// Copyright (c) 2016, the SDSL Project Authors.  All rights reserved.
// Please see the AUTHORS file for details.  Use of this source code is governed
// by a BSD license that can be found in the LICENSE file.
/*!\file memory_management.hpp
\brief memory_management.hpp contains two function for allocating and deallocating memory
\author Simon Gog
*/
#ifndef INCLUDED_SDSL_MEMORY_MANAGEMENT
#define INCLUDED_SDSL_MEMORY_MANAGEMENT

#include "uintx_t.hpp"
#include "config.hpp"
#include "bits.hpp"
#include "memory_tracking.hpp"
#include "ram_fs.hpp"
#include <chrono>
#include <algorithm>

namespace sdsl {

inline void output_event_json(std::ostream& out,const mm_event& ev,const tracker_storage& m)
{
    using namespace std::chrono;
    out << "\t\t" << "\"name\" : " << "\"" << ev.name << "\",\n";
    out << "\t\t" << "\"usage\" : [" << "\n";
    for (size_t j=0; j<ev.allocations.size(); j++)  {
        out << "\t\t\t[" << duration_cast<milliseconds>(ev.allocations[j].timestamp-m.start_log).count()
            << "," << ev.allocations[j].usage << "]";
        if (j+1<ev.allocations.size()) {
            out << ",\n";
        } else {
            out << "\n";
        }
    }
    out << "\t\t" << "]\n";
}

template<>
inline void write_mem_log<JSON_FORMAT>(std::ostream& out,const tracker_storage& m)
{
    auto events = m.completed_events;
    std::sort(events.begin(),events.end());

    // output
    out << "[\n";
    for (size_t i=0; i<events.size(); i++) {
        out << "\t{\n";
        output_event_json(out,events[i],m);
        if (i<events.size()-1) {
            out << "\t},\n";
        } else {
            out << "\t}\n";
        }
    }
    out << "]\n";
}

inline std::string create_mem_html_header()
{
	std::stringstream jsonheader;
	jsonheader << "<html>\n"
			   << "<head>\n"
			   << "<meta charset=\"utf-8\">\n"
			   << "<style>\n"
			   << "    body { font: 11px sans-serif; }\n"
			   << "    .rule { height: 90%; position: absolute; border-right: 1px dotted #000; "
				  "text-align: right; }\n"
			   << "</style>\n"
			   << "<title>sdsl memory usage visualization</title>\n"
			   << "<script src=\"http://d3js.org/d3.v3.js\"></script>\n"
			   << "</head>\n"
			   << "<body marginwidth=\"0\" marginheight=\"0\">\n"
			   << "<button><a id=\"download\">Save as SVG</a></button>\n"
			   << "<div class=\"chart\"><div id=\"visualization\"></div></div><script>\n";
	return jsonheader.str();
}

inline std::string create_mem_js_body(const std::string& jsonObject)
{
    std::stringstream jsonbody;
    jsonbody
            << "var events = " << jsonObject << ";\n"
            << "var w = window,d = document,e = d.documentElement,g = d.getElementsByTagName('body')[0],\n"
            << "  xw = w.innerWidth || e.clientWidth || g.clientWidth,\n"
            << "  yh = w.innerHeight || e.clientHeight || g.clientHeight;\n\n"
            << "var margin = {top: 20,right: 80,bottom: 120,left: 120},\n"
            << "  width = xw - margin.left - margin.right,height = yh - margin.top - margin.bottom;\n"
            << "var x = d3.scale.linear().range([0, width]);\n"
            << "var y = d3.scale.linear().range([height, 0]);\n"
            << "var xAxis = d3.svg.axis().scale(x).orient(\"bottom\");\n"
            << "var yAxis = d3.svg.axis().scale(y).orient(\"left\").ticks(5);\n"
            << "var color = d3.scale.category10();\n"
            << "var x_max = d3.max(events, function (d) { return d3.max(d.usage, function (u) { return u[0] / 1000;})})\n"
            << "var y_max = d3.max(events, function (d) { return d3.max(d.usage, function (u) { return 1.1 * u[1] / (1024 * 1024);})})\n"
            << "var peak = d3.max(events, function (d) { return d3.max(d.usage, function (u) { return u[1]; })})\n"
            << "var data = []\nevents.forEach(function (d) { data = data.concat(d.usage); });\n"
            << "var peakelem = data.filter(function (a) { return a[1] == peak; });\n"
            << "var peakelem = peakelem.splice(0,1);\n"
            << "x.domain([0, x_max]);\n y.domain([0, y_max]);\n"
            << "var svg = d3.select(\"#visualization\").append(\"svg\")\n"
            << "  .attr(\"width\", width + margin.left + margin.right)\n"
            << "  .attr(\"height\", height + margin.top + margin.bottom)\n"
            << "  .attr(\"xmlns\", \"http://www.w3.org/2000/svg\")\n"
            << "  .append(\"g\").attr(\"transform\",\"translate(\" + margin.left + \",\" + margin.top + \")\");\n\n"
            << "  svg.append(\"g\").attr(\"class\", \"xaxis\").attr(\"transform\", \"translate(0,\" + height + \")\")\n"
            << "  .call(xAxis).append(\"text\").attr(\"text-anchor\", \"end\")\n"
            << "  .attr(\"shape-rendering\", \"crispEdges\").attr(\"x\", width / 2 + 50).attr(\"y\", 70).attr(\"shape-rendering\", \"crispEdges\")\n"
            << "  .attr(\"font-family\", \"sans-serif\").attr(\"font-size\", \"20px\").text(\"Time (seconds)\");\n\n"
            << "svg.append(\"g\").attr(\"class\", \"yaxis\").call(yAxis).append(\"text\").attr(\"transform\", \"rotate(-90)\").attr(\"x\", -height / 2 + 50)\n"
            << "  .attr(\"y\", -80).attr(\"shape-rendering\", \"crispEdges\").attr(\"font-family\", \"sans-serif\").attr(\"font-size\", \"20px\").style(\"text-anchor\", \"end\")\n"
            << "  .text(\"Memory Usage (MiB)\");\n\n"
            << "svg.selectAll(\".tick text\").style(\"font-size\", \"20px\");\n"
            << "svg.selectAll(\".xaxis .tick text\").attr(\"dy\", 23);\nsvg.selectAll(\".yaxis .tick text\").attr(\"dx\", -10);\n"
            << "svg.selectAll(\"line\").attr(\"fill\", \"none\").attr(\"stroke\", \"black\")\nsvg.selectAll(\"path\").attr(\"fill\", \"none\").attr(\"stroke\", \"black\")\n\n"
            << "svg.selectAll(\"line.horizontalGrid\").data(y.ticks(5)).enter().append(\"line\")\n"
            << "  .attr({\"class\": \"horizontalGrid\",\"x1\": 0,\"x2\": width,\"y1\": function (d) { return y(d);},\n"
            << "     \"y2\": function (d) { return y(d); }, \"fill\": \"none\", \"shape-rendering\": \"crispEdges\",\n"
            << "     \"stroke\": \"lightgrey\",\"stroke-dasharray\": \"10,10\",\"stroke-width\": \"1.5px\"});\n\n"
            << "var area = d3.svg.area().x(function (d) { return x(d[0] / 1000);}).y0(height).y1(function (d) { return y(d[1] / (1024 * 1024))});\n\n"
            << "var ev = svg.selectAll(\".event\").data(events).enter().append(\"svg:path\").attr(\"class\", \"area\")\n"
            << "  .attr(\"fill\", function (d) { return d3.rgb(color(d.name)); })\n"
            << "  .attr(\"d\", function (d) { return area(d.usage) })\n"
            << "  .style(\"stroke\", function (d) { return d3.rgb(color(d.name)).darker(2);}).style(\"stroke-width\", \"2px\")\n\n"
            << "svg.selectAll(\".dot\").data(peakelem).enter().append(\"circle\").attr(\"r\", 3).attr(\"fill\", \"red\")\n"
            << "  .attr(\"cx\", function (d) {return x(d[0] / 1000)})\n"
            << "  .attr(\"cy\", function (d) {return y(d[1] / (1024 * 1024))})\n"
            << "  .attr(\"fill\", \"red\").attr(\"stroke-width\", 2).attr(\"stroke\", \"#cc0000\")\n\n"
            << "svg.selectAll(\".dot\").data(peakelem).enter().append(\"svg:text\")\n"
            << "  .attr(\"x\", function (d) {return x(d[0] / 1000)}).attr(\"y\", function (d) {return y(d[1] / (1024 * 1024) * 1.025)})\n"
            << "  .text(function (d) {return \"Peak Usage: \" + Math.round(d[1] / (1024 * 1024)) + \" MB\"})\n"
            << "  .attr(\"font-size\", 12).attr(\"fill\", \"red\");\n\n"
            << "svg.selectAll(\".dot\").data(peakelem).enter().append(\"circle\")\n"
            << "  .attr(\"r\", 5).attr(\"fill\", \"red\")\n"
            << "  .attr(\"cx\", function (d) {return x(d[0] / 1000)})\n"
            << "  .attr(\"cy\", function (d) {return y(d[1] / (1024 * 1024))})\n"
            << "  .attr(\"fill\", \"none\").attr(\"stroke-width\", 2).attr(\"stroke\", \"#cc0000\").each(pulsepeak());\n\n"
            << "function pulsepeak() { return function (d, i, j) {\n"
            << "  d3.select(this).attr(\"r\", 5).style(\"stroke-opacity\", 1.0).transition()\n"
            << "    .ease(\"linear\").duration(1000).attr(\"r\", 10).style(\"stroke-opacity\", 0.0).each(\"end\", pulsepeak());};}\n\n"
            << "var vertical = d3.select(\".chart\").append(\"div\").attr(\"class\", \"remove\")\n"
            << "  .style(\"position\", \"absolute\").style(\"z-index\", \"19\").style(\"width\", \"1px\")\n"
            << "  .style(\"height\", height - margin).style(\"top\", \"30px\").style(\"bottom\", \"50px\")\n"
            << "  .style(\"left\", \"0px\").style(\"opacity\", \"0.4\").style(\"background\", \"black\");\n\n"
            << "var tooltip = d3.select(\".chart\").append(\"div\").attr(\"class\", \"remove\")\n"
            << "  .style(\"position\", \"absolute\").style(\"z-index\", \"20\").style(\"visibility\", \"hidden\").style(\"top\", \"10px\");\n\n"
            << "var circle = svg.append(\"circle\").attr(\"cx\", 100).attr(\"cy\", 350).attr(\"r\", 3).attr(\"fill\", \"black\").style(\"opacity\", \"0\")\n\n"
            << "d3.select(\"svg\").on(\"mousemove\", function () {\n"
            << "  mousex = d3.mouse(this);\n"
            << "  if (mousex[0] < margin.left + 3 || mousex[0] >= xw - margin.right) {\n"
            << "    vertical.style(\"opacity\", \"0\"); tooltip.style(\"opacity\", \"0\"); circle.style(\"opacity\", \"0\")\n"
            << "  } else {\n"
            << "    var xvalue = x.invert(mousex[0] - margin.left); var pos = findPosition(xvalue)\n"
            << "    vertical.style(\"opacity\", \"0.4\"); tooltip.style(\"opacity\", \"1\"); circle.style(\"opacity\", \"1\")\n"
            << "    circle.attr(\"cx\", pos.x).attr(\"cy\", pos.y); vertical.style(\"left\", mousex[0] + \"px\");tooltip.style(\"left\", mousex[0] + 15 + \"px\")\n"
            << "    tooltip.html(\"<p>\" + xvalue.toFixed(2) + \" Seconds <br>\" + Math.round(pos.mem) + \" MiB <br> \" + pos.name + "
            << "  \"<br> Phase Time: \" + pos.ptime + \" Seconds </p>\").style(\"visibility\", \"visible\");\n"
            << "  }\n})"
            << ".on(\"mouseover\", function () {\n"
            << "  mousex = d3.mouse(this);\n  if (mousex[0] < margin.left + 3 || mousex[0] > xw - margin.right) {\n"
            << "    vertical.style(\"opacity\", \"0\")\n  } else {\n    vertical.style(\"opacity\", \"0.4\");vertical.style(\"left\", mousex[0] + 7 + \"px\")\n}})\n"
            << "d3.select(\"#download\").on(\"click\", function () {\n"
            << "d3.select(this).attr(\"href\", 'data:application/octet-stream;base64,' + btoa(d3.select(\"#visualization\").html())).attr(\"download\", \"viz.svg\")})\n\n"
            << "function findPosition(e){correctArea=d3.selectAll(\".area\").filter(function(t){if(t.usage[0][0]<=e*1e3&&t.usage[t.usage.length-1][0]>=e*1e3){return true}"
            << "return false});if(correctArea.empty()){return 0}var t=new Array;correctArea[0].forEach(function(n){t.push(findYValueinArea(n,e))});"
            << "max_elem=d3.max(t,function(e){return e.mem});var n=t.filter(function(e){return e.mem==max_elem});return n[0]}"
            << "function findYValueinArea(e,t){len=e.getTotalLength();var n=0;var r=len;for(var i=0;i<=len;i+=50){var s=e.getPointAtLength(i);"
            << "var o=x.invert(s.x);var u=y.invert(s.y);if(u>0&&o>t){n=Math.max(0,i-50);r=i;break}}var a=e.getPointAtLength(0);"
            << "var f=1;while(n<r){var l=(r+n)/2;a=e.getPointAtLength(l);target_x=x.invert(a.x);if((l==n||l==r)&&Math.abs(target_x-t)>.01){break}if(target_x>t)r=l;"
            << "else if(target_x<t)n=l;else{break}if(f>50){break}f++}var c=new function(){this.mem=y.invert(a.y);this.name=e.__data__.name;"
            << "this.min=d3.min(e.__data__.usage,function(e){return e[0]/1e3});this.max=d3.max(e.__data__.usage,function(e){return e[0]/1e3});"
            << "this.ptime=Math.round(this.max-this.min);this.x=a.x;this.y=a.y};return c}\n</script></body></html>";
    return jsonbody.str();
}


template<>
inline void write_mem_log<HTML_FORMAT>(std::ostream& out,const tracker_storage& m)
{
    std::stringstream json_data;
    write_mem_log<JSON_FORMAT>(json_data,m);

    out << create_mem_html_header();
    out << create_mem_js_body(json_data.str());
}

#pragma pack(push, 1)
typedef struct mm_block {
	size_t			 size;
	struct mm_block* next;
	struct mm_block* prev;
} mm_block_t;

typedef struct bfoot {
	size_t size;
} mm_block_foot_t;
#pragma pack(pop)

#define ALIGNMENT             sizeof(uint64_t)
#define ALIGNSPLIT(size)      (((size)) & ~0x7)
#define ALIGN(size)           (((size) + (ALIGNMENT-1)) & ~0x7)
#define MM_BLOCK_OVERHEAD     (sizeof(size_t)+sizeof(size_t))
#define MIN_BLOCKSIZE         (ALIGN(sizeof(mm_block_t)+sizeof(mm_block_foot_t)))
#define UNMASK_SIZE(size)     ((size)&~1)
#define ISFREE(size)          ((size)&1)
#define SETFREE(size)         ((size)|1)
#define SPLIT_THRESHOLD       (MIN_BLOCKSIZE)


inline mm_block_t* block_cur(void* ptr)
{
	mm_block_t* bptr = (mm_block_t*)((uint8_t*)ptr - sizeof(size_t));
	return bptr;
}

/* given a block retrieve the previous block if any. nullptr otherwise */
inline mm_block_t* block_prev(mm_block_t* cur_bptr, mm_block_t* first)
{
	/* start of the heap? */
	if (cur_bptr == first) return nullptr;
	mm_block_foot_t* prev_foot = (mm_block_foot_t*)((uint8_t*)cur_bptr - sizeof(mm_block_foot_t));
	mm_block_t*		 prev_bptr = (mm_block_t*)((uint8_t*)cur_bptr - UNMASK_SIZE(prev_foot->size));
	return prev_bptr;
}

/* given a block retrieve the next block if any. nullptr otherwise */
inline mm_block_t* block_next(mm_block_t* cur_bptr, uint8_t* top)
{
	/* end of the heap? */
	if ((uint8_t*)((uint8_t*)cur_bptr + UNMASK_SIZE(cur_bptr->size)) >= top) return nullptr;

	mm_block_t* next_bptr = (mm_block_t*)((uint8_t*)cur_bptr + UNMASK_SIZE(cur_bptr->size));
	return next_bptr;
}

/* calculate the size of a memory block */
inline size_t block_size(void* ptr)
{
	mm_block_t* bptr = block_cur(ptr);
	return UNMASK_SIZE(bptr->size);
}

inline bool block_isfree(mm_block_t* ptr)
{
	return ((ptr->size) & 1ULL);
}

/* is the next block free */
inline bool block_nextfree(mm_block_t* ptr, uint8_t* top)
{
	mm_block_t* next = block_next(ptr, top);
	if (next && block_isfree(next)) return true;
	return false;
}

/* is the prev block free */
inline bool block_prevfree(mm_block_t* ptr, mm_block_t* begin)
{
	mm_block_t* prev = block_prev(ptr, begin);
	if (prev && block_isfree(prev)) return 1;
	return 0;
}

/* update the footer with a new size */
inline void foot_update(mm_block_t* ptr, size_t size)
{
	mm_block_foot_t* fptr =
	(mm_block_foot_t*)((uint8_t*)ptr + UNMASK_SIZE(size) - sizeof(mm_block_foot_t));
	fptr->size = size;
}

/* update the block with a new size */
inline void block_update(mm_block_t* ptr, size_t size)
{
	ptr->size = size;
	foot_update(ptr, size);
}

/* return the pointer to the "data" */
inline void* block_data(mm_block_t* ptr) { return (void*)((uint8_t*)ptr + sizeof(size_t)); }

/* return size of the data that can be stored in the block */
inline size_t block_getdatasize(mm_block_t* ptr)
{
	size_t blocksize = UNMASK_SIZE(ptr->size);
	return blocksize - sizeof(size_t) - sizeof(mm_block_foot_t);
}

/* mark the block as free */
inline void block_markfree(mm_block_t* ptr) { block_update(ptr, SETFREE(ptr->size)); }

/* mark the block as used */
inline void block_markused(mm_block_t* ptr) { block_update(ptr, UNMASK_SIZE(ptr->size)); }

#ifndef MSVC_COMPILER

class hugepage_allocator {
private:
	uint8_t*	m_base		  = nullptr;
	mm_block_t* m_first_block = nullptr;
	uint8_t*	m_top		  = nullptr;
	size_t		m_total_size  = 0;
	std::multimap<size_t, mm_block_t*> m_free_large;

private:


    inline void block_print(int id, mm_block_t* bptr)
    {
        fprintf(stdout,
                "%d addr=%p size=%lu (%lu) free=%d\n",
                id,
                ((void*)bptr),
                UNMASK_SIZE(bptr->size),
                bptr->size,
                block_isfree(bptr));
        fflush(stdout);
    }

    inline uint64_t extract_number(std::string& line)
    {
        std::string num_str;
        for (size_t i = line.size() - 1; i + 1 >= 1; i--) {
            if (isdigit(line[i])) {
                num_str.insert(num_str.begin(), line[i]);
            } else {
                if (num_str.size() > 0) {
                    break;
                }
            }
        }
        return std::strtoull(num_str.c_str(), nullptr, 10);
    }

    inline uint64_t extract_multiplier(std::string& line)
    {
        uint64_t num = 1;
        if (line[line.size() - 2] == 'k' || line[line.size() - 2] == 'K') {
            num = 1024;
        }
        if (line[line.size() - 2] == 'm' || line[line.size() - 2] == 'M') {
            num = 1024 * 1024;
        }
        if (line[line.size() - 2] == 'g' || line[line.size() - 2] == 'G') {
            num = 1024 * 1024 * 1024;
        }
        return num;
    }

	size_t determine_available_hugepage_memory()
    {
        size_t			  size_in_bytes		 = 0;
        size_t			  page_size_in_bytes = 0;
        size_t			  num_free_pages	 = 0;
        const std::string meminfo_file		 = "/proc/meminfo";
        const std::string ps_str			 = "Hugepagesize:";
        const std::string pf_str			 = "HugePages_Free:";
        std::ifstream	 mifs(meminfo_file);
        if (mifs.is_open()) {
            // find size of one page
            std::string line;
            while (std::getline(mifs, line)) {
                auto ps = std::mismatch(ps_str.begin(), ps_str.end(), line.begin());
                if (ps.first == ps_str.end()) {
                    page_size_in_bytes = extract_number(line) * extract_multiplier(line);
                }
                auto pf = std::mismatch(pf_str.begin(), pf_str.end(), line.begin());
                if (pf.first == pf_str.end()) {
                    num_free_pages = extract_number(line);
                }
            }
            size_in_bytes = page_size_in_bytes * num_free_pages;
        } else {
            throw std::system_error(
            ENOMEM,
            std::system_category(),
            "hugepage_allocator could not automatically determine available hugepages");
        }
        return size_in_bytes;
    }


	void coalesce_block(mm_block_t* block)
    {
        //std::cout << "coalesce_block()" << std::endl;
        mm_block_t* newblock = block;
        if (block_nextfree(block, m_top)) {
            mm_block_t* next = block_next(block, m_top);
            /* remove the "next" block from the free list */
            remove_from_free_set(next);
            /* add the size of our block */
            block_update(block, UNMASK_SIZE(block->size) + UNMASK_SIZE(next->size));
        }
        if (block_prevfree(block, m_first_block)) {
            mm_block_t* prev = block_prev(block, m_first_block);
            /* we remove the old prev block and readd it to the correct
               size list if necessary */
            remove_from_free_set(prev);
            newblock = prev;
            block_update(prev, UNMASK_SIZE(prev->size) + UNMASK_SIZE(block->size));
        }
        if (newblock) {
            block_markfree(newblock);
            insert_into_free_set(newblock);
        }
    }

	void split_block(mm_block_t* bptr, size_t size)
    {
        //std::cout << "split_block("<< (void*)bptr << ")" << std::endl;
        size_t blocksize = UNMASK_SIZE(bptr->size);
        //std::cout << "cur_block_size = " << blocksize << std::endl;
        /* only split if we get at least a small block
           out of it */
        int64_t newblocksize = ALIGNSPLIT(blocksize - ALIGN(size + MM_BLOCK_OVERHEAD));
        //std::cout << "new_block_size = " << newblocksize << std::endl;
        if (newblocksize >= (int64_t)SPLIT_THRESHOLD) {
            /* update blocksize of old block */
            //std::cout << "block_update = " << blocksize-newblocksize << std::endl;
            block_update(bptr, blocksize - newblocksize);
            mm_block_t* newblock = (mm_block_t*)((char*)bptr + (blocksize - newblocksize));
            //std::cout << "new block ptr = " << (void*)newblock << std::endl;
            block_update(newblock, newblocksize);
            coalesce_block(newblock);
        }
    }
    
	uint8_t* hsbrk(size_t size)
    {
        ptrdiff_t left = (ptrdiff_t)m_total_size - (m_top - m_base);
        if (left < (ptrdiff_t)size) { // enough space left?
            throw std::system_error(
            ENOMEM, std::system_category(), "hugepage_allocator: not enough hugepage memory available");
        }
        uint8_t* new_mem = m_top;
        m_top += size;
        return new_mem;
    }

	mm_block_t* new_block(size_t size)
    {
        //std::cout << "new_block(" << size << ")" << std::endl;
        size						   = ALIGN(size + MM_BLOCK_OVERHEAD);
        if (size < MIN_BLOCKSIZE) size = MIN_BLOCKSIZE;
        mm_block_t* ptr				   = (mm_block_t*)hsbrk(size);
        block_update(ptr, size);
        return ptr;
    }

	void remove_from_free_set(mm_block_t* block)
    {
        //std::cout << "remove_from_free_set()" << std::endl;
        auto eq_range = m_free_large.equal_range(block->size);
        // find the block amoung the blocks with equal size
        auto itr   = eq_range.first;
        auto last  = eq_range.second;
        auto found = m_free_large.end();
        while (itr != last) {
            if (itr->second == block) {
                found = itr;
            }
            ++itr;
        }
        if (found == m_free_large.end()) {
            found = last;
        }
        m_free_large.erase(found);
    }

	void insert_into_free_set(mm_block_t* block)
    {
        //std::cout << "insert_into_free_set("<< (void*)block << "," << UNMASK_SIZE(block->size) << ")" << std::endl;
        //std::cout << "insert_into_free_set("<< (void*)block << "," << block->size << ")" << std::endl;
        m_free_large.insert({block->size, block});
    }

	mm_block_t* find_free_block(size_t size_in_bytes)
    {
        //std::cout << "find_free_block(" << size_in_bytes << ")" << std::endl;

        mm_block_t* bptr	   = nullptr;
        auto		free_block = m_free_large.lower_bound(size_in_bytes);
        if (free_block != m_free_large.end()) {
            bptr = free_block->second;
            m_free_large.erase(free_block);
        }
        return bptr;
    }
        
	mm_block_t* last_block()
    {
        mm_block_t* last = nullptr;
        //std::cout << "m_top = " << (void*)m_top << std::endl;
        //std::cout << "m_base = " << (void*)m_base << std::endl;
        if (m_top != m_base) {
            mm_block_foot_t* fptr = (mm_block_foot_t*)(m_top - sizeof(size_t));
            //std::cout << "foot of last = " << (void*)fptr << std::endl;
            //std::cout << "size of last = " << UNMASK_SIZE(fptr->size) << std::endl;
            last = (mm_block_t*)(((uint8_t*)fptr) - UNMASK_SIZE(fptr->size) + sizeof(size_t));
            //std::cout << "last = " << (void*)last << std::endl;
        }
        return last;
    }

    
	void print_heap()
    {
        mm_block_t* bptr = m_first_block;
        size_t		id   = 0;
        while (bptr) {
            block_print(id, bptr);
            id++;
            bptr = block_next(bptr, m_top);
        }
    }

public:
	void init(SDSL_UNUSED size_t size_in_bytes = 0)
	{
#ifdef MAP_HUGETLB
		if (size_in_bytes == 0) {
			size_in_bytes = determine_available_hugepage_memory();
		}

		m_total_size = size_in_bytes;
		m_base		 = (uint8_t*)mmap(nullptr,
								m_total_size,
								(PROT_READ | PROT_WRITE),
								(MAP_HUGETLB | MAP_ANONYMOUS | MAP_PRIVATE),
								0,
								0);
		if (m_base == MAP_FAILED) {
			throw std::system_error(
			ENOMEM, std::system_category(), "hugepage_allocator could not allocate hugepages");
		} else {
			// init the allocator
			m_top		  = m_base;
			m_first_block = (mm_block_t*)m_base;
		}
#else
		throw std::system_error(ENOMEM,
								std::system_category(),
								"hugepage_allocator: MAP_HUGETLB / hugepage support not available");
#endif
	}

	void* mm_realloc(void* ptr, size_t size)
    {
        //print_heap();
        //std::cout << "REALLOC(" << ptr << "," << size << ")" << std::endl;
        /* handle special cases first */
        if (nullptr == ptr) return mm_alloc(size);
        if (size == 0) {
            mm_free(ptr);
            return nullptr;
        }
        mm_block_t* bptr = block_cur(ptr);

        bool   need_malloc   = 0;
        size_t blockdatasize = block_getdatasize(bptr);
        /* we do nothing if the size is equal to the block */
        if (size == blockdatasize) {
            //std::cout << "return ptr = " << ptr << std::endl;
            return ptr; /* do nothing if size fits already */
        }
        if (size < blockdatasize) {
            /* we shrink */
            /* do we shrink enough to perform a split? */
            //std::cout << "shrink!" << std::endl;
            split_block(bptr, size);
        } else {
            //std::cout << "expand!" << std::endl;
            /* we expand */
            /* if the next block is free we could use it! */
            mm_block_t* next = block_next(bptr, m_top);
            if (!next) {
                //std::cout << "no next! -> expand!" << std::endl;
                // we are the last block so we just expand
                blockdatasize = block_getdatasize(bptr);
                size_t needed = ALIGN(size - blockdatasize);
                hsbrk(needed);
                block_update(bptr, UNMASK_SIZE(bptr->size) + needed);
                return block_data(bptr);
            } else {
                // we are not the last block
                //std::cout << "try combine next" << std::endl;
                if (next && block_isfree(next)) {
                    /* do we have enough space if we use the next block */
                    if (blockdatasize + UNMASK_SIZE(next->size) >= size) {
                        /* the next block is enough! */
                        /* remove the "next" block from the free list */
                        remove_from_free_set(next);
                        /* add the size of our block */
                        block_update(bptr, UNMASK_SIZE(bptr->size) + UNMASK_SIZE(next->size));
                    } else {
                        /* the next block is not enough. we allocate a new one instead */
                        need_malloc = true;
                    }
                } else {
                    /* try combing the previous block if free */
                    //std::cout << "try combine prev" << std::endl;
                    mm_block_t* prev = block_prev(bptr, m_first_block);
                    if (prev && block_isfree(prev)) {
                        if (blockdatasize + UNMASK_SIZE(prev->size) >= size) {
                            remove_from_free_set(prev);
                            size_t newsize = UNMASK_SIZE(prev->size) + UNMASK_SIZE(bptr->size);
                            block_update(prev, newsize);
                            block_markused(prev);
                            /* move the data into the previous block */
                            ptr = memmove(block_data(prev), ptr, blockdatasize);
                        } else {
                            /* not enough in the prev block */
                            need_malloc = true;
                        }
                    } else {
                        /* prev block not free. get more memory */
                        need_malloc = true;
                    }
                }
            }
        }
        if (need_malloc) {
            //std::cout << "need_alloc in REALLOC!" << std::endl;
            void* newptr = mm_alloc(size);
            memcpy(newptr, ptr, size);
            mm_free(ptr);
            ptr = newptr;
        }
        //print_heap();
        //std::cout << "return ptr = " << ptr << std::endl;
        return ptr;
    }


	void* mm_alloc(size_t size_in_bytes)
    {
        //std::cout << "ALLOC(" << size_in_bytes << ")" << std::endl;
        mm_block_t* bptr = nullptr;
        if ((bptr = find_free_block(size_in_bytes + MM_BLOCK_OVERHEAD)) != nullptr) {
            //std::cout << "found free block = " << (void*)bptr << std::endl;
            block_markused(bptr);
            /* split if we have a block too large for us? */
            split_block(bptr, size_in_bytes);
        } else {
            //std::cout << "no free block found that is big enough!" << std::endl;
            // check if last block is free
            //std::cout << "check last block" << std::endl;
            bptr = last_block();
            if (bptr && block_isfree(bptr)) {
                //std::cout << "last block is free. -> extend!" << std::endl;
                // extent last block as it is free
                size_t blockdatasize = block_getdatasize(bptr);
                size_t needed		 = ALIGN(size_in_bytes - blockdatasize);
                hsbrk(needed);
                remove_from_free_set(bptr);
                block_update(bptr, blockdatasize + needed + sizeof(size_t) + sizeof(mm_block_foot_t));
                //insert_into_free_set(bptr);
                block_markused(bptr);
            } else {
                bptr = new_block(size_in_bytes);
            }
        }
        //print_heap();
        //void* ptr = block_data(bptr);
        //std::cout << "return ptr = " << ptr << std::endl;
        return block_data(bptr);
    }


	void mm_free(void* ptr)
    {
        //print_heap();
        //std::cout << "FREE(" << ptr << ")" << std::endl;
        if (ptr) {
            mm_block_t* bptr = block_cur(ptr);
            block_markfree(bptr);
            /* coalesce if needed. otherwise just add */
            coalesce_block(bptr);
        }
        //print_heap();
    }


	bool in_address_space(void* ptr)
	{
		// check if ptr is in the hugepage address space
		if (ptr == nullptr) {
			return true;
		}
		if (ptr >= m_base && ptr < m_top) {
			return true;
		}
		return false;
	}
	static hugepage_allocator& the_allocator()
	{
		static hugepage_allocator a;
		return a;
	}
};
#endif

class memory_manager {
private:
	bool hugepages = false;

private:
	static memory_manager& the_manager()
	{
		static memory_manager m;
		return m;
	}

public:
	static uint64_t* alloc_mem(size_t size_in_bytes)
	{
#ifndef MSVC_COMPILER
		auto& m = the_manager();
		if (m.hugepages) {
			return (uint64_t*)hugepage_allocator::the_allocator().mm_alloc(size_in_bytes);
		}
#endif
		return (uint64_t*)calloc(size_in_bytes, 1);
	}
	static void free_mem(uint64_t* ptr)
	{
#ifndef MSVC_COMPILER
		auto& m = the_manager();
		if (m.hugepages and hugepage_allocator::the_allocator().in_address_space(ptr)) {
			hugepage_allocator::the_allocator().mm_free(ptr);
			return;
		}
#endif
		std::free(ptr);
	}
	static uint64_t* realloc_mem(uint64_t* ptr, size_t size)
	{
#ifndef MSVC_COMPILER
		auto& m = the_manager();
		if (m.hugepages and hugepage_allocator::the_allocator().in_address_space(ptr)) {
			return (uint64_t*)hugepage_allocator::the_allocator().mm_realloc(ptr, size);
		}
#endif
		return (uint64_t*)realloc(ptr, size);
	}

public:
	static void use_hugepages(size_t bytes = 0)
	{
#ifndef MSVC_COMPILER
		auto& m = the_manager();
		hugepage_allocator::the_allocator().init(bytes);
		m.hugepages = true;
#else
		throw std::runtime_error("hugepages not support on MSVC_COMPILER");
#endif
	}
	template <class t_vec>
	static void resize(t_vec& v, const typename t_vec::size_type capacity)
	{
		uint64_t old_capacity_in_bytes = ((v.m_capacity + 63) >> 6) << 3;
		uint64_t new_capacity_in_bytes = ((capacity + 63) >> 6) << 3;
		bool	 do_realloc		   = old_capacity_in_bytes != new_capacity_in_bytes;
		v.m_capacity      		   = ((capacity + 63) >> 6) << 6; // set new_capacity to a multiple of 64

		if (do_realloc || v.m_data == nullptr) {
			// Note that we allocate 8 additional bytes if m_capacity % 64 == 0.
			// We need this padding since rank data structures do a memory
			// access to this padding to answer rank(size()) if capacity()%64 ==0.
			// Note that this padding is not counted in the serialize method!
			size_t allocated_bytes = (size_t)(((v.m_capacity + 64) >> 6) << 3);
			v.m_data			   = memory_manager::realloc_mem(v.m_data, allocated_bytes);
			if (allocated_bytes != 0 && v.m_data == nullptr) {
				throw std::bad_alloc();
			}

			// update stats
			if (do_realloc) {
				memory_monitor::record((int64_t)new_capacity_in_bytes - (int64_t)old_capacity_in_bytes);
			}
		}
	}
	template <class t_vec>
	static void clear(t_vec& v)
	{
		int64_t size_in_bytes = ((v.m_size + 63) >> 6) << 3;
		// remove mem
		memory_manager::free_mem(v.m_data);
		v.m_data = nullptr;

		// update stats
		if (size_in_bytes) {
			memory_monitor::record(size_in_bytes * -1);
		}
	}

	static int open_file_for_mmap(std::string& filename, std::ios_base::openmode mode)
	{
		if (is_ram_file(filename)) {
			return ram_fs::open(filename);
		}
#ifdef MSVC_COMPILER
		int fd = -1;
		if (!(mode & std::ios_base::out))
			_sopen_s(&fd, filename.c_str(), _O_BINARY | _O_RDONLY, _SH_DENYNO, _S_IREAD);
		else
			_sopen_s(&fd, filename.c_str(), _O_BINARY | _O_RDWR, _SH_DENYNO, _S_IREAD | _S_IWRITE);
		return fd;
#else
		if (!(mode & std::ios_base::out))
			return open(filename.c_str(), O_RDONLY);
		else
			return open(filename.c_str(), O_RDWR);
#endif
		return -1;
	}

	static void* mmap_file(int fd, uint64_t file_size, std::ios_base::openmode mode)
	{
		if (file_size == 0) {
			std::cout << "file_size=0" << std::endl;
			return nullptr;
		}
		if (is_ram_file(fd)) {
			if (ram_fs::file_size(fd) < file_size) return nullptr;
			auto& file_content = ram_fs::content(fd);
			return file_content.data();
		}
		memory_monitor::record(file_size);
#ifdef MSVC_COMPILER
		HANDLE fh = (HANDLE)_get_osfhandle(fd);
		if (fh == INVALID_HANDLE_VALUE) {
			return nullptr;
		}
		HANDLE fm;
		if (!(mode & std::ios_base::out)) { // read only?
			fm = CreateFileMapping(fh, NULL, PAGE_READONLY, 0, 0, NULL);
		} else
			fm = CreateFileMapping(fh, NULL, PAGE_READWRITE, 0, 0, NULL);
		if (fm == NULL) {
			return nullptr;
		}
		void* map = nullptr;
		if (!(mode & std::ios_base::out)) { // read only?
			map = MapViewOfFile(fm, FILE_MAP_READ, 0, 0, file_size);
		} else
			map = MapViewOfFile(fm, FILE_MAP_WRITE | FILE_MAP_READ, 0, 0, file_size);
		// we can close the file handle before we unmap the view: (see UnmapViewOfFile Doc)
		// Although an application may close the file handle used to create a file mapping object,
		// the system holds the corresponding file open until the last view of the file is unmapped.
		// Files for which the last view has not yet been unmapped are held open with no sharing restrictions.
		CloseHandle(fm);
		return map;
#else
		void* map = nullptr;
		if (!(mode & std::ios_base::out))
			map = mmap(NULL, file_size, PROT_READ, MAP_SHARED, fd, 0);
		else
			map = mmap(NULL, file_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
		if (map == MAP_FAILED) map = nullptr; // unify windows and unix error behaviour
		return map;
#endif
		return nullptr;
	}

	static int mem_unmap(int fd, void* addr, const uint64_t size)
	{
		if (addr == nullptr) {
			return 0;
		}
		if (is_ram_file(fd)) {
			return 0;
		}
		memory_monitor::record(-((int64_t)size));
#ifdef MSVC_COMPILER
		if (UnmapViewOfFile(addr)) return 0;
		return -1;
#else
		return munmap(addr, size);
#endif
		return -1;
	}

	static int close_file_for_mmap(int fd)
	{
		if (is_ram_file(fd)) {
			return ram_fs::close(fd);
		}
#ifdef MSVC_COMPILER
		return _close(fd);
#else
		return close(fd);
#endif
		return -1;
	}

	static int truncate_file_mmap(int fd, const uint64_t new_size)
	{
		if (is_ram_file(fd)) {
			return ram_fs::truncate(fd, new_size);
		}
#ifdef MSVC_COMPILER
		auto ret		  = _chsize_s(fd, new_size);
		if (ret != 0) ret = -1;
		return ret;
#else
		return ftruncate(fd, new_size);
#endif
		return -1;
	}
};


#undef ALIGNMENT
#undef ALIGNSPLIT
#undef ALIGN
#undef MM_BLOCK_OVERHEAD
#undef MIN_BLOCKSIZE
#undef UNMASK_SIZE
#undef ISFREE
#undef SETFREE
#undef SPLIT_THRESHOLD

} // end namespace

#endif
