mirror of
https://github.com/uroni/urbackup_backend.git
synced 2025-10-26 11:36:50 +00:00
ad4ab91853
(cherry picked from commit 95274da710d3bbecdc5b88e45743c5fc4aaf4f71) # Conflicts: # Makefile.am_client # Makefile.am_server # UrBackupBackend.sln # cryptoplugin/cryptopp_inc.h # urbackupserver/cmdline_preprocessor.cpp # urbackupserver/dllmain.cpp # urbackupserver/urbackupserver.vcxproj.filters
99 lines
3.2 KiB
C++
99 lines
3.2 KiB
C++
/*
|
|
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.
|
|
Mark Adler
|
|
madler@alumni.caltech.edu
|
|
*/
|
|
|
|
#include <stdlib.h>
|
|
#include <stdint.h>
|
|
|
|
/* CRC-32C (iSCSI) polynomial in reversed bit order. */
|
|
#define POLY 0x82f63b78
|
|
|
|
namespace
|
|
{
|
|
/* Table for a quadword-at-a-time software crc. */
|
|
static uint32_t crc32c_table[8][256];
|
|
|
|
/* Construct table for software CRC-32C calculation. */
|
|
static void crc32c_init_sw(void)
|
|
{
|
|
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;
|
|
}
|
|
}
|
|
}
|
|
|
|
class Crc32cInit
|
|
{
|
|
public:
|
|
Crc32cInit()
|
|
{
|
|
crc32c_init_sw();
|
|
}
|
|
};
|
|
|
|
static Crc32cInit crc32c_init;
|
|
}
|
|
|
|
/* Table-driven software version as a fall-back. This is about 15 times slower
|
|
than using the hardware instructions. This assumes little-endian integers,
|
|
as is the case on Intel processors that the assembler code here is for. */
|
|
uint32_t crc32c_sw(const char *buf, size_t len, uint32_t crci)
|
|
{
|
|
const unsigned char *next = reinterpret_cast<const unsigned char*>(buf);
|
|
uint64_t crc;
|
|
|
|
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;
|
|
} |