From 4964552718b81dba2c36fc08494aefae89a799f4 Mon Sep 17 00:00:00 2001
From: Diego Nehab <diego@tecgraf.puc-rio.br>
Date: Tue, 12 Oct 2004 22:35:20 +0000
Subject: My own ltn12.filter.chain is done. Implemented part of DB's
 suggestion for ftp. Mimetest.lua generates the test file for base64 instead
 of loading from disk.

---
 src/ftp.lua   |  9 ++++++---
 src/ltn12.lua | 58 +++++++++++++++++++++++++++++-----------------------------
 2 files changed, 35 insertions(+), 32 deletions(-)

(limited to 'src')

diff --git a/src/ftp.lua b/src/ftp.lua
index 43c62c2..9902c88 100644
--- a/src/ftp.lua
+++ b/src/ftp.lua
@@ -125,8 +125,10 @@ function metat.__index:send(sendt)
     if string.find(code, "1..") then self.try(self.tp:check("2..")) end
     -- done with data connection
     self.data:close()
+    -- find out how many bytes were sent
+    local sent = socket.skip(1, self.data:getstats())
     self.data = nil
-    return 1
+    return sent
 end
 
 function metat.__index:receive(recvt)
@@ -186,9 +188,10 @@ local function tput(putt)
     f:login(putt.user, putt.password)
     if putt.type then f:type(putt.type) end
     f:pasv()
-    f:send(putt)
+    local sent = f:send(putt)
     f:quit()
-    return f:close()
+    f:close()
+    return sent
 end
 
 local default = {
diff --git a/src/ltn12.lua b/src/ltn12.lua
index 6c5ea28..9917ce8 100644
--- a/src/ltn12.lua
+++ b/src/ltn12.lua
@@ -31,40 +31,40 @@ function filter.cycle(low, ctx, extra)
     end
 end
 
--- chains a bunch of filters together 
--- by Wim Couwenberg
-function filter.chain(...)
-    local current = 1
-    local bottom = 1
-    local top = table.getn(arg)
-    local retry = "" 
+local function chain2(f1, f2)
+    local ff1, ff2 = "", ""
     return function(chunk)
-        if chunk ~= retry then
-            current = bottom
-            retry = chunk and retry
+        local rf1 = chunk and ""
+        local rf2 = ff1 and ""
+        -- if f2 still has pending data, get it and return it
+        if ff2 ~= rf2 then
+            ff2 = f2(rf2)
+            if ff2 ~= "" then return ff2 end
+        end
+        -- here we know f2 needs more data
+        -- we try to get it from f1
+        ff1 = f1(chunk)
+        while 1 do
+            -- if f1 can't produce data, we need more data from the user
+            if ff1 == "" then return "" end
+            -- otherwise we pass new data to f2 until it produces something
+            -- or f1 runs out of data too
+            ff2 = f2(ff1) 
+            if ff2 ~= "" then return ff2 end
+            ff1 = f1(rf1)
         end
-        repeat
-            if current == bottom then
-                chunk = arg[current](chunk)
-                if chunk == "" or bottom == top then return chunk
-                elseif chunk then current = current + 1
-                else 
-                    bottom = bottom + 1 
-                    current = bottom
-                end
-            else
-                chunk = arg[current](chunk or "")
-                if chunk == "" then
-                    chunk = retry
-                    current = current - 1
-                elseif current == top then return chunk
-                else current = current + 1
-                end
-            end
-        until false
     end
 end
 
+-- chains a bunch of filters together 
+function filter.chain(...)
+     local f = arg[1]
+     for i = 2, table.getn(arg) do
+         f = chain2(f, arg[i])
+     end
+     return f
+end
+
 -----------------------------------------------------------------------------
 -- Source stuff
 -----------------------------------------------------------------------------
-- 
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