From 4168c23c8f0f4a2043a65e75d4f8ebe808d8b341 Mon Sep 17 00:00:00 2001
From: rsiddharth <s@ricketyspace.net>
Date: Sun, 6 Sep 2020 14:53:07 -0400
Subject: lib: add BreakIntoBlocks

* lib/blocks.go (BreakIntoBlocks): New function.
---
 lib/blocks.go | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 lib/blocks.go

(limited to 'lib/blocks.go')

diff --git a/lib/blocks.go b/lib/blocks.go
new file mode 100644
index 0000000..3805d86
--- /dev/null
+++ b/lib/blocks.go
@@ -0,0 +1,32 @@
+// Copyright © 2020 rsiddharth <s@ricketyspace.net>
+// SPDX-License-Identifier: ISC
+
+package lib
+
+// Breaks 'cb' into blocks of 'keysize'
+func BreakIntoBlocks(cb []byte, keysize int) [][]byte {
+	if len(cb) < 1 {
+		return make([][]byte, 0)
+	}
+
+	// Compute the number of blocks.
+	nb := len(cb) / keysize
+	if len(cb)%keysize != 0 {
+		nb += 1
+	}
+	blocks := make([][]byte, nb)
+
+	for i, j, k := 0, 0, 0; i < len(cb); i++ {
+		if len(blocks[k]) == 0 {
+			blocks[k] = make([]byte, keysize)
+		}
+		blocks[k][j] = cb[i]
+
+		j += 1
+		if j == 8 {
+			j = 0
+			k += 1
+		}
+	}
+	return blocks
+}
-- 
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