/* ----------------------------------------------------------------------------

Copyright (c) 2018-2021, Microsoft Research, Daan Leijen

This is free software; you can redistribute it and/or modify it under the

terms of the MIT license. A copy of the license can be found in the file

"LICENSE" at the root of this distribution.

-----------------------------------------------------------------------------*/

#include "mimalloc.h"

#include "mimalloc/internal.h"

#include "mimalloc/atomic.h"

#include "mimalloc/prim.h"

#include <string.h> // memset

#if defined(_MSC_VER) && (_MSC_VER < 1920)

#pragma warning(disable:4204)  // non-constant aggregate initializer

#endif

/* -----------------------------------------------------------

  Statistics operations

----------------------------------------------------------- */

static bool mi_is_in_main(void* stat) {

  return ((uint8_t*)stat >= (uint8_t*)&_mi_stats_main

         && (uint8_t*)stat < ((uint8_t*)&_mi_stats_main + sizeof(mi_stats_t)));

}

static void mi_stat_update(mi_stat_count_t* stat, int64_t amount) {

  if (amount == 0) return;

  if mi_unlikely(mi_is_in_main(stat))

  {

    // add atomically (for abandoned pages)

    int64_t current = mi_atomic_addi64_relaxed(&stat->current, amount);

    // if (stat == &_mi_stats_main.committed) { mi_assert_internal(current + amount >= 0); };

    mi_atomic_maxi64_relaxed(&stat->peak, current + amount);

    if (amount > 0) {

      mi_atomic_addi64_relaxed(&stat->total,amount);

    }

  }

  else {

    // add thread local

    stat->current += amount;

    if (stat->current > stat->peak) { stat->peak = stat->current; }

    if (amount > 0) { stat->total += amount; }

  }

}

void _mi_stat_counter_increase(mi_stat_counter_t* stat, size_t amount) {

  if (mi_is_in_main(stat)) {

    mi_atomic_addi64_relaxed( &stat->total, (int64_t)amount );

  }

  else {

    stat->total += amount;

  }

}

void _mi_stat_increase(mi_stat_count_t* stat, size_t amount) {

  mi_stat_update(stat, (int64_t)amount);

}

void _mi_stat_decrease(mi_stat_count_t* stat, size_t amount) {

  mi_stat_update(stat, -((int64_t)amount));

}

static void mi_stat_adjust(mi_stat_count_t* stat, int64_t amount) {

  if (amount == 0) return;

  if mi_unlikely(mi_is_in_main(stat))

  {

    // adjust atomically

    mi_atomic_addi64_relaxed(&stat->current, amount);

    mi_atomic_addi64_relaxed(&stat->total,amount);

  }

  else {

    // adjust local

    stat->current += amount;

    stat->total += amount;

  }

}

void _mi_stat_adjust_decrease(mi_stat_count_t* stat, size_t amount) {

  mi_stat_adjust(stat, -((int64_t)amount));

}

// must be thread safe as it is called from stats_merge

static void mi_stat_count_add_mt(mi_stat_count_t* stat, const mi_stat_count_t* src) {

  if (stat==src) return;

  mi_atomic_void_addi64_relaxed(&stat->total, &src->total);

  const int64_t prev_current = mi_atomic_addi64_relaxed(&stat->current, src->current);

  // Global current plus thread peak approximates new global peak

  // note: peak scores do really not work across threads.

  // we used to just add them together but that often overestimates in practice.

  // similarly, max does not seem to work well. The current approach

  // by Artem Kharytoniuk (@artem-lunarg) seems to work better, see PR#1112

  // for a longer description.

  mi_atomic_maxi64_relaxed(&stat->peak, prev_current + src->peak);

}

static void mi_stat_counter_add_mt(mi_stat_counter_t* stat, const mi_stat_counter_t* src) {

  if (stat==src) return;

  mi_atomic_void_addi64_relaxed(&stat->total, &src->total);

}

#define MI_STAT_COUNT(stat)    mi_stat_count_add_mt(&stats->stat, &src->stat);

#define MI_STAT_COUNTER(stat)  mi_stat_counter_add_mt(&stats->stat, &src->stat);

// must be thread safe as it is called from stats_merge

static void mi_stats_add(mi_stats_t* stats, const mi_stats_t* src) {

  if (stats==src) return;

  // copy all fields

  MI_STAT_FIELDS()

  #if MI_STAT>1

  for (size_t i = 0; i <= MI_BIN_HUGE; i++) {

    mi_stat_count_add_mt(&stats->malloc_bins[i], &src->malloc_bins[i]);

  }

  #endif

  for (size_t i = 0; i <= MI_BIN_HUGE; i++) {

    mi_stat_count_add_mt(&stats->page_bins[i], &src->page_bins[i]);

  }

}

#undef MI_STAT_COUNT

#undef MI_STAT_COUNTER

/* -----------------------------------------------------------

  Display statistics

----------------------------------------------------------- */

// unit > 0 : size in binary bytes

// unit == 0: count as decimal

// unit < 0 : count in binary

static void mi_printf_amount(int64_t n, int64_t unit, mi_output_fun* out, void* arg, bool limitwidth) {

  char buf[32]; buf[0] = 0;

  int  len = 32;

  const char* suffix = (unit <= 0 ? " " : "B");

  const int64_t base = (unit == 0 ? 1000 : 1024);

  if (unit>0) n *= unit;

  const int64_t pos = (n < 0 ? -n : n);

  if (pos < base) {

    if (n!=1 || suffix[0] != 'B') {  // skip printing 1 B for the unit column

      _mi_snprintf(buf, len, "%lld   %-3s", (long long)n, (n==0 ? "" : suffix));

    }

  }

  else {

    int64_t divider = base;

    const char* magnitude = "K";

    if (pos >= divider*base) { divider *= base; magnitude = "M"; }

    if (pos >= divider*base) { divider *= base; magnitude = "G"; }

    const int64_t tens = (n / (divider/10));

    const long whole = (long)(tens/10);

    const long frac1 = (long)(tens%10);

    char unitdesc[8];

    _mi_snprintf(unitdesc, 8, "%s%s%s", magnitude, (base==1024 ? "i" : ""), suffix);

    _mi_snprintf(buf, len, "%ld.%ld %-3s", whole, (frac1 < 0 ? -frac1 : frac1), unitdesc);

  }

  if (limitwidth) {

    _mi_fprintf(out, arg, "%12s", buf);

  }

  else {

    _mi_fprintf(out, arg, "%s", buf);

  }

}

static void mi_print_amount(int64_t n, int64_t unit, mi_output_fun* out, void* arg) {

  mi_printf_amount(n,unit,out,arg,true);

}

static void mi_print_count(int64_t n, int64_t unit, mi_output_fun* out, void* arg) {

  if (unit==1) _mi_fprintf(out, arg, "%12s"," ");

          else mi_print_amount(n,0,out,arg);

}

static void mi_stat_print_ex(const mi_stat_count_t* stat, const char* msg, int64_t unit, mi_output_fun* out, void* arg, const char* notok ) {

  _mi_fprintf(out, arg,"%10s:", msg);

  if (unit != 0) {

    if (unit > 0) {

      mi_print_amount(stat->peak, unit, out, arg);

      mi_print_amount(stat->total, unit, out, arg);

      // mi_print_amount(stat->freed, unit, out, arg);

      mi_print_amount(stat->current, unit, out, arg);

      mi_print_amount(unit, 1, out, arg);

      mi_print_count(stat->total, unit, out, arg);

    }

    else {

      mi_print_amount(stat->peak, -1, out, arg);

      mi_print_amount(stat->total, -1, out, arg);

      // mi_print_amount(stat->freed, -1, out, arg);

      mi_print_amount(stat->current, -1, out, arg);

      if (unit == -1) {

        _mi_fprintf(out, arg, "%24s", "");

      }

      else {

        mi_print_amount(-unit, 1, out, arg);

        mi_print_count((stat->total / -unit), 0, out, arg);

      }

    }

    if (stat->current != 0) {

      _mi_fprintf(out, arg, "  ");

      _mi_fprintf(out, arg, "%s", (notok == NULL ? "not all freed" : notok));

      _mi_fprintf(out, arg, "\n");

    }

    else {

      _mi_fprintf(out, arg, "  ok\n");

    }

  }

  else {

    mi_print_amount(stat->peak, 0, out, arg);

    mi_print_amount(stat->total, 0, out, arg);

    mi_print_amount(stat->current, 0, out, arg);

    _mi_fprintf(out, arg, "\n");

  }

}

static void mi_stat_print(const mi_stat_count_t* stat, const char* msg, int64_t unit, mi_output_fun* out, void* arg) {

  mi_stat_print_ex(stat, msg, unit, out, arg, NULL);

}

#if MI_STAT>1

static void mi_stat_total_print(const mi_stat_count_t* stat, const char* msg, int64_t unit, mi_output_fun* out, void* arg) {

  _mi_fprintf(out, arg, "%10s:", msg);

  _mi_fprintf(out, arg, "%12s", " ");  // no peak

  mi_print_amount(stat->total, unit, out, arg);

  _mi_fprintf(out, arg, "\n");

}

#endif

static void mi_stat_counter_print(const mi_stat_counter_t* stat, const char* msg, mi_output_fun* out, void* arg ) {

  _mi_fprintf(out, arg, "%10s:", msg);

  mi_print_amount(stat->total, 0, out, arg);

  _mi_fprintf(out, arg, "\n");

}

static void mi_stat_counter_print_size(const mi_stat_counter_t* stat, const char* msg, mi_output_fun* out, void* arg ) {

  _mi_fprintf(out, arg, "%10s:", msg);

  mi_print_amount(stat->total, 1, out, arg);

  _mi_fprintf(out, arg, "\n");

}

static void mi_stat_average_print(int64_t count, int64_t total, const char* msg, mi_output_fun* out, void* arg) {

  const int64_t avg_tens = (count == 0 ? 0 : (total*10 / count));

  const int64_t avg_whole = avg_tens/10;

  const int64_t avg_frac1 = avg_tens%10;

  _mi_fprintf(out, arg, "%10s: %5lld.%lld avg\n", msg, avg_whole, avg_frac1);

}

static void mi_print_header(mi_output_fun* out, void* arg ) {

  _mi_fprintf(out, arg, "%10s: %11s %11s %11s %11s %11s\n", "heap stats", "peak   ", "total   ", "current   ", "block   ", "total#   ");

}

#if MI_STAT>1

static void mi_stats_print_bins(const mi_stat_count_t* bins, size_t max, const char* fmt, mi_output_fun* out, void* arg) {

  bool found = false;

  char buf[64];

  for (size_t i = 0; i <= max; i++) {

    if (bins[i].total > 0) {

      found = true;

      int64_t unit = _mi_bin_size((uint8_t)i);

      _mi_snprintf(buf, 64, "%s %3lu", fmt, (long)i);

      mi_stat_print(&bins[i], buf, unit, out, arg);

    }

  }

  if (found) {

    _mi_fprintf(out, arg, "\n");

    mi_print_header(out, arg);

  }

}

#endif

//------------------------------------------------------------

// Use an output wrapper for line-buffered output

// (which is nice when using loggers etc.)

//------------------------------------------------------------

typedef struct buffered_s {

  mi_output_fun* out;   // original output function

  void*          arg;   // and state

  char*          buf;   // local buffer of at least size `count+1`

  size_t         used;  // currently used chars `used <= count`

  size_t         count; // total chars available for output

} buffered_t;

static void mi_buffered_flush(buffered_t* buf) {

  buf->buf[buf->used] = 0;

  _mi_fputs(buf->out, buf->arg, NULL, buf->buf);

  buf->used = 0;

}

static void mi_cdecl mi_buffered_out(const char* msg, void* arg) {

  buffered_t* buf = (buffered_t*)arg;

  if (msg==NULL || buf==NULL) return;

  for (const char* src = msg; *src != 0; src++) {

    char c = *src;

    if (buf->used >= buf->count) mi_buffered_flush(buf);

    mi_assert_internal(buf->used < buf->count);

    buf->buf[buf->used++] = c;

    if (c == '\n') mi_buffered_flush(buf);

  }

}

//------------------------------------------------------------

// Print statistics

//------------------------------------------------------------

static void _mi_stats_print(mi_stats_t* stats, mi_output_fun* out0, void* arg0) mi_attr_noexcept {

  // wrap the output function to be line buffered

  char buf[256];

  buffered_t buffer = { out0, arg0, NULL, 0, 255 };

  buffer.buf = buf;

  mi_output_fun* out = &mi_buffered_out;

  void* arg = &buffer;

  // and print using that

  mi_print_header(out,arg);

  #if MI_STAT>1

  mi_stats_print_bins(stats->malloc_bins, MI_BIN_HUGE, "bin",out,arg);

  #endif

  #if MI_STAT

  mi_stat_print(&stats->malloc_normal, "binned", (stats->malloc_normal_count.total == 0 ? -1 : 1), out, arg);

  mi_stat_print(&stats->malloc_huge, "huge", (stats->malloc_huge_count.total == 0 ? -1 : 1), out, arg);

  mi_stat_count_t total = { 0,0,0 };

  mi_stat_count_add_mt(&total, &stats->malloc_normal);

  // mi_stat_count_add(&total, &stats->malloc_large);

  mi_stat_count_add_mt(&total, &stats->malloc_huge);

  mi_stat_print_ex(&total, "total", 1, out, arg, "");

  #endif

  #if MI_STAT>1

  mi_stat_total_print(&stats->malloc_requested, "malloc req", 1, out, arg);

  _mi_fprintf(out, arg, "\n");

  #endif

  mi_stat_print_ex(&stats->reserved, "reserved", 1, out, arg, "");

  mi_stat_print_ex(&stats->committed, "committed", 1, out, arg, "");

  mi_stat_counter_print_size(&stats->reset, "reset", out, arg );

  mi_stat_counter_print_size(&stats->purged, "purged", out, arg );

  mi_stat_print_ex(&stats->page_committed, "touched", 1, out, arg, "");

  mi_stat_print(&stats->segments, "segments", 0, out, arg);

  mi_stat_print(&stats->segments_abandoned, "-abandoned", 0, out, arg);

  mi_stat_print(&stats->segments_cache, "-cached", 0, out, arg);

  mi_stat_print(&stats->pages, "pages", 0, out, arg);

  mi_stat_print(&stats->pages_abandoned, "-abandoned", 0, out, arg);

  mi_stat_counter_print(&stats->pages_extended, "-extended", out, arg);

  mi_stat_counter_print(&stats->pages_retire, "-retire", out, arg);

  mi_stat_counter_print(&stats->arena_count, "arenas", out, arg);

  // mi_stat_counter_print(&stats->arena_crossover_count, "-crossover", out, arg);

  mi_stat_counter_print(&stats->arena_rollback_count, "-rollback", out, arg);

  mi_stat_counter_print(&stats->mmap_calls, "mmaps", out, arg);

  mi_stat_counter_print(&stats->commit_calls, "commits", out, arg);

  mi_stat_counter_print(&stats->reset_calls, "resets", out, arg);

  mi_stat_counter_print(&stats->purge_calls, "purges", out, arg);

  mi_stat_counter_print(&stats->malloc_guarded_count, "guarded", out, arg);

  mi_stat_print(&stats->threads, "threads", 0, out, arg);

  mi_stat_average_print(stats->page_searches_count.total, stats->page_searches.total, "searches", out, arg);

  _mi_fprintf(out, arg, "%10s: %5i\n", "numa nodes", _mi_os_numa_node_count());

  size_t elapsed;

  size_t user_time;

  size_t sys_time;

  size_t current_rss;

  size_t peak_rss;

  size_t current_commit;

  size_t peak_commit;

  size_t page_faults;

  mi_process_info(&elapsed, &user_time, &sys_time, &current_rss, &peak_rss, &current_commit, &peak_commit, &page_faults);

  _mi_fprintf(out, arg, "%10s: %5zu.%03zu s\n", "elapsed", elapsed/1000, elapsed%1000);

  _mi_fprintf(out, arg, "%10s: user: %zu.%03zu s, system: %zu.%03zu s, faults: %zu, peak rss: ", "process",

              user_time/1000, user_time%1000, sys_time/1000, sys_time%1000, page_faults );

  mi_printf_amount((int64_t)peak_rss, 1, out, arg, false);

  if (peak_commit > 0) {

    _mi_fprintf(out, arg, ", peak commit: ");

    mi_printf_amount((int64_t)peak_commit, 1, out, arg, false);

  }

  _mi_fprintf(out, arg, "\n");

}

static mi_msecs_t mi_process_start; // = 0

static mi_stats_t* mi_stats_get_default(void) {

  mi_heap_t* heap = mi_heap_get_default();

  return &heap->tld->stats;

}

static void mi_stats_merge_from(mi_stats_t* stats) {

  if (stats != &_mi_stats_main) {

    mi_stats_add(&_mi_stats_main, stats);

    memset(stats, 0, sizeof(mi_stats_t));

  }

}

void mi_stats_reset(void) mi_attr_noexcept {

  mi_stats_t* stats = mi_stats_get_default();

  if (stats != &_mi_stats_main) { memset(stats, 0, sizeof(mi_stats_t)); }

  memset(&_mi_stats_main, 0, sizeof(mi_stats_t));

  if (mi_process_start == 0) { mi_process_start = _mi_clock_start(); };

}

void mi_stats_merge(void) mi_attr_noexcept {

  mi_stats_merge_from( mi_stats_get_default() );

}

void _mi_stats_merge_thread(mi_tld_t* tld) {

  mi_stats_merge_from( &tld->stats );

}

void _mi_stats_done(mi_stats_t* stats) {  // called from `mi_thread_done`

  mi_stats_merge_from(stats);

}

void mi_stats_print_out(mi_output_fun* out, void* arg) mi_attr_noexcept {

  mi_stats_merge_from(mi_stats_get_default());

  _mi_stats_print(&_mi_stats_main, out, arg);

}

void mi_stats_print(void* out) mi_attr_noexcept {

  // for compatibility there is an `out` parameter (which can be `stdout` or `stderr`)

  mi_stats_print_out((mi_output_fun*)out, NULL);

}

void mi_thread_stats_print_out(mi_output_fun* out, void* arg) mi_attr_noexcept {

  _mi_stats_print(mi_stats_get_default(), out, arg);

}

// ----------------------------------------------------------------

// Basic timer for convenience; use milli-seconds to avoid doubles

// ----------------------------------------------------------------

static mi_msecs_t mi_clock_diff;

mi_msecs_t _mi_clock_now(void) {

  return _mi_prim_clock_now();

}

mi_msecs_t _mi_clock_start(void) {

  if (mi_clock_diff == 0.0) {

    mi_msecs_t t0 = _mi_clock_now();

    mi_clock_diff = _mi_clock_now() - t0;

  }

  return _mi_clock_now();

}

mi_msecs_t _mi_clock_end(mi_msecs_t start) {

  mi_msecs_t end = _mi_clock_now();

  return (end - start - mi_clock_diff);

}

// --------------------------------------------------------

// Basic process statistics

// --------------------------------------------------------

mi_decl_export void mi_process_info(size_t* elapsed_msecs, size_t* user_msecs, size_t* system_msecs, size_t* current_rss, size_t* peak_rss, size_t* current_commit, size_t* peak_commit, size_t* page_faults) mi_attr_noexcept

{

  mi_process_info_t pinfo;

  _mi_memzero_var(pinfo);

  pinfo.elapsed        = _mi_clock_end(mi_process_start);

  pinfo.current_commit = (size_t)(mi_atomic_loadi64_relaxed((_Atomic(int64_t)*)&_mi_stats_main.committed.current));

  pinfo.peak_commit    = (size_t)(mi_atomic_loadi64_relaxed((_Atomic(int64_t)*)&_mi_stats_main.committed.peak));

  pinfo.current_rss    = pinfo.current_commit;

  pinfo.peak_rss       = pinfo.peak_commit;

  pinfo.utime          = 0;

  pinfo.stime          = 0;

  pinfo.page_faults    = 0;

  _mi_prim_process_info(&pinfo);

  if (elapsed_msecs!=NULL)  *elapsed_msecs  = (pinfo.elapsed < 0 ? 0 : (pinfo.elapsed < (mi_msecs_t)PTRDIFF_MAX ? (size_t)pinfo.elapsed : PTRDIFF_MAX));

  if (user_msecs!=NULL)     *user_msecs     = (pinfo.utime < 0 ? 0 : (pinfo.utime < (mi_msecs_t)PTRDIFF_MAX ? (size_t)pinfo.utime : PTRDIFF_MAX));

  if (system_msecs!=NULL)   *system_msecs   = (pinfo.stime < 0 ? 0 : (pinfo.stime < (mi_msecs_t)PTRDIFF_MAX ? (size_t)pinfo.stime : PTRDIFF_MAX));

  if (current_rss!=NULL)    *current_rss    = pinfo.current_rss;

  if (peak_rss!=NULL)       *peak_rss       = pinfo.peak_rss;

  if (current_commit!=NULL) *current_commit = pinfo.current_commit;

  if (peak_commit!=NULL)    *peak_commit    = pinfo.peak_commit;

  if (page_faults!=NULL)    *page_faults    = pinfo.page_faults;

}

// --------------------------------------------------------

// Return statistics

// --------------------------------------------------------

bool mi_stats_get(mi_stats_t* stats) mi_attr_noexcept {

  if (stats == NULL || stats->size != sizeof(mi_stats_t) || stats->version != MI_STAT_VERSION) return false;

  _mi_memzero(stats,stats->size);

  _mi_memcpy(stats, &_mi_stats_main, sizeof(mi_stats_t));

  return true;

}

// --------------------------------------------------------

// Statics in json format

// --------------------------------------------------------

typedef struct mi_heap_buf_s {

  char*   buf;

  size_t  size;

  size_t  used;

  bool    can_realloc;

} mi_heap_buf_t;

static bool mi_heap_buf_expand(mi_heap_buf_t* hbuf) {

  if (hbuf==NULL) return false;

  if (hbuf->buf != NULL && hbuf->size>0) {

    hbuf->buf[hbuf->size-1] = 0;

  }

  if (hbuf->size > SIZE_MAX/2 || !hbuf->can_realloc) return false;

  const size_t newsize = (hbuf->size == 0 ? mi_good_size(12*MI_KiB) : 2*hbuf->size);

  char* const  newbuf  = (char*)mi_rezalloc(hbuf->buf, newsize);

  if (newbuf == NULL) return false;

  hbuf->buf = newbuf;

  hbuf->size = newsize;

  return true;

}

static void mi_heap_buf_print(mi_heap_buf_t* hbuf, const char* msg) {

  if (msg==NULL || hbuf==NULL) return;

  if (hbuf->used + 1 >= hbuf->size && !hbuf->can_realloc) return;

  for (const char* src = msg; *src != 0; src++) {

    char c = *src;

    if (hbuf->used + 1 >= hbuf->size) {

      if (!mi_heap_buf_expand(hbuf)) return;

    }

    mi_assert_internal(hbuf->used < hbuf->size);

    hbuf->buf[hbuf->used++] = c;

  }

  mi_assert_internal(hbuf->used < hbuf->size);

  hbuf->buf[hbuf->used] = 0;

}

static void mi_heap_buf_print_count_bin(mi_heap_buf_t* hbuf, const char* prefix, mi_stat_count_t* stat, size_t bin, bool add_comma) {

  const size_t binsize = _mi_bin_size(bin);

  const size_t pagesize = (binsize <= MI_SMALL_OBJ_SIZE_MAX ? MI_SMALL_PAGE_SIZE :

                            (binsize <= MI_MEDIUM_OBJ_SIZE_MAX ? MI_MEDIUM_PAGE_SIZE :

                              #if MI_LARGE_PAGE_SIZE

                              (binsize <= MI_LARGE_OBJ_SIZE_MAX ? MI_LARGE_PAGE_SIZE : 0)

                              #else

                              0

                              #endif

                              ));

  char buf[128];

  _mi_snprintf(buf, 128, "%s{ \"total\": %lld, \"peak\": %lld, \"current\": %lld, \"block_size\": %zu, \"page_size\": %zu }%s\n", prefix, stat->total, stat->peak, stat->current, binsize, pagesize, (add_comma ? "," : ""));

  buf[127] = 0;

  mi_heap_buf_print(hbuf, buf);

}

static void mi_heap_buf_print_count(mi_heap_buf_t* hbuf, const char* prefix, mi_stat_count_t* stat, bool add_comma) {

  char buf[128];

  _mi_snprintf(buf, 128, "%s{ \"total\": %lld, \"peak\": %lld, \"current\": %lld }%s\n", prefix, stat->total, stat->peak, stat->current, (add_comma ? "," : ""));

  buf[127] = 0;

  mi_heap_buf_print(hbuf, buf);

}

static void mi_heap_buf_print_count_value(mi_heap_buf_t* hbuf, const char* name, mi_stat_count_t* stat) {

  char buf[128];

  _mi_snprintf(buf, 128, "  \"%s\": ", name);

  buf[127] = 0;

  mi_heap_buf_print(hbuf, buf);

  mi_heap_buf_print_count(hbuf, "", stat, true);

}

static void mi_heap_buf_print_value(mi_heap_buf_t* hbuf, const char* name, int64_t val) {

  char buf[128];

  _mi_snprintf(buf, 128, "  \"%s\": %lld,\n", name, val);

  buf[127] = 0;

  mi_heap_buf_print(hbuf, buf);

}

static void mi_heap_buf_print_size(mi_heap_buf_t* hbuf, const char* name, size_t val, bool add_comma) {

  char buf[128];

  _mi_snprintf(buf, 128, "    \"%s\": %zu%s\n", name, val, (add_comma ? "," : ""));

  buf[127] = 0;

  mi_heap_buf_print(hbuf, buf);

}

static void mi_heap_buf_print_counter_value(mi_heap_buf_t* hbuf, const char* name, mi_stat_counter_t* stat) {

  mi_heap_buf_print_value(hbuf, name, stat->total);

}

#define MI_STAT_COUNT(stat)    mi_heap_buf_print_count_value(&hbuf, #stat, &stats->stat);

#define MI_STAT_COUNTER(stat)  mi_heap_buf_print_counter_value(&hbuf, #stat, &stats->stat);

char* mi_stats_get_json(size_t output_size, char* output_buf) mi_attr_noexcept {

  mi_heap_buf_t hbuf = { NULL, 0, 0, true };

  if (output_size > 0 && output_buf != NULL) {

    _mi_memzero(output_buf, output_size);

    hbuf.buf = output_buf;

    hbuf.size = output_size;

    hbuf.can_realloc = false;

  }

  else {

    if (!mi_heap_buf_expand(&hbuf)) return NULL;

  }

  mi_heap_buf_print(&hbuf, "{\n");

  mi_heap_buf_print_value(&hbuf, "stat_version", MI_STAT_VERSION);

  mi_heap_buf_print_value(&hbuf, "mimalloc_version", MI_MALLOC_VERSION);

  // process info

  mi_heap_buf_print(&hbuf, "  \"process\": {\n");

  size_t elapsed;

  size_t user_time;

  size_t sys_time;

  size_t current_rss;

  size_t peak_rss;

  size_t current_commit;

  size_t peak_commit;

  size_t page_faults;

  mi_process_info(&elapsed, &user_time, &sys_time, &current_rss, &peak_rss, &current_commit, &peak_commit, &page_faults);

  mi_heap_buf_print_size(&hbuf, "elapsed_msecs", elapsed, true);

  mi_heap_buf_print_size(&hbuf, "user_msecs", user_time, true);

  mi_heap_buf_print_size(&hbuf, "system_msecs", sys_time, true);

  mi_heap_buf_print_size(&hbuf, "page_faults", page_faults, true);

  mi_heap_buf_print_size(&hbuf, "rss_current", current_rss, true);

  mi_heap_buf_print_size(&hbuf, "rss_peak", peak_rss, true);

  mi_heap_buf_print_size(&hbuf, "commit_current", current_commit, true);

  mi_heap_buf_print_size(&hbuf, "commit_peak", peak_commit, false);

  mi_heap_buf_print(&hbuf, "  },\n");

  // statistics

  mi_stats_t* stats = &_mi_stats_main;

  MI_STAT_FIELDS()

  // size bins

  mi_heap_buf_print(&hbuf, "  \"malloc_bins\": [\n");

  for (size_t i = 0; i <= MI_BIN_HUGE; i++) {

    mi_heap_buf_print_count_bin(&hbuf, "    ", &stats->malloc_bins[i], i, i!=MI_BIN_HUGE);

  }

  mi_heap_buf_print(&hbuf, "  ],\n");

  mi_heap_buf_print(&hbuf, "  \"page_bins\": [\n");

  for (size_t i = 0; i <= MI_BIN_HUGE; i++) {

    mi_heap_buf_print_count_bin(&hbuf, "    ", &stats->page_bins[i], i, i!=MI_BIN_HUGE);

  }

  mi_heap_buf_print(&hbuf, "  ]\n");

  mi_heap_buf_print(&hbuf, "}\n");

  if (hbuf.used >= hbuf.size) {

    // failed

    if (hbuf.can_realloc) { mi_free(hbuf.buf); }

    return NULL;

  }

  else {

    return hbuf.buf;

  }

}