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#pragma once
#include <util/system/defaults.h>
#define CRC16INIT 0
#define CRC32INIT 0
#define CRC64INIT ULL(0xFFFFFFFFFFFFFFFF)
// CCITT CRC-16
inline ui16 crc16(const char* buf, size_t buflen, ui32 crcinit = CRC16INIT) {
ui32 crc = 0xFFFF & ((crcinit >> 8) ^ (crcinit << 8));
const char* end = buf + buflen;
extern const ui32* crctab16;
while (buf < end) {
crc = (crc >> 8) ^ crctab16[(crc ^ *buf) & 0xFF];
++buf;
}
return (ui16)(0xFFFF & ((crc >> 8) ^ (crc << 8)));
}
struct IdTR {
Y_FORCE_INLINE static ui8 T(ui8 a) {
return a;
}
};
// CCITT CRC-32
template <class TR>
inline ui32 crc32(const char* buf, size_t buflen, ui32 crcinit = CRC32INIT) {
ui32 crc = crcinit ^ 0xFFFFFFFF;
const char* end = buf + buflen;
extern const ui32* crctab32;
while (buf < end) {
crc = (crc >> 8) ^ crctab32[(crc ^ TR::T((ui8)*buf)) & 0xFF];
++buf;
}
return crc ^ 0xFFFFFFFF;
}
inline ui32 crc32(const char* buf, size_t buflen, ui32 crcinit = CRC32INIT) {
return crc32<IdTR>(buf, buflen, crcinit);
}
inline ui32 crc32(const void* buf, size_t buflen, ui32 crcinit = CRC32INIT) {
return crc32((const char*)buf, buflen, crcinit);
}
// Copyright (C) Sewell Development Corporation, 1994 - 1998.
inline ui64 crc64(const void* buf, size_t buflen, ui64 crcinit = CRC64INIT) {
const unsigned char* ptr = (const unsigned char*)buf;
extern const ui64* crctab64;
while (buflen--) {
crcinit = crctab64[((crcinit >> 56) ^ *ptr++)] ^ (crcinit << 8);
}
return crcinit;
}
namespace NCrcPrivate {
template <unsigned N>
struct TCrcHelper;
#define DEF_CRC_FUNC(t) \
template <> \
struct TCrcHelper<t> { \
static const ui##t Init = CRC##t##INIT; \
static inline ui##t Crc(const void* buf, size_t buflen, ui##t crcinit) { \
return crc##t((const char*)buf, buflen, crcinit); \
} \
};
DEF_CRC_FUNC(16)
DEF_CRC_FUNC(32)
DEF_CRC_FUNC(64)
#undef DEF_CRC_FUNC
}
template <class T>
static inline T Crc(const void* buf, size_t len, T init) {
return (T)NCrcPrivate::TCrcHelper<8 * sizeof(T)>::Crc(buf, len, init);
}
template <class T>
static inline T Crc(const void* buf, size_t len) {
return Crc<T>(buf, len, (T)NCrcPrivate::TCrcHelper<8 * sizeof(T)>::Init);
}
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