zone.c

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/*
Copyright (C) 1996-1997 Id Software, Inc.
 
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
 
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 
See the GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 
*/
// Z_zone.c
 
#include "darkplaces.h"
 
#ifdef WIN32
#include <windows.h>
#include <winbase.h>
#else
#include <unistd.h>
#endif
 
#define MEMHEADER_SENTINEL_FOR_ADDRESS(p) ((sentinel_seed ^ (unsigned int) (uintptr_t) (p)) + sentinel_seed)
unsigned int sentinel_seed;
 
qbool mem_bigendian = false;
void *mem_mutex = NULL;
 
// divVerent: enables file backed malloc using mmap to conserve swap space (instead of malloc)
#ifndef FILE_BACKED_MALLOC
# define FILE_BACKED_MALLOC 0
#endif
 
// LadyHavoc: enables our own low-level allocator (instead of malloc)
#ifndef MEMCLUMPING
# define MEMCLUMPING 0
#endif
#ifndef MEMCLUMPING_FREECLUMPS
# define MEMCLUMPING_FREECLUMPS 0
#endif
 
#if MEMCLUMPING
// smallest unit we care about is this many bytes
#define MEMUNIT 128
// try to do 32MB clumps, but overhead eats into this
#ifndef MEMWANTCLUMPSIZE
# define MEMWANTCLUMPSIZE (1<<27)
#endif
// give malloc padding so we can't waste most of a page at the end
#define MEMCLUMPSIZE (MEMWANTCLUMPSIZE - MEMWANTCLUMPSIZE/MEMUNIT/32 - 128)
#define MEMBITS (MEMCLUMPSIZE / MEMUNIT)
#define MEMBITINTS (MEMBITS / 32)
 
typedef struct memclump_s
{
    // contents of the clump
    unsigned char block[MEMCLUMPSIZE];
    // should always be MEMCLUMP_SENTINEL
    unsigned int sentinel1;
    // if a bit is on, it means that the MEMUNIT bytes it represents are
    // allocated, otherwise free
    unsigned int bits[MEMBITINTS];
    // should always be MEMCLUMP_SENTINEL
    unsigned int sentinel2;
    // if this drops to 0, the clump is freed
    size_t blocksinuse;
    // largest block of memory available (this is reset to an optimistic
    // number when anything is freed, and updated when alloc fails the clump)
    size_t largestavailable;
    // next clump in the chain
    struct memclump_s *chain;
}
memclump_t;
 
#if MEMCLUMPING == 2
static memclump_t masterclump;
#endif
static memclump_t *clumpchain = NULL;
#endif
 
 
cvar_t developer_memory = {CF_CLIENT | CF_SERVER, "developer_memory", "0", "prints debugging information about memory allocations"};
cvar_t developer_memorydebug = {CF_CLIENT | CF_SERVER, "developer_memorydebug", "0", "enables memory corruption checks (very slow)"};
cvar_t developer_memoryreportlargerthanmb = {CF_CLIENT | CF_SERVER, "developer_memorylargerthanmb", "16", "prints debugging information about memory allocations over this size"};
cvar_t sys_memsize_physical = {CF_CLIENT | CF_SERVER | CF_READONLY, "sys_memsize_physical", "", "physical memory size in MB (or empty if unknown)"};
cvar_t sys_memsize_virtual = {CF_CLIENT | CF_SERVER | CF_READONLY, "sys_memsize_virtual", "", "virtual memory size in MB (or empty if unknown)"};
 
static mempool_t *poolchain = NULL;
 
void Mem_PrintStats(void);
void Mem_PrintList(size_t minallocationsize);
 
#if FILE_BACKED_MALLOC
#include <stdlib.h>
#include <sys/mman.h>
#ifndef MAP_NORESERVE
#define MAP_NORESERVE 0
#endif
typedef struct mmap_data_s
{
    size_t len;
}
mmap_data_t;
static void *mmap_malloc(size_t size)
{
    char vabuf[MAX_OSPATH + 1];
    char *tmpdir = getenv("TEMP");
    mmap_data_t *data;
    int fd;
    size += sizeof(mmap_data_t); // waste block
    dpsnprintf(vabuf, sizeof(vabuf), "%s/darkplaces.XXXXXX", tmpdir ? tmpdir : "/tmp");
    fd = mkstemp(vabuf);
    if(fd < 0)
        return NULL;
    ftruncate(fd, size);
    data = (unsigned char *) mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_NORESERVE, fd, 0);
    close(fd);
    unlink(vabuf);
    if(!data || data == (void *)-1)
        return NULL;
    data->len = size;
    return (void *) (data + 1);
}
static void mmap_free(void *mem)
{
    mmap_data_t *data;
    if(!mem)
        return;
    data = ((mmap_data_t *) mem) - 1;
    munmap(data, data->len);
}
#define malloc mmap_malloc
#define free mmap_free
#endif
 
#if MEMCLUMPING != 2
// some platforms have a malloc that returns NULL but succeeds later
// (Windows growing its swapfile for example)
static void *attempt_malloc(size_t size)
{
#ifndef WIN32
    return malloc(size);
#else
    void *base;
    // try for half a second or so
    unsigned int attempts = 500;
    while (attempts--)
    {
        base = (void *)malloc(size);
        if (base)
            return base;
        Sys_Sleep(1000);
    }
    return NULL;
#endif
}
#endif
 
#if MEMCLUMPING
static memclump_t *Clump_NewClump(void)
{
    memclump_t **clumpchainpointer;
    memclump_t *clump;
#if MEMCLUMPING == 2
    if (clumpchain)
        return NULL;
    clump = &masterclump;
#else
    clump = (memclump_t*)attempt_malloc(sizeof(memclump_t));
    if (!clump)
        return NULL;
#endif
 
    // initialize clump
    if (developer_memorydebug.integer)
        memset(clump, 0xEF, sizeof(*clump));
    clump->sentinel1 = MEMHEADER_SENTINEL_FOR_ADDRESS(&clump->sentinel1);
    memset(clump->bits, 0, sizeof(clump->bits));
    clump->sentinel2 = MEMHEADER_SENTINEL_FOR_ADDRESS(&clump->sentinel2);
    clump->blocksinuse = 0;
    clump->largestavailable = 0;
    clump->chain = NULL;
 
    // link clump into chain
    for (clumpchainpointer = &clumpchain;*clumpchainpointer;clumpchainpointer = &(*clumpchainpointer)->chain)
        ;
    *clumpchainpointer = clump;
 
    return clump;
}
#endif
 
// low level clumping functions, all other memory functions use these
static void *Clump_AllocBlock(size_t size)
{
    unsigned char *base;
#if MEMCLUMPING
    if (size <= MEMCLUMPSIZE)
    {
        intptr_t index;
        size_t bit;
        size_t needbits;
        size_t startbit;
        size_t endbit;
        size_t needints;
        intptr_t startindex;
        intptr_t endindex;
        unsigned int value;
        unsigned int mask;
        unsigned int *array;
        memclump_t **clumpchainpointer;
        memclump_t *clump;
        needbits = (size + MEMUNIT - 1) / MEMUNIT;
        needints = (needbits+31)>>5;
        for (clumpchainpointer = &clumpchain;;clumpchainpointer = &(*clumpchainpointer)->chain)
        {
            clump = *clumpchainpointer;
            if (!clump)
            {
                clump = Clump_NewClump();
                if (!clump)
                    return NULL;
            }
            if (clump->sentinel1 != MEMHEADER_SENTINEL_FOR_ADDRESS(&clump->sentinel1))
                Sys_Error("Clump_AllocBlock: trashed sentinel1\n");
            if (clump->sentinel2 != MEMHEADER_SENTINEL_FOR_ADDRESS(&clump->sentinel2))
                Sys_Error("Clump_AllocBlock: trashed sentinel2\n");
            startbit = 0;
            endbit = startbit + needbits;
            array = clump->bits;
            // do as fast a search as possible, even if it means crude alignment
            if (needbits >= 32)
            {
                // large allocations are aligned to large boundaries
                // furthermore, they are allocated downward from the top...
                endindex = MEMBITINTS;
                startindex = endindex - needints;
                index = endindex;
                while (--index >= startindex)
                {
                    if (array[index])
                    {
                        endindex = index;
                        startindex = endindex - needints;
                        if (startindex < 0)
                            goto nofreeblock;
                    }
                }
                startbit = startindex*32;
                goto foundblock;
            }
            else
            {
                // search for a multi-bit gap in a single int
                // (not dealing with the cases that cross two ints)
                mask = (1<<needbits)-1;
                endbit = 32-needbits;
                bit = endbit;
                for (index = 0;index < MEMBITINTS;index++)
                {
                    value = array[index];
                    if (value != 0xFFFFFFFFu)
                    {
                        // there may be room in this one...
                        for (bit = 0;bit < endbit;bit++)
                        {
                            if (!(value & (mask<<bit)))
                            {
                                startbit = index*32+bit;
                                goto foundblock;
                            }
                        }
                    }
                }
                goto nofreeblock;
            }
foundblock:
            endbit = startbit + needbits;
            // mark this range as used
            // TODO: optimize
            for (bit = startbit;bit < endbit;bit++)
                if (clump->bits[bit>>5] & (1<<(bit & 31)))
                    Sys_Error("Clump_AllocBlock: internal error (%i needbits)\n", needbits);
            for (bit = startbit;bit < endbit;bit++)
                clump->bits[bit>>5] |= (1<<(bit & 31));
            clump->blocksinuse += needbits;
            base = clump->block + startbit * MEMUNIT;
            if (developer_memorydebug.integer)
                memset(base, 0xBF, needbits * MEMUNIT);
            return base;
nofreeblock:
            ;
        }
        // never reached
        return NULL;
    }
    // too big, allocate it directly
#endif
#if MEMCLUMPING == 2
    return NULL;
#else
    base = (unsigned char *)attempt_malloc(size);
    if (base && developer_memorydebug.integer)
        memset(base, 0xAF, size);
    return base;
#endif
}
static void Clump_FreeBlock(void *base, size_t size)
{
#if MEMCLUMPING
    size_t needbits;
    size_t startbit;
    size_t endbit;
    size_t bit;
    memclump_t **clumpchainpointer;
    memclump_t *clump;
    unsigned char *start = (unsigned char *)base;
    for (clumpchainpointer = &clumpchain;(clump = *clumpchainpointer);clumpchainpointer = &(*clumpchainpointer)->chain)
    {
        if (start >= clump->block && start < clump->block + MEMCLUMPSIZE)
        {
            if (clump->sentinel1 != MEMHEADER_SENTINEL_FOR_ADDRESS(&clump->sentinel1))
                Sys_Error("Clump_FreeBlock: trashed sentinel1\n");
            if (clump->sentinel2 != MEMHEADER_SENTINEL_FOR_ADDRESS(&clump->sentinel2))
                Sys_Error("Clump_FreeBlock: trashed sentinel2\n");
            if (start + size > clump->block + MEMCLUMPSIZE)
                Sys_Error("Clump_FreeBlock: block overrun\n");
            // the block belongs to this clump, clear the range
            needbits = (size + MEMUNIT - 1) / MEMUNIT;
            startbit = (start - clump->block) / MEMUNIT;
            endbit = startbit + needbits;
            // first verify all bits are set, otherwise this may be misaligned or a double free
            for (bit = startbit;bit < endbit;bit++)
                if ((clump->bits[bit>>5] & (1<<(bit & 31))) == 0)
                    Sys_Error("Clump_FreeBlock: double free\n");
            for (bit = startbit;bit < endbit;bit++)
                clump->bits[bit>>5] &= ~(1<<(bit & 31));
            clump->blocksinuse -= needbits;
            memset(base, 0xFF, needbits * MEMUNIT);
            // if all has been freed, free the clump itself
            if (clump->blocksinuse == 0)
            {
                *clumpchainpointer = clump->chain;
                if (developer_memorydebug.integer)
                    memset(clump, 0xFF, sizeof(*clump));
#if MEMCLUMPING != 2
                free(clump);
#endif
            }
            return;
        }
    }
    // does not belong to any known chunk...  assume it was a direct allocation
#endif
#if MEMCLUMPING != 2
    memset(base, 0xFF, size);
    free(base);
#endif
}
 
void *_Mem_Alloc(mempool_t *pool, void *olddata, size_t size, size_t alignment, const char *filename, int fileline)
{
    unsigned int sentinel1;
    unsigned int sentinel2;
    size_t realsize;
    size_t sharedsize;
    size_t remainsize;
    memheader_t *mem;
    memheader_t *oldmem;
    unsigned char *base;
 
    if (size <= 0)
    {
        if (olddata)
            _Mem_Free(olddata, filename, fileline);
        return NULL;
    }
    if (pool == NULL)
    {
        if(olddata)
            pool = ((memheader_t *)((unsigned char *) olddata - sizeof(memheader_t)))->pool;
        else
            Sys_Error("Mem_Alloc: pool == NULL (alloc at %s:%i)", filename, fileline);
    }
    if (mem_mutex)
        Thread_LockMutex(mem_mutex);
    if (developer_memory.integer || size >= developer_memoryreportlargerthanmb.value * 1048576)
        Con_DPrintf("Mem_Alloc: pool %s, file %s:%i, size %f bytes (%f MB)\n", pool->name, filename, fileline, (double)size, (double)size / 1048576.0f);
    //if (developer.integer > 0 && developer_memorydebug.integer)
    //  _Mem_CheckSentinelsGlobal(filename, fileline);
    pool->totalsize += size;
    realsize = alignment + sizeof(memheader_t) + size + sizeof(sentinel2);
    pool->realsize += realsize;
    base = (unsigned char *)Clump_AllocBlock(realsize);
    if (base == NULL)
    {
        Mem_PrintList(0);
        Mem_PrintStats();
        Mem_PrintList(1<<30);
        Mem_PrintStats();
        Sys_Error("Mem_Alloc: out of memory (alloc of size %f (%.3fMB) at %s:%i)", (double)realsize, (double)realsize / (1 << 20), filename, fileline);
    }
    // calculate address that aligns the end of the memheader_t to the specified alignment
    mem = (memheader_t*)((((size_t)base + sizeof(memheader_t) + (alignment-1)) & ~(alignment-1)) - sizeof(memheader_t));
    mem->baseaddress = (void*)base;
    mem->filename = filename;
    mem->fileline = fileline;
    mem->size = size;
    mem->pool = pool;
 
    // calculate sentinels (detects buffer overruns, in a way that is hard to exploit)
    sentinel1 = MEMHEADER_SENTINEL_FOR_ADDRESS(&mem->sentinel);
    sentinel2 = MEMHEADER_SENTINEL_FOR_ADDRESS((unsigned char *) mem + sizeof(memheader_t) + mem->size);
    mem->sentinel = sentinel1;
    memcpy((unsigned char *) mem + sizeof(memheader_t) + mem->size, &sentinel2, sizeof(sentinel2));
 
    // append to head of list
    List_Add(&mem->list, &pool->chain);
 
    if (mem_mutex)
        Thread_UnlockMutex(mem_mutex);
 
    // copy the shared portion in the case of a realloc, then memset the rest
    sharedsize = 0;
    remainsize = size;
    if (olddata)
    {
        oldmem = (memheader_t*)olddata - 1;
        sharedsize = min(oldmem->size, size);
        memcpy((void *)((unsigned char *) mem + sizeof(memheader_t)), olddata, sharedsize);
        remainsize -= sharedsize;
        _Mem_Free(olddata, filename, fileline);
    }
    memset((void *)((unsigned char *) mem + sizeof(memheader_t) + sharedsize), 0, remainsize);
    return (void *)((unsigned char *) mem + sizeof(memheader_t));
}
 
// only used by _Mem_Free and _Mem_FreePool
static void _Mem_FreeBlock(memheader_t *mem, const char *filename, int fileline)
{
    mempool_t *pool;
    size_t size;
    size_t realsize;
    unsigned int sentinel1;
    unsigned int sentinel2;
 
    // check sentinels (detects buffer overruns, in a way that is hard to exploit)
    sentinel1 = MEMHEADER_SENTINEL_FOR_ADDRESS(&mem->sentinel);
    sentinel2 = MEMHEADER_SENTINEL_FOR_ADDRESS((unsigned char *) mem + sizeof(memheader_t) + mem->size);
    if (mem->sentinel != sentinel1)
        Sys_Error("Mem_Free: trashed head sentinel (alloc at %s:%i, free at %s:%i)", mem->filename, mem->fileline, filename, fileline);
    if (memcmp((unsigned char *) mem + sizeof(memheader_t) + mem->size, &sentinel2, sizeof(sentinel2)))
        Sys_Error("Mem_Free: trashed tail sentinel (alloc at %s:%i, free at %s:%i)", mem->filename, mem->fileline, filename, fileline);
 
    pool = mem->pool;
    if (developer_memory.integer)
        Con_DPrintf("Mem_Free: pool %s, alloc %s:%i, free %s:%i, size %i bytes\n", pool->name, mem->filename, mem->fileline, filename, fileline, (int)(mem->size));
    // unlink memheader from doubly linked list
    if (mem->list.prev->next != &mem->list || mem->list.next->prev != &mem->list)
        Sys_Error("Mem_Free: not allocated or double freed (free at %s:%i)", filename, fileline);
    if (mem_mutex)
        Thread_LockMutex(mem_mutex);
    List_Delete(&mem->list);
    // memheader has been unlinked, do the actual free now
    size = mem->size;
    realsize = sizeof(memheader_t) + size + sizeof(sentinel2);
    pool->totalsize -= size;
    pool->realsize -= realsize;
    Clump_FreeBlock(mem->baseaddress, realsize);
    if (mem_mutex)
        Thread_UnlockMutex(mem_mutex);
}
 
void _Mem_Free(void *data, const char *filename, int fileline)
{
    if (data == NULL)
    {
        Con_DPrintf("Mem_Free: data == NULL (called at %s:%i)\n", filename, fileline);
        return;
    }
 
    if (developer_memorydebug.integer)
    {
        //_Mem_CheckSentinelsGlobal(filename, fileline);
        if (!Mem_IsAllocated(NULL, data))
            Sys_Error("Mem_Free: data is not allocated (called at %s:%i)", filename, fileline);
    }
 
    _Mem_FreeBlock((memheader_t *)((unsigned char *) data - sizeof(memheader_t)), filename, fileline);
}
 
mempool_t *_Mem_AllocPool(const char *name, unsigned flags, mempool_t *parent, const char *filename, int fileline)
{
    mempool_t *pool;
    if (developer_memorydebug.integer)
        _Mem_CheckSentinelsGlobal(filename, fileline);
    pool = (mempool_t *)Clump_AllocBlock(sizeof(mempool_t));
    if (pool == NULL)
    {
        Mem_PrintList(0);
        Mem_PrintStats();
        Mem_PrintList(1<<30);
        Mem_PrintStats();
        Sys_Error("Mem_AllocPool: out of memory (allocpool at %s:%i)", filename, fileline);
    }
    memset(pool, 0, sizeof(mempool_t));
    pool->sentinel1 = MEMHEADER_SENTINEL_FOR_ADDRESS(&pool->sentinel1);
    pool->sentinel2 = MEMHEADER_SENTINEL_FOR_ADDRESS(&pool->sentinel2);
    pool->filename = filename;
    pool->fileline = fileline;
    pool->flags = flags;
    List_Create(&pool->chain);
    pool->totalsize = 0;
    pool->realsize = sizeof(mempool_t);
    dp_strlcpy (pool->name, name, sizeof (pool->name));
    pool->parent = parent;
    pool->next = poolchain;
    poolchain = pool;
    return pool;
}
 
void _Mem_FreePool(mempool_t **poolpointer, const char *filename, int fileline)
{
    mempool_t *pool = *poolpointer;
    mempool_t **chainaddress, *iter, *temp;
 
    if (developer_memorydebug.integer)
        _Mem_CheckSentinelsGlobal(filename, fileline);
    if (pool)
    {
        // unlink pool from chain
        for (chainaddress = &poolchain;*chainaddress && *chainaddress != pool;chainaddress = &((*chainaddress)->next));
        if (*chainaddress != pool)
            Sys_Error("Mem_FreePool: pool already free (freepool at %s:%i)", filename, fileline);
        if (pool->sentinel1 != MEMHEADER_SENTINEL_FOR_ADDRESS(&pool->sentinel1))
            Sys_Error("Mem_FreePool: trashed pool sentinel 1 (allocpool at %s:%i, freepool at %s:%i)", pool->filename, pool->fileline, filename, fileline);
        if (pool->sentinel2 != MEMHEADER_SENTINEL_FOR_ADDRESS(&pool->sentinel2))
            Sys_Error("Mem_FreePool: trashed pool sentinel 2 (allocpool at %s:%i, freepool at %s:%i)", pool->filename, pool->fileline, filename, fileline);
        *chainaddress = pool->next;
 
        // free memory owned by the pool
        while (!List_Is_Empty(&pool->chain))
            _Mem_FreeBlock(List_First_Entry(&pool->chain, memheader_t, list), filename, fileline);
 
        // free child pools, too
        for(iter = poolchain; iter; iter = temp) {
            temp = iter->next;
            if(iter->parent == pool)
                _Mem_FreePool(&temp, filename, fileline);
        }
 
        // free the pool itself
        Clump_FreeBlock(pool, sizeof(*pool));
 
        *poolpointer = NULL;
    }
}
 
void _Mem_EmptyPool(mempool_t *pool, const char *filename, int fileline)
{
    mempool_t *chainaddress;
 
    if (developer_memorydebug.integer)
    {
        //_Mem_CheckSentinelsGlobal(filename, fileline);
        // check if this pool is in the poolchain
        for (chainaddress = poolchain;chainaddress;chainaddress = chainaddress->next)
            if (chainaddress == pool)
                break;
        if (!chainaddress)
            Sys_Error("Mem_EmptyPool: pool is already free (emptypool at %s:%i)", filename, fileline);
    }
    if (pool == NULL)
        Sys_Error("Mem_EmptyPool: pool == NULL (emptypool at %s:%i)", filename, fileline);
    if (pool->sentinel1 != MEMHEADER_SENTINEL_FOR_ADDRESS(&pool->sentinel1))
        Sys_Error("Mem_EmptyPool: trashed pool sentinel 1 (allocpool at %s:%i, emptypool at %s:%i)", pool->filename, pool->fileline, filename, fileline);
    if (pool->sentinel2 != MEMHEADER_SENTINEL_FOR_ADDRESS(&pool->sentinel2))
        Sys_Error("Mem_EmptyPool: trashed pool sentinel 2 (allocpool at %s:%i, emptypool at %s:%i)", pool->filename, pool->fileline, filename, fileline);
 
    // free memory owned by the pool
    while (!List_Is_Empty(&pool->chain))
        _Mem_FreeBlock(List_First_Entry(&pool->chain, memheader_t, list), filename, fileline);
 
    // empty child pools, too
    for(chainaddress = poolchain; chainaddress; chainaddress = chainaddress->next)
        if(chainaddress->parent == pool)
            _Mem_EmptyPool(chainaddress, filename, fileline);
 
}
 
void _Mem_CheckSentinels(void *data, const char *filename, int fileline)
{
    memheader_t *mem;
    unsigned int sentinel1;
    unsigned int sentinel2;
 
    if (data == NULL)
        Sys_Error("Mem_CheckSentinels: data == NULL (sentinel check at %s:%i)", filename, fileline);
 
    mem = (memheader_t *)((unsigned char *) data - sizeof(memheader_t));
    sentinel1 = MEMHEADER_SENTINEL_FOR_ADDRESS(&mem->sentinel);
    sentinel2 = MEMHEADER_SENTINEL_FOR_ADDRESS((unsigned char *) mem + sizeof(memheader_t) + mem->size);
    if (mem->sentinel != sentinel1)
        Sys_Error("Mem_Free: trashed head sentinel (alloc at %s:%i, sentinel check at %s:%i)", mem->filename, mem->fileline, filename, fileline);
    if (memcmp((unsigned char *) mem + sizeof(memheader_t) + mem->size, &sentinel2, sizeof(sentinel2)))
        Sys_Error("Mem_Free: trashed tail sentinel (alloc at %s:%i, sentinel check at %s:%i)", mem->filename, mem->fileline, filename, fileline);
}
 
#if MEMCLUMPING
static void _Mem_CheckClumpSentinels(memclump_t *clump, const char *filename, int fileline)
{
    // this isn't really very useful
    if (clump->sentinel1 != MEMHEADER_SENTINEL_FOR_ADDRESS(&clump->sentinel1))
        Sys_Error("Mem_CheckClumpSentinels: trashed sentinel 1 (sentinel check at %s:%i)", filename, fileline);
    if (clump->sentinel2 != MEMHEADER_SENTINEL_FOR_ADDRESS(&clump->sentinel2))
        Sys_Error("Mem_CheckClumpSentinels: trashed sentinel 2 (sentinel check at %s:%i)", filename, fileline);
}
#endif
 
void _Mem_CheckSentinelsGlobal(const char *filename, int fileline)
{
    memheader_t *mem;
#if MEMCLUMPING
    memclump_t *clump;
#endif
    mempool_t *pool;
    for (pool = poolchain;pool;pool = pool->next)
    {
        if (pool->sentinel1 != MEMHEADER_SENTINEL_FOR_ADDRESS(&pool->sentinel1))
            Sys_Error("Mem_CheckSentinelsGlobal: trashed pool sentinel 1 (allocpool at %s:%i, sentinel check at %s:%i)", pool->filename, pool->fileline, filename, fileline);
        if (pool->sentinel2 != MEMHEADER_SENTINEL_FOR_ADDRESS(&pool->sentinel2))
            Sys_Error("Mem_CheckSentinelsGlobal: trashed pool sentinel 2 (allocpool at %s:%i, sentinel check at %s:%i)", pool->filename, pool->fileline, filename, fileline);
    }
    for (pool = poolchain;pool;pool = pool->next)
        List_For_Each_Entry(mem, &pool->chain, memheader_t, list)
            _Mem_CheckSentinels((void *)((unsigned char *) mem + sizeof(memheader_t)), filename, fileline);
#if MEMCLUMPING
    for (pool = poolchain;pool;pool = pool->next)
        for (clump = clumpchain;clump;clump = clump->chain)
            _Mem_CheckClumpSentinels(clump, filename, fileline);
#endif
}
 
qbool Mem_IsAllocated(mempool_t *pool, const void *data)
{
    memheader_t *header;
    memheader_t *target;
 
    if (pool)
    {
        // search only one pool
        target = (memheader_t *)((unsigned char *) data - sizeof(memheader_t));
        List_For_Each_Entry(header, &pool->chain, memheader_t, list)
            if( header == target )
                return true;
    }
    else
    {
        // search all pools
        for (pool = poolchain;pool;pool = pool->next)
            if (Mem_IsAllocated(pool, data))
                return true;
    }
    return false;
}
 
void Mem_ExpandableArray_NewArray(memexpandablearray_t *l, mempool_t *mempool, size_t recordsize, int numrecordsperarray)
{
    memset(l, 0, sizeof(*l));
    l->mempool = mempool;
    l->recordsize = recordsize;
    l->numrecordsperarray = numrecordsperarray;
}
 
void Mem_ExpandableArray_FreeArray(memexpandablearray_t *l)
{
    size_t i;
    if (l->maxarrays)
    {
        for (i = 0;i != l->numarrays;i++)
            Mem_Free(l->arrays[i].data);
        Mem_Free(l->arrays);
    }
    memset(l, 0, sizeof(*l));
}
 
void *Mem_ExpandableArray_AllocRecord(memexpandablearray_t *l)
{
    size_t i, j;
    for (i = 0;;i++)
    {
        if (i == l->numarrays)
        {
            if (l->numarrays == l->maxarrays)
            {
                memexpandablearray_array_t *oldarrays = l->arrays;
                l->maxarrays = max(l->maxarrays * 2, 128);
                l->arrays = (memexpandablearray_array_t*) Mem_Alloc(l->mempool, l->maxarrays * sizeof(*l->arrays));
                if (oldarrays)
                {
                    memcpy(l->arrays, oldarrays, l->numarrays * sizeof(*l->arrays));
                    Mem_Free(oldarrays);
                }
            }
            l->arrays[i].numflaggedrecords = 0;
            l->arrays[i].data = (unsigned char *) Mem_Alloc(l->mempool, (l->recordsize + 1) * l->numrecordsperarray);
            l->arrays[i].allocflags = l->arrays[i].data + l->recordsize * l->numrecordsperarray;
            l->numarrays++;
        }
        if (l->arrays[i].numflaggedrecords < l->numrecordsperarray)
        {
            for (j = 0;j < l->numrecordsperarray;j++)
            {
                if (!l->arrays[i].allocflags[j])
                {
                    l->arrays[i].allocflags[j] = true;
                    l->arrays[i].numflaggedrecords++;
                    memset(l->arrays[i].data + l->recordsize * j, 0, l->recordsize);
                    return (void *)(l->arrays[i].data + l->recordsize * j);
                }
            }
        }
    }
}
 
/*****************************************************************************
 * IF YOU EDIT THIS:
 * If this function was to change the size of the "expandable" array, you have
 * to update r_shadow.c
 * Just do a search for "range =", R_ShadowClearWorldLights would be the first
 * function to look at. (And also seems like the only one?) You  might have to
 * move the  call to Mem_ExpandableArray_IndexRange  back into for(...) loop's
 * condition
 */
void Mem_ExpandableArray_FreeRecord(memexpandablearray_t *l, void *record) // const!
{
    size_t i, j;
    unsigned char *p = (unsigned char *)record;
    for (i = 0;i != l->numarrays;i++)
    {
        if (p >= l->arrays[i].data && p < (l->arrays[i].data + l->recordsize * l->numrecordsperarray))
        {
            j = (p - l->arrays[i].data) / l->recordsize;
            if (p != l->arrays[i].data + j * l->recordsize)
                Sys_Error("Mem_ExpandableArray_FreeRecord: no such record %p\n", (void *)p);
            if (!l->arrays[i].allocflags[j])
                Sys_Error("Mem_ExpandableArray_FreeRecord: record %p is already free!\n", (void *)p);
            l->arrays[i].allocflags[j] = false;
            l->arrays[i].numflaggedrecords--;
            return;
        }
    }
}
 
size_t Mem_ExpandableArray_IndexRange(const memexpandablearray_t *l)
{
    size_t i, j, k, end = 0;
    for (i = 0;i < l->numarrays;i++)
    {
        for (j = 0, k = 0;k < l->arrays[i].numflaggedrecords;j++)
        {
            if (l->arrays[i].allocflags[j])
            {
                end = l->numrecordsperarray * i + j + 1;
                k++;
            }
        }
    }
    return end;
}
 
void *Mem_ExpandableArray_RecordAtIndex(const memexpandablearray_t *l, size_t index)
{
    size_t i, j;
    i = index / l->numrecordsperarray;
    j = index % l->numrecordsperarray;
    if (i >= l->numarrays || !l->arrays[i].allocflags[j])
        return NULL;
    return (void *)(l->arrays[i].data + j * l->recordsize);
}
 
 
// used for temporary memory allocations around the engine, not for longterm
// storage, if anything in this pool stays allocated during gameplay, it is
// considered a leak
mempool_t *tempmempool;
// only for zone
mempool_t *zonemempool;
 
void Mem_PrintStats(void)
{
    size_t count = 0, size = 0, realsize = 0;
    mempool_t *pool;
    memheader_t *mem;
    Mem_CheckSentinelsGlobal();
    for (pool = poolchain;pool;pool = pool->next)
    {
        count++;
        size += pool->totalsize;
        realsize += pool->realsize;
    }
    Con_Printf("%lu memory pools, totalling %lu bytes (%.3fMB)\n", (unsigned long)count, (unsigned long)size, size / 1048576.0);
    Con_Printf("total allocated size: %lu bytes (%.3fMB)\n", (unsigned long)realsize, realsize / 1048576.0);
    for (pool = poolchain;pool;pool = pool->next)
    {
        if ((pool->flags & POOLFLAG_TEMP) && !List_Is_Empty(&pool->chain))
        {
            Con_Printf(CON_WARN "Memory pool %p has sprung a leak totalling %lu bytes (%.3fMB)!  Listing contents...\n", (void *)pool, (unsigned long)pool->totalsize, pool->totalsize / 1048576.0);
            List_For_Each_Entry(mem, &pool->chain, memheader_t, list)
                Con_Printf("%10lu bytes allocated at %s:%i\n", (unsigned long)mem->size, mem->filename, mem->fileline);
        }
    }
}
 
void Mem_PrintList(size_t minallocationsize)
{
    mempool_t *pool;
    memheader_t *mem;
    Mem_CheckSentinelsGlobal();
    Con_Print("memory pool list:\n"
               "size    name\n");
    for (pool = poolchain;pool;pool = pool->next)
    {
        Con_Printf("%10luk (%10luk actual) %s (%+li byte change) %s\n", (unsigned long) ((pool->totalsize + 1023) / 1024), (unsigned long)((pool->realsize + 1023) / 1024), pool->name, (long)(pool->totalsize - pool->lastchecksize), (pool->flags & POOLFLAG_TEMP) ? "TEMP" : "");
        pool->lastchecksize = pool->totalsize;
        List_For_Each_Entry(mem, &pool->chain, memheader_t, list)
            if (mem->size >= minallocationsize)
                Con_Printf("%10lu bytes allocated at %s:%i\n", (unsigned long)mem->size, mem->filename, mem->fileline);
    }
}
 
static void MemList_f(cmd_state_t *cmd)
{
    switch(Cmd_Argc(cmd))
    {
    case 1:
        Mem_PrintList(1<<30);
        Mem_PrintStats();
        break;
    case 2:
        Mem_PrintList(atoi(Cmd_Argv(cmd, 1)) * 1024);
        Mem_PrintStats();
        break;
    default:
        Con_Print("MemList_f: unrecognized options\nusage: memlist [all]\n");
        break;
    }
}
 
static void MemStats_f(cmd_state_t *cmd)
{
    Mem_CheckSentinelsGlobal();
    Mem_PrintStats();
}
 
 
char *_Mem_strdup(mempool_t *pool, const char *s, const char *filename, int fileline)
{
    char* p;
    size_t sz;
    if (s == NULL)
        return NULL;
    sz = strlen (s) + 1;
    p = (char*)_Mem_Alloc (pool, NULL, sz, alignof(char), filename, fileline);
    dp_strlcpy (p, s, sz);
    return p;
}
 
/*
========================
Memory_Init
========================
*/
void Memory_Init (void)
{
    static union {unsigned short s;unsigned char b[2];} u;
    u.s = 0x100;
    mem_bigendian = u.b[0] != 0;
 
    sentinel_seed = rand();
    poolchain = NULL;
    tempmempool = Mem_AllocPool("Temporary Memory", POOLFLAG_TEMP, NULL);
    zonemempool = Mem_AllocPool("Zone", 0, NULL);
 
    if (Thread_HasThreads())
        mem_mutex = Thread_CreateMutex();
}
 
void Memory_Shutdown (void)
{
//  Mem_FreePool (&zonemempool);
//  Mem_FreePool (&tempmempool);
 
    if (mem_mutex)
        Thread_DestroyMutex(mem_mutex);
    mem_mutex = NULL;
}
 
void Memory_Init_Commands (void)
{
    Cmd_AddCommand(CF_SHARED, "memstats", MemStats_f, "prints memory system statistics");
    Cmd_AddCommand(CF_SHARED, "memlist", MemList_f, "prints memory pool information (or if used as memlist 5 lists individual allocations of 5K or larger, 0 lists all allocations)");
 
    Cvar_RegisterVariable (&developer_memory);
    Cvar_RegisterVariable (&developer_memorydebug);
    Cvar_RegisterVariable (&developer_memoryreportlargerthanmb);
    Cvar_RegisterVariable (&sys_memsize_physical);
    Cvar_RegisterVariable (&sys_memsize_virtual);
 
#if defined(WIN32)
#ifdef _WIN64
    {
        MEMORYSTATUSEX status;
        // first guess
        Cvar_SetValueQuick(&sys_memsize_virtual, 8388608);
        // then improve
        status.dwLength = sizeof(status);
        if(GlobalMemoryStatusEx(&status))
        {
            Cvar_SetValueQuick(&sys_memsize_physical, status.ullTotalPhys / 1048576.0);
            Cvar_SetValueQuick(&sys_memsize_virtual, min(sys_memsize_virtual.value, status.ullTotalVirtual / 1048576.0));
        }
    }
#else
    {
        MEMORYSTATUS status;
        // first guess
        Cvar_SetValueQuick(&sys_memsize_virtual, 2048);
        // then improve
        status.dwLength = sizeof(status);
        GlobalMemoryStatus(&status);
        Cvar_SetValueQuick(&sys_memsize_physical, status.dwTotalPhys / 1048576.0);
        Cvar_SetValueQuick(&sys_memsize_virtual, min(sys_memsize_virtual.value, status.dwTotalVirtual / 1048576.0));
    }
#endif
#else
    {
        // first guess
        Cvar_SetValueQuick(&sys_memsize_virtual, (sizeof(void*) == 4) ? 2048 : 268435456);
        // then improve
        {
            // Linux, and BSD with linprocfs mounted
            FILE *f = fopen("/proc/meminfo", "r");
            if(f)
            {
                static char buf[1024];
                while(fgets(buf, sizeof(buf), f))
                {
                    const char *p = buf;
                    if(!COM_ParseToken_Console(&p))
                        continue;
                    if(!strcmp(com_token, "MemTotal:"))
                    {
                        if(!COM_ParseToken_Console(&p))
                            continue;
                        Cvar_SetValueQuick(&sys_memsize_physical, atof(com_token) / 1024.0);
                    }
                    if(!strcmp(com_token, "SwapTotal:"))
                    {
                        if(!COM_ParseToken_Console(&p))
                            continue;
                        Cvar_SetValueQuick(&sys_memsize_virtual, min(sys_memsize_virtual.value , atof(com_token) / 1024.0 + sys_memsize_physical.value));
                    }
                }
                fclose(f);
            }
        }
    }
#endif
}