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// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
// Copyright (c) 2017 International Business Machines Corp.
// 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).
#define CRC_TABLE
#include <stdint.h>
#include <stdlib.h>
#include <strings.h>
#include "util/crc32c_ppc_constants.h"
#define VMX_ALIGN 16
#define VMX_ALIGN_MASK (VMX_ALIGN - 1)
#ifdef REFLECT
static unsigned int crc32_align(unsigned int crc, unsigned char const *p,
unsigned long len) {
while (len--) crc = crc_table[(crc ^ *p++) & 0xff] ^ (crc >> 8);
return crc;
}
#endif
#ifdef HAVE_POWER8
unsigned int __crc32_vpmsum(unsigned int crc, unsigned char const *p,
unsigned long len);
static uint32_t crc32_vpmsum(uint32_t crc, unsigned char const *data,
unsigned len) {
unsigned int prealign;
unsigned int tail;
#ifdef CRC_XOR
crc ^= 0xffffffff;
#endif
if (len < VMX_ALIGN + VMX_ALIGN_MASK) {
crc = crc32_align(crc, data, (unsigned long)len);
goto out;
}
if ((unsigned long)data & VMX_ALIGN_MASK) {
prealign = VMX_ALIGN - ((unsigned long)data & VMX_ALIGN_MASK);
crc = crc32_align(crc, data, prealign);
len -= prealign;
data += prealign;
}
crc = __crc32_vpmsum(crc, data, (unsigned long)len & ~VMX_ALIGN_MASK);
tail = len & VMX_ALIGN_MASK;
if (tail) {
data += len & ~VMX_ALIGN_MASK;
crc = crc32_align(crc, data, tail);
}
out:
#ifdef CRC_XOR
crc ^= 0xffffffff;
#endif
return crc;
}
/* This wrapper function works around the fact that crc32_vpmsum
* does not gracefully handle the case where the data pointer is NULL. There
* may be room for performance improvement here.
*/
uint32_t crc32c_ppc(uint32_t crc, unsigned char const *data, unsigned len) {
unsigned char *buf2;
if (!data) {
buf2 = (unsigned char *)malloc(len);
bzero(buf2, len);
crc = crc32_vpmsum(crc, buf2, len);
free(buf2);
} else {
crc = crc32_vpmsum(crc, data, (unsigned long)len);
}
return crc;
}
#else /* HAVE_POWER8 */
/* This symbol has to exist on non-ppc architectures (and on legacy
* ppc systems using power7 or below) in order to compile properly
* there, even though it won't be called.
*/
uint32_t crc32c_ppc(uint32_t crc, unsigned char const *data, unsigned len) {
return 0;
}
#endif /* HAVE_POWER8 */
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