// SPDX-License-Identifier: MIT
// Copyright 2010, SIL International, All rights reserved.

#pragma once

#include <cstdlib>
#include "graphite2/Types.h"

#ifdef GRAPHITE2_CUSTOM_HEADER
#include GRAPHITE2_CUSTOM_HEADER
#endif

namespace graphite2 {

typedef uint8_t        byte;

#ifdef GRAPHITE2_TELEMETRY
struct telemetry
{
    class category;

    static size_t   * _category;
    static void set_category(size_t & t) throw()    { _category = &t; }
    static void stop() throw()                      { _category = 0; }
    static void count_bytes(size_t n) throw()       { if (_category) *_category += n; }

    size_t  misc,
            silf,
            glyph,
            code,
            states,
            starts,
            transitions;

    telemetry() : misc(0), silf(0), glyph(0), code(0), states(0), starts(0), transitions(0) {}
};

class telemetry::category
{
    size_t * _prev;
public:
    category(size_t & t) : _prev(_category) { _category = &t; }
    ~category() { _category = _prev; }
};

#else
struct telemetry  {};
#endif

// Checked multiplaction to catch overflow or underflow when allocating memory
#if defined(__has_builtin)
  #if __has_builtin(__builtin_mul_overflow)
    #define HAVE_BUILTIN_OVERFLOW
  #endif
#elif defined(__GNUC__) && (__GNUC__ >= 5) && !defined(__INTEL_COMPILER)
  #define HAVE_BUILTIN_OVERFLOW
#endif
#if defined(__has_include)
  #if __has_include(<intsafe.h>) && !defined(__CYGWIN__)
    #define HAVE_INTSAFE_H
  #endif
#elif defined(_WIN32)
  #define HAVE_INTSAFE_H
#endif

// Need to import intsafe into the top level namespace
#if defined(HAVE_INTSAFE_H)
} // namespace graphite2

#include <intsafe.h>

namespace graphite2 {
#endif

#if defined(HAVE_BUILTIN_OVERFLOW)
inline
bool checked_mul(const size_t a, const size_t b, size_t & t) {
    return __builtin_mul_overflow(a, b, &t);
}
#elif defined(HAVE_INTSAFE_H)
inline
bool checked_mul(const size_t a, const size_t b, size_t & t) {
    return SizeTMult(a, b, &t) == INTSAFE_E_ARITHMETIC_OVERFLOW;
}
#else
inline
bool checked_mul(const size_t a, const size_t b, size_t & t) {
  t = a*b;
  return (((a | b) & (~size_t(0) << (sizeof(size_t) << 2))) && (t / a != b));
}
#endif

// typesafe wrapper around malloc for simple types
// use free(pointer) to deallocate

template <typename T> T * gralloc(size_t n)
{
    size_t total;
    if (checked_mul(n, sizeof(T), total))
      return 0;
#ifdef GRAPHITE2_TELEMETRY
    telemetry::count_bytes(total);
#endif
    return static_cast<T*>(malloc(total));
}

template <typename T> T * grzeroalloc(size_t n)
{
#ifdef GRAPHITE2_TELEMETRY
    telemetry::count_bytes(sizeof(T) * n);
#endif
    return static_cast<T*>(calloc(n, sizeof(T)));
}

template <typename T>
inline T min(const T a, const T b)
{
    return a < b ? a : b;
}

template <typename T>
inline T max(const T a, const T b)
{
    return a > b ? a : b;
}

} // namespace graphite2

#define CLASS_NEW_DELETE \
    void * operator new   (size_t size){ return gralloc<byte>(size);} \
    void * operator new   (size_t, void * p) throw() { return p; } \
    void * operator new[] (size_t size) {return gralloc<byte>(size);} \
    void * operator new[] (size_t, void * p) throw() { return p; } \
    void operator delete   (void * p) throw() { free(p);} \
    void operator delete   (void *, void *) throw() {} \
    void operator delete[] (void * p)throw() { free(p); } \
    void operator delete[] (void *, void *) throw() {}

#if defined(__GNUC__)  || defined(__clang__)
#define GR_MAYBE_UNUSED __attribute__((unused))
#else
#define GR_MAYBE_UNUSED
#endif

#ifndef __has_cpp_attribute
#  define __has_cpp_attribute(x) 0
#endif

#if __has_cpp_attribute(clang::fallthrough)
#  define GR_FALLTHROUGH [[clang::fallthrough]]
#elif __has_cpp_attribute(gnu::fallthrough)
#  define GR_FALLTHROUGH [[gnu::fallthrough]]
#elif defined(_MSC_VER)
   /*
    * MSVC's __fallthrough annotations are checked by /analyze (Code Analysis):
    * https://msdn.microsoft.com/en-us/library/ms235402%28VS.80%29.aspx
    */
    #include <sal.h>
    #define GR_FALLTHROUGH __fallthrough
#elif __GNUC__ >= 7
    #define GR_FALLTHROUGH __attribute__ ((fallthrough))
#else
    #define GR_FALLTHROUGH /* fallthrough */
#endif


// TODO: Remove these specialisations once full refactor of SlotBuffer and iterators is done.
#include <iterator>
struct gr_slot;

template<> gr_slot * std::prev<gr_slot*>(gr_slot *, ptrdiff_t);
template<> gr_slot const * std::prev<gr_slot const*>(gr_slot const *, ptrdiff_t);
template<> gr_slot * std::next<gr_slot*>(gr_slot *, ptrdiff_t);
template<> gr_slot const * std::next<gr_slot const*>(gr_slot const *, ptrdiff_t);

#ifdef _MSC_VER
#pragma warning(disable: 4800)
#pragma warning(disable: 4355)
#endif