74cc9e41fa
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@3157 a1c6a512-1295-4272-9138-f99709370657
634 lines
20 KiB
C
634 lines
20 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2002 by Daniel Stenberg
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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/*****************************************************************************
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*
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* Dynamic small-blocks Memory Allocation
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*
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* Author: Daniel Stenberg <daniel@haxx.se>
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*
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* Read THOUGHTS for theories and details on the implementation.
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*
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*****************************************************************************/
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#include <stdio.h>
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#include <string.h> /* memcpy */
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#ifdef DEBUG_MALLOC
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#include <stdarg.h>
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#endif
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#ifdef PSOS
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#include <psos.h>
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#define SEMAPHORE /* the PSOS routines use semaphore protection */
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#else
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#endif
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#define BMALLOC /* we use our own big-malloc system */
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#ifdef BMALLOC
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#include "bmalloc.h"
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#endif
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/* Each TOP takes care of a chain of BLOCKS */
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struct MemTop {
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struct MemBlock *chain; /* pointer to the BLOCK chain */
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long nfree; /* total number of free FRAGMENTS in the chain */
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short nmax; /* total number of FRAGMENTS in this kind of BLOCK */
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size_t fragsize; /* the size of each FRAGMENT */
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#ifdef SEMAPHORE /* if we're protecting the list with SEMAPHORES */
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long semaphore_id; /* semaphore used to lock this particular list */
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#endif
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};
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/* Each BLOCK takes care of an amount of FRAGMENTS */
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struct MemBlock {
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struct MemTop *top; /* our TOP struct */
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struct MemBlock *next; /* next BLOCK */
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struct MemBlock *prev; /* prev BLOCK */
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struct MemFrag *first; /* the first free FRAGMENT in this block */
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short nfree; /* number of free FRAGMENTS in this BLOCK */
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};
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/* This is the data kept in all _free_ FRAGMENTS */
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struct MemFrag {
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struct MemFrag *next; /* next free FRAGMENT */
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struct MemFrag *prev; /* prev free FRAGMENT */
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};
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/* This is the data kept in all _allocated_ FRAGMENTS and BLOCKS. We add this
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to the allocation size first thing in the ALLOC function to make room for
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this smoothly. */
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struct MemInfo {
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void *block;
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/* which BLOCK is our father, if BLOCK_BIT is set it means this is a
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stand-alone, large allocation and then the rest of the bits should be
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treated as the size of the block */
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#define BLOCK_BIT 1
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};
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/* ---------------------------------------------------------------------- */
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/* Defines */
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/* ---------------------------------------------------------------------- */
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#ifdef DEBUG_VERBOSE
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#define MEMINCR(addr,x) memchange(addr, x)
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#define MEMDECR(addr,x) memchange(addr,-(x))
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#else
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#define MEMINCR(a,x)
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#define MEMDECR(a,x)
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#endif
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/* The low level functions used to get memory from the OS and to return memory
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to the OS, we may also define a stub that does the actual allocation and
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free, these are the defined function names used in the dmalloc system
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anyway: */
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#ifdef PSOS
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#ifdef DEBUG_MALLOC
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#define DMEM_OSALLOCMEM(size,pointer,type) pointer=(type)dbgmalloc(size)
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#define DMEM_OSFREEMEM(x) dbgfree(x)
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#else
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#define DMEM_OSALLOCMEM(size,pointer,type) rn_getseg(0,size,RN_NOWAIT,0,(void **)&pointer)
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/* Similar, but this returns the memory */
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#define DMEM_OSFREEMEM(x) rn_retseg(0, x)
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#endif
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/* Argument: <id> */
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#define SEMAPHOREOBTAIN(x) sm_p(x, SM_WAIT, 0)
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/* Argument: <id> */
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#define SEMAPHORERETURN(x) sm_v(x)
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/* Argument: <name> <id-variable name> */
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#define SEMAPHORECREATE(x,y) sm_create(x, 1, SM_FIFO, (ULONG *)&(y))
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#else
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#ifdef BMALLOC /* use our own big-memory-allocation system */
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#define DMEM_OSALLOCMEM(size,pointer,type) pointer=(type)bmalloc(size)
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#define DMEM_OSFREEMEM(x) bfree(x)
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#elif DEBUG_MALLOC
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#define DMEM_OSALLOCMEM(size,pointer,type) pointer=(type)dbgmalloc(size)
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#define DMEM_OSFREEMEM(x) dbgfree(x)
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#else
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#define DMEM_OSALLOCMEM(size,pointer,type) pointer=(type)malloc(size)
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#define DMEM_OSFREEMEM(x) free(x)
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#endif
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#endif
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/* the largest memory allocation that is made a FRAGMENT: (grab the highest
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number from the list below) */
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#define DMEM_LARGESTSIZE 2032
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/* The total size of a BLOCK used for FRAGMENTS
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In order to make this use only *1* even alignment from the big-block-
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allocation-system (possible the bmalloc() system also written by me)
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we need to subtract the [maximum] struct sizes that could get added all
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the way through to the grab from the memory. */
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#define DMEM_BLOCKSIZE 4064 /* (4096 - sizeof(struct MemBlock) - 12) */
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/* Since the blocksize isn't an even 2^X story anymore, we make a table with
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the FRAGMENT sizes and amounts that fills up a BLOCK nicely */
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/* a little 'bc' script that helps us maximize the usage:
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- for 32-bit aligned addresses (SPARC crashes otherwise):
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for(i=20; i<2040; i+=4) { a=4064/i; if(a*i >= 4060) { {i;} } }
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I try to approximate a double of each size, starting with ~20. We don't do
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ODD sizes since several CPU flavours dump core when accessing such
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addresses. We try to do 32-bit aligned to make ALL kinds of CPUs to remain
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happy with us.
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*/
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static const unsigned short qinfo[]= {
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20, 28, 52, 116, 312, 580, 1016, 2032
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};
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#define MIN(x,y) ((x)<(y)?(x):(y))
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/* ---------------------------------------------------------------------- */
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/* Globals */
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/* ---------------------------------------------------------------------- */
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/* keeper of the chain of BLOCKS */
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static struct MemTop top[ sizeof(qinfo)/sizeof(qinfo[0]) ];
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/* ---------------------------------------------------------------------- */
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/* Start of the real code */
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/* ---------------------------------------------------------------------- */
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#ifdef DEBUG_MALLOC
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/************
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* A few functions that are verbose and tells us about the current status
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* of the dmalloc system
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***********/
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void dmalloc_status(void)
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{
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unsigned int i;
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int used;
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int num;
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int totalfree=0;
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struct MemBlock *block;
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for(i=0; i<sizeof(qinfo)/sizeof(qinfo[0]);i++) {
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block = top[i].chain;
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used = 0;
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num = 0;
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while(block) {
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used += top[i].nmax-block->nfree;
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num++;
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block = block->next;
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}
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printf("Q %d (FRAG %4d), USED %4d FREE %4ld (SIZE %4ld) BLOCKS %d\n",
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i, top[i].fragsize, used, top[i].nfree,
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top[i].nfree*top[i].fragsize, num);
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totalfree += top[i].nfree*top[i].fragsize;
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}
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printf("Total unused memory stolen by dmalloc: %d\n", totalfree);
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}
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#endif
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#ifdef DEBUG_VERBOSE
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static void dmalloc_failed(size_t size)
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{
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printf("*** " __FILE__ " Couldn't allocate %d bytes\n", size);
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dmalloc_status();
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}
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#else
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#define dmalloc_failed(x)
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#endif
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#ifdef DEBUG_VERBOSE
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#define DBG(x) syslog x
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void syslog(char *fmt, ...)
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{
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va_list ap;
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va_start(ap, fmt);
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vfprintf(stdout, fmt, ap);
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va_end(ap);
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}
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void memchange(void *a, int x)
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{
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static int memory=0;
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static int count=0;
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static int max=0;
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if(memory > max)
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max = memory;
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memory += x;
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DBG(("%d. PTR %p / %d TOTAL %d MAX %d\n", ++count, a, x, memory, max));
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}
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#else
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#define DBG(x)
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#endif
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/****************************************************************************
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*
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* FragBlock()
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*
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* This function makes FRAGMENTS of the BLOCK sent as argument.
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*
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***************************************************************************/
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static void FragBlock(char *memp, int size)
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{
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struct MemFrag *frag=(struct MemFrag *)memp;
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struct MemFrag *prev=NULL; /* no previous in the first round */
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int count=0;
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while((count+size) <= DMEM_BLOCKSIZE) {
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frag->next = (struct MemFrag *)((char *)frag + size);
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frag->prev = prev;
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prev = frag;
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(char *)frag += size;
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count += size;
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}
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prev->next = NULL; /* the last one has no next struct */
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}
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/***************************************************************************
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*
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* dmalloc_initialize();
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*
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* Call before the first dmalloc(). Inits a few memory things.
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*
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**************************************************************************/
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void dmalloc_initialize(void)
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{
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unsigned int i;
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/* Setup the nmax and fragsize fields of the top structs */
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for(i=0; i< sizeof(qinfo)/sizeof(qinfo[0]); i++) {
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top[i].fragsize = qinfo[i];
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top[i].nmax = DMEM_BLOCKSIZE/qinfo[i];
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#ifdef PSOS
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/* for some reason, these aren't nulled from start: */
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top[i].chain = NULL; /* no BLOCKS */
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top[i].nfree = 0; /* no FRAGMENTS */
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#endif
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#ifdef SEMAPHORE
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{
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char name[7];
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snprintf(name, 7, "MEM%d", i);
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SEMAPHORECREATE(name, top[i].semaphore_id);
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/* doesn't matter if it failed, we continue anyway ;-( */
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}
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#endif
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}
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}
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/****************************************************************************
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*
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* fragfromblock()
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*
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* This should return a fragment from the block and mark it as used
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* accordingly.
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*
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***************************************************************************/
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static void *fragfromblock(struct MemBlock *block)
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{
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/* make frag point to the first free FRAGMENT */
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struct MemFrag *frag = block->first;
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struct MemInfo *mem = (struct MemInfo *)frag;
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/*
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* Remove the FRAGMENT from the list and decrease the free counters.
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*/
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block->first = frag->next; /* new first free FRAGMENT */
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block->nfree--; /* BLOCK counter */
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block->top->nfree--; /* TOP counter */
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/* heal the FRAGMENT list */
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if(frag->prev) {
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frag->prev->next = frag->next;
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}
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if(frag->next) {
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frag->next->prev = frag->prev;
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}
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mem->block = block; /* no block bit set here */
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return ((char *)mem)+sizeof(struct MemInfo);
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}
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/***************************************************************************
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*
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* dmalloc()
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*
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* This needs no explanation. A malloc() look-alike.
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*
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**************************************************************************/
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void *malloc(size_t size)
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{
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void *mem;
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DBG(("malloc(%d)\n", size));
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/* First, we make room for the space needed in every allocation */
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size += sizeof(struct MemInfo);
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if(size < DMEM_LARGESTSIZE) {
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/* get a FRAGMENT */
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struct MemBlock *block=NULL; /* SAFE */
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struct MemBlock *newblock=NULL; /* SAFE */
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struct MemTop *memtop=NULL; /* SAFE */
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/* Determine which queue to use */
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unsigned int queue;
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for(queue=0; size > qinfo[queue]; queue++)
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;
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do {
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/* This is the head master of our chain: */
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memtop = &top[queue];
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DBG(("Top info: CHAIN %p FREE %d MAX %d FRAGSIZE %d\n",
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memtop->chain,
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memtop->nfree,
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memtop->nmax,
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memtop->fragsize));
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#ifdef SEMAPHORE
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if(SEMAPHOREOBTAIN(memtop->semaphore_id))
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return NULL; /* failed somehow */
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#endif
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/* get the first BLOCK in the chain */
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block = memtop->chain;
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/* check if we have a free FRAGMENT */
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if(memtop->nfree) {
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/* there exists a free FRAGMENT in this chain */
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/**** We'd prefer to not have this loop here! ****/
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/* search for the free FRAGMENT */
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while(!block->nfree)
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block = block->next; /* check next BLOCK */
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/*
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* Now 'block' is the first BLOCK with a free FRAGMENT
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*/
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mem = fragfromblock(block);
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}
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else {
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/* we do *not* have a free FRAGMENT but need to get us a new
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* BLOCK */
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DMEM_OSALLOCMEM(DMEM_BLOCKSIZE + sizeof(struct MemBlock),
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newblock,
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struct MemBlock *);
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if(!newblock) {
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if(++queue < sizeof(qinfo)/sizeof(qinfo[0])) {
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/* There are queues for bigger FRAGMENTS that we
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* should check before we fail this for real */
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#ifdef DEBUG_VERBOSE
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printf("*** " __FILE__ " Trying a bigger Q: %d\n",
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queue);
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#endif
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mem = NULL;
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}
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else {
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dmalloc_failed(size- sizeof(struct MemInfo));
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return NULL; /* not enough memory */
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}
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}
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else {
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/* allocation of big BLOCK was successful */
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MEMINCR(newblock, DMEM_BLOCKSIZE +
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sizeof(struct MemBlock));
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memtop->chain = newblock; /* attach this BLOCK to the
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chain */
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newblock->next = block; /* point to the previous first
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BLOCK */
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if(block)
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block->prev = newblock; /* point back on this new
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BLOCK */
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newblock->prev = NULL; /* no previous */
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newblock->top = memtop; /* our head master */
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/* point to the new first FRAGMENT */
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newblock->first = (struct MemFrag *)
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((char *)newblock+sizeof(struct MemBlock));
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/* create FRAGMENTS of the BLOCK: */
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FragBlock((char *)newblock->first, memtop->fragsize);
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/* fix the nfree counters */
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newblock->nfree = memtop->nmax;
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memtop->nfree += memtop->nmax;
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/* get a FRAGMENT from the BLOCK */
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mem = fragfromblock(newblock);
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}
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}
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#ifdef SEMAPHORE
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SEMAPHORERETURN(memtop->semaphore_id); /* let it go */
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#endif
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} while(NULL == mem); /* if we should retry a larger FRAGMENT */
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}
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else {
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/* get a stand-alone BLOCK */
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struct MemInfo *meminfo;
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if(size&1)
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/* don't leave this with an odd size since we'll use that bit for
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information */
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size++;
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DMEM_OSALLOCMEM(size, meminfo, struct MemInfo *);
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if(meminfo) {
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MEMINCR(meminfo, size);
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meminfo->block = (void *)(size|BLOCK_BIT);
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mem = (char *)meminfo + sizeof(struct MemInfo);
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}
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else {
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dmalloc_failed(size);
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mem = NULL;
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}
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}
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return (void *)mem;
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}
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/***************************************************************************
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*
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* dfree()
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*
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* This needs no explanation. A free() look-alike.
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*
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**************************************************************************/
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void free(void *memp)
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{
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struct MemInfo *meminfo = (struct MemInfo *)
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((char *)memp- sizeof(struct MemInfo));
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DBG(("free(%p)\n", memp));
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if(!((size_t)meminfo->block&BLOCK_BIT)) {
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/* this is a FRAGMENT we have to deal with */
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struct MemBlock *block=meminfo->block;
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struct MemTop *memtop = block->top;
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#ifdef SEMAPHORE
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SEMAPHOREOBTAIN(memtop->semaphore_id);
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#endif
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/* increase counters */
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block->nfree++;
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memtop->nfree++;
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/* is this BLOCK completely empty now? */
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if(block->nfree == memtop->nmax) {
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/* yes, return the BLOCK to the system */
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if(block->prev)
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block->prev->next = block->next;
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else
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memtop->chain = block->next;
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if(block->next)
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block->next->prev = block->prev;
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memtop->nfree -= memtop->nmax; /* total counter subtraction */
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MEMDECR(block, DMEM_BLOCKSIZE + sizeof(struct MemBlock));
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DMEM_OSFREEMEM((void *)block); /* return the whole block */
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}
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else {
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/* there are still used FRAGMENTS in the BLOCK, link this one
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into the chain of free ones */
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struct MemFrag *frag = (struct MemFrag *)meminfo;
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frag->prev = NULL;
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frag->next = block->first;
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if(block->first)
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block->first->prev = frag;
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block->first = frag;
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}
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#ifdef SEMAPHORE
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SEMAPHORERETURN(memtop->semaphore_id);
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#endif
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}
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else {
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/* big stand-alone block, just give it back to the OS: */
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/* clean BLOCK_BIT */
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MEMDECR(meminfo->block, (size_t)meminfo->block&~BLOCK_BIT);
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DMEM_OSFREEMEM((void *)meminfo);
|
|
}
|
|
}
|
|
|
|
/***************************************************************************
|
|
*
|
|
* drealloc()
|
|
*
|
|
* This needs no explanation. A realloc() look-alike.
|
|
*
|
|
**************************************************************************/
|
|
|
|
void *realloc(void *ptr, size_t size)
|
|
{
|
|
struct MemInfo *meminfo = (struct MemInfo *)
|
|
((char *)ptr- sizeof(struct MemInfo));
|
|
/*
|
|
* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
|
|
* NOTE: the ->size field of the meminfo will now contain the MemInfo
|
|
* struct size too!
|
|
* ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
|
|
*/
|
|
void *mem=NULL; /* SAFE */
|
|
size_t prevsize;
|
|
|
|
/* NOTE that this is only valid if BLOCK_BIT isn't set: */
|
|
struct MemBlock *block;
|
|
|
|
DBG(("realloc(%p, %d)\n", ptr, size));
|
|
|
|
if(NULL == ptr)
|
|
return malloc( size );
|
|
|
|
block = meminfo->block;
|
|
|
|
/* Here we check if this is a FRAGMENT and if the new size is
|
|
still smaller than the fragsize for this block. */
|
|
if(!((size_t)block&BLOCK_BIT) &&
|
|
(size + sizeof(struct MemInfo) < block->top->fragsize )) {
|
|
|
|
prevsize = block->top->fragsize;
|
|
/* This is a FRAGMENT and new size is possible to retain within the
|
|
same FRAGMENT */
|
|
if((prevsize > qinfo[0]) &&
|
|
/* this is not the smallest memory Q */
|
|
(size < (block->top-1)->fragsize))
|
|
/* This fits in a smaller fragment, so we will make a realloc
|
|
here */
|
|
;
|
|
else
|
|
mem = ptr; /* Just return the same pointer as we got in. */
|
|
}
|
|
if(!mem) {
|
|
if((size_t)meminfo->block&BLOCK_BIT) {
|
|
/* This is a stand-alone BLOCK */
|
|
prevsize = ((size_t)meminfo->block&~BLOCK_BIT) -
|
|
sizeof(struct MemInfo);
|
|
}
|
|
else
|
|
/* a FRAGMENT realloc that no longer fits within the same FRAGMENT
|
|
* or one that fits in a smaller */
|
|
prevsize = block->top->fragsize;
|
|
|
|
/* No tricks involved here, just grab a new bite of memory, copy the
|
|
* data from the old place and free the old memory again. */
|
|
mem = malloc(size);
|
|
if(mem) {
|
|
memcpy(mem, ptr, MIN(size, prevsize) );
|
|
free(ptr);
|
|
}
|
|
}
|
|
return mem;
|
|
}
|
|
|
|
/***************************************************************************
|
|
*
|
|
* dcalloc()
|
|
*
|
|
* This needs no explanation. A calloc() look-alike.
|
|
*
|
|
**************************************************************************/
|
|
/* Allocate an array of NMEMB elements each SIZE bytes long.
|
|
The entire array is initialized to zeros. */
|
|
void *
|
|
calloc (size_t nmemb, size_t size)
|
|
{
|
|
void *result = malloc (nmemb * size);
|
|
|
|
if (result != NULL)
|
|
memset (result, 0, nmemb * size);
|
|
|
|
return result;
|
|
}
|