lsinitcpio: add support for lz4 compressed image

Note that this requires a very recent version of lz4 utilities as it
uses lz4, and not the original lz4c tool, in order to be command line
API compliant with other compression tools. See upstream discussions:

  https://code.google.com/p/lz4/issues/detail?id=83

Signed-off-by: Dave Reisner <dreisner@archlinux.org>

3 files changed, 8 insertions, 1 deletions

diff --git a/PKGBUILD b/PKGBUILD
index 440e691..89613a4 100644
--- a/PKGBUILD
+++ b/PKGBUILD
@@ -14,6 +14,7 @@ makedepends=('asciidoc' 'git' 'sed')
 optdepends=('xz: Use lzma or xz compression for the initramfs image'
             'bzip2: Use bzip2 compression for the initramfs image'
             'lzop: Use lzo compression for the initramfs image'
+            'lz4: Use lz4 compression for the initramfs image'
             'mkinitcpio-nfs-utils: Support for root filesystem on NFS')
 backup=(etc/mkinitcpio.conf)
 
diff --git a/lsinitcpio b/lsinitcpio
index c1c5e21..5f19326 100755
--- a/lsinitcpio
+++ b/lsinitcpio
@@ -69,7 +69,7 @@ size_to_human() {
 }
 
 detect_filetype() {
-    case $(hexdump -n 6 -e '"%c"' "$1") in 
+    case $(hexdump -n 6 -e '"%c"' "$1") in
         '070701')
             # no compression
             return
@@ -90,6 +90,11 @@ detect_filetype() {
         return
     fi
 
+    if [[ $(hexdump -n 4 -e '"%x"' "$1") == '184d2204' ]]; then
+        echo 'lz4'
+        return
+    fi
+
     if [[ $(hexdump -n 3 -e '"%c"' "$1") == 'BZh' ]]; then
         echo 'bzip2'
         return
diff --git a/mkinitcpio.conf b/mkinitcpio.conf
index 7616809..c4d5e06 100644
--- a/mkinitcpio.conf
+++ b/mkinitcpio.conf
@@ -59,6 +59,7 @@ HOOKS="base udev autodetect modconf block filesystems keyboard fsck"
 #COMPRESSION="lzma"
 #COMPRESSION="xz"
 #COMPRESSION="lzop"
+#COMPRESSION="lz4"
 
 # COMPRESSION_OPTIONS
 # Additional options for the compressor