From 2d04580e0ec8978cfcd817171086f80ceb566e7b Mon Sep 17 00:00:00 2001 From: ubq323 Date: Thu, 5 Jun 2025 16:04:05 +0100 Subject: import rle.lua from hexemu --- rle.lua | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 rle.lua diff --git a/rle.lua b/rle.lua new file mode 100644 index 0000000..2944c4c --- /dev/null +++ b/rle.lua @@ -0,0 +1,50 @@ +-- run length encoding + +local function encode(l) + local out = {} + + local last = l[1] + local count = 1 + + local function ap() + if count == 1 then + table.insert(out,last) + elseif count == 2 then + table.insert(out,last) + table.insert(out,last) + else + table.insert(out,{count,last}) + end + end + + for ix=2,#l do + local val = l[ix] + if val == last then + count = count + 1 + else + ap() + last = val + count = 1 + end + end + + ap() + + return out +end + +local function decode(l) + local out = {} + for _,r in ipairs(l) do + if type(r) == "table" and #r == 2 then + for i = 1,r[1] do + table.insert(out,r[2]) + end + else + table.insert(out,r) + end + end + return out +end + +return {encode=encode,decode=decode} -- cgit v1.2.3