1 files changed, 110 insertions, 0 deletions
diff --git a/tex/context/base/util-pck.lua b/tex/context/base/util-pck.lua
new file mode 100644
index 000000000..835c70800
--- /dev/null
+++ b/tex/context/base/util-pck.lua
@@ -0,0 +1,110 @@
+if not modules then modules = { } end modules ['util-pck'] = {
+    version   = 1.001,
+    comment   = "companion to luat-lib.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+-- moved from core-uti
+
+local next, tostring, type = next, tostring, type
+local sort, concat = table.sort, table.concat
+
+utilities         = utilities         or { }
+utilities.packers = utilities.packers or { }
+local packers     = utilities.packers
+packers.version   = 1.00
+
+local function hashed(t)
+    local s = { }
+    for k, v in next, t do
+        if type(v) == "table" then
+            s[#s+1] = k.."={"..hashed(v).."}"
+        else
+            s[#s+1] = k.."="..tostring(v)
+        end
+    end
+    sort(s)
+    return concat(s,",")
+end
+
+local function pack(t,keys,hash,index)
+    for k,v in next, t do
+        if type(v) == "table" then
+            pack(v,keys,hash,index)
+        end
+        if keys[k] and type(v) == "table" then
+            local h = hashed(v)
+            local i = hash[h]
+            if not i then
+                i = #index+1
+                index[i] = v
+                hash[h] = i
+            end
+            t[k] = i
+        end
+    end
+end
+
+local function unpack(t,keys,index)
+    for k,v in next, t do
+        if keys[k] and type(v) == "number" then
+            local iv = index[v]
+            if iv then
+                v = iv
+                t[k] = v
+            end
+        end
+        if type(v) == "table" then
+            unpack(v,keys,index)
+        end
+    end
+end
+
+function packers.new(keys,version)
+    return {
+        version = version or packers.version,
+        keys    = table.tohash(keys),
+        hash    = { },
+        index   = { },
+    }
+end
+
+function packers.pack(t,p,shared)
+    if shared then
+        pack(t,p.keys,p.hash,p.index)
+    elseif not t.packer then
+        pack(t,p.keys,p.hash,p.index)
+        if #p.index > 0 then
+            t.packer = {
+                version = p.version or packers.version,
+                keys = p.keys,
+                index = p.index,
+            }
+        end
+        p.hash, p.index = { }, { }
+    end
+end
+
+function packers.unpack(t,p,shared)
+    if shared then
+        if p then
+            unpack(t,p.keys,p.index)
+        end
+    else
+        local tp = t.packer
+        if tp then
+            if tp.version == (p and p.version or packers.version) then
+                unpack(t,tp.keys,tp.index)
+            else
+                -- fatal error, wrong version
+            end
+            t.packer = nil
+        end
+    end
+end
+
+function packers.strip(p)
+    p.hash = nil
+end