1 files changed, 66 insertions, 12 deletions
diff --git a/tex/context/base/l-md5.lua b/tex/context/base/l-md5.lua
index 4deb9bd74..8640ad54e 100644
--- a/tex/context/base/l-md5.lua
+++ b/tex/context/base/l-md5.lua
@@ -1,18 +1,72 @@
--- filename : l-md5.lua
--- author   : Hans Hagen, PRAGMA-ADE, Hasselt NL
--- copyright: PRAGMA ADE / ConTeXt Development Team
--- license  : see context related readme files
+if not modules then modules = { } end modules ['l-md5'] = {
+    version   = 1.001,
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
 
-if not versions then versions = { } end versions['l-md5'] = 1.001
+-- This also provides file checksums and checkers.
 
-if md5 then do
+local gsub, format, byte = string.gsub, string.format, string.byte
 
-    local function convert(str,fmt)
-        return (string.gsub(md5.sum(str),".",function(chr) return string.format(fmt,string.byte(chr)) end))
+local function convert(str,fmt)
+    return (gsub(md5.sum(str),".",function(chr) return format(fmt,byte(chr)) end))
+end
+
+if not md5.HEX then function md5.HEX(str) return convert(str,"%02X") end end
+if not md5.hex then function md5.hex(str) return convert(str,"%02x") end end
+if not md5.dec then function md5.dec(str) return convert(str,"%03i") end end
+
+--~ if not md5.HEX then
+--~     local function remap(chr) return format("%02X",byte(chr)) end
+--~     function md5.HEX(str) return (gsub(md5.sum(str),".",remap)) end
+--~ end
+--~ if not md5.hex then
+--~     local function remap(chr) return format("%02x",byte(chr)) end
+--~     function md5.hex(str) return (gsub(md5.sum(str),".",remap)) end
+--~ end
+--~ if not md5.dec then
+--~     local function remap(chr) return format("%03i",byte(chr)) end
+--~     function md5.dec(str) return (gsub(md5.sum(str),".",remap)) end
+--~ end
+
+file.needs_updating_threshold = 1
+
+function file.needs_updating(oldname,newname) -- size modification access change
+    local oldtime = lfs.attributes(oldname, modification)
+    local newtime = lfs.attributes(newname, modification)
+    if newtime >= oldtime then
+        return false
+    elseif oldtime - newtime < file.needs_updating_threshold then
+        return false
+    else
+        return true
     end
+end
 
-    if not md5.HEX then function md5.HEX(str) return convert(str,"%02X") end end
-    if not md5.hex then function md5.hex(str) return convert(str,"%02x") end end
-    if not md5.dec then function md5.dec(str) return convert(str,"%03i") end end
+function file.checksum(name)
+    if md5 then
+        local data = io.loaddata(name)
+        if data then
+            return md5.HEX(data)
+        end
+    end
+    return nil
+end
+
+function file.loadchecksum(name)
+    if md5 then
+        local data = io.loaddata(name .. ".md5")
+        return data and data:gsub("%s","")
+    end
+    return nil
+end
 
-end end
+function file.savechecksum(name, checksum)
+    if not checksum then checksum = file.checksum(name) end
+    if checksum then
+        io.savedata(name .. ".md5",checksum)
+        return checksum
+    end
+    return nil
+end