From d30e3f9600a7d20e5899e02de93bfdf45c476b51 Mon Sep 17 00:00:00 2001
From: Bill Rossi <bassguitarbill@gmail.com>
Date: Sat, 6 Dec 2025 10:19:08 -0500
Subject: [PATCH] More intcode

---
 ruby/2019/2/lib/intcode.rb |  79 -------------------
 ruby/2019/5/bin/problem    |  16 ++++
 ruby/2019/lib/intcode.rb   | 155 +++++++++++++++++++++++++++++++++++++
 ruby/bin/run               |   2 +-
 4 files changed, 172 insertions(+), 80 deletions(-)
 delete mode 100644 ruby/2019/2/lib/intcode.rb
 create mode 100644 ruby/2019/5/bin/problem
 create mode 100644 ruby/2019/lib/intcode.rb

diff --git a/ruby/2019/2/lib/intcode.rb b/ruby/2019/2/lib/intcode.rb
deleted file mode 100644
index 4c5e1b4..0000000
--- a/ruby/2019/2/lib/intcode.rb
+++ /dev/null
@@ -1,79 +0,0 @@
-class Intcode
-  attr_reader :memory, :pc, :stopped
-  def initialize(memory)
-    @initial_memory = memory
-    @memory = memory.clone
-    @pc = 0
-    @stopped = true
-  end
-
-  def self.for(string)
-    new string.split(",").map(&:to_i)
-  end
-
-  def run!
-    @stopped = false
-    @pc = 0
-    step! until stopped
-  end
-
-  def reset!
-    @memory = @initial_memory.clone
-    @pc = 0
-  end
-
-  def step!
-    case instruction
-    when 1
-      add!
-    when 2
-      multiply!
-    when 99
-      halt!
-    else
-      raise "invalid instuction #{instruction} at #{pc}"
-    end
-  end
-
-  def add!
-    v1 = peek(peek(pc + 1))
-    v2 = peek(peek(pc + 2))
-    log "adding #{v1} and #{v2}"
-    poke(peek(pc + 3), v1 + v2)
-    @pc += 4
-  end
-
-  def multiply!
-    v1 = peek(peek(pc + 1))
-    v2 = peek(peek(pc + 2))
-    log "multiplying #{v1} and #{v2}"
-    poke(peek(pc + 3), v1 * v2)
-    @pc += 4
-  end
-
-  def halt!
-    log "halting!"
-    @stopped = true
-  end
-
-  def instruction
-    peek pc
-  end
-
-  def peek(address)
-    memory[address]
-  end
-
-  def poke(address, value)
-    log "poking #{value} into #{address}"
-    memory[address] = value
-  end
-
-  def log(message)
-    puts message if logging?
-  end
-
-  def logging?
-    false
-  end
-end
diff --git a/ruby/2019/5/bin/problem b/ruby/2019/5/bin/problem
new file mode 100644
index 0000000..7cb2c1c
--- /dev/null
+++ b/ruby/2019/5/bin/problem
@@ -0,0 +1,16 @@
+#!/usr/bin/env ruby
+
+require "intcode"
+
+intcode = Intcode.for STDIN.read.chomp
+intcode.input.push 1
+intcode.run!
+
+puts "Part 1: #{intcode.output.last}"
+
+intcode.reset!
+intcode.input.push 5
+intcode.run!
+
+puts "Part 2: #{intcode.output.first}"
+
diff --git a/ruby/2019/lib/intcode.rb b/ruby/2019/lib/intcode.rb
new file mode 100644
index 0000000..642fb28
--- /dev/null
+++ b/ruby/2019/lib/intcode.rb
@@ -0,0 +1,155 @@
+class Intcode
+  attr_reader :memory, :pc, :stopped, :input, :output
+  def initialize(memory)
+    @initial_memory = memory
+    @memory = memory.clone
+    @pc = 0
+    @stopped = true
+    @input = []
+    @output = []
+  end
+
+  def self.for(string)
+    new string.split(",").map(&:to_i)
+  end
+
+  def run!
+    @stopped = false
+    @pc = 0
+    step! until stopped
+  end
+
+  def reset!
+    @memory = @initial_memory.clone
+    @pc = 0
+    @output = []
+    @input = []
+  end
+
+  def step!
+    log "pc: #{pc}, instruction: #{instruction}"
+    case opcode
+    when 1
+      add!
+    when 2
+      multiply!
+    when 3
+      read_input!
+    when 4
+      write_output!
+    when 5
+      jump_if_true!
+    when 6
+      jump_if_false!
+    when 7
+      less_than!
+    when 8
+      equals!
+    when 99
+      halt!
+    else
+      raise "invalid opcode #{opcode} at #{pc}"
+    end
+  end
+
+  def parameters
+    parameter_modes.each_with_index.map do |mode, index|
+      case mode
+      when 0
+        peek(pc + 1 + index)
+      when 1
+        pc + 1 + index
+      else
+        raise "Invalid parameter mode #{mode}"
+      end
+    end
+  end
+
+  def add!
+    log "adding #{peek(parameters[0])} and #{(parameters[1])}"
+    poke(parameters[2], peek(parameters[0]) + peek(parameters[1]))
+    @pc += 4
+  end
+
+  def multiply!
+    log "multiplying #{peek(parameters[0])} and #{peek(parameters[1])}"
+    poke(parameters[2], peek(parameters[0]) * peek(parameters[1]))
+    @pc += 4
+  end
+
+  def read_input!
+    i = input.shift
+    log "reading input #{i} into #{parameters[0]}"
+    poke(parameters[0], i)
+    @pc += 2
+  end
+
+  def write_output!
+    o = peek(parameters[0])
+    log "outputting #{o} from #{parameters[0]}"
+    output.push o
+    @pc += 2
+  end
+
+  def jump_if_true!
+    predicate = peek(parameters[0])
+    log "jumping to #{peek(parameters[1])} if #{predicate}"
+    @pc = predicate > 0 ? peek(parameters[1]) : @pc + 3
+  end
+
+  def jump_if_false!
+    predicate = peek(parameters[0])
+    log "jumping to #{peek(parameters[1])} unless #{predicate}"
+    @pc = predicate == 0 ? peek(parameters[1]) : @pc + 3
+  end
+
+  def less_than!
+    lt = peek(parameters[0]) < peek(parameters[1])
+    poke(parameters[2], lt ? 1 : 0)
+    @pc += 4
+  end
+
+  def equals!
+    eq = peek(parameters[0]) == peek(parameters[1])
+    poke(parameters[2], eq ? 1 : 0)
+    @pc += 4
+  end
+
+  def halt!
+    log "halting!"
+    @stopped = true
+  end
+
+  def instruction
+    peek pc
+  end
+
+  def opcode
+    instruction % 100
+  end
+
+  def parameter_modes
+    [
+      instruction / 100 % 10,
+      instruction / 1000 % 10,
+      instruction / 10000 % 10,
+    ]
+  end
+
+  def peek(address)
+    memory[address]
+  end
+
+  def poke(address, value)
+    log "poking #{value} into #{address}"
+    memory[address] = value
+  end
+
+  def log(message)
+    puts message if logging?
+  end
+
+  def logging?
+    false
+  end
+end
diff --git a/ruby/bin/run b/ruby/bin/run
index f9c5d56..25df725 100755
--- a/ruby/bin/run
+++ b/ruby/bin/run
@@ -11,4 +11,4 @@ if [[ -z $source_file ]] ; then
     exit 1
 fi
 
-time (cat ../data/$year/$day/input.txt | ruby -I$year/$day/lib $source_file)
+time (cat ../data/$year/$day/input.txt | ruby -I$year/$day/lib -I$year/lib $source_file)