typedef struct AllocBlockData
{
    AllocSet    aset;           /* aset that owns this block */
    AllocBlock  next;           /* next block in aset's blocks list */
    char       *freeptr;        /* start of free space in this block */
    char       *endptr;         /* end of space in this block */
}   AllocBlockData;

typedef struct AllocBlockData *AllocBlock;