os.hpp

#pragma once
 
#include <cstdlib>
#include <cstdio>
#include <string>
#include <thread>
#include <new>
 
#define TF_OS_LINUX 0
#define TF_OS_DRAGONFLY 0
#define TF_OS_FREEBSD 0
#define TF_OS_NETBSD 0
#define TF_OS_OPENBSD 0
#define TF_OS_DARWIN 0
#define TF_OS_WINDOWS 0
#define TF_OS_CNK 0
#define TF_OS_HURD 0
#define TF_OS_SOLARIS 0
#define TF_OS_UNIX 0
 
#ifdef _WIN32
#undef TF_OS_WINDOWS
#define TF_OS_WINDOWS 1
#endif
 
#ifdef __CYGWIN__
#undef TF_OS_WINDOWS
#define TF_OS_WINDOWS 1
#endif
 
#if (defined __APPLE__ && defined __MACH__)
#undef TF_OS_DARWIN
#define TF_OS_DARWIN 1
#endif
 
// in some ppc64 linux installations, only the second condition is met
#if (defined __linux)
#undef TF_OS_LINUX
#define TF_OS_LINUX 1
#elif (defined __linux__)
#undef TF_OS_LINUX
#define TF_OS_LINUX 1
#else
#endif
 
#if (defined __DragonFly__)
#undef TF_OS_DRAGONFLY
#define TF_OS_DRAGONFLY 1
#endif
 
#if (defined __FreeBSD__)
#undef TF_OS_FREEBSD
#define TF_OS_FREEBSD 1
#endif
 
#if (defined __NetBSD__)
#undef TF_OS_NETBSD
#define TF_OS_NETBSD 1
#endif
 
#if (defined __OpenBSD__)
#undef TF_OS_OPENBSD
#define TF_OS_OPENBSD 1
#endif
 
#if (defined __bgq__)
#undef TF_OS_CNK
#define TF_OS_CNK 1
#endif
 
#if (defined __GNU__)
#undef TF_OS_HURD
#define TF_OS_HURD 1
#endif
 
#if (defined __sun)
#undef TF_OS_SOLARIS
#define TF_OS_SOLARIS 1
#endif
 
#if (1 !=                                                                  \
     TF_OS_LINUX + TF_OS_DRAGONFLY + TF_OS_FREEBSD + TF_OS_NETBSD +        \
     TF_OS_OPENBSD + TF_OS_DARWIN + TF_OS_WINDOWS + TF_OS_HURD +           \
     TF_OS_SOLARIS)
#define TF_OS_UNKNOWN 1
#endif
 
#if TF_OS_LINUX || TF_OS_DRAGONFLY || TF_OS_FREEBSD || TF_OS_NETBSD ||     \
    TF_OS_OPENBSD || TF_OS_DARWIN || TF_OS_HURD || TF_OS_SOLARIS
#undef TF_OS_UNIX
#define TF_OS_UNIX 1
#endif
 
// ------------------------------------------------------------------------------------------------
// Number of bits used by the OS for user-space virtual addresses
// Used as the default PtrBits for TaggedHead64 to leave the remaining
// high bits free for the ABA version counter.
// ------------------------------------------------------------------------------------------------
//
// No standard C++ mechanism exposes the VA width; we derive it from
// architecture-specific predefined macros. Override by defining
// TF_POINTER_BITS before including this header if your environment
// differs (e.g. x86-64 with LA57 5-level paging uses 57 bits).
 
#if defined(TF_POINTER_BITS)
  // user-defined override — accepted as-is
 
#elif defined(__x86_64__) || defined(_M_X64) || defined(_M_AMD64)
  // 4-level paging: 48 bits. If your kernel enables LA57 (5-level paging,
  // 57-bit VA), compile with -DTF_POINTER_BITS=57. Note that only 7 bits
  // remain for the ABA tag in that case; TaggedHead128 is a better choice.
  #define TF_POINTER_BITS 48
 
#elif defined(__aarch64__) || defined(_M_ARM64)
  #define TF_POINTER_BITS 48   // ARMv8 48-bit VA (TTBR0 range)
 
#elif defined(__riscv) && __riscv_xlen == 64
  #define TF_POINTER_BITS 48   // SV48 worst case; SV39 gives 25 free bits
 
#else
  #define TF_POINTER_BITS (sizeof(void*) * CHAR_BIT)  // 32-bit or unknown
#endif
 
 
// ------------------------------------------------------------------------------------------------
// Cache line size detection.
//
// Underestimating causes false sharing (hurts performance).
// Overestimating wastes memory.
// 64B is correct for the vast majority of modern server/desktop CPUs.
// ------------------------------------------------------------------------------------------------
 
#if defined(__i386__) || defined(__x86_64__) || \
    defined(_M_IX86)  || defined(_M_AMD64)
  // All modern x86/x86_64 CPUs (Intel, AMD) since Pentium 4.
  #define TF_CACHELINE_SIZE 64
 
#elif defined(__aarch64__) || defined(__arm64__) || defined(_M_ARM64)
  // 64-bit ARM: Apple Silicon (M1/M2/M3), AWS Graviton, Qualcomm Oryon, etc.
  #define TF_CACHELINE_SIZE 64
 
#elif defined(__arm__) || defined(_M_ARM)
  // 32-bit ARM — cache line size depends on the ARM architecture revision.
  #if defined(__ARM_ARCH_5T__)  || \
      defined(__ARM_ARCH_5TE__) || \
      defined(__ARM_ARCH_6__)
    #define TF_CACHELINE_SIZE 32
  #else
    // ARMv7-A (Cortex-A5/A7/A8/A9/A15) and later 32-bit ARM.
    #define TF_CACHELINE_SIZE 64
  #endif
 
#elif defined(__powerpc64__) || defined(__ppc64__)
  // IBM POWER7/8/9/10 and PowerPC64 (e.g., original Xbox 360-era G5).
  #define TF_CACHELINE_SIZE 128
 
#elif defined(__powerpc__) || defined(__ppc__)
  // Older 32-bit PowerPC (G3/G4 era embedded systems).
  #define TF_CACHELINE_SIZE 32
 
#elif defined(__s390x__) || defined(__zarch__)
  // IBM Z (z13 and later). Unusually large at 256B.
  #define TF_CACHELINE_SIZE 256
 
#elif defined(__riscv)
  // RISC-V: SiFive U74, Alibaba T-Head, etc.
  #define TF_CACHELINE_SIZE 64
 
#elif defined(__mips__) || defined(__mips64)
  // MIPS32/MIPS64 (embedded and networking SoCs).
  #define TF_CACHELINE_SIZE 64
 
#elif defined(__sparc__) || defined(__sparc64__)
  // Oracle/Fujitsu SPARC.
  #define TF_CACHELINE_SIZE 64
 
#elif defined(__loongarch64)
  // LoongArch (Loongson 3A5000 and later).
  #define TF_CACHELINE_SIZE 64
 
#elif defined(__alpha__)
  // DEC/Compaq Alpha.
  #define TF_CACHELINE_SIZE 64
 
#endif
 
#ifndef TF_CACHELINE_SIZE
  // Conservative fallback. If we land here, the architecture is unknown.
  // 64B is correct for virtually all modern CPUs. Overestimating wastes
  // a small amount of space; underestimating causes false sharing.
  #define TF_CACHELINE_SIZE 64
#endif
 
namespace tf {

template <typename T>
class CachelineAligned {
  public:
  alignas (TF_CACHELINE_SIZE) T data;

  T& get() { return data; }
  
  const T& get() const { return data; }
};

inline std::string get_env(const std::string& str) {
#ifdef _MSC_VER
  char *ptr = nullptr;
  size_t len = 0;
 
  if(_dupenv_s(&ptr, &len, str.c_str()) == 0 && ptr != nullptr) {
    std::string res(ptr, len);
    std::free(ptr);
    return res;
  }
  return "";
 
#else
  auto ptr = std::getenv(str.c_str());
  return ptr ? ptr : "";
#endif
}

inline bool has_env(const std::string& str) {
#ifdef _MSC_VER
  char *ptr = nullptr;
  size_t len = 0;
 
  if(_dupenv_s(&ptr, &len, str.c_str()) == 0 && ptr != nullptr) {
    std::string res(ptr, len);
    std::free(ptr);
    return true;
  }
  return false;
 
#else
  auto ptr = std::getenv(str.c_str());
  return ptr ? true : false;
#endif
}
 
 
}  // end of namespace tf -----------------------------------------------------