From 11dac6494d90c73545f0a9e03732c6ef7bad88b7 Mon Sep 17 00:00:00 2001
From: Julien Dessaux
Date: Tue, 21 Sep 2021 00:28:31 +0200
Subject: Began implementing the stack and the stack stack

---
 pkg/stack/stack-stack.go | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 pkg/stack/stack-stack.go

(limited to 'pkg/stack/stack-stack.go')

diff --git a/pkg/stack/stack-stack.go b/pkg/stack/stack-stack.go
new file mode 100644
index 0000000..db5a405
--- /dev/null
+++ b/pkg/stack/stack-stack.go
@@ -0,0 +1,44 @@
+package stack
+
+import (
+	"git.adyxax.org/adyxax/gofunge/pkg/pointer"
+)
+
+type StackStack struct {
+	head   *Stack
+	height int
+}
+
+func NewStackStack() *StackStack {
+	return &StackStack{
+		head:   NewStack(),
+		height: 1,
+	}
+}
+
+func (ss *StackStack) Begin(p *pointer.Pointer) {
+	soss := ss.head
+	n := soss.Pop()
+	np := n
+	if np < 0 {
+		np = -np
+	}
+	toss := &Stack{
+		size:   np,
+		height: np,
+		data:   make([]int, np),
+		next:   soss,
+	}
+	ss.head = toss
+	max := n - soss.height
+	if max < 0 {
+		max = 0
+	}
+	for i := n - 1; i >= max; i-- {
+		toss.data[i] = soss.data[soss.height-n+i]
+	}
+	x, y := p.GetStorageOffset()
+	soss.Push(x)
+	soss.Push(y)
+	p.CalculateNewStorageOffset()
+}
-- 
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