From f68605ffea24282ae9ffc7a0619e9b3a16755eff Mon Sep 17 00:00:00 2001
From: XeonSquared <redtailedairways@gmail.com>
Date: Thu, 9 Apr 2020 15:44:23 +1000
Subject: [PATCH] added a better replacement VT100 emulator

---
 module/nvt100.lua  | 142 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 module/vt-task.lua |   2 +-
 2 files changed, 143 insertions(+), 1 deletion(-)
 create mode 100644 module/nvt100.lua

diff --git a/module/nvt100.lua b/module/nvt100.lua
new file mode 100644
index 0000000..e128e99
--- /dev/null
+++ b/module/nvt100.lua
@@ -0,0 +1,142 @@
+function vt100emu(gpu) -- takes GPU component proxy *gpu* and returns a function to write to it in a manner like an ANSI terminal
+ local colours = {0x0,0xFF0000,0x00FF00,0xFFFF00,0x0000FF,0xFF00FF,0x00B6FF,0xFFFFFF}
+ local mx, my = gpu.maxResolution()
+ local cx, cy = 1, 1
+ local pc = " "
+ local lc = ""
+ local mode = 0 -- 0 normal, 1 escape, 2 command
+ local lw = true
+ local sx, sy = 1,1
+ local cs = ""
+ local bg, fg = 0, 0xFFFFFF
+
+ -- setup
+ gpu.setResolution(mx,my)
+ gpu.fill(1,1,mx,my," ")
+ local function checkCursor()
+  if cx > mx and lw then
+   cx, cy = 1, cy+1
+  end
+  if cy > my then
+   gpu.copy(1,2,mx,my-1,0,-1)
+   gpu.fill(1,my,mx,1," ")
+   cy=my
+  end
+  if cy < 1 then cy = 1 end
+  if cx < 1 then cx = 1 end
+ end
+
+ local function termwrite(s)
+  dprint("attempting termwrite")
+  dprint("writing "..tostring(s))
+  local wb = ""
+  local function flushwb()
+   dprint("flush")
+   while wb:len() > 0 do
+    dprint("flushing "..tostring(wb:len()).." chars: "..tostring(wb))
+    checkCursor()
+    local wl = wb:sub(1,mx-cx+1)
+    wb = wb:sub(wl:len()+1)
+    gpu.set(cx, cy, wl)
+    cx = cx + wl:len()
+   end
+  end
+  local rs = ""
+  s=s:gsub("\8","\27[D")
+  pc = gpu.get(cx,cy)
+  gpu.setForeground(fg)
+  gpu.setBackground(bg)
+  gpu.set(cx,cy,pc)
+  for cc in s:gmatch(".") do
+   if mode == 0 then
+    if string.byte(cc) > 31 and string.byte(cc) < 128 then -- probably printable
+     wb = wb .. cc
+    elseif cc == "\n" then
+     flushwb()
+     cx,cy = 1, cy+1
+    elseif cc == "\t" then
+     cx = 8*((cx+9)//8)
+    elseif cc == "\27" then
+     flushwb()
+     mode = 1
+    end
+   elseif mode == 1 then
+    if cc == "[" then
+     dprint("entering escape code mode")
+     mode = 2
+    else
+     mode = 0
+    end
+   elseif mode == 2 then
+    if cc:match("[%d;]") then
+     cs = cs .. cc
+    else
+     mode = 0
+     dprint("command: "..tostring(cc))
+     local tA = {}
+     for s in cs:gmatch("%d+") do
+      tA[#tA+1] = tonumber(s)
+      dprint("arg: "..tostring(s))
+     end
+     if cc == "H" then
+      cx, cy = tA[1] or 1, tA[2] or 1
+     elseif cc == "A" then
+      cy = cy - (tA[1] or 1)
+     elseif cc == "B" then
+      cy = cy + (tA[1] or 1)
+     elseif cc == "C" then
+      cx = cx + (tA[1] or 1)
+     elseif cc == "D" then
+      cx = cx - (tA[1] or 1)
+     elseif cc == "s" then
+      sx, sy = cx, cy
+     elseif cc == "u" then
+      cx, cy = sx, sy
+     elseif cc == "n" and tA[1] == 6 then
+      rs = string.format("%s\27[%d;%dR",rs,cx,cy)
+     elseif cc == "K" and tA[1] == 1 then
+      gpu.fill(1,cy,cx,1," ")
+     elseif cc == "K" and tA[1] == 2 then
+      gpu.fill(cx,cy,mx,1," ")
+     elseif cc == "K" then
+      gpu.fill(1,cy,mx,1," ")
+     elseif cc == "J" and tA[1] == 1 then
+      gpu.fill(1,1,mx,cy," ")
+     elseif cc == "J" and tA[1] == 2 then
+      gpu.full(1,1,mx,my," ")
+      cx, cy = 1, 1
+     elseif cc == "J" then
+      gpu.fill(1,cy,mx,my," ")
+     elseif cc == "m" then
+      for _,num in ipairs(tA) do
+       if num == 0 then
+        fg,bg = 0xFFFFFF,0
+       elseif num == 7 then
+        local nfg,nbg = bg, fg
+        fg, bg = nfg, nbg
+       elseif num > 29 and num < 38 then
+        fg = colours[num-29]
+       elseif num > 39 and num < 48 then
+        bg = colours[num-39]
+       end
+      end
+      gpu.setForeground(fg)
+      gpu.setBackground(bg)
+     end
+     cs = ""
+     checkCursor()
+    end
+   end
+  end
+  flushwb()
+  pc = gpu.get(cx,cy)
+  gpu.setForeground(bg)
+  gpu.setBackground(fg)
+  gpu.set(cx,cy,pc)
+  gpu.setForeground(fg)
+  gpu.setBackground(bg)
+  return rs
+ end
+
+ return termwrite
+end
diff --git a/module/vt-task.lua b/module/vt-task.lua
index ded07d4..0631eef 100644
--- a/module/vt-task.lua
+++ b/module/vt-task.lua
@@ -1,5 +1,5 @@
 do
---#include "module/vt100.lua"
+--#include "module/nvt100.lua"
 function vtemu(gpua,scra) -- creates a process to handle the GPU and screen address combination *gpua*/*scra*. Returns read, write and "close" functions.
  local gpu = component.proxy(gpua)
  gpu.bind(scra)