On Sun, 2009-03-01 at 02:17 +0100, Bruno Haible wrote:
> Alan Hourihane wrote:
> + fp->__pushback_bufp = 0;
> + if (fp->__mode.__write)
> + fp->__put_limit = fp->__buffer;
> + fp->__bufp = fp->__get_limit;
>
> I don't think the last statement is right. The purpose of fpurge, on the read
> side, is to empty the buffer, i.e. drop all read contents. I do agree that
> at the end of this function, fp->__bufp == fp->__get_limit, should hold.
>
> Compare what is done on glibc systems. There, essentially
> #define getc(fp) (fp->_IO_read_ptr < fp->_IO_read_end ?
> *_fp->_IO_read_ptr++ : ...)
> and fpurge does
> fp->_IO_read_end = fp->_IO_read_ptr;
> Consequently, on FreeMiNT, where getc is essentially
> #define getc(fp) (fp->__bufp < fp->__get_limit ? *fp->__bufp++ : ...)
> hence fpurge has to do
> fp->__get_limit = fp->__bufp;
Quite right. Good catch.
> I propose this instead in fpurge.c
>
> # elif defined __MINT__ /* Atari FreeMiNT */
> if (fp->__pushed_back)
> {
> fp->__bufp = fp->__pushback_bufp;
> fp->__pushed_back = 0;
> }
> /* Preserve the current file position. */
> if (fp->__target != -1)
> fp->__target += fp->__bufp - fp->__buffer;
> fp->__bufp = fp->__buffer;
> /* Nothing in the buffer, next getc is nontrivial. */
> fp->__get_limit = fp->__bufp;
> /* Nothing in the buffer, next putc is nontrivial. */
> fp->__put_limit = fp->__buffer;
> return 0;
>
> (The 'if (fp->__mode.__write)' in your variant is certainly redundant, right?)
Yes. This works too.
Alan.
