------------------------------------------------------------------------
-- Copyright (C) 1994-2008 Lua.org, PUC-Rio.  All rights reserved.
--
-- Permission is hereby granted, free of charge, to any person obtaining
-- a copy of this software and associated documentation files (the
-- "Software"), to deal in the Software without restriction, including
-- without limitation the rights to use, copy, modify, merge, publish,
-- distribute, sublicense, and/or sell copies of the Software, and to
-- permit persons to whom the Software is furnished to do so, subject to
-- the following conditions:
--
-- The above copyright notice and this permission notice shall be
-- included in all copies or substantial portions of the Software.
--
-- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
-- EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
-- IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
-- CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
-- TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
-- SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
------------------------------------------------------------------------

-- UTF-8 Support http://www.lua.org/manual/5.3/manual.html#6.5
-- This library provides basic support for UTF-8 encoding. It provides all its functions inside the table utf8. This library does not provide any support for Unicode other than the handling of the encoding. Any operation that needs the meaning of a character, such as character classification, is outside its scope.
-- Unless stated otherwise, all functions that expect a byte position as a parameter assume that the given position is either the start of a byte sequence or one plus the length of the subject string. As in the string library, negative indices count from the end of the string.
utf8 = {}

-- The pattern (a string, not a function) "[\0-\x7F\xC2-\xF4][\x80-\xBF]*" (see §6.4.1), which matches exactly one UTF-8 byte sequence, assuming that the subject is a valid UTF-8 string.
utf8.charpattern = ""

-- Receives zero or more integers, converts each one to its corresponding UTF-8 byte sequence and returns a string with the concatenation of all these sequences.
function utf8.char(...) end

-- Returns values so that the construction
--      for p, c in utf8.codes(s) do body end
-- will iterate over all characters in string s, with p being the position (in bytes) and c the code point of each character. It raises an error if it meets any invalid byte sequence.
function utf8.codes(s) end

-- Returns the codepoints (as integers) from all characters in s that start between byte position i and j (both included). The default for i is 1 and for j is i. It raises an error if it meets any invalid byte sequence.
function utf8.codepoint (s, i, j) end

-- Returns the number of UTF-8 characters in string s that start between positions i and j (both inclusive). The default for i is 1 and for j is -1. If it finds any invalid byte sequence, returns a false value plus the position of the first invalid byte.
function utf8.len(s, i, j) end

-- Returns the position (in bytes) where the encoding of the n-th character of s (counting from position i) starts. A negative n gets characters before position i. The default for i is 1 when n is non-negative and #s + 1 otherwise, so that utf8.offset(s, -n) gets the offset of the n-th character from the end of the string. If the specified character is neither in the subject nor right after its end, the function returns nil.
-- As a special case, when n is 0 the function returns the start of the encoding of the character that contains the i-th byte of s.
-- This function assumes that s is a valid UTF-8 string.
function utf8.offset (s, n, i) end
