#51 crypto system

lockbox/util/stream.lua

@@ -0,0 +1,99 @@
+local Queue = require("lockbox.util.queue");
+local String = require("string");
+
+local Stream = {};
+
+
+Stream.fromString = function(string)
+    local i = 0;
+    return function()
+        i = i + 1;
+        return String.byte(string, i);
+    end
+end
+
+
+Stream.toString = function(stream)
+    local array = {};
+    local i = 1;
+
+    local byte = stream();
+    while byte ~= nil do
+        array[i] = String.char(byte);
+        i = i + 1;
+        byte = stream();
+    end
+
+    return table.concat(array);
+end
+
+
+Stream.fromArray = function(array)
+    local queue = Queue();
+    local i = 1;
+
+    local byte = array[i];
+    while byte ~= nil do
+        queue.push(byte);
+        i = i + 1;
+        byte = array[i];
+    end
+
+    return queue.pop;
+end
+
+
+Stream.toArray = function(stream)
+    local array = {};
+    local i = 1;
+
+    local byte = stream();
+    while byte ~= nil do
+        array[i] = byte;
+        i = i + 1;
+        byte = stream();
+    end
+
+    return array;
+end
+
+
+local fromHexTable = {};
+for i = 0, 255 do
+    fromHexTable[String.format("%02X", i)] = i;
+    fromHexTable[String.format("%02x", i)] = i;
+end
+
+Stream.fromHex = function(hex)
+    local queue = Queue();
+
+    for i = 1, String.len(hex) / 2 do
+        local h = String.sub(hex, i * 2 - 1, i * 2);
+        queue.push(fromHexTable[h]);
+    end
+
+    return queue.pop;
+end
+
+
+
+local toHexTable = {};
+for i = 0, 255 do
+    toHexTable[i] = String.format("%02X", i);
+end
+
+Stream.toHex = function(stream)
+    local hex = {};
+    local i = 1;
+
+    local byte = stream();
+    while byte ~= nil do
+        hex[i] = toHexTable[byte];
+        i = i + 1;
+        byte = stream();
+    end
+
+    return table.concat(hex);
+end
+
+return Stream;