stdio.hpp

Go to the documentation of this file.

// SPDX-FileCopyrightText: 2026 Jarosław Pelczar <jarek@jpelczar.com>
//
// SPDX-License-Identifier: BSD-2-Clause
 
#pragma once
 
#include "../microfmt.hpp"
#include <cstdio>
#include <string_view>
 
#if MICROFMT_HAS_POSIX_FD
#include <unistd.h>
#endif
 
namespace microfmt {
 
// ============================================================================
// FILE* Sink Adapter
// ============================================================================
 
// bridges to a C/platform API (FILE*, syslog, android log, raw chunk storage) that takes raw pointers.
RELOCO_BEGIN_UNSAFE_CODE
[[nodiscard]] inline sink file_sink(std::FILE *file) noexcept {
  return sink{file, [](void *ctx, microfmt::string_view sv) noexcept {
                if (ctx != nullptr && !sv.empty()) {
                  RELOCO_BEGIN_UNSAFE_BUFFER_USAGE;
                  std::fwrite(sv.data(), 1, sv.size(), static_cast<std::FILE *>(ctx));
                  RELOCO_END_UNSAFE_BUFFER_USAGE;
                }
              }};
}
RELOCO_END_UNSAFE_CODE
 
[[nodiscard]] inline sink stdout_sink() noexcept { return file_sink(stdout); }
 
[[nodiscard]] inline sink stderr_sink() noexcept { return file_sink(stderr); }
 
// ============================================================================
// POSIX File Descriptor Sink Adapter (write(2))
// ============================================================================
 
#if MICROFMT_HAS_POSIX_FD
// bridges to a C/platform API (FILE*, syslog, android log, raw chunk storage) that takes raw pointers.
RELOCO_BEGIN_UNSAFE_CODE
[[nodiscard]] inline sink fd_sink(int fd) noexcept {
  // Store fd inside the pointer context value without allocation
  return sink{reinterpret_cast<void *>(static_cast<intptr_t>(fd)), [](void *ctx, microfmt::string_view sv) noexcept {
                RELOCO_BEGIN_UNSAFE_BUFFER_USAGE;
 
                const int target_fd = static_cast<int>(reinterpret_cast<intptr_t>(ctx));
                if (target_fd >= 0 && !sv.empty()) {
                  const char *ptr = sv.data();
                  size_t remaining = sv.size();
                  while (remaining > 0) {
                    const ssize_t written = ::write(target_fd, ptr, remaining);
                    if (written <= 0) {
                      break; // Non-blocking full / broken pipe
                    }
                    ptr += written;
                    remaining -= static_cast<size_t>(written);
                  }
                }
 
                RELOCO_END_UNSAFE_BUFFER_USAGE;
              }};
}
RELOCO_END_UNSAFE_CODE
#endif
 
// =============================================================================
// Direct stdout printing
// =============================================================================
 
// Compile-time stdout overloads
template <typename StrProvider, typename... Args>
inline void print(compile_string_holder<StrProvider> fmt, const Args &...args) noexcept {
  auto s = stdout_sink();
  format_to(s, fmt, args...);
}
 
template <typename StrProvider, typename... Args>
inline void println(compile_string_holder<StrProvider> fmt, const Args &...args) noexcept {
  auto s = stdout_sink();
  format_to(s, fmt, args...);
  s.put('\n');
}
 
// Runtime stdout overloads
template <typename... Args> inline void print(microfmt::string_view fmt_str, const Args &...args) noexcept {
  auto s = stdout_sink();
  format_to(s, fmt_str, args...);
}
 
template <typename... Args> inline void println(microfmt::string_view fmt_str, const Args &...args) noexcept {
  auto s = stdout_sink();
  format_to(s, fmt_str, args...);
  s.put('\n');
}
 
// =============================================================================
// Target std::FILE* stream printing
// =============================================================================
 
// Compile-time FILE* overloads
// bridges to a C/platform API (FILE*, syslog, android log, raw chunk storage) that takes raw pointers.
RELOCO_BEGIN_UNSAFE_CODE
template <typename StrProvider, typename... Args>
inline void print(std::FILE *file, compile_string_holder<StrProvider> fmt, const Args &...args) noexcept {
  auto s = file_sink(file);
  format_to(s, fmt, args...);
}
RELOCO_END_UNSAFE_CODE
 
// bridges to a C/platform API (FILE*, syslog, android log, raw chunk storage) that takes raw pointers.
RELOCO_BEGIN_UNSAFE_CODE
template <typename StrProvider, typename... Args>
inline void println(std::FILE *file, compile_string_holder<StrProvider> fmt, const Args &...args) noexcept {
  auto s = file_sink(file);
  format_to(s, fmt, args...);
  s.put('\n');
}
RELOCO_END_UNSAFE_CODE
 
// Runtime FILE* overloads
// bridges to a C/platform API (FILE*, syslog, android log, raw chunk storage) that takes raw pointers.
RELOCO_BEGIN_UNSAFE_CODE
template <typename... Args>
inline void print(std::FILE *file, microfmt::string_view fmt_str, const Args &...args) noexcept {
  auto s = file_sink(file);
  format_to(s, fmt_str, args...);
}
RELOCO_END_UNSAFE_CODE
 
// bridges to a C/platform API (FILE*, syslog, android log, raw chunk storage) that takes raw pointers.
RELOCO_BEGIN_UNSAFE_CODE
template <typename... Args>
inline void println(std::FILE *file, microfmt::string_view fmt_str, const Args &...args) noexcept {
  auto s = file_sink(file);
  format_to(s, fmt_str, args...);
  s.put('\n');
}
RELOCO_END_UNSAFE_CODE
 
// =============================================================================
// Target POSIX FD printing
// =============================================================================
 
#if MICROFMT_HAS_POSIX_FD
// Compile-time FD overloads
template <typename StrProvider, typename... Args>
inline void print(int fd, compile_string_holder<StrProvider> fmt, const Args &...args) noexcept {
  auto s = fd_sink(fd);
  format_to(s, fmt, args...);
}
 
template <typename StrProvider, typename... Args>
inline void println(int fd, compile_string_holder<StrProvider> fmt, const Args &...args) noexcept {
  auto s = fd_sink(fd);
  format_to(s, fmt, args...);
  s.put('\n');
}
 
// Runtime FD overloads
template <typename... Args> inline void print(int fd, microfmt::string_view fmt_str, const Args &...args) noexcept {
  auto s = fd_sink(fd);
  format_to(s, fmt_str, args...);
}
 
template <typename... Args> inline void println(int fd, microfmt::string_view fmt_str, const Args &...args) noexcept {
  auto s = fd_sink(fd);
  format_to(s, fmt_str, args...);
  s.put('\n');
}
#endif
 
// =============================================================================
// Target Sink printing
// =============================================================================
 
// Compile-time Sink overloads
template <typename StrProvider, typename... Args>
inline void print(sink s, compile_string_holder<StrProvider> fmt, const Args &...args) noexcept {
  format_to(s, fmt, args...);
}
 
template <typename StrProvider, typename... Args>
inline void println(sink s, compile_string_holder<StrProvider> fmt, const Args &...args) noexcept {
  format_to(s, fmt, args...);
  s.put('\n');
}
 
// Runtime Sink overloads
template <typename... Args> inline void print(sink s, microfmt::string_view fmt_str, const Args &...args) noexcept {
  format_to(s, fmt_str, args...);
}
 
template <typename... Args> inline void println(sink s, microfmt::string_view fmt_str, const Args &...args) noexcept {
  format_to(s, fmt_str, args...);
  s.put('\n');
}
 
// =============================================================================
// Bare newline helpers
// =============================================================================
 
inline void println(sink s) noexcept { s.put('\n'); }
 
inline void println() noexcept { stdout_sink().put('\n'); }
 
// bridges to a C/platform API (FILE*, syslog, android log, raw chunk storage) that takes raw pointers.
RELOCO_BEGIN_UNSAFE_CODE
inline void println(std::FILE *file) noexcept { file_sink(file).put('\n'); }
RELOCO_END_UNSAFE_CODE
 
#if MICROFMT_HAS_POSIX_FD
inline void println(int fd) noexcept { fd_sink(fd).put('\n'); }
#endif
 
} // namespace microfmt