util.dbuffer: Add efficient shortcuts for discard() in certain cases
If the buffer is already empty, nothing to do. If we're throwing away the
whole buffer, we can just empty it and avoid read_chunk() (which in turn
may collapse()). These shortcuts are much more efficient.
-- Prosody IM
-- Copyright (C) 2008-2010 Matthew Wild
-- Copyright (C) 2008-2010 Waqas Hussain
--
-- This project is MIT/X11 licensed. Please see the
-- COPYING file in the source package for more information.
--
-- XEP-0082: XMPP Date and Time Profiles
local os_date = os.date;
local os_time = os.time;
local os_difftime = os.difftime;
local floor = math.floor;
local tonumber = tonumber;
local _ENV = nil;
-- luacheck: std none
local function date(t)
return os_date("!%Y-%m-%d", t and floor(t) or nil);
end
local function datetime(t)
if t == nil or t % 1 == 0 then
return os_date("!%Y-%m-%dT%H:%M:%SZ", t);
end
local m = t % 1;
local s = floor(t);
return os_date("!%Y-%m-%dT%H:%M:%S.%%06dZ", s):format(floor(m * 1000000));
end
local function time(t)
if t == nil or t % 1 == 0 then
return os_date("!%H:%M:%S", t);
end
local m = t % 1;
local s = floor(t);
return os_date("!%H:%M:%S.%%06d", s):format(floor(m * 1000000));
end
local function legacy(t)
return os_date("!%Y%m%dT%H:%M:%S", t and floor(t) or nil);
end
local function parse(s)
if s then
local year, month, day, hour, min, sec, tzd = s:match("^(%d%d%d%d)%-?(%d%d)%-?(%d%d)T(%d%d):(%d%d):(%d%d%.?%d*)([Z+%-]?.*)$");
if year then
local now = os_time();
local time_offset = os_difftime(os_time(os_date("*t", now)), os_time(os_date("!*t", now))); -- to deal with local timezone
local tzd_offset = 0;
if tzd ~= "" and tzd ~= "Z" then
local sign, h, m = tzd:match("([+%-])(%d%d):?(%d*)");
if not sign then return; end
if #m ~= 2 then m = "0"; end
h, m = tonumber(h), tonumber(m);
tzd_offset = h * 60 * 60 + m * 60;
if sign == "-" then tzd_offset = -tzd_offset; end
end
local prec = sec%1;
sec = floor(sec + time_offset) - tzd_offset;
return os_time({year=year, month=month, day=day, hour=hour, min=min, sec=sec, isdst=false})+prec;
end
end
end
return {
date = date;
datetime = datetime;
time = time;
legacy = legacy;
parse = parse;
};