Adding some very basic lua support file.

1 files changed, 90 insertions, 0 deletions

diff --git a/lib/supportlib.lua b/lib/supportlib.lua
new file mode 100644
index 0000000..961c2c3
--- /dev/null
+++ b/lib/supportlib.lua
@@ -0,0 +1,90 @@
+function display(inp, n)
+    local i
+    if (type(inp) == "string") then
+        inp = Input(inp)
+    elseif (type(inp) ~= "table") then
+        error("Display needs a string or an Input object")
+    end
+    
+    i = 0
+    
+    while(not inp:isclosed()) do
+        i = i + 1
+        print(inp:read())
+        if ((n ~= nil) and (i >= n)) then
+            return
+        end
+    end
+end
+
+function pchar(n)
+    if (not ((n >= 32) and (n <= 127))) then
+        n = 46 -- aka '.' or 0x2e
+    end
+    return hex(n, "%c")
+end
+
+function hexdump(inp, from, to, width)
+    local size, nlines, remaining, data_array, line, byte, outstring
+    
+    if (type(inp) == "string") then
+        inp = Input(inp)
+    elseif (type(inp) ~= "table") then
+        error("Hexdump needs a string or an Input object")
+    end
+    
+    size = inp:getsize()
+
+    if (from == nil) then
+        from = 0
+    end
+    
+    if (to == nil) then
+        to = size
+    end
+    
+    if (to > size) then
+        to = size
+    end
+    
+    size = to - from
+    
+    if (width == nil) then
+        width = 16
+    end
+    
+    nlines = math.floor(size / width)
+    remaining = math.mod(size, width)
+    inp:seek(from)
+    data_array = inp:read(size)
+    
+    for line = 0, nlines - 1, 1 do
+        outstring = hex(line * width + from, "%08x   ")
+        for byte = 0, width - 1, 1 do
+            outstring = outstring .. hex(data_array[line * 16 + byte]) .. " "
+        end
+        outstring = outstring .. "  "
+        for byte = 0, width - 1, 1 do
+            outstring = outstring .. pchar(data_array[line * 16 + byte])
+        end
+        print(outstring)
+    end
+
+    if (remaining == 0) then
+        return
+    end
+    
+    outstring = hex(nlines * width + from, "%08x   ");
+    for byte = 0, remaining - 1, 1 do
+        outstring = outstring .. hex(data_array[nlines * 16 + byte]) .. " "
+    end
+    for byte = remaining + 1, width - 1, 1 do
+        outstring = outstring .. "   "
+    end
+    outstring = outstring .. "  "
+    for byte = 0, remaining - 1, 1 do
+        outstring = outstring .. pchar(data_array[nlines * 16 + byte])
+    end
+
+    print(outstring)
+end