[RFC 5/5] scripts/carray: change to using single awk invocation to generate .c

[Ben Dooks]

The shell script makes multiple call-outs to awk to get information
from the configuration file. It would be easier to just write the
whole thing in one .awk script and have the makefile altered to call
that instead.

There should be no functional difference other than the script type
and has been tested with PLATFORM=generic build. This should be both
quicker and easier to understand.

Signed-off-by: Ben Dooks <ben.dooks at codethink.co.uk>
---
v2:
  - updated with the new bits from Samuel Holland's changes
  - minor tweaks to the awk script to fix the output spacings
v3:
  - fixups for not being rather reliant on gawk (not on all distros)
  - send error messages to stderr, otherwise they end up in .c output
  - add no-var list a warning
  - add debug output on env variable
  - make awk script part of .sh script (easier to deal with change)
  - fix rebase issues
---
 scripts/carray.sh | 132 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 99 insertions(+), 33 deletions(-)

diff --git a/scripts/carray.sh b/scripts/carray.sh
index a2b05d3..475dfec 100755
--- a/scripts/carray.sh
+++ b/scripts/carray.sh
@@ -45,42 +45,108 @@ if [ ! -f "${CONFIG_FILE}" ]; then
 	usage
 fi
 
-TYPE_HEADER=$(awk '{ if ($1 == "HEADER:") { printf $2; exit 0; } }' "${CONFIG_FILE}")
-if [ -z "${TYPE_HEADER}" ]; then
-	echo "Must specify HEADER: in input config file"
-	usage
-fi
+# use single awk script to run conversion, but leave in .sh file as awk is
+# bad for getopt, and leaves the original script name alone.
 
-TYPE_NAME=$(awk '{ if ($1 == "TYPE:") { printf $2; for (i=3; i<=NF; i++) printf " %s", $i; exit 0; } }' "${CONFIG_FILE}")
-if [ -z "${TYPE_NAME}" ]; then
-	echo "Must specify TYPE: in input config file"
-	usage
-fi
+awk -v"SCRIPT_NAME=${CONFIG_FILE}" -v "SCRIPT_NAME=`basename $0`" -v"VARLIST=${VAR_LIST}" '
+function array_length(a)
+{
+    result = 0
 
-ARRAY_NAME=$(awk '{ if ($1 == "NAME:") { printf $2; exit 0; } }' "${CONFIG_FILE}")
-if [ -z "${ARRAY_NAME}" ]; then
-	echo "Must specify NAME: in input config file"
-	usage
-fi
+    for (i in a)
+	result++
 
-MEMBER_NAME=$(awk '{ if ($1 == "MEMBER-NAME:") { printf $2; exit 0; } }' "${CONFIG_FILE}")
-MEMBER_TYPE=$(awk '{ if ($1 == "MEMBER-TYPE:") { printf $2; for (i=3; i<=NF; i++) printf " %s", $i; exit 0; } }' "${CONFIG_FILE}")
-if [ -n "${MEMBER_NAME}" ] && [ -z "${MEMBER_TYPE}" ]; then
-	echo "Must specify MEMBER-TYPE: when using MEMBER-NAME:"
-	usage
-fi
+    return result
+}
 
-printf "// Generated with $(basename $0) from $(basename ${CONFIG_FILE})\n"
-printf "#include <%s>\n\n" "${TYPE_HEADER}"
+function get_fields(start, end)
+{
+    result = $start;
 
-for VAR in ${VAR_LIST}; do
-	printf "extern %s %s;\n" "${TYPE_NAME}" "${VAR}"
-done
-printf "\n"
+    for (nr = start+1; nr <= end; nr++) {
+	result = result " " $nr
+    }
+    return result;
+}
+
+BEGIN {
+      split(VARLIST,VAR_LIST," ")
+}
+
+# process items from the config file
+
+/^HEADER:/	{ TYPE_HEADER = $2 }
+/^TYPE:/	{ TYPE_NAME = get_fields(2, NF); }
+/^NAME:/	{ ARRAY_NAME = $2}
+/^MEMBER-NAME:/	{ MEMBER_NAME = $2 }
+/^MEMBER-TYPE:/ { MEMBER_TYPE = get_fields(2, NF); }
+
+# code to dump the generated .c file once config file is processed
+
+END {
+    # enable for debug
+    if (length(ENVIRON["CARRAY_DEBUG"]) > 0) {
+	print "ARRAY_NAME  " ARRAY_NAME > "/dev/stderr"
+	print "TYPE_HEADER " TYPE_HEADER > "/dev/stderr"
+	print "TYPE_NAME   " TYPE_NAME > "/dev/stderr"
+
+	print "VAR_LIST length is " array_length(VAR_LIST) > "/dev/stderr"
+	for (v in VAR_LIST) {
+	    print "VAR_LIST " v  " = " VAR_LIST[v] > "/dev/stderr"
+	}
+    }
+
+    if (array_length(VAR_LIST) == 0) {
+	print "Warning; no VAR list on command line"  > "/dev/stderr"
+    }
+
+    if (length(ARRAY_NAME) == 0) {
+	print "Must specify NAME: in input config file"  > "/dev/stderr"
+	exit 1
+    }
+
+    if (length(TYPE_NAME) == 0) {
+	print "Must specify TYPE: in input config file"  > "/dev/stderr"
+	exit 1
+    }
+
+    if (length(TYPE_HEADER) == 0) {
+	print "Must specify HEADER: in input config file"  > "/dev/stderr"
+	exit 1
+    }
+
+    if (length(MEMBER_NAME) > 0 && length(MEMBER_TYPE) == 0) {
+	print "Must specify MEMBER-TYPE: when using MEMBER-NAME:" > "/dev/stderr"
+	exit 1
+    }
+
+    printf "// Generated with %s from %s\n", SCRIPT_NAME, CONFIG_FILE
+    printf "// DO NOT EDIT THIS FILE DIRECTLY\n"
+    printf "\n"
+    printf("#include <%s>\n\n", TYPE_HEADER)
+
+    for (v in VAR_LIST) {
+	printf("extern %s %s;\n", TYPE_NAME, VAR_LIST[v])
+    }
+    print ""
+
+    if (length(MEMBER_TYPE) > 0) {
+	TYPE_NAME = MEMBER_TYPE;
+    }
+
+    if (length(MEMBER_NAME) > 0) {
+	VAR_SUFFIX = "." MEMBER_NAME;
+    } else {
+	VAR_SUFFIX = ""
+    }
+
+    printf("%s *const %s[] = {\n", TYPE_NAME, ARRAY_NAME)
+    for (v in VAR_LIST) {
+	printf("\t&%s%s,\n", VAR_LIST[v], VAR_SUFFIX)
+    }
+    printf("\tNULL\n");
+
+    printf("};\n");
+}
+' < ${CONFIG_FILE} || usage
 
-printf "%s *const %s[] = {\n" "${MEMBER_TYPE:-${TYPE_NAME}}" "${ARRAY_NAME}"
-for VAR in ${VAR_LIST}; do
-	printf "\t&%s,\n" "${VAR}${MEMBER_NAME:+.}${MEMBER_NAME}"
-done
-	printf "\tNULL\n"
-printf "};\n"
-- 
2.37.2.352.g3c44437643