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Faster string.split implementation.

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kaeza authored and kwolekr committed Dec 29, 2014
1 parent 86cfbc2 commit ab55da589c27e65e54956b32a1550e21169447ae
Showing with 22 additions and 22 deletions.
  1. +22 −22 builtin/common/misc_helpers.lua
@@ -155,33 +155,33 @@ function dump(o, indent, nested, level)
end

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function string.split(str, delim, include_empty, max_splits)
-- Localize functions to avoid table lookups (better performance).
local table_insert = table.insert
local str_sub, str_find = string.sub, string.find
function string.split(str, delim, include_empty, max_splits, sep_is_pattern)
delim = delim or ","
max_splits = max_splits or 0
local fields = {}
local num_splits = 0
local last_pos = 0
for part, pos in str:gmatch("(.-)[" .. delim .. "]()") do
last_pos = pos
if include_empty or part ~= "" then
num_splits = num_splits + 1
fields[num_splits] = part
if max_splits > 0 and num_splits + 1 >= max_splits then
break
end
max_splits = max_splits or -1
local items = {}
local pos, len, seplen = 1, #str, #delim
local plain = not sep_is_pattern
max_splits = max_splits + 1
repeat
local np, npe = str_find(str, delim, pos, plain)
np, npe = (np or (len+1)), (npe or (len+1))
if (not np) or (max_splits == 1) then
np = len + 1
npe = np
end
end
-- Handle the last field
if max_splits <= 0 or num_splits <= max_splits then
local last_part = str:sub(last_pos)
if include_empty or last_part ~= "" then
fields[num_splits + 1] = last_part
local s = str_sub(str, pos, np - 1)
if include_empty or (s ~= "") then
max_splits = max_splits - 1
table_insert(items, s)
end
end
return fields
pos = npe + 1
until (max_splits == 0) or (pos > len)
return items
end


--------------------------------------------------------------------------------
function file_exists(filename)
local f = io.open(filename, "r")

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