source: libcfa/src/heap.cfa@ d76bd79

//
// Cforall Version 1.0.0 Copyright (C) 2017 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// heap.c --
//
// Author           : Peter A. Buhr
// Created On       : Tue Dec 19 21:58:35 2017
// Last Modified By : Peter A. Buhr
// Last Modified On : Sun Nov 24 17:56:15 2019
// Update Count     : 638
//

#include <unistd.h>                                                                             // sbrk, sysconf
#include <stdbool.h>                                                                    // true, false
#include <stdio.h>                                                                              // snprintf, fileno
#include <errno.h>                                                                              // errno
#include <string.h>                                                                             // memset, memcpy
extern "C" {
#include <sys/mman.h>                                                                   // mmap, munmap
} // extern "C"

// #comment TD : Many of these should be merged into math I believe
#include "bits/align.hfa"                                                               // libPow2
#include "bits/defs.hfa"                                                                // likely, unlikely
#include "bits/locks.hfa"                                                               // __spinlock_t
#include "startup.hfa"                                                                  // STARTUP_PRIORITY_MEMORY
//#include "stdlib.hfa"                                                                 // bsearchl
#include "malloc.h"

#define MIN(x, y) (y > x ? x : y)

static bool traceHeap = false;

inline bool traceHeap() {
        return traceHeap;
} // traceHeap

bool traceHeapOn() {
        bool temp = traceHeap;
        traceHeap = true;
        return temp;
} // traceHeapOn

bool traceHeapOff() {
        bool temp = traceHeap;
        traceHeap = false;
        return temp;
} // traceHeapOff


static bool prtFree = false;

inline bool prtFree() {
        return prtFree;
} // prtFree

bool prtFreeOn() {
        bool temp = prtFree;
        prtFree = true;
        return temp;
} // prtFreeOn

bool prtFreeOff() {
        bool temp = prtFree;
        prtFree = false;
        return temp;
} // prtFreeOff


// static bool traceHeapTerm = false;

// inline bool traceHeapTerm() {
//      return traceHeapTerm;
// } // traceHeapTerm

// bool traceHeapTermOn() {
//      bool temp = traceHeapTerm;
//      traceHeapTerm = true;
//      return temp;
// } // traceHeapTermOn

// bool traceHeapTermOff() {
//      bool temp = traceHeapTerm;
//      traceHeapTerm = false;
//      return temp;
// } // traceHeapTermOff


enum {
        // Define the default extension heap amount in units of bytes. When the uC++ supplied heap reaches the brk address,
        // the brk address is extended by the extension amount.
        __CFA_DEFAULT_HEAP_EXPANSION__ = (1 * 1024 * 1024),

        // Define the mmap crossover point during allocation. Allocations less than this amount are allocated from buckets;
        // values greater than or equal to this value are mmap from the operating system.
        __CFA_DEFAULT_MMAP_START__ = (512 * 1024 + 1),
};

size_t default_mmap_start() __attribute__(( weak )) {
        return __CFA_DEFAULT_MMAP_START__;
} // default_mmap_start

size_t default_heap_expansion() __attribute__(( weak )) {
        return __CFA_DEFAULT_HEAP_EXPANSION__;
} // default_heap_expansion


#ifdef __CFA_DEBUG__
static unsigned int allocFree;                                                  // running total of allocations minus frees

static void prtUnfreed() {
        if ( allocFree != 0 ) {
                // DO NOT USE STREAMS AS THEY MAY BE UNAVAILABLE AT THIS POINT.
                // char helpText[512];
                // int len = snprintf( helpText, sizeof(helpText), "CFA warning (UNIX pid:%ld) : program terminating with %u(0x%x) bytes of storage allocated but not freed.\n"
                //                                      "Possible cause is unfreed storage allocated by the program or system/library routines called from the program.\n",
                //                                      (long int)getpid(), allocFree, allocFree ); // always print the UNIX pid
                // __cfaabi_dbg_bits_write( STDERR_FILENO, helpText, len ); // print debug/nodebug
        } // if
} // prtUnfreed

extern "C" {
        void heapAppStart() {                                                           // called by __cfaabi_appready_startup
                allocFree = 0;
        } // heapAppStart

        void heapAppStop() {                                                            // called by __cfaabi_appready_startdown
                fclose( stdin ); fclose( stdout );
                prtUnfreed();
        } // heapAppStop
} // extern "C"
#endif // __CFA_DEBUG__


// statically allocated variables => zero filled.
static size_t pageSize;                                                                 // architecture pagesize
static size_t heapExpand;                                                               // sbrk advance
static size_t mmapStart;                                                                // cross over point for mmap
static unsigned int maxBucketsUsed;                                             // maximum number of buckets in use


#define SPINLOCK 0
#define LOCKFREE 1
#define BUCKETLOCK SPINLOCK
#if BUCKETLOCK == LOCKFREE
#include <uStackLF.h>
#endif // LOCKFREE

// Recursive definitions: HeapManager needs size of bucket array and bucket area needs sizeof HeapManager storage.
// Break recusion by hardcoding number of buckets and statically checking number is correct after bucket array defined.
enum { NoBucketSizes = 91 };                                                    // number of buckets sizes

struct HeapManager {
//      struct FreeHeader;                                                                      // forward declaration

        struct Storage {
                struct Header {                                                                 // header
                        union Kind {
                                struct RealHeader {
                                        union {
                                                struct {                                                // 4-byte word => 8-byte header, 8-byte word => 16-byte header
                                                        #if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ && __SIZEOF_POINTER__ == 4
                                                        uint32_t padding;                       // unused, force home/blocksize to overlay alignment in fake header
                                                        #endif // __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ && __SIZEOF_POINTER__ == 4

                                                        union {
//                                                              FreeHeader * home;              // allocated block points back to home locations (must overlay alignment)
                                                                void * home;                    // allocated block points back to home locations (must overlay alignment)
                                                                size_t blockSize;               // size for munmap (must overlay alignment)
                                                                #if BUCKLOCK == SPINLOCK
                                                                Storage * next;                 // freed block points next freed block of same size
                                                                #endif // SPINLOCK
                                                        };

                                                        #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ && __SIZEOF_POINTER__ == 4
                                                        uint32_t padding;                       // unused, force home/blocksize to overlay alignment in fake header
                                                        #endif // __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ && __SIZEOF_POINTER__ == 4
                                                };
                                                // future code
                                                #if BUCKLOCK == LOCKFREE
                                                Stack<Storage>::Link next;              // freed block points next freed block of same size (double-wide)
                                                #endif // LOCKFREE
                                        };
                                } real; // RealHeader
                                struct FakeHeader {
                                        #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
                                        uint32_t alignment;                                     // low-order bits of home/blockSize used for tricks
                                        #endif // __ORDER_LITTLE_ENDIAN__

                                        uint32_t offset;

                                        #if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
                                        uint32_t alignment;                                     // low-order bits of home/blockSize used for tricks
                                        #endif // __ORDER_BIG_ENDIAN__
                                } fake; // FakeHeader
                        } kind; // Kind
                } header; // Header
                char pad[libAlign() - sizeof( Header )];
                char data[0];                                                                   // storage
        }; // Storage

        static_assert( libAlign() >= sizeof( Storage ), "libAlign() < sizeof( Storage )" );

        struct FreeHeader {
                #if BUCKLOCK == SPINLOCK
                __spinlock_t lock;                                                              // must be first field for alignment
                Storage * freeList;
                #elif BUCKLOCK == LOCKFREE
                // future code
                StackLF<Storage> freeList;
                #else
                        #error undefined lock type for bucket lock
                #endif // SPINLOCK
                size_t blockSize;                                                               // size of allocations on this list
        }; // FreeHeader

        // must be first fields for alignment
        __spinlock_t extlock;                                                           // protects allocation-buffer extension
        FreeHeader freeLists[NoBucketSizes];                            // buckets for different allocation sizes

        void * heapBegin;                                                                       // start of heap
        void * heapEnd;                                                                         // logical end of heap
        size_t heapRemaining;                                                           // amount of storage not allocated in the current chunk
}; // HeapManager

static inline size_t getKey( const HeapManager.FreeHeader & freeheader ) { return freeheader.blockSize; }


#define FASTLOOKUP
#define __STATISTICS__

// Bucket size must be multiple of 16.
// Powers of 2 are common allocation sizes, so make powers of 2 generate the minimum required size.
static const unsigned int bucketSizes[] @= {                    // different bucket sizes
        16, 32, 48, 64 + sizeof(HeapManager.Storage), // 4
        96, 112, 128 + sizeof(HeapManager.Storage), // 3
        160, 192, 224, 256 + sizeof(HeapManager.Storage), // 4
        320, 384, 448, 512 + sizeof(HeapManager.Storage), // 4
        640, 768, 896, 1_024 + sizeof(HeapManager.Storage), // 4
        1_536, 2_048 + sizeof(HeapManager.Storage), // 2
        2_560, 3_072, 3_584, 4_096 + sizeof(HeapManager.Storage), // 4
        6_144, 8_192 + sizeof(HeapManager.Storage), // 2
        9_216, 10_240, 11_264, 12_288, 13_312, 14_336, 15_360, 16_384 + sizeof(HeapManager.Storage), // 8
        18_432, 20_480, 22_528, 24_576, 26_624, 28_672, 30_720, 32_768 + sizeof(HeapManager.Storage), // 8
        36_864, 40_960, 45_056, 49_152, 53_248, 57_344, 61_440, 65_536 + sizeof(HeapManager.Storage), // 8
        73_728, 81_920, 90_112, 98_304, 106_496, 114_688, 122_880, 131_072 + sizeof(HeapManager.Storage), // 8
        147_456, 163_840, 180_224, 196_608, 212_992, 229_376, 245_760, 262_144 + sizeof(HeapManager.Storage), // 8
        294_912, 327_680, 360_448, 393_216, 425_984, 458_752, 491_520, 524_288 + sizeof(HeapManager.Storage), // 8
        655_360, 786_432, 917_504, 1_048_576 + sizeof(HeapManager.Storage), // 4
        1_179_648, 1_310_720, 1_441_792, 1_572_864, 1_703_936, 1_835_008, 1_966_080, 2_097_152 + sizeof(HeapManager.Storage), // 8
        2_621_440, 3_145_728, 3_670_016, 4_194_304 + sizeof(HeapManager.Storage), // 4
};

static_assert( NoBucketSizes == sizeof(bucketSizes) / sizeof(bucketSizes[0]), "size of bucket array wrong" );

#ifdef FASTLOOKUP
enum { LookupSizes = 65_536 + sizeof(HeapManager.Storage) }; // number of fast lookup sizes
static unsigned char lookup[LookupSizes];                               // O(1) lookup for small sizes
#endif // FASTLOOKUP

static int mmapFd = -1;                                                                 // fake or actual fd for anonymous file
#ifdef __CFA_DEBUG__
static bool heapBoot = 0;                                                               // detect recursion during boot
#endif // __CFA_DEBUG__
static HeapManager heapManager __attribute__(( aligned (128) )) @= {}; // size of cache line to prevent false sharing


#ifdef __STATISTICS__
// Heap statistics counters.
static unsigned long long int mmap_storage;
static unsigned int mmap_calls;
static unsigned long long int munmap_storage;
static unsigned int munmap_calls;
static unsigned long long int sbrk_storage;
static unsigned int sbrk_calls;
static unsigned long long int malloc_storage;
static unsigned int malloc_calls;
static unsigned long long int free_storage;
static unsigned int free_calls;
static unsigned long long int calloc_storage;
static unsigned int calloc_calls;
static unsigned long long int memalign_storage;
static unsigned int memalign_calls;
static unsigned long long int cmemalign_storage;
static unsigned int cmemalign_calls;
static unsigned long long int realloc_storage;
static unsigned int realloc_calls;
// Statistics file descriptor (changed by malloc_stats_fd).
static int statfd = STDERR_FILENO;                                              // default stderr

// Use "write" because streams may be shutdown when calls are made.
static void printStats() {
        char helpText[512];
        __cfaabi_bits_print_buffer( STDERR_FILENO, helpText, sizeof(helpText),
                                                                        "\nHeap statistics:\n"
                                                                        "  malloc: calls %u / storage %llu\n"
                                                                        "  calloc: calls %u / storage %llu\n"
                                                                        "  memalign: calls %u / storage %llu\n"
                                                                        "  cmemalign: calls %u / storage %llu\n"
                                                                        "  realloc: calls %u / storage %llu\n"
                                                                        "  free: calls %u / storage %llu\n"
                                                                        "  mmap: calls %u / storage %llu\n"
                                                                        "  munmap: calls %u / storage %llu\n"
                                                                        "  sbrk: calls %u / storage %llu\n",
                                                                        malloc_calls, malloc_storage,
                                                                        calloc_calls, calloc_storage,
                                                                        memalign_calls, memalign_storage,
                                                                        cmemalign_calls, cmemalign_storage,
                                                                        realloc_calls, realloc_storage,
                                                                        free_calls, free_storage,
                                                                        mmap_calls, mmap_storage,
                                                                        munmap_calls, munmap_storage,
                                                                        sbrk_calls, sbrk_storage
                );
} // printStats

static int printStatsXML( FILE * stream ) {                             // see malloc_info
        char helpText[512];
        int len = snprintf( helpText, sizeof(helpText),
                                                "<malloc version=\"1\">\n"
                                                "<heap nr=\"0\">\n"
                                                "<sizes>\n"
                                                "</sizes>\n"
                                                "<total type=\"malloc\" count=\"%u\" size=\"%llu\"/>\n"
                                                "<total type=\"calloc\" count=\"%u\" size=\"%llu\"/>\n"
                                                "<total type=\"memalign\" count=\"%u\" size=\"%llu\"/>\n"
                                                "<total type=\"cmemalign\" count=\"%u\" size=\"%llu\"/>\n"
                                                "<total type=\"realloc\" count=\"%u\" size=\"%llu\"/>\n"
                                                "<total type=\"free\" count=\"%u\" size=\"%llu\"/>\n"
                                                "<total type=\"mmap\" count=\"%u\" size=\"%llu\"/>\n"
                                                "<total type=\"munmap\" count=\"%u\" size=\"%llu\"/>\n"
                                                "<total type=\"sbrk\" count=\"%u\" size=\"%llu\"/>\n"
                                                "</malloc>",
                                                malloc_calls, malloc_storage,
                                                calloc_calls, calloc_storage,
                                                memalign_calls, memalign_storage,
                                                cmemalign_calls, cmemalign_storage,
                                                realloc_calls, realloc_storage,
                                                free_calls, free_storage,
                                                mmap_calls, mmap_storage,
                                                munmap_calls, munmap_storage,
                                                sbrk_calls, sbrk_storage
                );
        __cfaabi_bits_write( fileno( stream ), helpText, len ); // ensures all bytes written or exit
        return len;
} // printStatsXML
#endif // __STATISTICS__


// #comment TD : Is this the samething as Out-of-Memory?
static inline void noMemory() {
        abort( "Heap memory exhausted at %zu bytes.\n"
                   "Possible cause is very large memory allocation and/or large amount of unfreed storage allocated by the program or system/library routines.",
                   ((char *)(sbrk( 0 )) - (char *)(heapManager.heapBegin)) );
} // noMemory


static inline void checkAlign( size_t alignment ) {
        if ( alignment < libAlign() || ! libPow2( alignment ) ) {
                abort( "Alignment %zu for memory allocation is less than %d and/or not a power of 2.", alignment, libAlign() );
        } // if
} // checkAlign


static inline bool setHeapExpand( size_t value ) {
  if ( heapExpand < pageSize ) return true;
        heapExpand = value;
        return false;
} // setHeapExpand


// thunk problem
size_t Bsearchl( unsigned int key, const unsigned int * vals, size_t dim ) {
        size_t l = 0, m, h = dim;
        while ( l < h ) {
                m = (l + h) / 2;
                if ( (unsigned int &)(vals[m]) < key ) {                // cast away const
                        l = m + 1;
                } else {
                        h = m;
                } // if
        } // while
        return l;
} // Bsearchl


static inline bool setMmapStart( size_t value ) {               // true => mmapped, false => sbrk
  if ( value < pageSize || bucketSizes[NoBucketSizes - 1] < value ) return true;
        mmapStart = value;                                                                      // set global

        // find the closest bucket size less than or equal to the mmapStart size
        maxBucketsUsed = Bsearchl( (unsigned int)mmapStart, bucketSizes, NoBucketSizes ); // binary search
        assert( maxBucketsUsed < NoBucketSizes );                       // subscript failure ?
        assert( mmapStart <= bucketSizes[maxBucketsUsed] ); // search failure ?
        return false;
} // setMmapStart


static inline void checkHeader( bool check, const char * name, void * addr ) {
        if ( unlikely( check ) ) {                                                      // bad address ?
                abort( "Attempt to %s storage %p with address outside the heap.\n"
                           "Possible cause is duplicate free on same block or overwriting of memory.",
                           name, addr );
        } // if
} // checkHeader


static inline void fakeHeader( HeapManager.Storage.Header *& header, size_t & alignment ) {
        if ( unlikely( (header->kind.fake.alignment & 1) == 1 ) ) { // fake header ?
                size_t offset = header->kind.fake.offset;
                alignment = header->kind.fake.alignment & -2;   // remove flag from value
                #ifdef __CFA_DEBUG__
                checkAlign( alignment );                                                // check alignment
                #endif // __CFA_DEBUG__
                header = (HeapManager.Storage.Header *)((char *)header - offset);
        } // if
} // fakeHeader


// <-------+----------------------------------------------------> bsize (bucket size)
// |header |addr
//==================================================================================
//                                | alignment
// <-----------------<------------+-----------------------------> bsize (bucket size)
//                   |fake-header | addr
#define headerAddr( addr ) ((HeapManager.Storage.Header *)( (char *)addr - sizeof(HeapManager.Storage) ))

// <-------<<--------------------- dsize ---------------------->> bsize (bucket size)
// |header |addr
//==================================================================================
//                                | alignment
// <------------------------------<<---------- dsize --------->>> bsize (bucket size)
//                   |fake-header |addr
#define dataStorage( bsize, addr, header ) (bsize - ( (char *)addr - (char *)header ))


static inline bool headers( const char * name __attribute__(( unused )), void * addr, HeapManager.Storage.Header *& header, HeapManager.FreeHeader *& freeElem, size_t & size, size_t & alignment ) with ( heapManager ) {
        header = headerAddr( addr );

        if ( unlikely( heapEnd < addr ) ) {                                     // mmapped ?
                fakeHeader( header, alignment );
                size = header->kind.real.blockSize & -3;                // mmap size
                return true;
        } // if

        #ifdef __CFA_DEBUG__
        checkHeader( addr < heapBegin || header < (HeapManager.Storage.Header *)heapBegin, name, addr ); // bad low address ?
        #endif // __CFA_DEBUG__

        // header may be safe to dereference
        fakeHeader( header, alignment );
        #ifdef __CFA_DEBUG__
        checkHeader( header < (HeapManager.Storage.Header *)heapBegin || (HeapManager.Storage.Header *)heapEnd < header, name, addr ); // bad address ? (offset could be + or -)
        #endif // __CFA_DEBUG__

        freeElem = (HeapManager.FreeHeader *)((size_t)header->kind.real.home & -3);
        #ifdef __CFA_DEBUG__
        if ( freeElem < &freeLists[0] || &freeLists[NoBucketSizes] <= freeElem ) {
                abort( "Attempt to %s storage %p with corrupted header.\n"
                           "Possible cause is duplicate free on same block or overwriting of header information.",
                           name, addr );
        } // if
        #endif // __CFA_DEBUG__
        size = freeElem->blockSize;
        return false;
} // headers


static inline void * extend( size_t size ) with ( heapManager ) {
        lock( extlock __cfaabi_dbg_ctx2 );
        ptrdiff_t rem = heapRemaining - size;
        if ( rem < 0 ) {
                // If the size requested is bigger than the current remaining storage, increase the size of the heap.

                size_t increase = libCeiling( size > heapExpand ? size : heapExpand, libAlign() );
                if ( sbrk( increase ) == (void *)-1 ) {
                        unlock( extlock );
                        errno = ENOMEM;
                        return 0p;
                } // if
                #ifdef __STATISTICS__
                sbrk_calls += 1;
                sbrk_storage += increase;
                #endif // __STATISTICS__
                #ifdef __CFA_DEBUG__
                // Set new memory to garbage so subsequent uninitialized usages might fail.
                memset( (char *)heapEnd + heapRemaining, '\377', increase );
                #endif // __CFA_DEBUG__
                rem = heapRemaining + increase - size;
        } // if

        HeapManager.Storage * block = (HeapManager.Storage *)heapEnd;
        heapRemaining = rem;
        heapEnd = (char *)heapEnd + size;
        unlock( extlock );
        return block;
} // extend


static inline void * doMalloc( size_t size ) with ( heapManager ) {
        HeapManager.Storage * block;                                            // pointer to new block of storage

        // Look up size in the size list.  Make sure the user request includes space for the header that must be allocated
        // along with the block and is a multiple of the alignment size.

  if ( unlikely( size > ~0ul - sizeof(HeapManager.Storage) ) ) return 0p;
        size_t tsize = size + sizeof(HeapManager.Storage);
        if ( likely( tsize < mmapStart ) ) {                            // small size => sbrk
                size_t posn;
                #ifdef FASTLOOKUP
                if ( tsize < LookupSizes ) posn = lookup[tsize];
                else
                #endif // FASTLOOKUP
                        posn = Bsearchl( (unsigned int)tsize, bucketSizes, (size_t)maxBucketsUsed );
                HeapManager.FreeHeader * freeElem = &freeLists[posn];
                // #ifdef FASTLOOKUP
                // if ( tsize < LookupSizes )
                //      freeElem = &freeLists[lookup[tsize]];
                // else
                // #endif // FASTLOOKUP
                //      freeElem = bsearchl( tsize, freeLists, (size_t)maxBucketsUsed ); // binary search
                // HeapManager.FreeHeader * freeElem =
                //      #ifdef FASTLOOKUP
                //      tsize < LookupSizes ? &freeLists[lookup[tsize]] :
                //      #endif // FASTLOOKUP
                //      bsearchl( tsize, freeLists, (size_t)maxBucketsUsed ); // binary search
                assert( freeElem <= &freeLists[maxBucketsUsed] ); // subscripting error ?
                assert( tsize <= freeElem->blockSize );                 // search failure ?
                tsize = freeElem->blockSize;                                    // total space needed for request

                // Spin until the lock is acquired for this particular size of block.

                #if defined( SPINLOCK )
                lock( freeElem->lock __cfaabi_dbg_ctx2 );
                block = freeElem->freeList;                                             // remove node from stack
                #else
                block = freeElem->freeList.pop();
                #endif // SPINLOCK
                if ( unlikely( block == 0p ) ) {                                // no free block ?
                        #if defined( SPINLOCK )
                        unlock( freeElem->lock );
                        #endif // SPINLOCK

                        // Freelist for that size was empty, so carve it out of the heap if there's enough left, or get some more
                        // and then carve it off.

                        block = (HeapManager.Storage *)extend( tsize ); // mutual exclusion on call
  if ( unlikely( block == 0p ) ) return 0p;
                #if defined( SPINLOCK )
                } else {
                        freeElem->freeList = block->header.kind.real.next;
                        unlock( freeElem->lock );
                #endif // SPINLOCK
                } // if

                block->header.kind.real.home = freeElem;                // pointer back to free list of apropriate size
        } else {                                                                                        // large size => mmap
  if ( unlikely( size > ~0ul - pageSize ) ) return 0p;
                tsize = libCeiling( tsize, pageSize );                  // must be multiple of page size
                #ifdef __STATISTICS__
                __atomic_add_fetch( &mmap_calls, 1, __ATOMIC_SEQ_CST );
                __atomic_add_fetch( &mmap_storage, tsize, __ATOMIC_SEQ_CST );
                #endif // __STATISTICS__
                block = (HeapManager.Storage *)mmap( 0, tsize, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, mmapFd, 0 );
                if ( block == (HeapManager.Storage *)MAP_FAILED ) {
                        // Do not call strerror( errno ) as it may call malloc.
                        abort( "(HeapManager &)0x%p.doMalloc() : internal error, mmap failure, size:%zu error:%d.", &heapManager, tsize, errno );
                } // if
                #ifdef __CFA_DEBUG__
                // Set new memory to garbage so subsequent uninitialized usages might fail.
                memset( block, '\377', tsize );
                #endif // __CFA_DEBUG__
                block->header.kind.real.blockSize = tsize;              // storage size for munmap
        } // if

        void * addr = &(block->data);                                           // adjust off header to user bytes

        #ifdef __CFA_DEBUG__
        assert( ((uintptr_t)addr & (libAlign() - 1)) == 0 ); // minimum alignment ?
        __atomic_add_fetch( &allocFree, tsize, __ATOMIC_SEQ_CST );
        if ( traceHeap() ) {
                enum { BufferSize = 64 };
                char helpText[BufferSize];
                int len = snprintf( helpText, BufferSize, "%p = Malloc( %zu ) (allocated %zu)\n", addr, size, tsize );
                // int len = snprintf( helpText, BufferSize, "Malloc %p %zu\n", addr, size );
                __cfaabi_bits_write( STDERR_FILENO, helpText, len ); // print debug/nodebug
        } // if
        #endif // __CFA_DEBUG__

        return addr;
} // doMalloc


static inline void doFree( void * addr ) with ( heapManager ) {
        #ifdef __CFA_DEBUG__
        if ( unlikely( heapManager.heapBegin == 0p ) ) {
                abort( "doFree( %p ) : internal error, called before heap is initialized.", addr );
        } // if
        #endif // __CFA_DEBUG__

        HeapManager.Storage.Header * header;
        HeapManager.FreeHeader * freeElem;
        size_t size, alignment;                                                         // not used (see realloc)

        if ( headers( "free", addr, header, freeElem, size, alignment ) ) { // mmapped ?
                #ifdef __STATISTICS__
                __atomic_add_fetch( &munmap_calls, 1, __ATOMIC_SEQ_CST );
                __atomic_add_fetch( &munmap_storage, size, __ATOMIC_SEQ_CST );
                #endif // __STATISTICS__
                if ( munmap( header, size ) == -1 ) {
                        #ifdef __CFA_DEBUG__
                        abort( "Attempt to deallocate storage %p not allocated or with corrupt header.\n"
                                   "Possible cause is invalid pointer.",
                                   addr );
                        #endif // __CFA_DEBUG__
                } // if
        } else {
                #ifdef __CFA_DEBUG__
                // Set free memory to garbage so subsequent usages might fail.
                memset( ((HeapManager.Storage *)header)->data, '\377', freeElem->blockSize - sizeof( HeapManager.Storage ) );
                #endif // __CFA_DEBUG__

                #ifdef __STATISTICS__
                free_storage += size;
                #endif // __STATISTICS__
                #if defined( SPINLOCK )
                lock( freeElem->lock __cfaabi_dbg_ctx2 );               // acquire spin lock
                header->kind.real.next = freeElem->freeList;    // push on stack
                freeElem->freeList = (HeapManager.Storage *)header;
                unlock( freeElem->lock );                                               // release spin lock
                #else
                freeElem->freeList.push( *(HeapManager.Storage *)header );
                #endif // SPINLOCK
        } // if

        #ifdef __CFA_DEBUG__
        __atomic_add_fetch( &allocFree, -size, __ATOMIC_SEQ_CST );
        if ( traceHeap() ) {
                enum { BufferSize = 64 };
                char helpText[BufferSize];
                int len = snprintf( helpText, sizeof(helpText), "Free( %p ) size:%zu\n", addr, size );
                __cfaabi_bits_write( STDERR_FILENO, helpText, len ); // print debug/nodebug
        } // if
        #endif // __CFA_DEBUG__
} // doFree


size_t prtFree( HeapManager & manager ) with ( manager ) {
        size_t total = 0;
        #ifdef __STATISTICS__
        __cfaabi_bits_acquire();
        __cfaabi_bits_print_nolock( STDERR_FILENO, "\nBin lists (bin size : free blocks on list)\n" );
        #endif // __STATISTICS__
        for ( unsigned int i = 0; i < maxBucketsUsed; i += 1 ) {
                size_t size = freeLists[i].blockSize;
                #ifdef __STATISTICS__
                unsigned int N = 0;
                #endif // __STATISTICS__

                #if defined( SPINLOCK )
                for ( HeapManager.Storage * p = freeLists[i].freeList; p != 0p; p = p->header.kind.real.next ) {
                #else
                for ( HeapManager.Storage * p = freeLists[i].freeList.top(); p != 0p; p = p->header.kind.real.next.top ) {
                #endif // SPINLOCK
                        total += size;
                        #ifdef __STATISTICS__
                        N += 1;
                        #endif // __STATISTICS__
                } // for

                #ifdef __STATISTICS__
                __cfaabi_bits_print_nolock( STDERR_FILENO, "%7zu, %-7u  ", size, N );
                if ( (i + 1) % 8 == 0 ) __cfaabi_bits_print_nolock( STDERR_FILENO, "\n" );
                #endif // __STATISTICS__
        } // for
        #ifdef __STATISTICS__
        __cfaabi_bits_print_nolock( STDERR_FILENO, "\ntotal free blocks:%zu\n", total );
        __cfaabi_bits_release();
        #endif // __STATISTICS__
        return (char *)heapEnd - (char *)heapBegin - total;
} // prtFree


static void ?{}( HeapManager & manager ) with ( manager ) {
        pageSize = sysconf( _SC_PAGESIZE );

        for ( unsigned int i = 0; i < NoBucketSizes; i += 1 ) { // initialize the free lists
                freeLists[i].blockSize = bucketSizes[i];
        } // for

        #ifdef FASTLOOKUP
        unsigned int idx = 0;
        for ( unsigned int i = 0; i < LookupSizes; i += 1 ) {
                if ( i > bucketSizes[idx] ) idx += 1;
                lookup[i] = idx;
        } // for
        #endif // FASTLOOKUP

        if ( setMmapStart( default_mmap_start() ) ) {
                abort( "HeapManager : internal error, mmap start initialization failure." );
        } // if
        heapExpand = default_heap_expansion();

        char * end = (char *)sbrk( 0 );
        sbrk( (char *)libCeiling( (long unsigned int)end, libAlign() ) - end ); // move start of heap to multiple of alignment
        heapBegin = heapEnd = sbrk( 0 );                                        // get new start point
} // HeapManager


static void ^?{}( HeapManager & ) {
        #ifdef __STATISTICS__
        // if ( traceHeapTerm() ) {
        //      printStats();
        //      if ( prtfree() ) prtFree( heapManager, true );
        // } // if
        #endif // __STATISTICS__
} // ~HeapManager


static void memory_startup( void ) __attribute__(( constructor( STARTUP_PRIORITY_MEMORY ) ));
void memory_startup( void ) {
        #ifdef __CFA_DEBUG__
        if ( unlikely( heapBoot ) ) {                                           // check for recursion during system boot
                // DO NOT USE STREAMS AS THEY MAY BE UNAVAILABLE AT THIS POINT.
                abort( "boot() : internal error, recursively invoked during system boot." );
        } // if
        heapBoot = true;
        #endif // __CFA_DEBUG__

        //assert( heapManager.heapBegin != 0 );
        //heapManager{};
        if ( heapManager.heapBegin == 0p ) heapManager{};
} // memory_startup

static void memory_shutdown( void ) __attribute__(( destructor( STARTUP_PRIORITY_MEMORY ) ));
void memory_shutdown( void ) {
        ^heapManager{};
} // memory_shutdown


static inline void * mallocNoStats( size_t size ) {             // necessary for malloc statistics
        //assert( heapManager.heapBegin != 0 );
        if ( unlikely( heapManager.heapBegin == 0p ) ) heapManager{}; // called before memory_startup ?
        void * addr = doMalloc( size );
        if ( unlikely( addr == 0p ) ) errno = ENOMEM;           // POSIX
        return addr;
} // mallocNoStats


static inline void * callocNoStats( size_t noOfElems, size_t elemSize ) {
        size_t size = noOfElems * elemSize;
        char * addr = (char *)mallocNoStats( size );
  if ( unlikely( addr == 0p ) ) return 0p;

        HeapManager.Storage.Header * header;
        HeapManager.FreeHeader * freeElem;
        size_t bsize, alignment;
        bool mapped __attribute__(( unused )) = headers( "calloc", addr, header, freeElem, bsize, alignment );
        #ifndef __CFA_DEBUG__
        // Mapped storage is zero filled, but in debug mode mapped memory is scrubbed in doMalloc, so it has to be reset to zero.
        if ( ! mapped )
        #endif // __CFA_DEBUG__
                // Zero entire data space even when > than size => realloc without a new allocation and zero fill works.
                // <-------00000000000000000000000000000000000000000000000000000> bsize (bucket size)
                // `-header`-addr                      `-size
                memset( addr, '\0', bsize - sizeof(HeapManager.Storage) ); // set to zeros

        header->kind.real.blockSize |= 2;                                       // mark as zero filled
        return addr;
} // callocNoStats


static inline void * memalignNoStats( size_t alignment, size_t size ) { // necessary for malloc statistics
        #ifdef __CFA_DEBUG__
        checkAlign( alignment );                                                        // check alignment
        #endif // __CFA_DEBUG__

        // if alignment <= default alignment, do normal malloc as two headers are unnecessary
  if ( unlikely( alignment <= libAlign() ) ) return mallocNoStats( size );

        // Allocate enough storage to guarantee an address on the alignment boundary, and sufficient space before it for
        // administrative storage. NOTE, WHILE THERE ARE 2 HEADERS, THE FIRST ONE IS IMPLICITLY CREATED BY DOMALLOC.
        //      .-------------v-----------------v----------------v----------,
        //      | Real Header | ... padding ... |   Fake Header  | data ... |
        //      `-------------^-----------------^-+--------------^----------'
        //      |<--------------------------------' offset/align |<-- alignment boundary

        // subtract libAlign() because it is already the minimum alignment
        // add sizeof(Storage) for fake header
        char * addr = (char *)mallocNoStats( size + alignment - libAlign() + sizeof(HeapManager.Storage) );
  if ( unlikely( addr == 0p ) ) return addr;

        // address in the block of the "next" alignment address
        char * user = (char *)libCeiling( (uintptr_t)(addr + sizeof(HeapManager.Storage)), alignment );

        // address of header from malloc
        HeapManager.Storage.Header * realHeader = headerAddr( addr );
        // address of fake header * before* the alignment location
        HeapManager.Storage.Header * fakeHeader = headerAddr( user );
        // SKULLDUGGERY: insert the offset to the start of the actual storage block and remember alignment
        fakeHeader->kind.fake.offset = (char *)fakeHeader - (char *)realHeader;
        // SKULLDUGGERY: odd alignment imples fake header
        fakeHeader->kind.fake.alignment = alignment | 1;

        return user;
} // memalignNoStats


static inline void * cmemalignNoStats( size_t alignment, size_t noOfElems, size_t elemSize ) {
        size_t size = noOfElems * elemSize;
        char * addr = (char *)memalignNoStats( alignment, size );
  if ( unlikely( addr == 0p ) ) return 0p;
        HeapManager.Storage.Header * header;
        HeapManager.FreeHeader * freeElem;
        size_t bsize;
        bool mapped __attribute__(( unused )) = headers( "cmemalign", addr, header, freeElem, bsize, alignment );
        #ifndef __CFA_DEBUG__
        // Mapped storage is zero filled, but in debug mode mapped memory is scrubbed in doMalloc, so it has to be reset to zero.
        if ( ! mapped )
        #endif // __CFA_DEBUG__
                memset( addr, '\0', dataStorage( bsize, addr, header ) ); // set to zeros
        header->kind.real.blockSize |= 2;                               // mark as zero filled

        return addr;
} // cmemalignNoStats


// supported mallopt options
#ifndef M_MMAP_THRESHOLD
#define M_MMAP_THRESHOLD (-1)
#endif // M_TOP_PAD
#ifndef M_TOP_PAD
#define M_TOP_PAD (-2)
#endif // M_TOP_PAD


extern "C" {
        // The malloc() function allocates size bytes and returns a pointer to the allocated memory. The memory is not
        // initialized. If size is 0, then malloc() returns either 0p, or a unique pointer value that can later be
        // successfully passed to free().
        void * malloc( size_t size ) {
                #ifdef __STATISTICS__
                __atomic_add_fetch( &malloc_calls, 1, __ATOMIC_SEQ_CST );
                __atomic_add_fetch( &malloc_storage, size, __ATOMIC_SEQ_CST );
                #endif // __STATISTICS__

                return mallocNoStats( size );
        } // malloc

        // The calloc() function allocates memory for an array of nmemb elements of size bytes each and returns a pointer to
        // the allocated memory. The memory is set to zero. If nmemb or size is 0, then calloc() returns either 0p, or a
        // unique pointer value that can later be successfully passed to free().
        void * calloc( size_t noOfElems, size_t elemSize ) {
                #ifdef __STATISTICS__
                __atomic_add_fetch( &calloc_calls, 1, __ATOMIC_SEQ_CST );
                __atomic_add_fetch( &calloc_storage, noOfElems * elemSize, __ATOMIC_SEQ_CST );
                #endif // __STATISTICS__

                return callocNoStats( noOfElems, elemSize );
        } // calloc

        // The realloc() function changes the size of the memory block pointed to by ptr to size bytes. The contents will be
        // unchanged in the range from the start of the region up to the minimum of the old and new sizes. If the new size
        // is larger than the old size, the added memory will not be initialized.  If ptr is 0p, then the call is
        // equivalent to malloc(size), for all values of size; if size is equal to zero, and ptr is not 0p, then the call
        // is equivalent to free(ptr). Unless ptr is 0p, it must have been returned by an earlier call to malloc(),
        // calloc() or realloc(). If the area pointed to was moved, a free(ptr) is done.
        void * realloc( void * oaddr, size_t size ) {
                #ifdef __STATISTICS__
                __atomic_add_fetch( &realloc_calls, 1, __ATOMIC_SEQ_CST );
                #endif // __STATISTICS__

          if ( unlikely( size == 0 ) ) { free( oaddr ); return 0p; } // special cases
          if ( unlikely( oaddr == 0p ) ) return mallocNoStats( size );

                HeapManager.Storage.Header * header;
                HeapManager.FreeHeader * freeElem;
                size_t bsize, oalign = 0;
                headers( "realloc", oaddr, header, freeElem, bsize, oalign );

                size_t odsize = dataStorage( bsize, oaddr, header ); // data storage available in bucket
          if ( size <= odsize && odsize <= size * 2 ) { // allow up to 50% wasted storage in smaller size
                        // Do not know size of original allocation => cannot do 0 fill for any additional space because do not know
                        // where to start filling, i.e., do not overwrite existing values in space.
                        //
                        // This case does not result in a new profiler entry because the previous one still exists and it must match with
                        // the free for this memory.  Hence, this realloc does not appear in the profiler output.
                        return oaddr;
                } // if

                #ifdef __STATISTICS__
                __atomic_add_fetch( &realloc_storage, size, __ATOMIC_SEQ_CST );
                #endif // __STATISTICS__

                // change size and copy old content to new storage

                void * naddr;
                if ( unlikely( oalign != 0 ) ) {                                // previous request memalign?
                        if ( unlikely( header->kind.real.blockSize & 2 ) ) { // previous request zero fill
                                naddr = cmemalignNoStats( oalign, 1, size ); // create new aligned area
                        } else {
                                naddr = memalignNoStats( oalign, size ); // create new aligned area
                        } // if
                } else {
                        if ( unlikely( header->kind.real.blockSize & 2 ) ) { // previous request zero fill
                                naddr = callocNoStats( 1, size );               // create new area
                        } else {
                                naddr = mallocNoStats( size );                  // create new area
                        } // if
                } // if
          if ( unlikely( naddr == 0p ) ) return 0p;

                headers( "realloc", naddr, header, freeElem, bsize, oalign );
                size_t ndsize = dataStorage( bsize, naddr, header ); // data storage avilable in bucket
                // To preserve prior fill, the entire bucket must be copied versus the size.
                memcpy( naddr, oaddr, MIN( odsize, ndsize ) );  // copy bytes
                free( oaddr );
                return naddr;
        } // realloc

        // The obsolete function memalign() allocates size bytes and returns a pointer to the allocated memory. The memory
        // address will be a multiple of alignment, which must be a power of two.
        void * memalign( size_t alignment, size_t size ) {
                #ifdef __STATISTICS__
                __atomic_add_fetch( &memalign_calls, 1, __ATOMIC_SEQ_CST );
                __atomic_add_fetch( &memalign_storage, size, __ATOMIC_SEQ_CST );
                #endif // __STATISTICS__

                return memalignNoStats( alignment, size );
        } // memalign


        // The cmemalign() function is the same as calloc() with memory alignment.
        void * cmemalign( size_t alignment, size_t noOfElems, size_t elemSize ) {
                #ifdef __STATISTICS__
                __atomic_add_fetch( &cmemalign_calls, 1, __ATOMIC_SEQ_CST );
                __atomic_add_fetch( &cmemalign_storage, noOfElems * elemSize, __ATOMIC_SEQ_CST );
                #endif // __STATISTICS__

                return cmemalignNoStats( alignment, noOfElems, elemSize );
        } // cmemalign

        // The function aligned_alloc() is the same as memalign(), except for the added restriction that size should be a
        // multiple of alignment.
        void * aligned_alloc( size_t alignment, size_t size ) {
                return memalign( alignment, size );
        } // aligned_alloc


        // The function posix_memalign() allocates size bytes and places the address of the allocated memory in *memptr. The
        // address of the allocated memory will be a multiple of alignment, which must be a power of two and a multiple of
        // sizeof(void *). If size is 0, then posix_memalign() returns either 0p, or a unique pointer value that can later
        // be successfully passed to free(3).
        int posix_memalign( void ** memptr, size_t alignment, size_t size ) {
          if ( alignment < sizeof(void *) || ! libPow2( alignment ) ) return EINVAL; // check alignment
                * memptr = memalign( alignment, size );
          if ( unlikely( * memptr == 0p ) ) return ENOMEM;
                return 0;
        } // posix_memalign

        // The obsolete function valloc() allocates size bytes and returns a pointer to the allocated memory. The memory
        // address will be a multiple of the page size.  It is equivalent to memalign(sysconf(_SC_PAGESIZE),size).
        void * valloc( size_t size ) {
                return memalign( pageSize, size );
        } // valloc


        // The free() function frees the memory space pointed to by ptr, which must have been returned by a previous call to
        // malloc(), calloc() or realloc().  Otherwise, or if free(ptr) has already been called before, undefined behavior
        // occurs. If ptr is 0p, no operation is performed.
        void free( void * addr ) {
                #ifdef __STATISTICS__
                __atomic_add_fetch( &free_calls, 1, __ATOMIC_SEQ_CST );
                #endif // __STATISTICS__

          if ( unlikely( addr == 0p ) ) {                                       // special case
                        // #ifdef __CFA_DEBUG__
                        // if ( traceHeap() ) {
                        //      #define nullmsg "Free( 0x0 ) size:0\n"
                        //      // Do not debug print free( 0p ), as it can cause recursive entry from sprintf.
                        //      __cfaabi_dbg_write( nullmsg, sizeof(nullmsg) - 1 );
                        // } // if
                        // #endif // __CFA_DEBUG__
                        return;
                } // exit

                doFree( addr );
        } // free


        // The malloc_alignment() function returns the alignment of the allocation.
        size_t malloc_alignment( void * addr ) {
          if ( unlikely( addr == 0p ) ) return libAlign();      // minimum alignment
                HeapManager.Storage.Header * header = headerAddr( addr );
                if ( (header->kind.fake.alignment & 1) == 1 ) { // fake header ?
                        return header->kind.fake.alignment & -2;        // remove flag from value
                } else {
                        return libAlign ();                                                     // minimum alignment
                } // if
        } // malloc_alignment


        // The malloc_zero_fill() function returns true if the allocation is zero filled, i.e., initially allocated by calloc().
        bool malloc_zero_fill( void * addr ) {
          if ( unlikely( addr == 0p ) ) return false;           // null allocation is not zero fill
                HeapManager.Storage.Header * header = headerAddr( addr );
                if ( (header->kind.fake.alignment & 1) == 1 ) { // fake header ?
                        header = (HeapManager.Storage.Header *)((char *)header - header->kind.fake.offset);
                } // if
                return (header->kind.real.blockSize & 2) != 0;  // zero filled (calloc/cmemalign) ?
        } // malloc_zero_fill


        // The malloc_usable_size() function returns the number of usable bytes in the block pointed to by ptr, a pointer to
        // a block of memory allocated by malloc(3) or a related function.
        size_t malloc_usable_size( void * addr ) {
          if ( unlikely( addr == 0p ) ) return 0;                       // null allocation has 0 size
                HeapManager.Storage.Header * header;
                HeapManager.FreeHeader * freeElem;
                size_t bsize, alignment;

                headers( "malloc_usable_size", addr, header, freeElem, bsize, alignment );
                return dataStorage( bsize, addr, header );      // data storage in bucket
        } // malloc_usable_size


        // The malloc_stats() function prints (on default standard error) statistics about memory allocated by malloc(3) and
        // related functions.
        void malloc_stats( void ) {
                #ifdef __STATISTICS__
                printStats();
                if ( prtFree() ) prtFree( heapManager );
                #endif // __STATISTICS__
        } // malloc_stats

        // The malloc_stats_fd() function changes the file descripter where malloc_stats() writes the statistics.
        int malloc_stats_fd( int fd __attribute__(( unused )) ) {
                #ifdef __STATISTICS__
                int temp = statfd;
                statfd = fd;
                return temp;
                #else
                return -1;
                #endif // __STATISTICS__
        } // malloc_stats_fd


        // The mallopt() function adjusts parameters that control the behavior of the memory-allocation functions (see
        // malloc(3)). The param argument specifies the parameter to be modified, and value specifies the new value for that
        // parameter.
        int mallopt( int option, int value ) {
                choose( option ) {
                  case M_TOP_PAD:
                        if ( setHeapExpand( value ) ) return 1;
                  case M_MMAP_THRESHOLD:
                        if ( setMmapStart( value ) ) return 1;
                } // switch
                return 0;                                                                               // error, unsupported
        } // mallopt

        // The malloc_trim() function attempts to release free memory at the top of the heap (by calling sbrk(2) with a
        // suitable argument).
        int malloc_trim( size_t ) {
                return 0;                                                                               // => impossible to release memory
        } // malloc_trim


        // The malloc_info() function exports an XML string that describes the current state of the memory-allocation
        // implementation in the caller.  The string is printed on the file stream stream.  The exported string includes
        // information about all arenas (see malloc(3)).
        int malloc_info( int options, FILE * stream ) {
                if ( options != 0 ) { errno = EINVAL; return -1; }
                return printStatsXML( stream );
        } // malloc_info


        // The malloc_get_state() function records the current state of all malloc(3) internal bookkeeping variables (but
        // not the actual contents of the heap or the state of malloc_hook(3) functions pointers).  The state is recorded in
        // a system-dependent opaque data structure dynamically allocated via malloc(3), and a pointer to that data
        // structure is returned as the function result.  (It is the caller's responsibility to free(3) this memory.)
        void * malloc_get_state( void ) {
                return 0p;                                                                              // unsupported
        } // malloc_get_state


        // The malloc_set_state() function restores the state of all malloc(3) internal bookkeeping variables to the values
        // recorded in the opaque data structure pointed to by state.
        int malloc_set_state( void * ptr ) {
                return 0;                                                                               // unsupported
        } // malloc_set_state
} // extern "C"


// Must have CFA linkage to overload with C linkage realloc.
void * realloc( void * oaddr, size_t nalign, size_t size ) {
        #ifdef __STATISTICS__
        __atomic_add_fetch( &realloc_calls, 1, __ATOMIC_SEQ_CST );
        #endif // __STATISTICS__

  if ( unlikely( size == 0 ) ) { free( oaddr ); return 0p; } // special cases
  if ( unlikely( oaddr == 0p ) ) return mallocNoStats( size );

        if ( unlikely( nalign == 0 ) ) nalign = libAlign();     // reset alignment to minimum
        #ifdef __CFA_DEBUG__
        else
                checkAlign( nalign );                                                   // check alignment
        #endif // __CFA_DEBUG__

        HeapManager.Storage.Header * header;
        HeapManager.FreeHeader * freeElem;
        size_t bsize, oalign = 0;
        headers( "realloc", oaddr, header, freeElem, bsize, oalign );
        size_t odsize = dataStorage( bsize, oaddr, header ); // data storage available in bucket

  if ( oalign != 0 && (uintptr_t)oaddr % nalign == 0 ) { // has alignment and just happens to work out
                headerAddr( oaddr )->kind.fake.alignment = nalign | 1; // update alignment (could be the same)
                return realloc( oaddr, size );
        } // if

        #ifdef __STATISTICS__
        __atomic_add_fetch( &realloc_storage, size, __ATOMIC_SEQ_CST );
        #endif // __STATISTICS__

        // change size and copy old content to new storage

        void * naddr;
        if ( unlikely( header->kind.real.blockSize & 2 ) ) { // previous request zero fill
                naddr = cmemalignNoStats( nalign, 1, size );    // create new aligned area
        } else {
                naddr = memalignNoStats( nalign, size );                // create new aligned area
        } // if

        headers( "realloc", naddr, header, freeElem, bsize, oalign );
        size_t ndsize = dataStorage( bsize, naddr, header ); // data storage avilable in bucket
        // To preserve prior fill, the entire bucket must be copied versus the size.
        memcpy( naddr, oaddr, MIN( odsize, ndsize ) );          // copy bytes
        free( oaddr );
        return naddr;
} // realloc


// Local Variables: //
// tab-width: 4 //
// compile-command: "cfa -nodebug -O2 heap.cfa" //
// End: //