35 

    36 /*

    37  * Interface for small allocations. If you need a little scratch space for

    38  *  a throwaway buffer or string, use this. It will make small allocations

    39  *  on the stack if possible, and use allocator.Malloc() if they are too

    40  *  large. This helps reduce malloc pressure.

    41  * There are some rules, though:

    42  * NEVER return a pointer from this, as stack-allocated buffers go away

    43  *  when your function returns.

    44  * NEVER allocate in a loop, as stack-allocated pointers will pile up. Call

    45  *  a function that uses smallAlloc from your loop, so the allocation can

    46  *  free each time.

    47  * NEVER call smallAlloc with any complex expression (it's a macro that WILL

    48  *  have side effects...it references the argument multiple times). Use a

    49  *  variable or a literal.

    50  * NEVER free a pointer from this with anything but smallFree. It will not

    51  *  be a valid pointer to the allocator, regardless of where the memory came

    52  *  from.

    53  * NEVER realloc a pointer from this.

    54  * NEVER forget to use smallFree: it may not be a pointer from the stack.

    55  * NEVER forget to check for NULL...allocation can fail here, of course!

    56  */

    57 #define __PHYSFS_SMALLALLOCTHRESHOLD 128

    58 void *__PHYSFS_initSmallAlloc(void *ptr, PHYSFS_uint64 len);

    59 

    60 #define __PHYSFS_smallAlloc(bytes) ( \

    61     __PHYSFS_initSmallAlloc(((bytes < __PHYSFS_SMALLALLOCTHRESHOLD) ? \

    62                              alloca(bytes+1) : NULL), bytes) \

    63 )

    64 

    65 void __PHYSFS_smallFree(void *ptr);

    66