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#pragma once
#include "guid.h"
#include <algorithm>
#include <array>
#include <util/generic/strbuf.h>
namespace NYT {
////////////////////////////////////////////////////////////////////////////////
//! A dead-simple string formatter.
/*!
* This formatter is intended to be as simple as possible and async signal safe.
* This is the reason we do not use printf(): it does not meet signal-safety
* requirements.
*/
class TBaseFormatter
{
public:
TBaseFormatter(char* buffer, int length)
: Begin_(buffer)
, Cursor_(buffer)
, End_(buffer + length)
{ }
//! Returns an underlying cursor.
char* GetCursor()
{
return Cursor_;
}
//! Returns an pointer to the underlying buffer.
const char* GetData() const
{
return Begin_;
}
//! Returns the number of bytes written in the buffer.
int GetBytesWritten() const
{
return Cursor_ - Begin_;
}
//! Returns the number of bytes available in the buffer.
int GetBytesRemaining() const
{
return End_ - Cursor_;
}
//! Advances the internal cursor #count symbols forward (assuming the data is already present).
void Advance(int count)
{
Cursor_ += count;
if (Cursor_ > End_) {
Cursor_ = End_;
}
}
//! Drops trailing #count symbols (assuming these are present).
void Revert(int count)
{
Cursor_ -= count;
}
//! Appends the string and updates the internal cursor.
void AppendString(const char* string)
{
while (*string != '\0' && Cursor_ < End_) {
*Cursor_++ = *string++;
}
}
//! Appends the string and updates the internal cursor.
void AppendString(TStringBuf string)
{
size_t position = 0;
while (position < string.length() && Cursor_ < End_) {
*Cursor_++ = string[position++];
}
}
//! Appends a single character and updates the internal cursor.
void AppendChar(char ch)
{
if (Cursor_ < End_) {
*Cursor_++ = ch;
}
}
//! Formats |number| in base |radix| and updates the internal cursor.
void AppendNumber(uintptr_t number, int radix = 10, int width = 0, char ch = ' ')
{
int digits = 0;
if (radix == 16) {
// Optimize output of hex numbers.
uintptr_t reverse = 0;
int length = 0;
do {
reverse <<= 4;
reverse |= number & 0xf;
number >>= 4;
++length;
} while (number > 0);
for (int index = 0; index < length && Cursor_ + digits < End_; ++index) {
unsigned int modulus = reverse & 0xf;
Cursor_[digits] = (modulus < 10 ? '0' + modulus : 'a' + modulus - 10);
++digits;
reverse >>= 4;
}
} else {
while (Cursor_ + digits < End_) {
const int modulus = number % radix;
number /= radix;
Cursor_[digits] = (modulus < 10 ? '0' + modulus : 'a' + modulus - 10);
++digits;
if (number == 0) {
break;
}
}
// Reverse the bytes written.
std::reverse(Cursor_, Cursor_ + digits);
}
if (digits < width) {
auto delta = width - digits;
std::copy(Cursor_, Cursor_ + digits, Cursor_ + delta);
std::fill(Cursor_, Cursor_ + delta, ch);
Cursor_ += width;
} else {
Cursor_ += digits;
}
}
//! Formats |number| as hexadecimal number and updates the internal cursor.
//! Padding will be added in front if needed.
void AppendNumberAsHexWithPadding(uintptr_t number, int width)
{
char* begin = Cursor_;
AppendString("0x");
AppendNumber(number, 16);
// Move to right and add padding in front if needed.
if (Cursor_ < begin + width) {
auto delta = begin + width - Cursor_;
std::copy(begin, Cursor_, begin + delta);
std::fill(begin, begin + delta, ' ');
Cursor_ = begin + width;
}
}
//! Formats |guid| and updates the internal cursor.
void AppendGuid(TGuid guid)
{
if (Y_LIKELY(End_ - Cursor_ >= MaxGuidStringSize)) {
// Fast path.
Cursor_ = WriteGuidToBuffer(Cursor_, guid);
} else {
// Slow path.
std::array<char, MaxGuidStringSize> buffer;
auto* end = WriteGuidToBuffer(buffer.data(), guid);
AppendString(TStringBuf(buffer.data(), end));
}
}
//! Resets the underlying cursor.
void Reset()
{
Cursor_ = Begin_;
}
TStringBuf GetBuffer() const
{
return {Begin_, Cursor_};
}
private:
char* const Begin_;
char* Cursor_;
char* const End_;
};
template <size_t N>
class TRawFormatter
: public TBaseFormatter
{
public:
TRawFormatter()
: TBaseFormatter(Buffer_, N)
{ }
TRawFormatter(char* buffer, int length)
: TBaseFormatter(buffer, length)
{ }
private:
char Buffer_[N];
};
////////////////////////////////////////////////////////////////////////////////
} // namespace NYT
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