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Support binary unit prefixes in command line arguments

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This commit is contained in:
Eelco Dolstra 2021-01-08 12:51:19 +01:00
parent 6548b89cc4
commit 17beae299d
4 changed files with 29 additions and 27 deletions
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28
src/libutil/util.hh
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@ -401,12 +401,34 @@ template<class N>
std::optional<N> string2Int(const std::string & s)
{
if (s.substr(0, 1) == "-" && !std::numeric_limits<N>::is_signed)
return {};
return std::nullopt;
std::istringstream str(s);
N n;
str >> n;
if (str && str.get() == EOF) return n;
return {};
return std::nullopt;
}
/* Like string2Int(), but support an optional suffix 'K', 'M', 'G' or
'T' denoting a binary unit prefix. */
template<class N>
N string2IntWithUnitPrefix(std::string s)
{
N multiplier = 1;
if (!s.empty()) {
char u = std::toupper(*s.rbegin());
if (std::isalpha(u)) {
if (u == 'K') multiplier = 1ULL << 10;
else if (u == 'M') multiplier = 1ULL << 20;
else if (u == 'G') multiplier = 1ULL << 30;
else if (u == 'T') multiplier = 1ULL << 40;
else throw UsageError("invalid unit specifier '%1%'", u);
s.resize(s.size() - 1);
}
}
if (auto n = string2Int<N>(s))
return *n * multiplier;
throw UsageError("'%s' is not an integer", s);
}
/* Parse a string into a float. */
@ -417,7 +439,7 @@ std::optional<N> string2Float(const string & s)
N n;
str >> n;
if (str && str.get() == EOF) return n;
return {};
return std::nullopt;
}