crc32c.cc File Reference

#include <cstdio>
#include <cstdlib>
#include <cstdint>
#include <unistd.h>
#include <pthread.h>

Go to the source code of this file.

Macros
#define	POLY   0x82f63b78

Functions
uint32_t	crc32c (uint32_t crc, const unsigned char *buf, size_t len)
bool	crc32c_hw_test ()
static void	crc32c_init_sw (void)
static uint32_t	crc32c_sw (uint32_t crci, const unsigned char *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

#define POLY   0x82f63b78

Definition at line 49 of file crc32c.cc.

Referenced by crc32c_init_sw(), and crc32c_sw().

Function Documentation

uint32_t crc32c	(	uint32_t	crc,
		const unsigned char *	buf,
		size_t	len
	)

Definition at line 340 of file crc32c.cc.

References crc32c_sw().

Referenced by FedRawDataInputSource::getNextEvent(), FRDStreamSource::setRunAndEventInfo(), and RawEventOutputModuleForBU< Consumer >::write().

{
#if defined(__x86_64__)
    int sse42;

    SSE42(sse42);
    return sse42 ? crc32c_hw(crc, buf, len) : crc32c_sw(crc, buf, len);
#else
    return crc32c_sw(crc, buf, len);
#endif
}

bool crc32c_hw_test

(

)

Definition at line 354 of file crc32c.cc.

Referenced by FedRawDataInputSource::FedRawDataInputSource().

{

#if defined(__x86_64__)
  int sse42;

  SSE42(sse42);
  return sse42;
#else
  return 0;
#endif
}

static void crc32c_init_sw ( void  )

static

Definition at line 56 of file crc32c.cc.

References crc32c_table, gen::k, gen::n, and POLY.

Referenced by crc32c_sw().

{
    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;
        }
    }
}

static uint32_t crc32c_sw ( uint32_t  crci, const unsigned char *  buf, size_t  len  )

static

Definition at line 84 of file crc32c.cc.

References crc32c_init_sw(), crc32c_once_sw, crc32c_table, end, gen::n, GetRecoTauVFromDQM_MC_cff::next, POLY, and square().

Referenced by crc32c().

{
    const unsigned char *next = buf;
    uint64_t crc;

    pthread_once(&crc32c_once_sw, crc32c_init_sw);
    crc = crci ^ 0xffffffff;
    while (len && ((const 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;
}

Variable Documentation

pthread_once_t crc32c_once_sw = PTHREAD_ONCE_INIT

static

Definition at line 52 of file crc32c.cc.

Referenced by crc32c_sw().

uint32_t crc32c_table[8][256]

static

Definition at line 53 of file crc32c.cc.

Referenced by crc32c_init_sw(), and crc32c_sw().