From e92f20e471e5fb766cc7a1144439b06c176940f3 Mon Sep 17 00:00:00 2001
From: Luxferre <lux@ferre>
Date: Tue, 12 Mar 2024 09:57:02 +0200
Subject: [PATCH] Added imeigen.awk

---
 README            |  2 +-
 games/awlite      |  2 +-
 utils/imeigen.awk | 30 ++++++++++++++++++++++++++++++
 3 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 utils/imeigen.awk

diff --git a/README b/README
index b35496e..b016c56 100644
--- a/README
+++ b/README
@@ -31,6 +31,6 @@ Other AWK scripts have the usage described in their comment headers.
 
 * utils/textereo.awk: ASCII art stereogram generator
 * utils/tgl.awk: The Great Library of useful functions missing in POSIX AWK
-
+* utils/imeigen.awk: Random valid IMEI generator (with optional TAC prefix)
 
 --- Luxferre ---
diff --git a/games/awlite b/games/awlite
index 026c365..5fe34df 160000
--- a/games/awlite
+++ b/games/awlite
@@ -1 +1 @@
-Subproject commit 026c365e50d9e602a5ec22501eb016a3ae515345
+Subproject commit 5fe34dfc944d5b05d326fb3675a1fa0ca4d37039
diff --git a/utils/imeigen.awk b/utils/imeigen.awk
new file mode 100644
index 0000000..68594d4
--- /dev/null
+++ b/utils/imeigen.awk
@@ -0,0 +1,30 @@
+# Valid IMEI generator script
+#
+# Usage: awk -f imeigen.awk [TAC]
+# you can pass any amount of digits, if less than 15 then the rest
+# is randomized and the checksum is calculated accordingly
+# if more, then it's truncated to 14 and the checksum is calculated 
+# if no TAC is passed, a fully random valid IMEI is generated
+#
+# Created by Luxferre in 2024, released into public domain
+
+# Luhn checksum (picoLuhn variation for 14 digits)
+function luhn(imeistr,  acc, i, l, d) {
+  acc = 0
+  l = length(imeistr) # must be even in this variation
+  for(i=0;i<l;i++) {
+    d = int(substr(imeistr, i+1, 1)) # get current digit
+    acc = (acc + int(d * ((i%2) == 1 ? 2.2 : 1))) % 10 # accumulate
+  }
+  return (10 - acc) % 10 # finalize the check digit
+}
+
+BEGIN {
+  srand() # init PRNG
+  imei=ARGV[1]
+  gsub(/[^0-9]/, "", imei) # remove all non-digits
+  for(i=0;i<14;i++) # append 14 random digits
+    imei = imei int(rand()*10)
+  imei = substr(imei, 1, 14) # truncate to first 14 digits
+  print(imei luhn(imei)) # output complete IMEI with checksum
+}