llvm/llvm/include/llvm/Support/Format.h

//===- Format.h - Efficient printf-style formatting for streams -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the format() function, which can be used with other
// LLVM subsystems to provide printf-style formatting.  This gives all the power
// and risk of printf.  This can be used like this (with raw_ostreams as an
// example):
//
//    OS << "mynumber: " << format("%4.5f", 1234.412) << '\n';
//
// Or if you prefer:
//
//  OS << format("mynumber: %4.5f\n", 1234.412);
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_SUPPORT_FORMAT_H
#define LLVM_SUPPORT_FORMAT_H

#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/DataTypes.h"
#include <cassert>
#include <cstdio>
#include <optional>
#include <tuple>
#include <utility>

namespace llvm {

/// This is a helper class used for handling formatted output.  It is the
/// abstract base class of a templated derived class.
class format_object_base { … };

/// These are templated helper classes used by the format function that
/// capture the object to be formatted and the format string. When actually
/// printed, this synthesizes the string into a temporary buffer provided and
/// returns whether or not it is big enough.

// Helper to validate that format() parameters are scalars or pointers.
template <typename... Args> struct validate_format_parameters;
validate_format_parameters<Arg, Args...>;
template <> struct validate_format_parameters<> { … };

template <typename... Ts>
class format_object final : public format_object_base { … };

/// These are helper functions used to produce formatted output.  They use
/// template type deduction to construct the appropriate instance of the
/// format_object class to simplify their construction.
///
/// This is typically used like:
/// \code
///   OS << format("%0.4f", myfloat) << '\n';
/// \endcode

template <typename... Ts>
inline format_object<Ts...> format(const char *Fmt, const Ts &... Vals) { … }

/// This is a helper class for left_justify, right_justify, and center_justify.
class FormattedString { … };

/// left_justify - append spaces after string so total output is
/// \p Width characters.  If \p Str is larger that \p Width, full string
/// is written with no padding.
inline FormattedString left_justify(StringRef Str, unsigned Width) { … }

/// right_justify - add spaces before string so total output is
/// \p Width characters.  If \p Str is larger that \p Width, full string
/// is written with no padding.
inline FormattedString right_justify(StringRef Str, unsigned Width) { … }

/// center_justify - add spaces before and after string so total output is
/// \p Width characters.  If \p Str is larger that \p Width, full string
/// is written with no padding.
inline FormattedString center_justify(StringRef Str, unsigned Width) { … }

/// This is a helper class used for format_hex() and format_decimal().
class FormattedNumber { … };

/// format_hex - Output \p N as a fixed width hexadecimal. If number will not
/// fit in width, full number is still printed.  Examples:
///   OS << format_hex(255, 4)              => 0xff
///   OS << format_hex(255, 4, true)        => 0xFF
///   OS << format_hex(255, 6)              => 0x00ff
///   OS << format_hex(255, 2)              => 0xff
inline FormattedNumber format_hex(uint64_t N, unsigned Width,
                                  bool Upper = false) { … }

/// format_hex_no_prefix - Output \p N as a fixed width hexadecimal. Does not
/// prepend '0x' to the outputted string.  If number will not fit in width,
/// full number is still printed.  Examples:
///   OS << format_hex_no_prefix(255, 2)              => ff
///   OS << format_hex_no_prefix(255, 2, true)        => FF
///   OS << format_hex_no_prefix(255, 4)              => 00ff
///   OS << format_hex_no_prefix(255, 1)              => ff
inline FormattedNumber format_hex_no_prefix(uint64_t N, unsigned Width,
                                            bool Upper = false) { … }

/// format_decimal - Output \p N as a right justified, fixed-width decimal. If
/// number will not fit in width, full number is still printed.  Examples:
///   OS << format_decimal(0, 5)     => "    0"
///   OS << format_decimal(255, 5)   => "  255"
///   OS << format_decimal(-1, 3)    => " -1"
///   OS << format_decimal(12345, 3) => "12345"
inline FormattedNumber format_decimal(int64_t N, unsigned Width) { … }

class FormattedBytes { … };

inline FormattedBytes
format_bytes(ArrayRef<uint8_t> Bytes,
             std::optional<uint64_t> FirstByteOffset = std::nullopt,
             uint32_t NumPerLine = 16, uint8_t ByteGroupSize = 4,
             uint32_t IndentLevel = 0, bool Upper = false) { … }

inline FormattedBytes
format_bytes_with_ascii(ArrayRef<uint8_t> Bytes,
                        std::optional<uint64_t> FirstByteOffset = std::nullopt,
                        uint32_t NumPerLine = 16, uint8_t ByteGroupSize = 4,
                        uint32_t IndentLevel = 0, bool Upper = false) { … }

} // end namespace llvm

#endif