Re: [PATCH v14 01/11] util/cutils: Add qemu_strtotime_ns()

[Eduardo Habkost]

On Mon, Oct 28, 2019 at 03:52:10PM +0800, Tao Xu wrote:
> To convert strings with time suffixes to numbers, support time unit are
> "ns" for nanosecond, "us" for microsecond, "ms" for millisecond or "s"
> for second. Add test for qemu_strtotime_ns, test the input of basic,
> time suffixes, float, invaild, trailing and overflow.
> 
> Signed-off-by: Tao Xu <address@hidden>
> ---
> 
> Changes in v14:
>     - Reuse the codes of do_strtosz to build qemu_strtotime_ns
>       (Eduardo)
>     - Squash patch v13 01/12 and 02/12 together (Daniel and Eduardo)
>     - Drop time unit picosecond (Eric)

Suggestion for the next version: if you are refactoring existing
do_strtosz() code, please refactor it in one patch, and add new
functionality in another patch.

> ---
>  include/qemu/cutils.h |   1 +
>  tests/test-cutils.c   | 204 ++++++++++++++++++++++++++++++++++++++++++
>  util/cutils.c         |  89 +++++++++++-------
>  3 files changed, 262 insertions(+), 32 deletions(-)
> 
> diff --git a/include/qemu/cutils.h b/include/qemu/cutils.h
> index b54c847e0f..ff2b3f4614 100644
> --- a/include/qemu/cutils.h
> +++ b/include/qemu/cutils.h
> @@ -182,5 +182,6 @@ int uleb128_decode_small(const uint8_t *in, uint32_t *n);
>   * *str1 is <, == or > than *str2.
>   */
>  int qemu_pstrcmp0(const char **str1, const char **str2);
> +int qemu_strtotime_ns(const char *nptr, const char **end, uint64_t *result);
>  
>  #endif
> diff --git a/tests/test-cutils.c b/tests/test-cutils.c
> index 1aa8351520..d6a0824efd 100644
> --- a/tests/test-cutils.c
> +++ b/tests/test-cutils.c
[...]
> +static void test_qemu_strtotime_ns_trailing(void)
> +{
> +    const char *str;
> +    const char *endptr;
> +    int err;
> +    uint64_t res = 0xbaadf00d;
> +
> +    str = "123xxx";
> +
> +    err = qemu_strtotime_ns(str, NULL, &res);
> +    g_assert_cmpint(err, ==, -EINVAL);
> +
> +    str = "1msxxx";
> +    err = qemu_strtotime_ns(str, &endptr, &res);
> +    g_assert_cmpint(err, ==, 0);
> +    g_assert_cmpint(res, ==, 1000000);
> +    g_assert(endptr == str + 3);
> +
> +    err = qemu_strtotime_ns(str, NULL, &res);
> +    g_assert_cmpint(err, ==, -EINVAL);
> +}

This is better than the test case in v13, where trailing strings
were not handled consistently.  Good.

[...]
> diff --git a/util/cutils.c b/util/cutils.c
> index fd591cadf0..d83825f8b4 100644
> --- a/util/cutils.c
> +++ b/util/cutils.c
> @@ -181,41 +181,38 @@ int fcntl_setfl(int fd, int flag)
>  }
>  #endif
>  
> -static int64_t suffix_mul(char suffix, int64_t unit)
> -{
> -    switch (qemu_toupper(suffix)) {
> -    case 'B':
> -        return 1;
> -    case 'K':
> -        return unit;
> -    case 'M':
> -        return unit * unit;
> -    case 'G':
> -        return unit * unit * unit;
> -    case 'T':
> -        return unit * unit * unit * unit;
> -    case 'P':
> -        return unit * unit * unit * unit * unit;
> -    case 'E':
> -        return unit * unit * unit * unit * unit * unit;
> +static int64_t suffix_mul(const char *suffixes[], int num_suffix,
> +                          const char *endptr, int *offset, int64_t unit)
> +{
> +    int i, suffix_len;
> +    int64_t mul = 1;
> +
> +    for (i = 0; i < num_suffix; i++) {
> +        suffix_len = strlen(suffixes[i]);
> +        if (strlen(endptr) >= suffix_len &&

Is the strlen(endptr) check here really necessary?


> +            g_ascii_strncasecmp(suffixes[i], endptr, suffix_len) == 0) {
> +            *offset = suffix_len;
> +            return mul;
> +        }
> +        mul *= unit;
>      }
> +
>      return -1;
>  }
>  
>  /*
> - * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
> - * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
> - * in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on
> - * other error.
> + * Convert string according to different suffixes. End pointer will be 
> returned
> + * in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on other 
> error.
>   */
> -static int do_strtosz(const char *nptr, const char **end,
> -                      const char default_suffix, int64_t unit,
> -                      uint64_t *result)
> +static int do_strtomul(const char *nptr, const char **end,
> +                       const char *suffixes[], int num_suffix,
> +                       const char *default_suffix, int64_t unit,
> +                       uint64_t *result)
>  {
>      int retval;
>      const char *endptr;
> -    unsigned char c;
>      int mul_required = 0;
> +    int offset = 0;
>      double val, mul, integral, fraction;
>  
>      retval = qemu_strtod_finite(nptr, &endptr, &val);
> @@ -226,12 +223,12 @@ static int do_strtosz(const char *nptr, const char 
> **end,
>      if (fraction != 0) {
>          mul_required = 1;
>      }
> -    c = *endptr;
> -    mul = suffix_mul(c, unit);
> +
> +    mul = suffix_mul(suffixes, num_suffix, endptr, &offset, unit);
>      if (mul >= 0) {
> -        endptr++;
> +        endptr += offset;
>      } else {
> -        mul = suffix_mul(default_suffix, unit);
> +        mul = suffix_mul(suffixes, num_suffix, default_suffix, &offset, 
> unit);
>          assert(mul >= 0);
>      }
>      if (mul == 1 && mul_required) {
> @@ -259,19 +256,47 @@ out:
>      return retval;
>  }
>  
> +/*
> + * Convert string to bytes, allowing either B/b for bytes, K/k for KB,
> + * M/m for MB, G/g for GB or T/t for TB. End pointer will be returned
> + * in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on
> + * other error.
> + */
> +static int do_strtosz(const char *nptr, const char **end,
> +                      const char *default_suffix, int64_t unit,
> +                      uint64_t *result)
> +{
> +    static const char *suffixes[] = { "B", "K", "M", "G", "T", "P", "E" };
> +
> +    return do_strtomul(nptr, end, suffixes, 7, default_suffix, unit, result);

[1] You can use ARRAY_SIZE(suffixes) instead of hardcoding the
array size.

> +}
> +
>  int qemu_strtosz(const char *nptr, const char **end, uint64_t *result)
>  {
> -    return do_strtosz(nptr, end, 'B', 1024, result);
> +    return do_strtosz(nptr, end, "B", 1024, result);
>  }
>  
>  int qemu_strtosz_MiB(const char *nptr, const char **end, uint64_t *result)
>  {
> -    return do_strtosz(nptr, end, 'M', 1024, result);
> +    return do_strtosz(nptr, end, "M", 1024, result);
>  }
>  
>  int qemu_strtosz_metric(const char *nptr, const char **end, uint64_t *result)
>  {
> -    return do_strtosz(nptr, end, 'B', 1000, result);
> +    return do_strtosz(nptr, end, "B", 1000, result);
> +}
> +
> +/*
> + * Convert string to time, support time unit are ns for nanosecond, us for
> + * microsecond, ms for millisecond and s for second. End pointer will be
> + * returned in *end, if not NULL. Return -ERANGE on overflow, and -EINVAL on
> + * other error.
> + */
> +int qemu_strtotime_ns(const char *nptr, const char **end, uint64_t *result)
> +{
> +    static const char *suffixes[] = { "ns", "us", "ms", "s" };
> +
> +    return do_strtomul(nptr, end, suffixes, 4, "ns", 1000, result);

Same as above[1].

>  }
>  
>  /**
> -- 
> 2.20.1
> 

-- 
Eduardo