alloc.c

window下的c编译器。

#include "c.h"
#define ALLOCSIZE 64*1024
struct block {
    struct block *next;
    char *limit;
    char *avail;
};
union align {
    long l;
    char *p;
    double d;
    int (*f) ARGS((void));
};
union header {
    struct block b;
    union align a;
};
#ifdef PURIFY
union header *arena[4];

void *allocate(n, a) unsigned long n, a; {
    union header *new = malloc(sizeof *new + n);

    assert(a < NELEMS(arena));
    if (new == NULL) {
        error(StrTab[425]);// <insufficient memory\n>
        exit(1);
    }
    new->b.next = (void *)arena[a];
    arena[a] = new;
    return new + 1;
}

void deallocate(a) unsigned a; {
    union header *p, *q;

    assert(a < NELEMS(arena));
    for (p = arena[a]; p; p = q) {
        q = (void *)p->b.next;
        free(p);
    }
    arena[a] = NULL;
}

void *newarray(m, n, a) unsigned long m, n; unsigned a; {
    return allocate(m*n, a);
}
#else
#ifndef ASM_LIB
static
#endif
struct block
     first[] = {  { NULL },  { NULL },  { NULL },{NULL},{NULL} },
    *arena[] = { &first[0], &first[1], &first[2],&first[3],&first[4]};
static struct block *freeblocks;
int memused=0;
void *allocateslow(register unsigned long n, unsigned a);
#ifndef ASM_LIB
void *allocate(unsigned long n,unsigned a)
{
    struct block *ap;
    void *r=NULL;
    ap = arena[a];
    n = roundup(n, sizeof (union align));
    if (ap->avail + n <= ap->limit) {
        r = ap->avail;
        ap->avail += n;
        return r;
    }
    else
    return allocateslow(n,a);
}
#else
extern void *allocate(unsigned long n,unsigned a);
#endif
extern void * _stdcall GlobalAlloc(unsigned int,unsigned long);

void *allocateslow(register unsigned long n, unsigned a)
{
    register struct block *ap;

//	assert(a < NELEMS(arena));
//	assert(n > 0);
    ap = arena[a];
//	n = roundup(n, sizeof (union align));
    while (ap->avail + n > ap->limit) {
        if ((ap->next = freeblocks) != NULL) {
            freeblocks = freeblocks->next;
            ap = ap->next;
        } else
            {
                ap->next = GlobalAlloc(0,ALLOCSIZE);
                ap = ap->next;
                if (ap == NULL) {
                    error(StrTab[426]);// <insufficient memory\n>
                    exit(1);
                }
                ap->limit = (char *)ap + ALLOCSIZE;
                memused += ALLOCSIZE;
            }
        ap->avail = (char *)((union header *)ap + 1);
        ap->next = NULL;
        arena[a] = ap;

    }
    ap->avail += n;
    return ap->avail - n;
}

void *newarray(unsigned long m,unsigned long n,unsigned a)
{
    return allocate(m*n, a);
}
void deallocate(unsigned a)
{
    assert(a < NELEMS(arena));
    arena[a]->next = freeblocks;
    freeblocks = first[a].next;
    first[a].next = NULL;
    arena[a] = &first[a];
}
#endif