MTA: SA file read methods performance tests

-- ------
-- CONFIG
-- ------
local smallBufferBytes, bigBufferBytes = 5000, 500 -- Arbitrary bytes to read into the buffer each iteration
local smallFileSize, bigFileSize = 2048, 5242880 -- File sizes in bytes (2 KB, 5 MB)

-- Do not abort execution
debug.sethook(nil)

-- Create files to test with
local smallFile = fileCreate("small.dat")
fileWrite(smallFile, string.rep("A", smallFileSize))

local bigFile = fileCreate("big.dat")
fileWrite(bigFile, string.rep("A", bigFileSize))

-- Reset file read position
fileSetPos(smallFile, 0)
fileSetPos(bigFile, 0)

outputServerLog"*****************************************"
outputServerLog"** FILE READ METHODS PERFORMANCE TESTS **"
outputServerLog"*****************************************"
outputServerLog"~ Information"
outputServerLog("Small file size is " .. smallFileSize / 1024 .. " KB, big file size is " .. bigFileSize / 1024 .. " KB")
outputServerLog("Small file loop iterations: " .. math.ceil(smallFileSize / smallBufferBytes) .. " (" .. smallBufferBytes .. " bytes buffer)")
outputServerLog("Big file loop iterations: " .. math.ceil(bigFileSize / bigBufferBytes) .. " (" .. bigBufferBytes .. " bytes buffer)")
outputServerLog"~ Test results"

-- Force GC to collect everything we could have created
collectgarbage()

-- ---------------------------------------------------
-- METHOD 1: READ ALL THE BYTES DIRECTLY INTO A STRING
-- ---------------------------------------------------
-- Small file
local memoryBefore, ticksBefore = collectgarbage("count"), getTickCount()
local fileContents = fileRead(smallFile, fileGetSize(smallFile))
-- Output results
local memoryNow, ticksNow = collectgarbage("count"), getTickCount()
outputServerLog("Test 1: small file, read into string directly\n" .. memoryNow - memoryBefore .. " KB of memory | " .. ticksNow - ticksBefore .. " ms")
memoryBefore, ticksBefore, memoryNow, ticksNow, fileContents = nil
collectgarbage()

-- Big file
local memoryBefore, ticksBefore = collectgarbage("count"), getTickCount()
local fileContents = fileRead(bigFile, fileGetSize(bigFile))
-- Output results
local memoryNow, ticksNow = collectgarbage("count"), getTickCount()
outputServerLog("Test 2: big file, read into string directly\n" .. memoryNow - memoryBefore .. " KB of memory | " .. ticksNow - ticksBefore .. " ms")
memoryBefore, ticksBefore, memoryNow, ticksNow, fileContents = nil
collectgarbage()

fileSetPos(smallFile, 0)
fileSetPos(bigFile, 0)

-- -------------------------------------------------------------------------
-- METHOD 2: CONCATENATING AN ARBITRARY NUMBER OF BYTES INTO A BUFFER STRING
-- -------------------------------------------------------------------------
-- Small file
local memoryBefore, ticksBefore = collectgarbage("count"), getTickCount()
local buffer = ""
while not fileIsEOF(smallFile) do
    buffer = buffer .. fileRead(smallFile, smallBufferBytes)
end
-- Output results
local memoryNow, ticksNow = collectgarbage("count"), getTickCount()
outputServerLog("Test 3: small file, concatenating into buffer string\n" .. memoryNow - memoryBefore .. " KB of memory | " .. ticksNow - ticksBefore .. " ms")
memoryBefore, ticksBefore, memoryNow, ticksNow, buffer = nil
collectgarbage()

-- Big file
local memoryBefore, ticksBefore = collectgarbage("count"), getTickCount()
local buffer = ""
while not fileIsEOF(bigFile) do
    buffer = buffer .. fileRead(bigFile, bigBufferBytes)
end
-- Output results
local memoryNow, ticksNow = collectgarbage("count"), getTickCount()
outputServerLog("Test 4: big file, concatenating into buffer string\n" .. memoryNow - memoryBefore .. " KB of memory | " .. ticksNow - ticksBefore .. " ms")
memoryBefore, ticksBefore, memoryNow, ticksNow, buffer = nil
collectgarbage()

fileSetPos(smallFile, 0)
fileSetPos(bigFile, 0)

-- ------------------------------------------------------------------------
-- METHOD 3: CONCATENATING AN ARBITRARY NUMBER OF BYTES INTO A BUFFER ARRAY
-- ------------------------------------------------------------------------
-- Small file
local memoryBefore, ticksBefore = collectgarbage("count"), getTickCount()
local buffer = {}
while not fileIsEOF(smallFile) do
    buffer[#buffer + 1] = fileRead(smallFile, smallBufferBytes)
end
local fileContents = table.concat(buffer)
-- Output results
local memoryNow, ticksNow = collectgarbage("count"), getTickCount()
outputServerLog("Test 5: small file, concatenating into buffer array\n" .. memoryNow - memoryBefore .. " KB of memory | " .. ticksNow - ticksBefore .. " ms")
memoryBefore, ticksBefore, memoryNow, ticksNow, buffer, fileContents = nil
collectgarbage()

-- Big file
local memoryBefore, ticksBefore = collectgarbage("count"), getTickCount()
local buffer = {}
while not fileIsEOF(bigFile) do
    buffer[#buffer + 1] = fileRead(bigFile, bigBufferBytes)
end
local fileContents = table.concat(buffer)
-- Output results
local memoryNow, ticksNow = collectgarbage("count"), getTickCount()
outputServerLog("Test 6: big file, concatenating into buffer array\n" .. memoryNow - memoryBefore .. " KB of memory | " .. ticksNow - ticksBefore .. " ms")
memoryBefore, ticksBefore, memoryNow, ticksNow, buffer, fileContents = nil

-- Dereference the files
-- (the GC will eventually take care of closing them)
smallFile, bigFile = nil