Improve error message while parsing posix timezone string

This commit is contained in:
Howard Hinnant 2020-08-02 10:55:45 -04:00
parent abe3ada04f
commit 569b2d6785

View File

@ -36,6 +36,9 @@
// Posix::time_zone tz{"EST5EDT,M3.2.0,M11.1.0"};
// zoned_time<system_clock::duration, Posix::time_zone> zt{tz, system_clock::now()};
//
// If the rule set is missing (everything starting with ','), then the rule is that the
// alternate offset is never enabled.
//
// Note, Posix-style time zones are not recommended for all of the reasons described here:
// https://stackoverflow.com/tags/timezone/info
//
@ -70,7 +73,8 @@ unsigned read_date(const string_t& s, unsigned i, rule& r);
unsigned read_name(const string_t& s, unsigned i, std::string& name);
unsigned read_signed_time(const string_t& s, unsigned i, std::chrono::seconds& t);
unsigned read_unsigned_time(const string_t& s, unsigned i, std::chrono::seconds& t);
unsigned read_unsigned(const string_t& s, unsigned i, unsigned limit, unsigned& u);
unsigned read_unsigned(const string_t& s, unsigned i, unsigned limit, unsigned& u,
const string_t& message = string_t{});
class rule
{
@ -584,7 +588,7 @@ throw_invalid(const string_t& s, unsigned i, const string_t& message)
std::string(s) + '\n' +
"\x1b[1;32m" +
std::string(i, '~') + '^' +
std::string(s.size()-i-1, '~') +
std::string(i < s.size() ? s.size()-i-1 : 0, '~') +
"\x1b[0m");
}
@ -600,7 +604,7 @@ read_date(const string_t& s, unsigned i, rule& r)
{
++i;
unsigned n;
i = read_unsigned(s, i, 3, n);
i = read_unsigned(s, i, 3, n, "Expected to find the Julian day [1, 365]");
r.mode_ = rule::J;
r.n_ = n;
}
@ -608,17 +612,17 @@ read_date(const string_t& s, unsigned i, rule& r)
{
++i;
unsigned m;
i = read_unsigned(s, i, 2, m);
i = read_unsigned(s, i, 2, m, "Expected to find month [1, 12]");
if (i == s.size() || s[i] != '.')
throw_invalid(s, i, "Expected '.' after month");
++i;
unsigned n;
i = read_unsigned(s, i, 1, n);
i = read_unsigned(s, i, 1, n, "Expected to find week number [1, 5]");
if (i == s.size() || s[i] != '.')
throw_invalid(s, i, "Expected '.' after weekday index");
++i;
unsigned wd;
i = read_unsigned(s, i, 1, wd);
i = read_unsigned(s, i, 1, wd, "Expected to find day of week [0, 6]");
r.mode_ = rule::M;
r.m_ = month{m};
r.wd_ = weekday{wd};
@ -708,17 +712,17 @@ read_unsigned_time(const string_t& s, unsigned i, std::chrono::seconds& t)
if (i == s.size())
throw_invalid(s, i, "Expected to read unsigned time, but found end of string");
unsigned x;
i = read_unsigned(s, i, 2, x);
i = read_unsigned(s, i, 2, x, "Expected to find hours [0, 24]");
t = hours{x};
if (i != s.size() && s[i] == ':')
{
++i;
i = read_unsigned(s, i, 2, x);
i = read_unsigned(s, i, 2, x, "Expected to find minutes [0, 59]");
t += minutes{x};
if (i != s.size() && s[i] == ':')
{
++i;
i = read_unsigned(s, i, 2, x);
i = read_unsigned(s, i, 2, x, "Expected to find seconds [0, 59]");
t += seconds{x};
}
}
@ -727,10 +731,11 @@ read_unsigned_time(const string_t& s, unsigned i, std::chrono::seconds& t)
inline
unsigned
read_unsigned(const string_t& s, unsigned i, unsigned limit, unsigned& u)
read_unsigned(const string_t& s, unsigned i, unsigned limit, unsigned& u,
const string_t& message)
{
if (i == s.size() || !std::isdigit(s[i]))
throw_invalid(s, i, "Expected to find a decimal digit");
throw_invalid(s, i, message);
u = static_cast<unsigned>(s[i] - '0');
unsigned count = 1;
for (++i; count < limit && i != s.size() && std::isdigit(s[i]); ++i, ++count)