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Re: [Qemu-devel] [ [PATCH 1/2] cutils:change strtosz_suffix_unit functio
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] [ [PATCH 1/2] cutils:change strtosz_suffix_unit function |
Date: |
Tue, 11 Dec 2012 10:52:41 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, Dec 07, 2012 at 11:49:49AM +0800, liguang wrote:
> if value to be translated is larger than INT64_MAX,
> this function will not be convenient for caller to
> be aware of it, so change a little for this.
>
> Signed-off-by: liguang <address@hidden>
> ---
> cutils.c | 5 +++--
> 1 files changed, 3 insertions(+), 2 deletions(-)
I don't understand what this patch is supposed to do.
Why change the type of mul from double to int64_t?
Are you using retval = 0 as a special value to indicate overflow? Then
the new return value should be documented. But it would be better to
change the function to return -errno values instead of 0/-1 so the
caller knows the reason for specific failure cases (e.g. -E2BIG).
Should the val < 0 case be checked earlier in the function? It seems
like a different failure case then INT64_MAX overflow.
> diff --git a/cutils.c b/cutils.c
> index 4f0692f..8905b5e 100644
> --- a/cutils.c
> +++ b/cutils.c
> @@ -219,11 +219,11 @@ static int64_t suffix_mul(char suffix, int64_t unit)
> int64_t strtosz_suffix_unit(const char *nptr, char **end,
> const char default_suffix, int64_t unit)
> {
> - int64_t retval = -1;
> + int64_t retval = -1, mul;
> char *endptr;
> unsigned char c;
> int mul_required = 0;
> - double val, mul, integral, fraction;
> + double val, integral, fraction;
>
> errno = 0;
> val = strtod(nptr, &endptr);
> @@ -246,6 +246,7 @@ int64_t strtosz_suffix_unit(const char *nptr, char **end,
> goto fail;
> }
> if ((val * mul >= INT64_MAX) || val < 0) {
> + retval = 0;
> goto fail;
> }
> retval = val * mul;
> --
> 1.7.2.5
>
>