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-rw-r--r--luaextra-md5.lua72
1 files changed, 72 insertions, 0 deletions
diff --git a/luaextra-md5.lua b/luaextra-md5.lua
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+++ b/luaextra-md5.lua
@@ -0,0 +1,72 @@
+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"
+}
+
+-- This also provides file checksums and checkers.
+
+local gsub, format, byte = string.gsub, string.format, string.byte
+
+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
+
+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 (gsub(data,"%s",""))
+ end
+ return nil
+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