88 lines
3 KiB
Text
88 lines
3 KiB
Text
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-- Copyright (c) 2007, Niels Martin Hansen, Rodrigo Braz Monteiro
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-- All rights reserved.
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--
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-- Redistribution and use in source and binary forms, with or without
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-- modification, are permitted provided that the following conditions are met:
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--
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-- * Redistributions of source code must retain the above copyright notice,
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-- this list of conditions and the following disclaimer.
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-- * Redistributions in binary form must reproduce the above copyright notice,
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-- this list of conditions and the following disclaimer in the documentation
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-- and/or other materials provided with the distribution.
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-- * Neither the name of the Aegisub Group nor the names of its contributors
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-- may be used to endorse or promote products derived from this software
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-- without specific prior written permission.
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--
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-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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-- ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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-- LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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-- CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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-- SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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-- INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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-- CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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-- ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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-- POSSIBILITY OF SUCH DAMAGE.
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-- Unicode (UTF-8) support functions for Aegisub Automation 4 Lua
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-- http://www.ietf.org/rfc/rfc2279.txt
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local unicode
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unicode =
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-- Return the number of bytes occupied by the character starting at the i'th byte in s
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charwidth: (s, i) ->
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b = s\byte i or 1
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-- FIXME, something in karaskel results in this case, shouldn't happen
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-- What would "proper" behaviour be? Zero? Or just explode?
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if not b then 1
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elseif b < 128 then 1
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elseif b < 224 then 2
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elseif b < 240 then 3
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else 4
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-- Returns an iterator function for iterating over the characters in s
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chars: (s) ->
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curchar, i = 0, 1
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->
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return if i > s\len()
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j = i
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curchar += 1
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i += unicode.charwidth s, i
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s\sub(j, i - 1), curchar
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-- Returns the number of characters in s
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-- Runs in O(s:len()) time!
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len: (s) ->
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n = 0
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n += 1 for c in unicode.chars s
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n
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-- Get codepoint of first char in s
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codepoint: (s) ->
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-- Basic case, ASCII
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b = s\byte 1
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return b if b < 128
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-- Use a naive decoding algorithm, and assume input is valid
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local res, w
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if b < 224 then
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-- prefix byte is 110xxxxx
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res = b - 192
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w = 2
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elseif b < 240 then
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-- prefix byte is 11100000
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res = b - 224
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w = 3
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else
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res = b - 240
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w = 4
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for i = 2, w
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res = res*64 + s\byte(i) - 128
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res
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return unicode
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