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-rw-r--r--tools/shmin.sh257
1 files changed, 257 insertions, 0 deletions
diff --git a/tools/shmin.sh b/tools/shmin.sh
new file mode 100644
index 0000000..9bf50b7
--- /dev/null
+++ b/tools/shmin.sh
@@ -0,0 +1,257 @@
+#!/bin/sh
+#
+# Shell command language minifier
+#
+# Copyright (C) 2015 Patrick "P. J." McDermott
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+set -u
+
+VERSION='0.1.0'
+HT=' '
+LF='
+'
+
+c=
+output=''
+
+die()
+{
+ local fmt="${1}"
+ shift 1
+
+ printf "shmin: ${fmt}\n" "${@}"
+ exit 2
+}
+
+fgetc()
+{
+ # Damn command substitutions eat trailing whitespace. Even if
+ # whitespace is the /only/ thing printed and exactly what we want from
+ # the command.
+ c="$(dd bs=1 count=1 <&3 2>/dev/null; printf '.')"
+ c="${c%.}"
+}
+
+minify()
+{
+ local input="${1}"
+ local buffer=''
+ local escaped=false
+
+ # Open input file.
+ if ! exec 3<"${input}"; then
+ die 'Cannot open file "%s"' "${input}"
+ fi
+
+ # Check for magic number or other first-line comment.
+ fgetc
+ if [ "x${c}" = 'x#' ]; then
+ # Comment
+ fgetc
+ if [ "x${c}" = 'x!' ]; then
+ # Magic number
+ buffer="${buffer}#!"
+ while :; do
+ fgetc
+ buffer="${buffer}${c}"
+ if [ "x${c}" = "x${LF}" ]; then
+ break
+ fi
+ done
+ else
+ while :; do
+ fgetc
+ if [ "x${c}" = "x${LF}" ]; then
+ break
+ fi
+ done
+ fi
+ fi
+
+ # Strip leading whitespace on the first line.
+ while :; do
+ case "${c}" in
+ ' ' | "${HT}" | "${LF}")
+ ;;
+ *)
+ break
+ ;;
+ esac
+ fgetc
+ done
+
+ # Parse the rest of the file.
+ # Like any good parser, this is some very ugly and fragile code.
+ # Whitespace code must come before comment code must come before newline
+ # code must come before everything else.
+ while :; do
+ if [ "x${c}" = 'x' ]; then
+ break
+ fi
+ if [ "x${c}" = 'x ' ] || [ "x${c}" = "x${HT}" ]; then
+ # Whitespace
+ while :; do
+ fgetc
+ case "${c}" in
+ ' ' | "${HT}")
+ ;;
+ "${LF}" | '#')
+ # Eat trailing whitespace.
+ break
+ ;;
+ *)
+ # Condense whitespace.
+ buffer="${buffer} "
+ break
+ ;;
+ esac
+ done
+ fi
+ if [ "x${c}" = 'x#' ]; then
+ # Comment
+ while :; do
+ fgetc
+ if [ "x${c}" = "x${LF}" ]; then
+ break
+ fi
+ done
+ fi
+ if [ "x${c}" = "x${LF}" ]; then
+ # Strip empty lines and leading whitespace.
+ while :; do
+ fgetc
+ case "${c}" in
+ ' ' | "${HT}" | "${LF}")
+ ;;
+ *)
+ buffer="${buffer}${LF}"
+ break
+ ;;
+ esac
+ done
+ fi
+ if [ "x${c}" = "x'" ]; then
+ # Single quotes
+ buffer="${buffer}${c}"
+ while :; do
+ fgetc
+ buffer="${buffer}${c}"
+ if [ "x${c}" = "x'" ]; then
+ break
+ fi
+ done
+ fgetc
+ continue
+ fi
+ if [ "x${c}" = 'x"' ]; then
+ # Double quotes
+ buffer="${buffer}${c}"
+ while :; do
+ fgetc
+ buffer="${buffer}${c}"
+ if ${escaped}; then
+ escaped=false
+ continue
+ fi
+ if [ "x${c}" = 'x\' ]; then
+ escaped=true
+ continue
+ fi
+ if [ "x${c}" = 'x"' ]; then
+ break
+ fi
+ done
+ fgetc
+ continue
+ fi
+ buffer="${buffer}${c}"
+ fgetc
+ done
+
+ # We made it. Now write the output.
+ if ! printf '%s' "${buffer}" >"${output}~"; then
+ die 'Cannot write file "%s"' "${output}~"
+ fi
+
+ # Set output file name.
+ if ! mv "${output}~" "${output}"; then
+ die 'Cannot rename file to "%s"' "${output}"
+ fi
+}
+
+usage()
+{
+ printf 'Usage: %s [option ...] <file>\n' "${0}"
+}
+
+help()
+{
+ usage
+ cat <<EOF
+Options:
+ -h Display this information
+ -V Display minifier version information
+ -o <output> Write the minified output to <output>, instead of replacing the
+ existing file
+EOF
+}
+
+version()
+{
+ cat <<EOF
+shmin ${VERSION}
+Copyright (C) 2015 Patrick "P. J." McDermott
+License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
+EOF
+}
+
+main()
+{
+ local input=
+
+ while getopts 'hVo:' opt; do
+ case "${opt}" in
+ 'h')
+ help
+ exit
+ ;;
+ 'V')
+ version
+ exit
+ ;;
+ 'o')
+ output="${OPTARG}"
+ ;;
+ esac
+ done
+ shift $(($OPTIND - 1))
+
+ if [ ${#} -ne 1 ]; then
+ usage >&2
+ exit 1
+ fi
+ input="${1}"
+
+ if [ "x${output}" = 'x' ]; then
+ output="${input}"
+ fi
+
+ minify "${input}"
+}
+
+main "${@}"