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#include "guid.h"
#include <library/cpp/yt/exception/exception.h>
#include <util/random/random.h>
#include <util/string/printf.h>
namespace NYT {
////////////////////////////////////////////////////////////////////////////////
namespace {
const ui8 HexDigits[16] = {
0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66
};
} // anonymous namespace
////////////////////////////////////////////////////////////////////////////////
TGuid TGuid::Create()
{
return TGuid(RandomNumber<ui64>(), RandomNumber<ui64>());
}
TGuid TGuid::FromString(TStringBuf str)
{
TGuid guid;
if (!FromString(str, &guid)) {
throw TSimpleException(Sprintf("Error parsing GUID \"%s\"",
std::string(str).c_str()));
}
return guid;
}
bool TGuid::FromString(TStringBuf str, TGuid* result)
{
size_t partId = 3;
ui64 partValue = 0;
bool isEmptyPart = true;
for (size_t i = 0; i != str.size(); ++i) {
const char c = str[i];
if (c == '-') {
if (isEmptyPart || partId == 0) { // x-y--z, -x-y-z or x-y-z-m-...
return false;
}
result->Parts32[partId] = static_cast<ui32>(partValue);
--partId;
partValue = 0;
isEmptyPart = true;
continue;
}
ui32 digit = 0;
if ('0' <= c && c <= '9') {
digit = c - '0';
} else if ('a' <= c && c <= 'f') {
digit = c - 'a' + 10;
} else if ('A' <= c && c <= 'F') {
digit = c - 'A' + 10;
} else {
return false; // non-hex character
}
partValue = partValue * 16 + digit;
isEmptyPart = false;
// overflow check
if (partValue > Max<ui32>()) {
return false;
}
}
if (partId != 0 || isEmptyPart) { // x-y or x-y-z-
return false;
}
result->Parts32[partId] = static_cast<ui32>(partValue);
return true;
}
TGuid TGuid::FromStringHex32(TStringBuf str)
{
TGuid guid;
if (!FromStringHex32(str, &guid)) {
throw TSimpleException(Sprintf("Error parsing Hex32 GUID \"%s\"",
str.data()));
}
return guid;
}
bool TGuid::FromStringHex32(TStringBuf str, TGuid* result)
{
if (str.size() != 32) {
return false;
}
bool ok = true;
int i = 0;
auto parseChar = [&] {
const char c = str[i++];
ui32 digit = 0;
if ('0' <= c && c <= '9') {
digit = c - '0';
} else if ('a' <= c && c <= 'f') {
digit = c - 'a' + 10;
} else if ('A' <= c && c <= 'F') {
digit = c - 'A' + 10;
} else {
ok = false;
}
return digit;
};
for (size_t j = 0; j < 16; ++j) {
result->ReversedParts8[15 - j] = parseChar() * 16 + parseChar();
}
return ok;
}
char* WriteGuidToBuffer(char* ptr, TGuid value)
{
// Each 32-bit component is emitted as lowercase hex with leading zeros
// stripped (so 1..8 digits). We derive the exact digit count from the
// position of the highest set bit and fill the digits back-to-front; this
// avoids the long branch cascade of the naive per-magnitude approach and
// writes exactly as many bytes as the component requires.
auto writeComponent = [&] (ui32 x) {
int digits = x == 0 ? 1 : (35 - __builtin_clz(x)) >> 2;
char* start = ptr;
char* cursor = ptr + digits;
ptr = cursor;
do {
*--cursor = HexDigits[x & 0xf];
x >>= 4;
} while (cursor != start);
};
writeComponent(value.Parts32[3]);
*ptr++ = '-';
writeComponent(value.Parts32[2]);
*ptr++ = '-';
writeComponent(value.Parts32[1]);
*ptr++ = '-';
writeComponent(value.Parts32[0]);
return ptr;
}
////////////////////////////////////////////////////////////////////////////////
TFormattableGuid::TFormattableGuid(TGuid guid)
: End_(WriteGuidToBuffer(Buffer_.data(), guid))
{ }
TStringBuf TFormattableGuid::ToStringBuf() const
{
return {Buffer_.data(), End_};
}
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT
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