Split by comma and space

csv_iterator.lua

local connection = "keep-alive"
local i = 0
local ngx_re       = require "ngx.re"
local re_split     = ngx_re.split
local lower        = string.lower
local gsub         = string.gsub
local find         = string.find
local sub          = string.sub

local function csv_iterator(s, b)
  if b == -1 then
    return
  end

  local e = find(s, ",", b, true)
  local v
  local l
  if e then
    if e == b then
      return csv_iterator(s, b + 1) -- empty string
    end
    v = sub(s, b, e - 1)
    l = e - b
    b = e + 1

  else
    if b > 1 then
      v = sub(s, b)
    else
      v = s
    end

    l = #v
    b = -1 -- end iteration
  end

  if l == 1 and (v == " " or v == ",") then
    return csv_iterator(s, b)
  end

  if sub(v, 1, 1) == " " then
    v = gsub(v, "^%s+", "")
  end

  if sub(v, -1) == " " then
    v = gsub(v, "%s+$", "")
  end

  if v == "" then
    return csv_iterator(s, b)
  end

  return b, lower(v)
end


local function csv(s)
  if type(s) ~= "string" or s == "" then
    return csv_iterator, s, -1
  end

  return csv_iterator, s, 1
end

for i = 1, 50000000 do
  for _, header_name in csv(connection) do
    -- print(header_name)
        -- some of these are already handled by the proxy module,
        -- proxy-authorization being an exception that is handled
        -- below with special semantics.
        if header_name ~= "close" and
           header_name ~= "upgrade" and
           header_name ~= "keep-alive" and
           header_name ~= "proxy-authorization" then
           i = i + 1
        end
  end
end

print("total cleared: ", i)

csv_token.lua

local connection = "keep-alive"
local i = 0
local ngx_re       = require "ngx.re"
local re_split     = ngx_re.split
local lower        = string.lower
local gsub         = string.gsub
local find         = string.find
local sub          = string.sub

local csv_iterator do
  local COMMA, SPACE = (", "):byte(1, -1)

  function csv_iterator(s, b)
    b = b or 1
    local first, last
    for i = b, #s do
      local c = s:byte(i)
      if c == COMMA then
        if first and last then
          return i+1, s:sub(first, last)
        else
          return i+1, ''
        end
      end
      if c ~= SPACE then
        if not first then first = i end
        last = i
      end
    end
    if first then
      return #s+1, s:sub(first, last)
    end
  end
end

local function csv(s)
  if type(s) ~= "string" or s == "" then
    return csv_iterator, s, -1
  end

  return csv_iterator, s, 1
end

for i = 1, 50000000 do
  for _, header_name in csv(connection) do
    -- print(header_name)
        -- some of these are already handled by the proxy module,
        -- proxy-authorization being an exception that is handled
        -- below with special semantics.
        if header_name ~= "close" and
           header_name ~= "upgrade" and
           header_name ~= "keep-alive" and
           header_name ~= "proxy-authorization" then
           i = i + 1
        end
  end
end

print("total cleared: ", i)