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force alignment of headers

This commit is contained in:
Yuichi Nishiwaki 2013-10-13 16:02:08 +09:00
parent c250d3b07f
commit d92bd71293
2 changed files with 39 additions and 35 deletions
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9
include/picrin/gc.h
View File

@ -1,13 +1,16 @@
#ifndef GC_H__
#define GC_H__
struct header {
struct header *ptr;
union header {
struct {
union header *ptr;
size_t size;
} s;
long alignment; /* force alignment for headers to be allocated at the size of long */
};
struct heap_page {
struct header *base, *freep;
union header *base, *freep;
size_t heap_size;
};

63
src/gc.c
View File

@ -6,44 +6,45 @@
void
init_heap_page(struct heap_page *heap)
{
struct header *base, *freep;
union header *base, *freep;
void *p;
p = (struct header *)malloc(PIC_HEAP_SIZE);
p = (union header *)malloc(PIC_HEAP_SIZE);
heap->base = base = (struct header *)
(((unsigned long)p + sizeof(struct header) -1) & ~(sizeof(struct header) - 1));
base->ptr = base + 1;
base->size = 0;
heap->base = base = (union header *)
(((unsigned long)p + sizeof(union header) -1) & ~(sizeof(union header) - 1));
base->s.ptr = base + 1;
base->s.size = 0;
heap->freep = freep = base->ptr;
freep->ptr = base;
freep->size = ((char *)p + PIC_HEAP_SIZE - (char *)freep) / sizeof(struct header);
heap->freep = freep = base->s.ptr;
freep->s.ptr = base;
freep->s.size = ((char *)p + PIC_HEAP_SIZE - (char *)freep) / sizeof(union header);
}
void *
pic_alloc(pic_state *pic, size_t size)
{
struct header *freep, *p, *prevp;
union header *freep, *p, *prevp;
size_t nunits;
nunits = (size + sizeof(struct header) - 1) / sizeof(struct header) + 1;
nunits = (size + sizeof(union header) - 1) / sizeof(union header) + 1;
freep = pic->heap->freep;
prevp = freep;
for (p = prevp->ptr; ; prevp = p, p = p->ptr) {
if (p->size >= nunits)
for (p = prevp->s.ptr; ; prevp = p, p = p->s.ptr) {
if (p->s.size >= nunits)
break;
if (p == freep)
if (p == freep) {
return 0;
}
if (p->size == nunits) {
prevp->ptr = p->ptr;
}
if (p->s.size == nunits) {
prevp->s.ptr = p->s.ptr;
}
else {
p->size -= nunits;
p += p->size;
p->size = nunits;
p->s.size -= nunits;
p += p->s.size;
p->s.size = nunits;
}
pic->heap->freep = prevp;
@ -53,26 +54,26 @@ pic_alloc(pic_state *pic, size_t size)
void
pic_free(pic_state *pic, void *ptr)
{
struct header *bp, *p;
union header *bp, *p;
bp = (struct header *)ptr - 1;
bp = (union header *)ptr - 1;
for (p = pic->heap->freep; !(p < bp && bp < p->ptr); p = p->ptr) {
if (p >= p->ptr && (bp > p || bp < p->ptr))
for (p = pic->heap->freep; !(p < bp && bp < p->s.ptr); p = p->s.ptr) {
if (p >= p->s.ptr && (bp > p || bp < p->s.ptr))
break;
}
if (bp + bp->size == p->ptr) {
bp->size += p->ptr->size;
bp->ptr = p->ptr->ptr;
if (bp + bp->s.size == p->s.ptr) {
bp->s.size += p->s.ptr->s.size;
bp->s.ptr = p->s.ptr->s.ptr;
}
else {
bp->ptr = p->ptr;
bp->s.ptr = p->s.ptr;
}
if (p + p->size == bp) {
p->size += bp->size;
p->ptr = bp->ptr;
if (p + p->s.size == bp) {
p->s.size += bp->s.size;
p->s.ptr = bp->s.ptr;
} else {
p->ptr = bp;
p->s.ptr = bp;
}
pic->heap->freep = p;
}