Let's provide a wrapper for strtod(). Reviewed-by: Eric Blake <ebl...@redhat.com> Signed-off-by: David Hildenbrand <da...@redhat.com> --- include/qemu/cutils.h | 2 ++ util/cutils.c | 65 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 67 insertions(+)
diff --git a/include/qemu/cutils.h b/include/qemu/cutils.h index 7071bfe2d4..756b41c193 100644 --- a/include/qemu/cutils.h +++ b/include/qemu/cutils.h @@ -146,6 +146,8 @@ int qemu_strtoi64(const char *nptr, const char **endptr, int base, int64_t *result); int qemu_strtou64(const char *nptr, const char **endptr, int base, uint64_t *result); +int qemu_strtod(const char *nptr, const char **endptr, double *result); +int qemu_strtod_finite(const char *nptr, const char **endptr, double *result); int parse_uint(const char *s, unsigned long long *value, char **endptr, int base); diff --git a/util/cutils.c b/util/cutils.c index 698bd315bd..c965dbfcad 100644 --- a/util/cutils.c +++ b/util/cutils.c @@ -544,6 +544,71 @@ int qemu_strtou64(const char *nptr, const char **endptr, int base, return check_strtox_error(nptr, ep, endptr, errno); } +/** + * Convert string @nptr to a double. + * + * This is a wrapper around strtod() that is harder to misuse. + * Semantics of @nptr and @endptr match strtod() with differences + * noted below. + * + * @nptr may be null, and no conversion is performed then. + * + * If no conversion is performed, store @nptr in *@endptr and return + * -EINVAL. + * + * If @endptr is null, and the string isn't fully converted, return + * -EINVAL. This is the case when the pointer that would be stored in + * a non-null @endptr points to a character other than '\0'. + * + * If the conversion overflows, store +/-HUGE_VAL in @result, depending + * on the sign, and return -ERANGE. + * + * If the conversion underflows, store ±0.0 in @result, depending on the + * sign, and return -ERANGE. + * + * Else store the converted value in @result, and return zero. + */ +int qemu_strtod(const char *nptr, const char **endptr, double *result) +{ + char *ep; + + if (!nptr) { + if (endptr) { + *endptr = nptr; + } + return -EINVAL; + } + + errno = 0; + *result = strtod(nptr, &ep); + return check_strtox_error(nptr, ep, endptr, errno); +} + +/** + * Convert string @nptr to a finite double. + * + * Works like qemu_strtod(), except that "NaN" and "inf" are rejected + * with -EINVAL and no conversion is performed. + */ +int qemu_strtod_finite(const char *nptr, const char **endptr, double *result) +{ + double tmp; + int ret; + + ret = qemu_strtod(nptr, endptr, &tmp); + if (ret) { + return ret; + } else if (!isfinite(tmp)) { + if (endptr) { + *endptr = nptr; + } + return -EINVAL; + } + + *result = tmp; + return ret; +} + /** * Searches for the first occurrence of 'c' in 's', and returns a pointer * to the trailing null byte if none was found. -- 2.17.2