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#pragma once
#include <util/system/compiler.h>
#include <util/system/defaults.h>
#include <util/system/unaligned_mem.h>
namespace NKikimr {
constexpr size_t MAX_PACKED32_SIZE = 5;
constexpr size_t MAX_PACKED64_SIZE = 9;
Y_FORCE_INLINE size_t GetPack32Length(ui32 value) {
if (value < 0x80) {
return 1;
}
else if (value < 0x4000) {
return 2;
}
else if (value < 0x200000) {
return 3;
}
else {
return 5;
}
}
[[nodiscard]] Y_FORCE_INLINE size_t Pack32(ui32 value, char buffer[MAX_PACKED32_SIZE]) {
if (value < 0x80) {
buffer[0] = value << 0x1;
return 1;
}
else if (value < 0x4000) {
WriteUnaligned<ui16>(((ui16*)(buffer)), ui16((value << 2) | 0x1));
return 2;
}
else if (value < 0x200000) {
WriteUnaligned<ui32>(((ui32*)(buffer)), ui32((value << 3) | 0x3));
return 3;
}
else {
buffer[0] = 0x7;
WriteUnaligned<ui32>((ui32*)(buffer + 1), ui32(value));
return 5;
}
}
[[nodiscard]] Y_FORCE_INLINE size_t Unpack32(const char* buffer, size_t length, ui32& value) {
if (Y_UNLIKELY(!length)) {
return 0;
}
size_t count;
if (0 == (buffer[0] & 0x1)) {
count = 1;
value = ((const ui8*)buffer)[0] >> 1;
} else if (0 == (buffer[0] & 0x2)) {
count = 2;
if (Y_UNLIKELY(length < count)) {
return 0;
}
value = ReadUnaligned<ui16>((const ui16*)buffer) >> 2;
} else if (0 == (buffer[0] & 0x4)) {
count = 3;
if (Y_UNLIKELY(length < count)) {
return 0;
}
value = (ReadUnaligned<ui16>((const ui16*)buffer) >> 3) | (((const ui8*)buffer)[2] << 13);
} else {
count = 5;
if (Y_UNLIKELY(length < count || buffer[0] != 0x7)) {
return 0;
}
value = ReadUnaligned<ui32>((const ui32*)(buffer + 1));
}
return count;
}
Y_FORCE_INLINE size_t GetPack64Length(ui64 value) {
if (value < 0x80) {
return 1;
}
else if (value < 0x4000) {
return 2;
}
else if (value < 0x200000) {
return 3;
}
else if (value < 0x10000000) {
return 4;
}
else if (value < 0x800000000) {
return 5;
}
else if (value < 0x40000000000) {
return 6;
}
else if (value < 0x2000000000000) {
return 7;
}
else {
return 9;
}
}
[[nodiscard]] Y_FORCE_INLINE size_t Pack64(ui64 value, char buffer[MAX_PACKED64_SIZE]) {
if (value < 0x80) {
buffer[0] = value << 1;
return 1;
}
else if (value < 0x4000) {
WriteUnaligned<ui16>((ui16*)(buffer), ui16((value << 2) | 0x1));
return 2;
}
else if (value < 0x200000) {
WriteUnaligned<ui32>((ui32*)(buffer), ui32((value << 3) | 0x3));
return 3;
}
else if (value < 0x10000000) {
WriteUnaligned<ui32>((ui32*)(buffer), ui32((value << 4) | 0x7));
return 4;
}
else if (value < 0x800000000) {
WriteUnaligned<ui64>((ui64*)(buffer), ui64((value << 5) | 0xF));
return 5;
}
else if (value < 0x40000000000) {
WriteUnaligned<ui64>((ui64*)(buffer), ui64((value << 6) | 0x1F));
return 6;
}
else if (value < 0x2000000000000) {
WriteUnaligned<ui64>((ui64*)(buffer), ui64((value << 7) | 0x3F));
return 7;
}
else {
buffer[0] = 0x7F;
WriteUnaligned<ui64>((ui64*)(buffer + 1), value);
return 9;
}
}
[[nodiscard]] Y_FORCE_INLINE size_t Unpack64(const char* buffer, size_t length, ui64& value) {
if (Y_UNLIKELY(!length)) {
return 0;
}
size_t count;
if (0 == (buffer[0] & 0x1)) {
count = 1;
value = ((const ui8*)buffer)[0] >> 1;
} else if (0 == (buffer[0] & 0x2)) {
count = 2;
if (Y_UNLIKELY(length < count)) {
return 0;
}
value = ReadUnaligned<ui16>((const ui16*)buffer) >> 2;
} else if (0 == (buffer[0] & 0x4)) {
count = 3;
if (Y_UNLIKELY(length < count)) {
return 0;
}
value = (ui64(ReadUnaligned<ui16>((const ui16*)buffer)) >> 3) | (ui64(((const ui8*)buffer)[2]) << 13);
} else if (0 == (buffer[0] & 0x8)) {
count = 4;
if (Y_UNLIKELY(length < count)) {
return 0;
}
value = ReadUnaligned<ui32>((const ui32*)buffer) >> 4;
} else if (0 == (buffer[0] & 0x10)) {
count = 5;
if (Y_UNLIKELY(length < count)) {
return 0;
}
value = (ui64(ReadUnaligned<ui32>((const ui32*)buffer)) >> 5) | (ui64(((const ui8*)buffer)[4]) << 27);
} else if (0 == (buffer[0] & 0x20)) {
count = 6;
if (Y_UNLIKELY(length < count)) {
return 0;
}
value = (ui64(ReadUnaligned<ui32>((const ui32*)buffer)) >> 6) | (ui64(ReadUnaligned<ui16>(((const ui16*)buffer) + 2)) << 26);
} else if (0 == (buffer[0] & 0x40)) {
count = 7;
if (Y_UNLIKELY(length < count)) {
return 0;
}
value = (ui64(ReadUnaligned<ui32>((const ui32*)buffer)) >> 7) | (ui64(ReadUnaligned<ui16>(((const ui16*)buffer) + 2)) << 25) | (ui64(((const ui8*)buffer)[6]) << 41);
} else {
count = 9;
if (Y_UNLIKELY(length < count || buffer[0] != 0x7F)) {
return 0;
}
value = ReadUnaligned<ui64>((const ui64*)(buffer + 1));
}
return count;
}
} // NKikimr
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