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/*
DEFMEM.C
Implement functions for memory management.
$Id: defmem.c,v 1.1 1993/08/27 18:32:09 munro Exp $
*/
/* Copyright (c) 1994. The Regents of the University of California.
All rights reserved. */
#include "defmem.h"
/* Don't bother to try to include <stdlib.h>; it might not exist. */
#ifdef STDC_HEADERS
#include <stdlib.h>
#else
extern void *malloc(unsigned long size);
extern void free(void *p);
extern void *realloc(void *p, unsigned long size);
#endif
extern long y_net_malloc; /* simplest possible bug detectors */
extern long y_net_blocks;
long y_net_malloc= 0;
long y_net_blocks= 0;
#ifdef DEBUG
static void *DebugMalloc(long size);
static void *DebugRealloc(void *p, long new);
static int DebugMCheck(void *p, int blow);
static void *DebugMalloc(long size)
{
void *p;
long *fill, *fmax, orig;
if (size<=0) size= 1;
orig= size;
size= (((size-1)>>3) + 4)<<3;
p= malloc(size);
if (p) {
fill= p;
fmax= (long *)((char *)p + size);
*fill++= orig;
while (fill<fmax) *(fill++)= -1;
p= (char *)p + 16;
}
return p;
}
static void *DebugRealloc(void *p, long new)
{
long *fill= (long *)((char *)p - 16);
long size= ((((*fill)-1)>>3) + 4)<<3;
long orig;
DebugMCheck(p, 1);
p= fill;
if (new<=0) new= 1;
orig= new;
new= (((new-1)>>3) + 4)<<3;
p= realloc(p, new);
if (p) {
long *fmax= (long *)((char *)p + new);
fill= p;
*fill= orig;
if (new > size) {
fill= (long *)((char *)p + size);
while (fill<fmax) *(fill++)= -1;
} else {
char *past= (char *)p + 16 + orig;
while (past<(char *)fmax) *(past++)= '\xff';
}
p= (char *)p + 16;
}
return p;
}
static int DebugMCheck(void *p, int blow)
{
if (p) {
long size, orig, *fill;
char *past, *pmax;
past= (char *)p - 16;
fill= (long *)past;
orig= *fill++;
size= (((orig-1)>>3) + 4)<<3;
while (fill<(long *)p) {
if (*fill++ != -1) {
if (blow) YError("****DEBUG**** memory underrun (Yfree/Yrealloc)");
return -1;
}
}
p= past;
pmax= past + size;
past+= 16+orig;
while (past<pmax) {
if (*past++ != '\xff') {
if (blow) YError("****DEBUG**** memory overrun (Yfree/Yrealloc)");
return 1;
}
}
}
return 0;
}
#endif
void *Ymalloc(long size)
{
#ifndef DEBUG
void *p= malloc(size>0? size : 1L);
#else
void *p= DebugMalloc(size);
#endif
if (!p) YError("****SEVERE**** memory manager failed (Ymalloc)");
y_net_malloc++;
return p;
}
void Yfree(void *p)
{
#ifndef DEBUG
if (p) { free(p); y_net_malloc--; }
#else
if (p) {
DebugMCheck(p, 1);
p= (char *)p - 16;
free(p);
y_net_malloc--;
}
#endif
}
void *Yrealloc(void *p, long size)
{
#ifndef DEBUG
if (p) p= realloc(p, size>0? size : 1L);
else { p= malloc(size>0? size : 1L); if (p) y_net_malloc++; }
#else
if (p) p= DebugRealloc(p, size);
else { p= DebugMalloc(size); if (p) y_net_malloc++; }
#endif
if (!p) YError("****SEVERE**** memory manager failed (Yrealloc)");
return p;
}
static void *NextBlock(MemoryBlock *block)
{
long unitSize= block->unitSize;
long n= block->blockSize;
char *newUnit= Ymalloc(n+unitSize); /* extra unit for block list */
void *newBlock;
/* Add to blockList (1st unit of each block reserved for this). */
*((void **)newUnit)= block->blockList;
block->blockList= newUnit;
/* Usable units begin with 2nd in block, this will be returned. */
newUnit+= unitSize;
newBlock= newUnit;
/* Free list begins with 3rd unit in block and continues to end.
Initialize the block as a chain of free units. */
n-= unitSize;
newUnit+= unitSize;
block->freeList= newUnit;
while ((n-=unitSize)>0) {
/* smallest legal n=2*unitSize barely fails to reach this point */
*((void **)newUnit)= newUnit+unitSize;
newUnit+= unitSize;
}
*((void **)newUnit)= 0;
return newBlock;
}
void *NextUnit(MemoryBlock *block)
{
void *nextFree= block->freeList;
y_net_blocks++;
if (nextFree) {
/* (void**)<->(void*) typecast in next line is equivalent to
list->next if list is a struct List {struct List *next;}... */
block->freeList= *(void **)nextFree;
return nextFree;
} else {
return NextBlock(block);
}
}
void FreeUnit(MemoryBlock *block, void *ptr)
{
*((void**)ptr)= block->freeList;
block->freeList= ptr;
y_net_blocks--;
}
void FreeAllUnits(MemoryBlock *block)
{
void *blockList, *next= block->blockList;
while ((blockList=next)) {
next= *(void**)blockList;
Yfree(blockList);
}
}
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