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#include <u.h>
#include <base.h>
#include "pool.h"
// -----------------------------------------------------------------------
// globals/macros
#define NOMAGIC 0xDEADFA11u
#define DEADMAGIC 0xDEADDEADu
#define TAILMAGIC0 0xBEu
#define TAILMAGIC1 0xEFu
#define FREEMAGIC 0xBA5EBA11u
#define USEDMAGIC 0x0A110C09u
#define UNUSEDMAGIC (0xCAB00D1Eu+1)
#define COREMAGIC (0xC0A1E5CEu+1)
#define CORETAILMAGIC (0xEC5E1A0Cu+1)
#define ALIGNMAGIC 0xA1F1D1C1u
#define POISON ((void*)0xCAFEBABEu)
// -----------------------------------------------------------------------
// hunk maintenance
#define HUNKTAIL(h) ((Tail*)((uchar*)(h)+(h)->size-sizeof(Tail)))
static uintptr
gethunksize(mem·Pool *pool, uintptr size)
{
size += sizeof(Head) + sizeof(Tail);
if(size < pool->minhunk)
size = pool->minhunk;
size = (size+pool->quantum) & ~(pool->quantum-1); // aligns to quantum
return size;
}
static Head *
sethunksize(Head *h, uintptr size)
{
Tail *t;
assert(h->magic != FREEMAGIC);
h->size = size;
t = HUNKTAIL(h);
t->size = size;
t->magic0 = TAILMAGIC0;
t->magic1 = TAILMAGIC1;
return h;
}
static void
checkhunk(mem·Pool *p, Head *h)
{
switch(h->magic){
default:
abort();
case FREEMAGIC:
case UNUSEDMAGIC:
case DEADMAGIC:
case COREMAGIC:
case CORETAILMAGIC:
case USEDMAGIC:
;
}
}
// -----------------------------------------------------------------------
// core maintenance
#define COREHEAD(c) ((Head*)((uchar*)(c)+(c)->len -sizeof(Head)))
static uintptr
getcoresize(mem·Pool *pool, uintptr size)
{
size += sizeof(Core) + sizeof(Tail);
if(size < pool->mincore)
size = pool->mincore;
size = (size+pool->quantum) & ~(pool->quantum-1);
return size;
}
static Core *
setcoresize(Core *c, uintptr size)
{
Head *h;
c->len = size;
h = COREHEAD(c);
h->size = 0;
h->magic = CORETAILMAGIC;
return c;
}
static void
newcore(mem·Pool *pool, uintptr size)
{
Core *c;
// XXX: check for size overflow
if(!(c = pool->mem.alloc(pool->heap, 1, size)))
return;
pool->cursize += size;
/* core header */
c->magic = COREMAGIC;
sethunksize((Head*)c, sizeof(Core));
setcoresize(c, size);
checkhunk(pool, (Head*)c);
}
// -----------------------------------------------------------------------
// free list maintenance
static Free *
findgreater(Free *root, uintptr size)
{
Free *last;
last = nil;
for(;;){
if(!root)
return last;
if(size == root->size)
return root;
if(size < root->size){
last = root;
root = root->left;
}else
root = root->right;
}
}
// -----------------------------------------------------------------------
// exported functions
/* constructors / destructors */
mem·Pool*
mem·makepool(mem·Allocator mem, void *heap, char *name, int flags, intptr maxsize, intptr mincore)
{
mem·Pool *pool = mem.alloc(heap, 1, sizeof(*pool));
mem·set(pool, sizeof(*pool), 0);
pool->mem = mem;
pool->heap = heap;
pool->name = name;
pool->flags = flags;
pool->mincore = mincore;
pool->maxsize = maxsize;
return pool;
}
void
mem·freepool(mem·Pool *pool)
{
void *heap = pool->heap;
mem·Allocator mem = pool->mem;
mem.free(heap, pool);
}
/* base functions */
void *
mem·poolalloc(mem·Pool *pool, long n, uintptr eltsize)
{
Free *node;
uintptr size, bksz;
if((size = n*eltsize) >= 0x80000000UL){
errorf("allocation overflow");
return nil;
}
bksz = gethunksize(pool, size);
node = findgreater(pool->free, bksz);
if(!node){
newcore(pool, getcoresize(pool, bksz));
if(!(node = findgreater(pool->free, bksz)))
return nil;
}
return nil;
}
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