import libary files from Context

1 files changed, 342 insertions, 0 deletions

diff --git a/lualibs-util-sta.lua b/lualibs-util-sta.lua
new file mode 100644
index 0000000..1a61ec4
--- /dev/null
+++ b/lualibs-util-sta.lua
@@ -0,0 +1,342 @@
+if not modules then modules = { } end modules ['util-sta'] = {
+    version   = 1.001,
+    comment   = "companion to util-ini.mkiv",
+    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
+    copyright = "PRAGMA ADE / ConTeXt Development Team",
+    license   = "see context related readme files"
+}
+
+local insert, remove, fastcopy, concat = table.insert, table.remove, table.fastcopy, table.concat
+local format = string.format
+local select, tostring = select, tostring
+
+local trace_stacker = false  trackers.register("stacker.resolve", function(v) trace_stacker = v end)
+
+local stacker = stacker or { }
+
+utilities.stacker = stacker
+
+local function start(s,t,first,last)
+    if s.mode == "switch" then
+        local n = tostring(t[last])
+        if trace_stacker then
+            s.report("start: %s",n)
+        end
+        return n
+    else
+        local r = { }
+        for i=first,last do
+            r[#r+1] = tostring(t[i])
+        end
+        local n = concat(r," ")
+        if trace_stacker then
+            s.report("start: %s",n)
+        end
+        return n
+    end
+end
+
+local function stop(s,t,first,last)
+    if s.mode == "switch" then
+        local n = tostring(false)
+        if trace_stacker then
+            s.report("stop: %s",n)
+        end
+        return n
+    else
+        local r = { }
+        for i=last,first,-1 do
+            r[#r+1] = tostring(false)
+        end
+        local n = concat(r," ")
+        if trace_stacker then
+            s.report("stop: %s",n)
+        end
+        return n
+    end
+end
+
+local function change(s,t1,first1,last1,t2,first2,last2)
+    if s.mode == "switch" then
+        local n = tostring(t2[last2])
+        if trace_stacker then
+            s.report("change: %s",n)
+        end
+        return n
+    else
+        local r = { }
+        for i=last1,first1,-1 do
+            r[#r+1] = tostring(false)
+        end
+        local n = concat(r," ")
+        for i=first2,last2 do
+            r[#r+1] = tostring(t2[i])
+        end
+        if trace_stacker then
+            s.report("change: %s",n)
+        end
+        return n
+    end
+end
+
+function stacker.new(name)
+
+    local s
+
+    local stack = { }
+    local list  = { }
+    local ids   = { }
+    local hash  = { }
+
+    local hashing = true
+
+    local function push(...)
+        for i=1,select("#",...) do
+            insert(stack,(select(i,...))) -- watch the ()
+        end
+        if hashing then
+            local c = concat(stack,"|")
+            local n = hash[c]
+            if not n then
+                n = #list+1
+                hash[c] = n
+                list[n] = fastcopy(stack)
+            end
+            insert(ids,n)
+            return n
+        else
+            local n = #list+1
+            list[n] = fastcopy(stack)
+            insert(ids,n)
+            return n
+        end
+    end
+
+    local function pop()
+        remove(stack)
+        remove(ids)
+        return ids[#ids] or s.unset or -1
+    end
+
+    local function clean()
+        if #stack == 0 then
+            if trace_stacker then
+                s.report("%s list entries, %s stack entries",#list,#stack)
+            end
+        end
+    end
+
+    local tops = { }
+    local top, switch
+
+    local function resolve_begin(mode)
+        if mode then
+            switch = mode == "switch"
+        else
+            switch = s.mode == "switch"
+        end
+        top = { switch = switch }
+        insert(tops,top)
+    end
+
+    local function resolve_step(ti) -- keep track of changes outside function !
+        -- todo: optimize for n=1 etc
+        local result = nil
+        local noftop = #top
+        if ti > 0 then
+            local current = list[ti]
+            if current then
+                local noflist = #current
+                local nofsame = 0
+                if noflist > noftop then
+                    for i=1,noflist do
+                        if current[i] == top[i] then
+                            nofsame = i
+                        else
+                            break
+                        end
+                    end
+                else
+                    for i=1,noflist do
+                        if current[i] == top[i] then
+                            nofsame = i
+                        else
+                            break
+                        end
+                    end
+                end
+                local plus = nofsame + 1
+                if plus <= noftop then
+                    if plus <= noflist then
+                        if switch then
+                            result = s.change(s,top,plus,noftop,current,nofsame,noflist)
+                        else
+                            result = s.change(s,top,plus,noftop,current,plus,noflist)
+                        end
+                    else
+                        if switch then
+                            result = s.change(s,top,plus,noftop,current,nofsame,noflist)
+                        else
+                            result = s.stop(s,top,plus,noftop)
+                        end
+                    end
+                elseif plus <= noflist then
+                    if switch then
+                        result = s.start(s,current,nofsame,noflist)
+                    else
+                        result = s.start(s,current,plus,noflist)
+                    end
+                end
+                top = current
+            else
+                if 1 <= noftop then
+                    result = s.stop(s,top,1,noftop)
+                end
+                top = { }
+            end
+            return result
+        else
+            if 1 <= noftop then
+                result = s.stop(s,top,1,noftop)
+            end
+            top = { }
+            return result
+        end
+    end
+
+    local function resolve_end()
+     -- resolve_step(s.unset)
+        local noftop = #top
+        if noftop > 0 then
+            local result = s.stop(s,top,1,#top)
+            remove(tops)
+            top = tops[#tops]
+            switch = top and top.switch
+            return result
+        end
+    end
+
+    local function resolve(t)
+        resolve_begin()
+        for i=1,#t do
+            resolve_step(t[i])
+        end
+        resolve_end()
+    end
+
+    local report = logs.reporter("stacker",name or nil)
+
+    s = {
+        name          = name or "unknown",
+        unset         = -1,
+        report        = report,
+        start         = start,
+        stop          = stop,
+        change        = change,
+        push          = push,
+        pop           = pop,
+        clean         = clean,
+        resolve       = resolve,
+        resolve_begin = resolve_begin,
+        resolve_step  = resolve_step,
+        resolve_end   = resolve_end,
+    }
+
+    return s -- we can overload functions
+
+end
+
+-- local s = utilities.stacker.new("demo")
+--
+-- local unset = s.unset
+-- local push  = s.push
+-- local pop   = s.pop
+--
+-- local t = {
+--     unset,
+--     unset,
+--     push("a"),     -- a
+--     push("b","c"), -- a b c
+--     pop(),         -- a b
+--     push("d"),     -- a b d
+--     pop(),         -- a b
+--     unset,
+--     pop(),         -- a
+--     pop(),         -- b
+--     unset,
+--     unset,
+-- }
+--
+-- s.resolve(t)
+
+-- demostacker = utilities.stacker.new("demos")
+--
+-- local whatever = {
+--     one     = "1 0 0 RG 1 0 0 rg",
+--     two     = "1 1 0 RG 1 1 0 rg",
+--     [false] = "0 G 0 g",
+-- }
+--
+-- local concat = table.concat
+--
+-- local pdfliteral = nodes.pool.pdfliteral
+--
+-- function demostacker.start(s,t,first,last)
+--     local n = whatever[t[last]]
+--  -- s.report("start: %s",n)
+--     return pdfliteral(n)
+-- end
+--
+-- function demostacker.stop(s,t,first,last)
+--     local n = whatever[false]
+--  -- s.report("stop: %s",n)
+--     return pdfliteral(n)
+-- end
+--
+-- function demostacker.change(s,t1,first1,last1,t2,first2,last2)
+--     local n = whatever[t2[last2]]
+--  -- s.report("change: %s",n)
+--     return pdfliteral(n)
+-- end
+--
+-- demostacker.mode = "switch"
+--
+-- local whatever = {
+--     one     = "/OC /test1 BDC",
+--     two     = "/OC /test2 BDC",
+--     [false] = "EMC",
+-- }
+--
+-- demostacker = utilities.stacker.new("demos")
+--
+-- function demostacker.start(s,t,first,last)
+--     local r = { }
+--     for i=first,last do
+--         r[#r+1] = whatever[t[i]]
+--     end
+--  -- s.report("start: %s",concat(r," "))
+--     return pdfliteral(concat(r," "))
+-- end
+--
+-- function demostacker.stop(s,t,first,last)
+--     local r = { }
+--     for i=last,first,-1 do
+--         r[#r+1] = whatever[false]
+--     end
+--  -- s.report("stop: %s",concat(r," "))
+--     return pdfliteral(concat(r," "))
+-- end
+--
+-- function demostacker.change(s,t1,first1,last1,t2,first2,last2)
+--     local r = { }
+--     for i=last1,first1,-1 do
+--         r[#r+1] = whatever[false]
+--     end
+--     for i=first2,last2 do
+--         r[#r+1] = whatever[t2[i]]
+--     end
+--  -- s.report("change: %s",concat(r," "))
+--     return pdfliteral(concat(r," "))
+-- end
+--
+-- demostacker.mode = "stack"