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| local io = require 'io' |
| local zlib = require 'zlib' |
|
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| local error, assert, setmetatable, tostring = error, assert, setmetatable, tostring |
|
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| local _M = {} |
|
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| function _M.open(filename, mode) |
| mode = mode or 'r' |
| local r = mode:find('r', 1, true) and true |
| local w = mode:find('w', 1, true) and true |
| local level = -1 |
|
|
| local lstart, lend = mode:find('%d') |
| if (lstart and lend) then |
| level = mode:sub(lstart, lend) |
| end |
|
|
| if (not (r or w)) then |
| error('file open mode must specify read or write operation') |
| end |
|
|
| local f, z |
|
|
| local mt = { |
| __index = { |
| read = function(self, ...) |
| return z:read(...) |
| end, |
| write = function(self, ...) |
| return z:write(...) |
| end, |
| seek = function(self, ...) |
| error 'seek not supported on gzip files' |
| end, |
| lines = function(self, ...) |
| return z:lines(...) |
| end, |
| flush = function(self, ...) |
| return z:flush(...) and f:flush() |
| end, |
| close = function(self, ...) |
| return z:close() and f:close() |
| end, |
| }, |
| __tostring = function(self) |
| return 'gzip object (' .. mode .. ') [' .. tostring(z) .. '] [' .. tostring(f) .. ']' |
| end, |
| } |
|
|
| if r then |
| f = assert(io.open(filename, 'rb')) |
| z = assert(zlib.inflate(f)) |
| else |
| f = assert(io.open(filename, 'wb')) |
| z = assert(zlib.deflate(f, level, nil, 15 + 16)) |
| end |
|
|
| return setmetatable({}, mt) |
| end |
|
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| function _M.lines(filename) |
| local gz = _M.open(filename, 'r') |
| return function() |
| local line = gz and gz:read() |
| if line == nil then |
| gz:close() |
| end |
| return line |
| end |
| end |
|
|
| return _M |
