90 lines
1.5 KiB
Lua
90 lines
1.5 KiB
Lua
-- Unicode library
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local pattern = '[%z\1-\127\194-\244][\128-\191]*'
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-- helper function
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local function posrelat(pos, len)
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if pos < 0 then
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pos = len + pos + 1
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end
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return pos
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end
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local utf8 = {}
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-- THE MEAT
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function utf8.map(s, f, no_subs)
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local i = 0
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if no_subs then
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for b, e in s:gmatch('()' .. pattern .. '()') do
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i = i + 1
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local c = e - b
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f(i, c, b)
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end
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else
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for b, c in s:gmatch('()(' .. pattern .. ')') do
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i = i + 1
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f(i, c, b)
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end
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end
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end
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-- THE REST
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function utf8.chars(s, no_subs)
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return coroutine.wrap(function()
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return utf8.map(s, coroutine.yield, no_subs)
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end)
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end
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function utf8.len(s)
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return select(2, s:gsub('[^\128-\193]', ''))
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end
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function utf8.replace(s, map)
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return s:gsub(pattern, map)
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end
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function utf8.reverse(s)
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s = s:gsub(pattern, function(c)
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return #c > 1 and c:reverse()
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end)
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return s:reverse()
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end
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function utf8.strip(s)
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return s:gsub(pattern, function(c)
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return #c > 1 and ''
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end)
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end
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function utf8.sub(s, i, j)
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local l = utf8.len(s)
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i = posrelat(i, l)
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j = j and posrelat(j, l) or l
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if i < 1 then i = 1 end
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if j > l then j = l end
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if i > j then return '' end
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local diff = j - i
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local iter = utf8.chars(s, true)
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for _ = 1, i - 1 do iter() end
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local c, b = select(2, iter())
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if diff == 0
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then return s:sub(b, b + c - 1) end
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i = b
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for _ = 1, diff - 1 do iter() end
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local c, b = select(2, iter())
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return s:sub(i, b + c - 1)
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end
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return utf8
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