crc32c.cxx File Reference

#include "crc32c.h"
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <unistd.h>
#include <pthread.h>

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Macros
#define	POLY   0x82f63b78
#define	LONG   8192
#define	LONGx1   "8192"
#define	LONGx2   "16384"
#define	SHORT   256
#define	SHORTx1   "256"
#define	SHORTx2   "512"

Functions
static void	crc32c_init_sw (void)
uint32_t	crc32c_sw (uint32_t crci, const void *buf, size_t len)
static uint32_t	gf2_matrix_times (uint32_t *mat, uint32_t vec)
static void	gf2_matrix_square (uint32_t *square, uint32_t *mat)
static uint32_t	crc32c_shift (uint32_t zeros[][256], uint32_t crc)
uint32_t	crc32c (uint32_t crc, const void *buf, size_t len)

Variables
static pthread_once_t	crc32c_once_sw = PTHREAD_ONCE_INIT
static uint32_t	crc32c_table [8][256]

Macro Definition Documentation

LONG

#define LONG   8192

Definition at line 230 of file crc32c.cxx.

LONGx1

#define LONGx1   "8192"

Definition at line 231 of file crc32c.cxx.

LONGx2

#define LONGx2   "16384"

Definition at line 232 of file crc32c.cxx.

POLY

#define POLY   0x82f63b78

Definition at line 64 of file crc32c.cxx.

SHORT

#define SHORT   256

Definition at line 233 of file crc32c.cxx.

SHORTx1

#define SHORTx1   "256"

Definition at line 234 of file crc32c.cxx.

SHORTx2

#define SHORTx2   "512"

Definition at line 235 of file crc32c.cxx.

Function Documentation

crc32c()

uint32_t crc32c	(	uint32_t	crc,
		const void *	buf,
		size_t	len
	)

Definition at line 391 of file crc32c.cxx.

{
#ifdef HAVE_HWCRC32C
    int sse42;
 
    SSE42(sse42);
    return sse42 ? crc32c_hw(crc, buf, len) : crc32c_sw(crc, buf, len);
#elif defined(__ARM_FEATURE_CRC32)
   return crc32c_arm_hw(crc, buf, len);
#else
#warning Hardware accelerated CRC32C is not available.
    return crc32c_sw(crc, buf, len);
#endif // HAVE_HWCRC32C
}

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crc32c_init_sw()

static void crc32c_init_sw ( void  )

static

Definition at line 71 of file crc32c.cxx.

{
    uint32_t n, crc, k;
 
    for (n = 0; n < 256; n++) {
        crc = n;
        crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
        crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
        crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
        crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
        crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
        crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
        crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
        crc = crc & 1 ? (crc >> 1) ^ POLY : crc >> 1;
        crc32c_table[0][n] = crc;
    }
    for (n = 0; n < 256; n++) {
        crc = crc32c_table[0][n];
        for (k = 1; k < 8; k++) {
            crc = crc32c_table[0][crc & 0xff] ^ (crc >> 8);
            crc32c_table[k][n] = crc;
        }
    }
}

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crc32c_shift()

static uint32_t crc32c_shift ( uint32_t  zeros[][256], uint32_t  crc  )

inlinestatic

Definition at line 221 of file crc32c.cxx.

{
    return zeros[0][crc & 0xff] ^ zeros[1][(crc >> 8) & 0xff] ^
           zeros[2][(crc >> 16) & 0xff] ^ zeros[3][crc >> 24];
}

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crc32c_sw()

uint32_t crc32c_sw	(	uint32_t	crci,
		const void *	buf,
		size_t	len
	)

Definition at line 99 of file crc32c.cxx.

{
   const unsigned char *next = (const unsigned char*)buf;
    uint64_t crc;
 
    pthread_once(&crc32c_once_sw, crc32c_init_sw);
    crc = crci ^ 0xffffffff;
    while (len && ((uintptr_t)next & 7) != 0) {
        crc = crc32c_table[0][(crc ^ *next++) & 0xff] ^ (crc >> 8);
        len--;
    }
    while (len >= 8) {
        crc ^= *(uint64_t *)next;
        crc = crc32c_table[7][crc & 0xff] ^
              crc32c_table[6][(crc >> 8) & 0xff] ^
              crc32c_table[5][(crc >> 16) & 0xff] ^
              crc32c_table[4][(crc >> 24) & 0xff] ^
              crc32c_table[3][(crc >> 32) & 0xff] ^
              crc32c_table[2][(crc >> 40) & 0xff] ^
              crc32c_table[1][(crc >> 48) & 0xff] ^
              crc32c_table[0][crc >> 56];
        next += 8;
        len -= 8;
    }
    while (len) {
        crc = crc32c_table[0][(crc ^ *next++) & 0xff] ^ (crc >> 8);
        len--;
    }
    return (uint32_t)crc ^ 0xffffffff;
}

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gf2_matrix_square()

static void gf2_matrix_square ( uint32_t *  square, uint32_t *  mat  )

inlinestatic

Definition at line 150 of file crc32c.cxx.

{
    int n;
 
    for (n = 0; n < 32; n++)
        square[n] = gf2_matrix_times(mat, mat[n]);
}

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gf2_matrix_times()

static uint32_t gf2_matrix_times ( uint32_t *  mat, uint32_t  vec  )

inlinestatic

Definition at line 134 of file crc32c.cxx.

{
    uint32_t sum;
 
    sum = 0;
    while (vec) {
        if (vec & 1)
            sum ^= *mat;
        vec >>= 1;
        mat++;
    }
    return sum;
}

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Variable Documentation

crc32c_once_sw

pthread_once_t crc32c_once_sw = PTHREAD_ONCE_INIT

static

Definition at line 67 of file crc32c.cxx.

crc32c_table

uint32_t crc32c_table[8][256]

static

Definition at line 68 of file crc32c.cxx.