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Howard Hinnant
2017-03-02 13:17:01 -10:00
parent 6466e58f94
commit c12319552a
1 changed files with 111 additions and 69 deletions
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@@ -26,7 +26,7 @@
<br/>
<br/>
<a href="mailto:howard.hinnant@gmail.com">Howard E. Hinnant</a><br/>
2017-02-26<br/>
2017-03-02<br/>
</address>
<hr/>
<h1 align=center>Time Zone Database Parser</h1>
@@ -59,6 +59,7 @@
<li><a href="#make_zoned"><code>make_zoned</code></a></li>
<li><a href="#to_stream"><code>to_stream</code></a></li>
<li><a href="#format"><code>format</code></a></li>
<li><a href="#from_stream"><code>from_stream</code></a></li>
<li><a href="#parse"><code>parse</code></a></li>
<li><a href="#utc_clock"><code>utc_clock</code></a></li>
<li><a href="#tai_clock"><code>tai_clock</code></a></li>
@@ -2172,74 +2173,62 @@ For the overloads taking a <code>zoned_time</code> it is the value returned by
</blockquote>
</blockquote>
<a name="parse"></a><h3><code>parse</code></h3>
<a name="from_stream"></a><h3><code>from_stream</code></h3>
<blockquote>
<p>
One can parse in a <code>year_month_day</code>, <code>sys_time&lt;Duration&gt;</code>,
<code>local_time&lt;Duration&gt;</code>, <code>utc_time&lt;Duration&gt;</code>,
<code>tai_time&lt;Duration&gt;</code>, <code>gps_time&lt;Duration&gt;</code>,
or a <code>duration&lt;Rep, Period&gt;</code>.
Optionally, one can also pass in a reference
to a <code>std::string</code> in order to capture the time zone abbreviation, or one
can pass in a reference to a <code>std::chrono::minutes</code> to capture a time zone
UTC offset (formatted as <code>+0000</code>), or one can pass in both in either order.
</p>
<p>
Each of the functions below return a <code>parse_manip</code> <i>manipulator</i> which is
specialized on the type to be parsed, and which can be used to extract the desired
information from a stream.
</p>
<pre>
template &lt;class Parsable, class CharT, class Traits = std::char_traits&lt;CharT&gt;&gt;
struct parse_manip;
template &lt;class CharT, class Traits&gt;
void
from_stream(std::basic_istream&lt;CharT, Traits&gt;&amp; is, const CharT* fmt,
year_month_day&amp; ymd, std::basic_string&lt;CharT, Traits&gt;* abbrev = nullptr,
std::chrono::minutes* offset = nullptr);
template &lt;class Parsable, class CharT, class Traits&gt;
typename parse_manip&lt;Parsable, CharT, Traits&gt;::type
parse(const std::basic_string&lt;CharT, Traits&gt;&amp; format, Parsable&amp; tp);
template &lt;class Duration, class CharT, class Traits&gt;
void
from_stream(std::basic_istream&lt;CharT, Traits&gt;&amp; is, const CharT* fmt,
sys_time&lt;Duration&gt;&amp; tp, std::basic_string&lt;CharT, Traits&gt;* abbrev = nullptr,
std::chrono::minutes* offset = nullptr);
template &lt;class Parsable, class CharT, class Traits&gt;
typename parse_manip&lt;Parsable, CharT, Traits&gt;::type
parse(const std::basic_string&lt;CharT, Traits&gt;&amp; format, Parsable&amp; tp,
std::basic_string&lt;CharT, Traits&gt;&amp; abbrev);
template &lt;class Duration, class CharT, class Traits&gt;
void
from_stream(std::basic_istream&lt;CharT, Traits&gt;&amp; is, const CharT* fmt,
local_time&lt;Duration&gt;&amp; tp, std::basic_string&lt;CharT, Traits&gt;* abbrev = nullptr,
std::chrono::minutes* offset = nullptr);
template &lt;class Parsable, class CharT, class Traits&gt;
typename parse_manip&lt;Parsable, CharT, Traits&gt;::type
parse(const std::basic_string&lt;CharT, Traits&gt;&amp; format, Parsable&amp; tp,
std::chrono::minutes&amp; offset);
template &lt;class Rep, class Period, class CharT, class Traits&gt;
void
from_stream(std::basic_istream&lt;CharT, Traits&gt;&amp; is, const CharT* fmt,
std::chrono::duration&lt;Rep, Period&gt;&amp; d,
std::basic_string&lt;CharT, Traits&gt;* abbrev = nullptr,
std::chrono::minutes* offset = nullptr);
template &lt;class Parsable, class CharT, class Traits&gt;
typename parse_manip&lt;Parsable, CharT, Traits&gt;::type
parse(const std::basic_string&lt;CharT, Traits&gt;&amp; format, Parsable&amp; tp,
std::basic_string&lt;CharT, Traits&gt;&amp; abbrev, std::chrono::minutes&amp; offset);
template &lt;class Duration, class CharT, class Traits&gt;
void
from_stream(std::basic_istream&lt;CharT, Traits&gt;&amp; is, const CharT* fmt,
utc_time&lt;Duration&gt;&amp; tp, std::basic_string&lt;CharT, Traits&gt;* abbrev = nullptr,
std::chrono::minutes* offset = nullptr);
// const CharT* formats
template &lt;class Duration, class CharT, class Traits&gt;
void
from_stream(std::basic_istream&lt;CharT, Traits&gt;&amp; is, const CharT* fmt,
tai_time&lt;Duration&gt;&amp; tp, std::basic_string&lt;CharT, Traits&gt;* abbrev = nullptr,
std::chrono::minutes* offset = nullptr);
template &lt;class Parsable, class CharT&gt;
typename parse_manip&lt;Parsable, CharT&gt;::type
parse(const CharT* format, Parsable&amp; tp);
template &lt;class Parsable, class CharT, class Traits&gt;
typename parse_manip&lt;Parsable, CharT&gt;::type
parse(const CharT* format, Parsable&amp; tp, std::basic_string&lt;CharT, Traits&gt;&amp; abbrev);
template &lt;class Parsable, class CharT&gt;
typename parse_manip&lt;Parsable, CharT&gt;::type
parse(const CharT* format, Parsable&amp; tp, std::chrono::minutes&amp; offset);
template &lt;class Parsable, class CharT, class Traits&gt;
typename parse_manip&lt;Parsable, CharT&gt;::type
parse(const CharT* format, Parsable&amp; tp,
std::basic_string&lt;CharT, Traits&gt;&amp; abbrev, std::chrono::minutes&amp; offset);
template &lt;class Duration, class CharT, class Traits&gt;
void
from_stream(std::basic_istream&lt;CharT, Traits&gt;&amp; is, const CharT* fmt,
gps_time&lt;Duration&gt;&amp; tp, std::basic_string&lt;CharT, Traits&gt;* abbrev = nullptr,
std::chrono::minutes* offset = nullptr);
</pre>
<blockquote>
<p>
<i>Effects:</i> These functions attempt to parse an object out of
<code>is</code> according to <code>format</code>. If the parse is unsuccessful,
<code>is</code> according to <code>fmt</code>. If the parse is unsuccessful,
calls <code>is.setstate(std::ios::failbit)</code> which may throw an exception.
<code>tp</code>, <code>abbrev</code>, and <code>offset</code> are altered only in
the event of a successful parse.
<code>tp</code>, <code>*abbrev</code>, and <code>*offset</code> are altered only in
the event of a successful parse, for the latter two, only if they are not equal to
<code>nullptr</code>.
</p>
<blockquote>
<p>
@@ -2253,23 +2242,24 @@ If <code>%F</code> appears in the <code>format</code> string it is interpreted a
</p></li>
<li><p>
If <code>%S</code> or <code>%T</code> appears in the <code>format</code> string
and the argument <code>tp</code> has precision finer than seconds, then the
seconds are parsed as a <code>double</code>, and if that parse is successful
If <code>%S</code> or <code>%T</code> appears in the <code>format</code> string and the
argument <code>tp</code> has precision that is not implicitly convertible to seconds, then
the seconds are parsed as a <code>double</code>, and if that parse is successful
contributes to the time stamp as if
<code>round&lt;Duration&gt;(duration&lt;double&gt;{s})</code> where
<code>s</code> is a local variable holding the parsed <code>double</code>.
<code>round&lt;Duration&gt;(duration&lt;double&gt;{s})</code> where <code>s</code> is a
local variable holding the parsed <code>double</code>.
</p></li>
<li><p>
If <code>%z</code> appears in the <code>format</code> string and an offset is
successfully parsed, the overloads taking <code>sys_time</code> interprets the
successfully parsed, the overloads taking <code>sys_time</code>, <code>utc_time</code>,
<code>tai_time</code> and <code>gps_time</code> interpret the
parsed time as a local time and subtracts the offset prior to assigning the
value to <code>tp</code>, resulting in a value of <code>tp</code> representing a
UTC timestamp. The overloads taking <code>local_time</code> require a valid
parse of the offset, but then ignore the offset in assigning a value to the
<code>local_time&lt;Duration&gt;&amp; tp</code>. If <code>offset</code> is
passed in, on successful parse it will hold the value represented by
UTC timestamp. The remaining overloads require a valid
parse of the offset, but then ignore the offset in assigning a value to
<code>tp</code>. If <code>offset</code> is not equal to <code>nullptr</code>,
on successful parse <code>*offset</code> will hold the value represented by
<code>%z</code> if present, or will be assigned <code>0min</code> if
<code>%z</code> is not present.
</p>
@@ -2285,11 +2275,13 @@ hours digit is optional:
<li><p>
If <code>%Z</code> appears in the <code>format</code> string then an
abbreviation is required in that position for a successful parse. The
abbreviation will be parsed as a <code>std::string</code> (delimited by white
abbreviation will be parsed as a <code>std::basic_string&lt;CharT, Traits&gt;</code>
(delimited by white
space). The parsed abbreviation does not have to be a valid time zone
abbreviation, and has no impact on the value parsed into <code>tp</code>. Using
the overloads that take a <code>std::string&amp;</code> one can discover what
that parsed abbreviation is. On successful parse, <code>abbrev</code> will be
abbreviation, and has no impact on the value parsed into <code>tp</code>. If
<code>abbrev</code> is not equal to <code>nullptr</code> one can discover what
that parsed abbreviation is. On successful parse, and if <code>abbrev != nullptr</code>,
<code>*abbrev</code> will be
assigned the value represented by <code>%Z</code> if present, or assigned the
empty string if <code>%Z</code> is not present.
</p></li>
@@ -2304,6 +2296,56 @@ Given a UTC offset, one might even narrow that list down further.
</blockquote>
</blockquote>
<a name="parse"></a><h3><code>parse</code></h3>
<blockquote>
<p>
Each of the functions below return a <i>manipulator</i> which can be used to extract the
desired information from a stream. These functions do not participate in overload
resolution unless <code>Parsable</code> has a corresponding <code>from_stream</code>
overload.
</p>
<pre>
template &lt;class Parsable, class CharT, class Traits&gt;
<i>unspecified</i>
parse(const std::basic_string&lt;CharT, Traits&gt;&amp; format, Parsable&amp; tp);
template &lt;class Parsable, class CharT, class Traits&gt;
<i>unspecified</i>
parse(const std::basic_string&lt;CharT, Traits&gt;&amp; format, Parsable&amp; tp,
std::basic_string&lt;CharT, Traits&gt;&amp; abbrev);
template &lt;class Parsable, class CharT, class Traits&gt;
<i>unspecified</i>
parse(const std::basic_string&lt;CharT, Traits&gt;&amp; format, Parsable&amp; tp,
std::chrono::minutes&amp; offset);
template &lt;class Parsable, class CharT, class Traits&gt;
<i>unspecified</i>
parse(const std::basic_string&lt;CharT, Traits&gt;&amp; format, Parsable&amp; tp,
std::basic_string&lt;CharT, Traits&gt;&amp; abbrev, std::chrono::minutes&amp; offset);
// const CharT* formats
template &lt;class Parsable, class CharT&gt;
<i>unspecified</i>
parse(const CharT* format, Parsable&amp; tp);
template &lt;class Parsable, class CharT, class Traits&gt;
<i>unspecified</i>
parse(const CharT* format, Parsable&amp; tp, std::basic_string&lt;CharT, Traits&gt;&amp; abbrev);
template &lt;class Parsable, class CharT&gt;
<i>unspecified</i>
parse(const CharT* format, Parsable&amp; tp, std::chrono::minutes&amp; offset);
template &lt;class Parsable, class CharT, class Traits&gt;
<i>unspecified</i>
parse(const CharT* format, Parsable&amp; tp,
std::basic_string&lt;CharT, Traits&gt;&amp; abbrev, std::chrono::minutes&amp; offset);
</pre>
</blockquote>
<a name="utc_clock"></a><h3><code>utc_clock</code></h3>
<blockquote>
<pre>