add RLE compression functions

7 files changed, 224 insertions, 38 deletions

diff --git a/.direnv/flake-profile b/.direnv/flake-profile
index 624f00f..0e6e742 120000
--- a/.direnv/flake-profile
+++ b/.direnv/flake-profile
@@ -1 +1 @@
-/nix/store/hk8227smba1l2lrk4np5fqy2hkb0jaf3-nix-shell-env
\ No newline at end of file
+/nix/store/q3bk2x9q1g2xnah8j9l9xpl2037ks0xv-nix-shell-env
\ No newline at end of file
diff --git a/.direnv/flake-profile.rc b/.direnv/flake-profile.rc
index 49f03d2..3796858 100644
--- a/.direnv/flake-profile.rc
+++ b/.direnv/flake-profile.rc
@@ -32,7 +32,7 @@ NIX_CC=/nix/store/i9a3zzf2spmw67jppvkj2yavnbka62id-gcc-wrapper-10.2.0
 export NIX_CC
 NIX_CC_WRAPPER_TARGET_HOST_x86_64_unknown_linux_gnu=1
 export NIX_CC_WRAPPER_TARGET_HOST_x86_64_unknown_linux_gnu
-NIX_CFLAGS_COMPILE=' -frandom-seed=hk8227smba -isystem /nix/store/91ym2jzh08470r4jb1d5pmh22vg2bpck-openssl-1.1.1i-dev/include -isystem /nix/store/saiwalr8jq58mbyipkn824r93gjjnw5x-ncurses-6.2-dev/include -isystem /nix/store/91ym2jzh08470r4jb1d5pmh22vg2bpck-openssl-1.1.1i-dev/include -isystem /nix/store/saiwalr8jq58mbyipkn824r93gjjnw5x-ncurses-6.2-dev/include'
+NIX_CFLAGS_COMPILE=' -frandom-seed=q3bk2x9q1g'
 export NIX_CFLAGS_COMPILE
 NIX_ENFORCE_NO_NATIVE=1
 export NIX_ENFORCE_NO_NATIVE
@@ -40,7 +40,7 @@ NIX_HARDENING_ENABLE='fortify stackprotector pic strictoverflow format relro bin
 export NIX_HARDENING_ENABLE
 NIX_INDENT_MAKE=1
 export NIX_INDENT_MAKE
-NIX_LDFLAGS='-rpath /home/np/code/rust/obi/outputs/out/lib64 -rpath /home/np/code/rust/obi/outputs/out/lib  -L/nix/store/ni0nxz7jnd3scrfqsdr6cragl95fqmyb-rust-1.50.0-nightly-2020-12-22-bb1fbbf84/lib -L/nix/store/kchm26396krqwdn2dkx6l0hb79lwlhr1-openssl-1.1.1i/lib -L/nix/store/d3nz4c5xf1bqz8rwr8m4gbsrny9ffidk-ncurses-6.2/lib -L/nix/store/ni0nxz7jnd3scrfqsdr6cragl95fqmyb-rust-1.50.0-nightly-2020-12-22-bb1fbbf84/lib -L/nix/store/kchm26396krqwdn2dkx6l0hb79lwlhr1-openssl-1.1.1i/lib -L/nix/store/d3nz4c5xf1bqz8rwr8m4gbsrny9ffidk-ncurses-6.2/lib'
+NIX_LDFLAGS='-rpath /home/np/code/rust/obi/outputs/out/lib64 -rpath /home/np/code/rust/obi/outputs/out/lib  -L/nix/store/58syiz9158g5s53gjh8f5b89bhhp1m0s-rust-1.53.0-nightly-2021-03-30-74874a690/lib -L/nix/store/58syiz9158g5s53gjh8f5b89bhhp1m0s-rust-1.53.0-nightly-2021-03-30-74874a690/lib'
 export NIX_LDFLAGS
 NIX_LIB64_IN_SELF_RPATH=1
 NIX_NO_SELF_RPATH=1
@@ -55,7 +55,7 @@ export OBJDUMP
 OPTERR=1
 OPTIND=1
 OSTYPE=linux-gnu
-PATH=/nix/store/ni0nxz7jnd3scrfqsdr6cragl95fqmyb-rust-1.50.0-nightly-2020-12-22-bb1fbbf84/bin:/nix/store/pj3m562kh9lr7wjk3hlyandhd1qpapgh-rust-analyzer-unstable-2021-02-22/bin:/nix/store/9p0yf4yzsc8by6xviags56c3mb3fxkkw-cargo-1.49.0/bin:/nix/store/71707dbkha4mryph7ywp48wi2r1sc0hf-openssl-1.1.1i-bin/bin:/nix/store/saiwalr8jq58mbyipkn824r93gjjnw5x-ncurses-6.2-dev/bin:/nix/store/d3nz4c5xf1bqz8rwr8m4gbsrny9ffidk-ncurses-6.2/bin:/nix/store/d7lyvmvzf1a8qqhsxhdc3r6dwbdmfcap-patchelf-0.12/bin:/nix/store/i9a3zzf2spmw67jppvkj2yavnbka62id-gcc-wrapper-10.2.0/bin:/nix/store/wxri3dc14yd1w997vjfvsnn6qml64l4r-gcc-10.2.0/bin:/nix/store/fr2k1vwmyd5ngmb3y0v090nh21nn6gqp-glibc-2.32-35-bin/bin:/nix/store/ypsd29c5hgj1x7xz5ddffanxw5d8fh7b-coreutils-8.32/bin:/nix/store/f4w8p656gg6v2k1v0whwmyk09kz3k8ic-binutils-wrapper-2.35.1/bin:/nix/store/9f8y44vmjnwdjvzlff0gm3f3g6ycyyqy-binutils-2.35.1/bin:/nix/store/fr2k1vwmyd5ngmb3y0v090nh21nn6gqp-glibc-2.32-35-bin/bin:/nix/store/ypsd29c5hgj1x7xz5ddffanxw5d8fh7b-coreutils-8.32/bin:/nix/store/ypsd29c5hgj1x7xz5ddffanxw5d8fh7b-coreutils-8.32/bin:/nix/store/nq9l23mrm8irvl9qvxgvxqqkm5sfnc9d-findutils-4.7.0/bin:/nix/store/7yq29nnglh2s576n7vdmzqryym22f8rj-diffutils-3.7/bin:/nix/store/0839nqri8w69c91amlsq9bawaqlzpmh9-gnused-4.8/bin:/nix/store/wmiyjdsaydyv024al5ddqd3liljrfvk7-gnugrep-3.6/bin:/nix/store/snmar11l5w9jrxva2s5d6143nqmdgzqb-gawk-5.1.0/bin:/nix/store/cisss0pcfh72kmnsv4qa6h41wcwb9mkv-gnutar-1.32/bin:/nix/store/prdifiyrxwgf6sp4rwmrqvfdnvf72gw2-gzip-1.10/bin:/nix/store/pp9shwhcdxxbhgp96fcaj0g8x5g54zrl-bzip2-1.0.6.0.1-bin/bin:/nix/store/fydw5vhlhpq438cxv4vwpa8pf8p8fv5s-gnumake-4.3/bin:/nix/store/yyy7wr7r9jwjjqkr1yn643g3wzv010zd-bash-4.4-p23/bin:/nix/store/qcw3qagp709qwfza259zqss5qh4wg789-patch-2.7.6/bin:/nix/store/q0jqhjabwaaak30l4sq3z0xi6jrkpnbn-xz-5.2.5-bin/bin
+PATH=/nix/store/58syiz9158g5s53gjh8f5b89bhhp1m0s-rust-1.53.0-nightly-2021-03-30-74874a690/bin:/nix/store/pj3m562kh9lr7wjk3hlyandhd1qpapgh-rust-analyzer-unstable-2021-02-22/bin:/nix/store/rfx0jz6pr3n2dcxm99finhbp99v45qx4-rustfmt-1.49.0/bin:/nix/store/9p0yf4yzsc8by6xviags56c3mb3fxkkw-cargo-1.49.0/bin:/nix/store/d7lyvmvzf1a8qqhsxhdc3r6dwbdmfcap-patchelf-0.12/bin:/nix/store/i9a3zzf2spmw67jppvkj2yavnbka62id-gcc-wrapper-10.2.0/bin:/nix/store/wxri3dc14yd1w997vjfvsnn6qml64l4r-gcc-10.2.0/bin:/nix/store/fr2k1vwmyd5ngmb3y0v090nh21nn6gqp-glibc-2.32-35-bin/bin:/nix/store/ypsd29c5hgj1x7xz5ddffanxw5d8fh7b-coreutils-8.32/bin:/nix/store/f4w8p656gg6v2k1v0whwmyk09kz3k8ic-binutils-wrapper-2.35.1/bin:/nix/store/9f8y44vmjnwdjvzlff0gm3f3g6ycyyqy-binutils-2.35.1/bin:/nix/store/fr2k1vwmyd5ngmb3y0v090nh21nn6gqp-glibc-2.32-35-bin/bin:/nix/store/ypsd29c5hgj1x7xz5ddffanxw5d8fh7b-coreutils-8.32/bin:/nix/store/ypsd29c5hgj1x7xz5ddffanxw5d8fh7b-coreutils-8.32/bin:/nix/store/nq9l23mrm8irvl9qvxgvxqqkm5sfnc9d-findutils-4.7.0/bin:/nix/store/7yq29nnglh2s576n7vdmzqryym22f8rj-diffutils-3.7/bin:/nix/store/0839nqri8w69c91amlsq9bawaqlzpmh9-gnused-4.8/bin:/nix/store/wmiyjdsaydyv024al5ddqd3liljrfvk7-gnugrep-3.6/bin:/nix/store/snmar11l5w9jrxva2s5d6143nqmdgzqb-gawk-5.1.0/bin:/nix/store/cisss0pcfh72kmnsv4qa6h41wcwb9mkv-gnutar-1.32/bin:/nix/store/prdifiyrxwgf6sp4rwmrqvfdnvf72gw2-gzip-1.10/bin:/nix/store/pp9shwhcdxxbhgp96fcaj0g8x5g54zrl-bzip2-1.0.6.0.1-bin/bin:/nix/store/fydw5vhlhpq438cxv4vwpa8pf8p8fv5s-gnumake-4.3/bin:/nix/store/yyy7wr7r9jwjjqkr1yn643g3wzv010zd-bash-4.4-p23/bin:/nix/store/qcw3qagp709qwfza259zqss5qh4wg789-patch-2.7.6/bin:/nix/store/q0jqhjabwaaak30l4sq3z0xi6jrkpnbn-xz-5.2.5-bin/bin
 export PATH
 PIPESTATUS=([0]="0")
 PS4='+ '
@@ -63,7 +63,11 @@ RANLIB=ranlib
 export RANLIB
 READELF=readelf
 export READELF
-RUST_SRC_PATH=/nix/store/ncxadjgpdacbf69yhpgwvwnqhmh5yk96-rust-lib-src
+RUST_BACKTRACE=1
+export RUST_BACKTRACE
+RUST_LOG=info
+export RUST_LOG
+RUST_SRC_PATH=/nix/store/m0k4il8v2wv0c7nniqndcxh72qmzvvg2-rust-src-1.53.0-nightly-2021-03-30-74874a690/lib/rustlib/src/rust/library
 export RUST_SRC_PATH
 SHELL=/nix/store/yyy7wr7r9jwjjqkr1yn643g3wzv010zd-bash-4.4-p23/bin/bash
 export SHELL
@@ -75,7 +79,7 @@ STRINGS=strings
 export STRINGS
 STRIP=strip
 export STRIP
-XDG_DATA_DIRS=/nix/store/ni0nxz7jnd3scrfqsdr6cragl95fqmyb-rust-1.50.0-nightly-2020-12-22-bb1fbbf84/share:/nix/store/9p0yf4yzsc8by6xviags56c3mb3fxkkw-cargo-1.49.0/share:/nix/store/d3nz4c5xf1bqz8rwr8m4gbsrny9ffidk-ncurses-6.2/share:/nix/store/d7lyvmvzf1a8qqhsxhdc3r6dwbdmfcap-patchelf-0.12/share
+XDG_DATA_DIRS=/nix/store/58syiz9158g5s53gjh8f5b89bhhp1m0s-rust-1.53.0-nightly-2021-03-30-74874a690/share:/nix/store/9p0yf4yzsc8by6xviags56c3mb3fxkkw-cargo-1.49.0/share:/nix/store/d7lyvmvzf1a8qqhsxhdc3r6dwbdmfcap-patchelf-0.12/share
 export XDG_DATA_DIRS
 _=export
 buildInputs=
@@ -115,7 +119,7 @@ fixupOutputHooks=([0]="if [ -z \"\${dontPatchELF-}\" ]; then patchELF \"\$prefix
 initialPath='/nix/store/ypsd29c5hgj1x7xz5ddffanxw5d8fh7b-coreutils-8.32 /nix/store/nq9l23mrm8irvl9qvxgvxqqkm5sfnc9d-findutils-4.7.0 /nix/store/7yq29nnglh2s576n7vdmzqryym22f8rj-diffutils-3.7 /nix/store/0839nqri8w69c91amlsq9bawaqlzpmh9-gnused-4.8 /nix/store/wmiyjdsaydyv024al5ddqd3liljrfvk7-gnugrep-3.6 /nix/store/snmar11l5w9jrxva2s5d6143nqmdgzqb-gawk-5.1.0 /nix/store/cisss0pcfh72kmnsv4qa6h41wcwb9mkv-gnutar-1.32 /nix/store/prdifiyrxwgf6sp4rwmrqvfdnvf72gw2-gzip-1.10 /nix/store/pp9shwhcdxxbhgp96fcaj0g8x5g54zrl-bzip2-1.0.6.0.1-bin /nix/store/fydw5vhlhpq438cxv4vwpa8pf8p8fv5s-gnumake-4.3 /nix/store/yyy7wr7r9jwjjqkr1yn643g3wzv010zd-bash-4.4-p23 /nix/store/qcw3qagp709qwfza259zqss5qh4wg789-patch-2.7.6 /nix/store/q0jqhjabwaaak30l4sq3z0xi6jrkpnbn-xz-5.2.5-bin'
 name=nix-shell
 export name
-nativeBuildInputs='/nix/store/ni0nxz7jnd3scrfqsdr6cragl95fqmyb-rust-1.50.0-nightly-2020-12-22-bb1fbbf84 /nix/store/pgzjwsl6ilg93ifsx70ck5l2yv85fknm-rust-src-1.50.0-nightly-2020-12-22-bb1fbbf84 /nix/store/pj3m562kh9lr7wjk3hlyandhd1qpapgh-rust-analyzer-unstable-2021-02-22 /nix/store/9p0yf4yzsc8by6xviags56c3mb3fxkkw-cargo-1.49.0 /nix/store/91ym2jzh08470r4jb1d5pmh22vg2bpck-openssl-1.1.1i-dev /nix/store/saiwalr8jq58mbyipkn824r93gjjnw5x-ncurses-6.2-dev'
+nativeBuildInputs='/nix/store/58syiz9158g5s53gjh8f5b89bhhp1m0s-rust-1.53.0-nightly-2021-03-30-74874a690 /nix/store/m0k4il8v2wv0c7nniqndcxh72qmzvvg2-rust-src-1.53.0-nightly-2021-03-30-74874a690 /nix/store/pj3m562kh9lr7wjk3hlyandhd1qpapgh-rust-analyzer-unstable-2021-02-22 /nix/store/rfx0jz6pr3n2dcxm99finhbp99v45qx4-rustfmt-1.49.0 /nix/store/9p0yf4yzsc8by6xviags56c3mb3fxkkw-cargo-1.49.0'
 export nativeBuildInputs
 nobuildPhase=$'echo\necho "This derivation is not meant to be built, aborting";\necho\nexit 1\n'
 export nobuildPhase
@@ -137,7 +141,7 @@ export patches
 phases=nobuildPhase
 export phases
 pkg=/nix/store/i9a3zzf2spmw67jppvkj2yavnbka62id-gcc-wrapper-10.2.0
-pkgsBuildHost=([0]="/nix/store/ni0nxz7jnd3scrfqsdr6cragl95fqmyb-rust-1.50.0-nightly-2020-12-22-bb1fbbf84" [1]="/nix/store/pgzjwsl6ilg93ifsx70ck5l2yv85fknm-rust-src-1.50.0-nightly-2020-12-22-bb1fbbf84" [2]="/nix/store/pj3m562kh9lr7wjk3hlyandhd1qpapgh-rust-analyzer-unstable-2021-02-22" [3]="/nix/store/9p0yf4yzsc8by6xviags56c3mb3fxkkw-cargo-1.49.0" [4]="/nix/store/91ym2jzh08470r4jb1d5pmh22vg2bpck-openssl-1.1.1i-dev" [5]="/nix/store/71707dbkha4mryph7ywp48wi2r1sc0hf-openssl-1.1.1i-bin" [6]="/nix/store/kchm26396krqwdn2dkx6l0hb79lwlhr1-openssl-1.1.1i" [7]="/nix/store/saiwalr8jq58mbyipkn824r93gjjnw5x-ncurses-6.2-dev" [8]="/nix/store/d3nz4c5xf1bqz8rwr8m4gbsrny9ffidk-ncurses-6.2" [9]="/nix/store/d7lyvmvzf1a8qqhsxhdc3r6dwbdmfcap-patchelf-0.12" [10]="/nix/store/mjjy30kxz775bhhi6j9phw81qh6dsbrf-move-docs.sh" [11]="/nix/store/kxw6q8v6isaqjm702d71n2421cxamq68-make-symlinks-relative.sh" [12]="/nix/store/cl3qd985p1yxyfkj96v0hqxiy3w69xq5-compress-man-pages.sh" [13]="/nix/store/h54dzwd7rdh2jlcv91424csl6d0ccgjy-strip.sh" [14]="/nix/store/bnj8d7mvbkg3vdb07yz74yhl3g107qq5-patch-shebangs.sh" [15]="/nix/store/cickvswrvann041nqxb0rxilc46svw1n-prune-libtool-files.sh" [16]="/nix/store/8zxndz5ag0p6s526c2xyllhk1nrn4c3i-audit-tmpdir.sh" [17]="/nix/store/c8n9kcdddp9np665xz6ri61b383nxvz8-move-systemd-user-units.sh" [18]="/nix/store/1i5y55x4b4m9qkx5dqbmr1r6bvrqbanw-multiple-outputs.sh" [19]="/nix/store/kd4xwxjpjxi71jkm6ka0np72if9rm3y0-move-sbin.sh" [20]="/nix/store/fyaryjvghbkpfnsyw97hb3lyb37s1pd6-move-lib64.sh" [21]="/nix/store/ngg1cv31c8c7bcm2n8ww4g06nq7s4zhm-set-source-date-epoch-to-latest.sh" [22]="/nix/store/pr6nzbscdpg94yvr151lrif2kg0csx7b-reproducible-builds.sh" [23]="/nix/store/i9a3zzf2spmw67jppvkj2yavnbka62id-gcc-wrapper-10.2.0" [24]="/nix/store/f4w8p656gg6v2k1v0whwmyk09kz3k8ic-binutils-wrapper-2.35.1")
+pkgsBuildHost=([0]="/nix/store/58syiz9158g5s53gjh8f5b89bhhp1m0s-rust-1.53.0-nightly-2021-03-30-74874a690" [1]="/nix/store/m0k4il8v2wv0c7nniqndcxh72qmzvvg2-rust-src-1.53.0-nightly-2021-03-30-74874a690" [2]="/nix/store/pj3m562kh9lr7wjk3hlyandhd1qpapgh-rust-analyzer-unstable-2021-02-22" [3]="/nix/store/rfx0jz6pr3n2dcxm99finhbp99v45qx4-rustfmt-1.49.0" [4]="/nix/store/9p0yf4yzsc8by6xviags56c3mb3fxkkw-cargo-1.49.0" [5]="/nix/store/d7lyvmvzf1a8qqhsxhdc3r6dwbdmfcap-patchelf-0.12" [6]="/nix/store/mjjy30kxz775bhhi6j9phw81qh6dsbrf-move-docs.sh" [7]="/nix/store/kxw6q8v6isaqjm702d71n2421cxamq68-make-symlinks-relative.sh" [8]="/nix/store/cl3qd985p1yxyfkj96v0hqxiy3w69xq5-compress-man-pages.sh" [9]="/nix/store/h54dzwd7rdh2jlcv91424csl6d0ccgjy-strip.sh" [10]="/nix/store/bnj8d7mvbkg3vdb07yz74yhl3g107qq5-patch-shebangs.sh" [11]="/nix/store/cickvswrvann041nqxb0rxilc46svw1n-prune-libtool-files.sh" [12]="/nix/store/8zxndz5ag0p6s526c2xyllhk1nrn4c3i-audit-tmpdir.sh" [13]="/nix/store/c8n9kcdddp9np665xz6ri61b383nxvz8-move-systemd-user-units.sh" [14]="/nix/store/1i5y55x4b4m9qkx5dqbmr1r6bvrqbanw-multiple-outputs.sh" [15]="/nix/store/kd4xwxjpjxi71jkm6ka0np72if9rm3y0-move-sbin.sh" [16]="/nix/store/fyaryjvghbkpfnsyw97hb3lyb37s1pd6-move-lib64.sh" [17]="/nix/store/ngg1cv31c8c7bcm2n8ww4g06nq7s4zhm-set-source-date-epoch-to-latest.sh" [18]="/nix/store/pr6nzbscdpg94yvr151lrif2kg0csx7b-reproducible-builds.sh" [19]="/nix/store/i9a3zzf2spmw67jppvkj2yavnbka62id-gcc-wrapper-10.2.0" [20]="/nix/store/f4w8p656gg6v2k1v0whwmyk09kz3k8ic-binutils-wrapper-2.35.1")
 postFixupHooks=([0]="_multioutPropagateDev")
 postUnpackHooks=([0]="_updateSourceDateEpochFromSourceRoot")
 preConfigureHooks=([0]="_multioutConfig")
@@ -1496,7 +1500,7 @@ updateSourceDateEpoch ()
     fi
 }
 
-export NIX_BUILD_TOP="$(mktemp -d --tmpdir nix-shell.XXXXXX)"
+export NIX_BUILD_TOP="$(mktemp -d -t nix-shell.XXXXXX)"
 export TMP="$NIX_BUILD_TOP"
 export TMPDIR="$NIX_BUILD_TOP"
 export TEMP="$NIX_BUILD_TOP"
diff --git a/src/decode.rs b/src/decode.rs
index a9abd37..9c6a065 100644
--- a/src/decode.rs
+++ b/src/decode.rs
@@ -4,7 +4,7 @@ use bitvec::prelude::*;
 use byteorder::{LittleEndian, ReadBytesExt};
 
 use crate::error::{OBIError, OBIResult};
-use crate::{FileHeader, Image, ImageInfoHeader};
+use crate::{CompressionType, FileHeader, Image, ImageInfoHeader};
 
 pub fn decode_image(obi_data: &mut Cursor<Vec<u8>>) -> OBIResult<Image> {
     // file header
@@ -43,22 +43,59 @@ pub fn decode_image(obi_data: &mut Cursor<Vec<u8>>) -> OBIResult<Image> {
         post_compression_size,
     };
 
-    // pixmap data
-    let mut data_bytes = vec![];
-    obi_data
-        .read_to_end(&mut data_bytes)
-        .map_err(|_| OBIError::Decode)?;
-    let data = data_bytes
-        .iter()
-        .map(|&b| {
-            BitVec::<Lsb0, u8>::from_element(b)
-                .into_iter()
-                .map(|e| e as bool)
-                .collect::<Vec<bool>>()
-        })
-        .flatten()
-        .collect::<Vec<_>>();
+    let data: Vec<bool> = match CompressionType::from_u32(compression_type) {
+        CompressionType::RLE => {
+            let mut rest = vec![];
+            let mut lengths = vec![];
+            loop {
+                let l = obi_data
+                    .read_u32::<LittleEndian>()
+                    .map_err(|_| OBIError::Encode)?;
+                if l == 0 {
+                    break;
+                }
+                lengths.push(l);
+            }
+            obi_data
+                .read_to_end(&mut rest)
+                .map_err(|_| OBIError::Decode)?;
+            let data_points = rest
+                .iter()
+                .map(|&b| {
+                    BitVec::<Lsb0, u8>::from_element(b)
+                        .into_iter()
+                        .map(|e| e as bool)
+                        .collect::<Vec<bool>>()
+                })
+                .flatten()
+                .collect::<Vec<bool>>();
 
+            let data = data_points
+                .into_iter()
+                .zip(lengths)
+                .map(|(d, l)| vec![d; l as usize])
+                .flatten()
+                .collect::<Vec<bool>>();
+            data
+        }
+        _ => {
+            let mut rest = vec![];
+            obi_data
+                .read_to_end(&mut rest)
+                .map_err(|_| OBIError::Decode)?;
+            let data_points = rest
+                .iter()
+                .map(|&b| {
+                    BitVec::<Lsb0, u8>::from_element(b)
+                        .into_iter()
+                        .map(|e| e as bool)
+                        .collect::<Vec<bool>>()
+                })
+                .flatten()
+                .collect::<Vec<_>>();
+            data_points
+        }
+    };
     return Ok(Image {
         file_header,
         image_info_header,
diff --git a/src/encode.rs b/src/encode.rs
index a8c58e0..30edc49 100644
--- a/src/encode.rs
+++ b/src/encode.rs
@@ -3,8 +3,11 @@ use std::borrow::Borrow;
 use bitvec::{prelude::*, vec::BitVec};
 use byteorder::{LittleEndian, WriteBytesExt};
 
-use crate::error::{OBIError, OBIResult};
-use crate::Image;
+use crate::{
+    error::{OBIError, OBIResult},
+    rle::RLE,
+    CompressionType, Image,
+};
 
 pub fn encode_image<I>(obi_image: I) -> OBIResult<Vec<u8>>
 where
@@ -40,17 +43,38 @@ where
         .write_u32::<LittleEndian>(image_info_header.post_compression_size)
         .map_err(|_| OBIError::Encode)?;
 
+    let write_pixel_data = |pixels: &Vec<bool>, obi_data: &mut Vec<u8>| -> OBIResult<()> {
+        for byte in pixels.chunks(8) {
+            let mut bv = BitVec::<Lsb0, u8>::new();
+            for &b in byte {
+                bv.push(b)
+            }
+            obi_data
+                .write_u8(bv.load::<u8>())
+                .map_err(|_| OBIError::Encode)?;
+        }
+        Ok(())
+    };
+
     // pixmap data
     let pixmap = &obi_image.data;
-    for byte in pixmap.chunks(8) {
-        let mut bv = BitVec::<Lsb0, u8>::new();
-        for &b in byte {
-            bv.push(b);
+    match CompressionType::from_u32(obi_image.image_info_header.compression_type) {
+        CompressionType::RLE => {
+            let (data_points, lengths): (Vec<_>, Vec<_>) = pixmap.compress().into_iter().unzip();
+            for l in lengths {
+                obi_data
+                    .write_u32::<LittleEndian>(l as u32)
+                    .map_err(|_| OBIError::Encode)?;
+            }
+            // end length sequence with zero
+            obi_data
+                .write_u32::<LittleEndian>(0)
+                .map_err(|_| OBIError::Encode)?;
+            // begin data point sequence
+            write_pixel_data(&data_points, &mut obi_data)?;
         }
-        obi_data
-            .write_u8(bv.load::<u8>())
-            .map_err(|_| OBIError::Encode)?;
-    }
+        _ => write_pixel_data(pixmap, &mut obi_data)?,
+    };
 
     return Ok(obi_data);
 }
diff --git a/src/lib.rs b/src/lib.rs
index f949d06..3995c16 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -7,8 +7,10 @@ use std::io;
 mod decode;
 mod encode;
 pub mod error;
+mod rle;
 
-use crate::error::{OBIError, OBIResult};
+use error::{OBIError, OBIResult};
+use rle::RLE;
 
 #[non_exhaustive]
 #[derive(Copy, Clone, Debug, PartialEq)]
@@ -83,6 +85,14 @@ impl CompressionType {
             _ => panic!("Invalid compression algorithm"),
         }
     }
+    pub fn to_u32(self) -> u32 {
+        match self {
+            CompressionType::None => 0,
+            CompressionType::RLE => 1,
+            CompressionType::Kosinki => 10,
+            _ => panic!("Invalid compression algorithm"),
+        }
+    }
 }
 
 #[derive(Debug)]
@@ -111,6 +121,10 @@ impl Image {
         }
     }
 
+    pub fn use_compression(&mut self, comp: CompressionType) {
+        self.image_info_header.compression_type = comp.to_u32();
+    }
+
     pub fn width(&self) -> u32 {
         self.image_info_header.width
     }
diff --git a/src/rle.rs b/src/rle.rs
new file mode 100644
index 0000000..f6d1e05
--- /dev/null
+++ b/src/rle.rs
@@ -0,0 +1,89 @@
+pub trait RLE {
+    type Data;
+    fn compress(&self) -> Vec<Run<Self::Data>>;
+    fn decompress(runs: Vec<Run<Self::Data>>) -> Vec<Self::Data>;
+}
+
+pub type Run<T> = (T, usize);
+
+impl<T> RLE for Vec<T>
+where
+    T: Clone + PartialEq,
+{
+    type Data = T;
+    fn compress(&self) -> Vec<Run<Self::Data>> {
+        let mut runs = vec![];
+        if self.is_empty() {
+            return runs;
+        }
+        let mut idx = 0;
+        loop {
+            let first = &self[idx];
+            let run_length = self[idx..].iter().take_while(|&item| item == first).count();
+
+            runs.push((first.clone(), run_length));
+
+            idx += run_length;
+            if idx > self.len() - 1 {
+                break;
+            }
+        }
+        runs
+    }
+    fn decompress(runs: Vec<Run<Self::Data>>) -> Vec<Self::Data> {
+        runs.into_iter()
+            .map(|(item, size)| vec![item; size])
+            .flatten()
+            .collect()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    fn singleton() {
+        let data = "a".chars().collect::<Vec<_>>();
+        assert_eq!(Vec::<char>::compress(&data), vec![('a', 1),]);
+    }
+    #[test]
+    fn identity() {
+        let data = "aabbccddaabbaa".chars().collect::<Vec<_>>();
+        assert_eq!(Vec::<char>::decompress(data.compress()), data);
+    }
+    #[test]
+    fn repeated_singleton() {
+        let data = "aaaaaaaaaaaaa".chars().collect::<Vec<_>>();
+        assert_eq!(Vec::<char>::compress(&data), vec![('a', 13),]);
+    }
+    #[test]
+    fn empty_runs() {
+        let data = "".chars().collect::<Vec<_>>();
+        assert!(data.compress().is_empty());
+    }
+    #[test]
+    fn empty_decompress() {
+        assert!(Vec::<char>::decompress(vec![]).is_empty());
+    }
+    #[test]
+    fn check_runs1() {
+        let data = "aaaabbbbcccc".chars().collect::<Vec<_>>();
+        assert_eq!(data.compress(), vec![('a', 4), ('b', 4), ('c', 4)]);
+    }
+    #[test]
+    fn check_runs2() {
+        let data = "aabbccddaabbaa".chars().collect::<Vec<_>>();
+        assert_eq!(
+            data.compress(),
+            vec![
+                ('a', 2),
+                ('b', 2),
+                ('c', 2),
+                ('d', 2),
+                ('a', 2),
+                ('b', 2),
+                ('a', 2)
+            ]
+        );
+    }
+}
diff --git a/tests/serde.rs b/tests/serde.rs
index 295b8d0..3701707 100644
--- a/tests/serde.rs
+++ b/tests/serde.rs
@@ -11,13 +11,14 @@ fn size_of_image_info_header() {
 
 #[test]
 fn compression() {
-    let img = Image::new(50, 5);
+    let mut img = Image::new(50, 5);
+    img.use_compression(CompressionType::RLE);
     let encoded = img.encode().unwrap();
     let mut cursor = Cursor::new(encoded);
     let decoded = Image::decode(&mut cursor).unwrap();
     assert_eq!(
         CompressionType::from_u32(decoded.image_info_header.compression_type),
-        CompressionType::None
+        CompressionType::RLE
     );
 }
 
@@ -42,3 +43,20 @@ fn size_round_nearest() {
     assert_eq!(decoded.image_info_header.width, 50);
     assert_eq!(decoded.image_info_header.height, 5);
 }
+
+#[test]
+fn size_compressed() {
+    let mut img = Image::new(100, 80);
+    img.use_compression(CompressionType::RLE);
+    let encoded = img.encode().unwrap();
+    // 26 - headers
+    // 4 - first and only length
+    // 4 - separator zero
+    // 1 - first and only data point
+    assert_eq!(encoded.len(), 26 + 4 + 4 + 1);
+    let mut cursor = Cursor::new(encoded);
+    let decoded = Image::decode(&mut cursor).unwrap();
+    assert_eq!(decoded.image_info_header.width, 100);
+    assert_eq!(decoded.image_info_header.height, 80);
+    assert!(decoded.data.iter().all(|x| !*x));
+}