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Optimize DALC structure marshalling in TNS

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Avoids unnecessary splitting of the input string value
This commit is contained in:
nnposter
2020-05-20 21:18:05 +00:00
parent aa6245b53a
commit 47ec607c6f
1 changed files with 19 additions and 34 deletions
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53
nselib/tns.lua
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@@ -1213,40 +1213,25 @@ Marshaller = {
marshalKvpComponent = function( value ) marshalKvpComponent = function( value )
value = value or "" value = value or ""
local result = {string.pack( "<I4", #value ),} local sb4len = string.pack("<I4", #value)
if ( #value > 0 ) then if #value == 0 then return sb4len end
-- 64 bytes seems to be the maximum length before Oracle starts local result = {sb4len}
-- chunking strings -- 64 bytes is the maximum before Oracle starts chunking strings
local MAX_CHUNK_LENGTH = 64 local MAX_CHUNK_LENGTH = 64
local split_into_chunks = ( #value > MAX_CHUNK_LENGTH ) if #value > MAX_CHUNK_LENGTH then
-- First, write the multiple-chunk indicator
if ( not( split_into_chunks ) ) then table.insert(result, "\xFE")
-- It's pretty easy if we don't have to split up the string -- Loop through the string value, chunk by chunk
result[#result+1] = string.pack( "s1", value ) local pos = 1
else repeat
-- Otherwise, it's a bit more involved: local nextpos = pos + MAX_CHUNK_LENGTH
-- First, write the multiple-chunk indicator table.insert(result, string.pack("s1", value:sub(pos, nextpos - 1)))
result[#result+1] = "\xFE" pos = nextpos
until pos > #value
-- Loop through the string, chunk by chunk -- Finish with an empty chunk
while ( #value > 0 ) do table.insert(result, "\0")
-- Figure out how much we're writing in this chunk, the else
-- remainder of the string, or the maximum, whichever is less table.insert(result, string.pack("s1", value))
local write_length = MAX_CHUNK_LENGTH
if (#value < MAX_CHUNK_LENGTH) then
write_length = #value
end
-- get a substring of what we're going to write...
local write_value = value:sub( 1, write_length )
-- ...and remove that piece from the remaining string
value = value:sub( write_length + 1 )
result[#result+1] = string.pack( "s1", write_value )
end
-- put a null byte at the end
result[#result+1] = '\0'
end
end end
return table.concat(result) return table.concat(result)