From 0b0e02875dbc4d7d795cafe6e5720aa66b32e1ac Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Sat, 2 Nov 2024 13:41:36 +0100
Subject: Naive approach to disk-based masking directly on the trigrams

---
 ascii+32.lua         |  6 ++----
 decimal.lua          |  8 ++------
 disk-simple-mask.lua | 27 +++++++++++++++++++++++++++
 disk/init.lua        | 12 ++++++++++++
 format.lua           | 22 ++++++++++++++++++++++
 reading.lua          | 21 ++++++++++++++++++---
 6 files changed, 83 insertions(+), 13 deletions(-)
 create mode 100755 disk-simple-mask.lua
 create mode 100644 disk/init.lua
 create mode 100644 format.lua

diff --git a/ascii+32.lua b/ascii+32.lua
index c16eb6f..cc4ce97 100755
--- a/ascii+32.lua
+++ b/ascii+32.lua
@@ -1,9 +1,7 @@
 #!/usr/bin/env lua
 local eyes = require "eyes"
+local format = require "format"
 local reading = require "reading"
 for _, message in ipairs(eyes) do
-	for _, value in reading.values(message) do
-		io.write(string.char(value + 32))
-	end
-	print()
+	print(format.ascii32(reading.tvalues(message)))
 end
diff --git a/decimal.lua b/decimal.lua
index 6f32e5d..df6975e 100755
--- a/decimal.lua
+++ b/decimal.lua
@@ -1,11 +1,7 @@
 #!/usr/bin/env lua
 local eyes = require "eyes"
+local format = require "format"
 local reading = require "reading"
 for _, message in ipairs(eyes) do
-	local start, value = reading.next_value(message)
-	io.write(value)
-	for _, value in reading.values(message, start) do
-		io.write(",", value)
-	end
-	print()
+	print(format.csv(reading.tvalues(message)))
 end
diff --git a/disk-simple-mask.lua b/disk-simple-mask.lua
new file mode 100755
index 0000000..ba41f7b
--- /dev/null
+++ b/disk-simple-mask.lua
@@ -0,0 +1,27 @@
+#!/usr/bin/env lua
+local disk = require "disk"
+local eyes = require "eyes"
+local format = require "format"
+local reading = require "reading"
+
+
+local function mask (ring, index, value)
+	local offset = (index - 1) % #ring
+	if ring[offset + 1] == 0 then
+		return value
+	else
+		return 0
+	end
+end
+
+
+for _, message in ipairs(eyes) do
+	local values = {}
+	for index, a, b, c in reading.trigrams(message) do
+		a = mask(disk.eyes1, index, a)
+		b = mask(disk.eyes2, index, b)
+		c = mask(disk.eyes3, index, c)
+		table.insert(values, reading.trigram_to_value(a, b, c))
+	end
+	print(format.ascii32(values))
+end
diff --git a/disk/init.lua b/disk/init.lua
new file mode 100644
index 0000000..056e6df
--- /dev/null
+++ b/disk/init.lua
@@ -0,0 +1,12 @@
+return {
+	require "disk.runes1",
+	require "disk.eyes1",
+	require "disk.eyes2",
+	require "disk.eyes3",
+	require "disk.runes2",
+	runes1 = require "disk.runes1",
+	eyes1 = require "disk.eyes1",
+	eyes2 = require "disk.eyes2",
+	eyes3 = require "disk.eyes3",
+	runes2 = require "disk.runes2",
+}
diff --git a/format.lua b/format.lua
new file mode 100644
index 0000000..3a126a9
--- /dev/null
+++ b/format.lua
@@ -0,0 +1,22 @@
+local format = {}
+
+
+function format.csv (tvalues)
+	local str = string.format("%d", tvalues[1])
+	for i=2, #tvalues do
+		str = str .. string.format(",%d", tvalues[i])
+	end
+	return str
+end
+
+
+function format.ascii32 (tvalues)
+	local str = ""
+	for _, value in ipairs(tvalues) do
+		str = str .. string.char(32 + value)
+	end
+	return str
+end
+
+
+return format
diff --git a/reading.lua b/reading.lua
index 2b74446..6c910e2 100644
--- a/reading.lua
+++ b/reading.lua
@@ -1,3 +1,8 @@
+local function trigram_to_value (a, b, c)
+	return a * 25 + b * 5 + c
+end
+
+
 local function next_trigram (message, index)
 	index = (index or 0) + 1
 	local offset = (index - 1) * 3
@@ -15,23 +20,33 @@ local function next_value (message, index)
 	if not index then
 		return nil
 	end
-	return index, a * 25 + b * 5 + c
+	return index, trigram_to_value(a, b, c)
 end
 
 
 local reading = {
+	trigram_to_value = trigram_to_value,
 	next_trigram = next_trigram,
 	next_value = next_value,
 }
 
 
 function reading.trigrams (message, start)
-	return next_trigram, message, start
+	return next_trigram, message, start or 0
 end
 
 
 function reading.values (message, start)
-	return next_value, message, start
+	return next_value, message, start or 0
+end
+
+
+function reading.tvalues (message)
+	local values = {}
+	for _, value in reading.values(message) do
+		table.insert(values, value)
+	end
+	return values
 end
 
 
-- 
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