On Thu, Sep 04, 2014 at 12:45:45PM -0700, Zach Brown wrote:
> --- a/utils.h
> +++ b/utils.h
> @@ -71,13 +71,17 @@ int check_mounted_where(int fd, const char *file, char
> *where, int size,
> int btrfs_device_already_in_root(struct btrfs_root *root, int fd,
> int super_offset);
>
> -int pretty_size_snprintf(u64 size, char *str, size_t str_bytes);
> -#define pretty_size(size) \
> - ({ \
> - static __thread char _str[24]; \
> - (void)pretty_size_snprintf((size), _str, sizeof(_str)); \
> - _str; \
> - })
> +/*
> + * It's annoying that gcc hasn't yet figured out how to learn about
> + * formats added by register_printf_specifier(). If that were the case
> + * we could just add some %P type and be done with it. Some day..
> + *
> + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47781
> + */
> +float pretty_float(u64 size);
> +char *pretty_suffix(u64 size);
> +#define PF "%.2f%s"
> +#define PA(x) pretty_float(x), pretty_suffix(x)
So I've crawled back to that patch and I'm not all happy to update every
use of pretty_size and the printf string. The user-defined printf format
handlers are not an option.
My proposal that would avoid that:
- predefine a static array of N strings where the pretty numbers would
fit, eg 32 bytes as is now
- pretty_size will:
- grab the first unused slot
- fill it with the string
- increase index to the array
- wrap at N
- return pointer to the prev entry
Normally we're using at most 2 pretty_size calls per printf, so if we
make eg. N = 10, we're relatively safe.
We can keep the easy %s + pretty_size, I really find it convenient to
write it that way.
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