
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0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
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0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
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0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
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0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
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0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
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0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
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0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
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0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
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0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
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0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
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0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
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0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
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0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
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0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
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0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
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};
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/*
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* Steps through buffer one byte at at time, calculates reflected
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* crc using table.
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*/
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u32 __crc32c_le(u32 crc, unsigned char const *data, size_t length)
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{
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while (length--)
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crc =
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crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
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return crc;
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}
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u32 crc32c_le(u32 crc, unsigned char const *data, size_t length)
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{
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return crc_function(crc, data, length);
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}
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