#!/bin/bash # ############################################################################# # # 7z2lzma.bash is very primitive .7z to .lzma converter. The input file must # have exactly one LZMA compressed stream, which has been created with the # default lc, lp, and pb values. The CRC32 in the .7z archive is not checked, # and the script may seem to succeed while it actually created a corrupt .lzma # file. You should always try uncompressing both the original .7z and the # created .lzma and compare that the output is identical. # # This script requires basic GNU tools and 7z or 7za tool from p7zip. # # Last modified: 2009-01-15 14:25+0200 # ############################################################################# # # Author: Lasse Collin <lasse.collin@tukaani.org> # # This file has been put into the public domain. # You can do whatever you want with this file. # ############################################################################# # You can use 7z or 7za, both will work. SEVENZIP=7za if [ $# != 2 -o -z "$1" -o -z "$2" ]; then echo "Usage: $0 input.7z output.lzma" exit 1 fi # Converts an integer variable to little endian binary integer. int2bin() { local LEN=$1 local NUM=$2 local HEX=(0 1 2 3 4 5 6 7 8 9 A B C D E F) local I for ((I=0; I < "$LEN"; ++I)); do printf "\\x${HEX[(NUM >> 4) & 0x0F]}${HEX[NUM & 0x0F]}" NUM=$((NUM >> 8)) done } # Make sure we get possible errors from pipes. set -o pipefail # Get information about the input file. At least older 7z and 7za versions # may return with zero exit status even when an error occurred, so check # if the output has any lines beginning with "Error". INFO=$("$SEVENZIP" l -slt "$1") if [ $? != 0 ] || printf '%s\n' "$INFO" | grep -q ^Error; then printf '%s\n' "$INFO" exit 1 fi # Check if the input file has more than one compressed block. if printf '%s\n' "$INFO" | grep -q '^Block = 1'; then echo "Cannot convert, because the input file has more than" echo "one compressed block." exit 1 fi # Get copmressed, uncompressed, and dictionary size. CSIZE=$(printf '%s\n' "$INFO" | sed -rn 's|^Packed Size = ([0-9]+$)|\1|p') USIZE=$(printf '%s\n' "$INFO" | sed -rn 's|^Size = ([0-9]+$)|\1|p') DICT=$(printf '%s\n' "$INFO" | sed -rn 's|^Method = LZMA:([0-9]+[bkm]?)$|\1|p') if [ -z "$CSIZE" -o -z "$USIZE" -o -z "$DICT" ]; then echo "Parsing output of $SEVENZIP failed. Maybe the file uses some" echo "other compression method than plain LZMA." exit 1 fi # The following assumes that the default lc, lp, and pb settings were used. # Otherwise the output will be corrupt. printf '\x5D' > "$2" # Dictionary size can be either was power of two, bytes, kibibytes, or # mebibytes. We need to convert it to bytes. case $DICT in *b) DICT=${DICT%b} ;; *k) DICT=${DICT%k} DICT=$((DICT << 10)) ;; *m) DICT=${DICT%m} DICT=$((DICT << 20)) ;; *) DICT=$((1 << DICT)) ;; esac int2bin 4 "$DICT" >> "$2" # Uncompressed size int2bin 8 "$USIZE" >> "$2" # Copy the actual compressed data. Using multiple dd commands to avoid # copying large amount of data with one-byte block size, which would be # annoyingly slow. BS=8192 BIGSIZE=$((CSIZE / BS)) CSIZE=$((CSIZE % BS)) { dd of=/dev/null bs=32 count=1 \ && dd bs="$BS" count="$BIGSIZE" \ && dd bs=1 count="$CSIZE" } < "$1" >> "$2" exit $?