Add experimental raw vt100 UI backend

The intention of this is not to slowly reimplement curses but to provide
a minimal working terminal UI backend which can also be used for debugging,
fuzzing and in environments where curses is not available.

Currently no attempt is made to optimize terminal output. The amount of
flickering will depend on the smartness of your terminal emulator.

1 files changed, 37 insertions, 28 deletions

diff --git a/configure b/configure
index 2c689db..29bb5c5 100755
--- a/configure
+++ b/configure
@@ -23,6 +23,7 @@ Fine tuning of the installation directories:
   --mandir=DIR            man pages [PREFIX/share/man]
 
 Optional features:
+  --enable-curses         build with Curses terminal output [yes]
   --enable-lua            build with Lua support [auto]
   --enable-lpeg           build with support for statically linking to LPeg [auto]
   --enable-tre            build with TRE regex support [auto]
@@ -116,6 +117,7 @@ SHAREDIR='$(PREFIX)/share'
 MANDIR='$(PREFIX)/share/man'
 
 help=yes
+curses=yes
 lua=auto
 lpeg=auto
 tre=auto
@@ -135,6 +137,8 @@ case "$arg" in
 --static) static=yes ;;
 --enable-help|--enable-help=yes) help=yes ;;
 --disable-help|--enable-help=no) help=no ;;
+--enable-curses|--enable-curses=yes) curses=yes ;;
+--disable-curses|--enable-curses=no) curses=no ;;
 --enable-lua|--enable-lua=yes) lua=yes ;;
 --disable-lua|--enable-lua=no) lua=no ;;
 --enable-lpeg|--enable-lpeg=yes) lpeg=yes ;;
@@ -293,9 +297,12 @@ else
 	CONFIG_HELP=0
 fi
 
-# libcurses is a mandatory dependency
+CONFIG_CURSES=0
+
+if test "$curses" != "no" ; then
+
+	printf "checking for libcurses...\n"
 
-printf "checking for libcurses...\n"
 cat > "$tmpc" <<EOF
 #include <curses.h>
 
@@ -306,36 +313,37 @@ int main(int argc, char *argv[]) {
 }
 EOF
 
-CONFIG_CURSES=0
+	for libcurses in ncursesw ncurses libcurses; do
+		printf " checking for %s... " "$libcurses"
 
-for curses in ncursesw ncurses curses; do
-	printf " checking for %s... " "$curses"
+		if test "$have_pkgconfig" = "yes" ; then
+			CFLAGS_CURSES=$(pkg-config --cflags $libcurses 2>/dev/null)
+			LDFLAGS_CURSES=$(pkg-config --libs $libcurses 2>/dev/null)
+			if test $? -eq 0 && $CC $CFLAGS $CFLAGS_CURSES "$tmpc" \
+				$LDFLAGS $LDFLAGS_CURSES -o "$tmpo" >/dev/null 2>&1 ; then
+				CONFIG_CURSES=1
+				printf "yes\n"
+				break
+			fi
+		fi
 
-	if test "$have_pkgconfig" = "yes" ; then
-		CFLAGS_CURSES=$(pkg-config --cflags $curses 2>/dev/null)
-		LDFLAGS_CURSES=$(pkg-config --libs $curses 2>/dev/null)
-		if test $? -eq 0 && $CC $CFLAGS $CFLAGS_CURSES "$tmpc" \
+		CFLAGS_CURSES=""
+		LDFLAGS_CURSES="-l$libcurses"
+
+		if $CC $CFLAGS $CFLAGS_CURSES "$tmpc" \
 			$LDFLAGS $LDFLAGS_CURSES -o "$tmpo" >/dev/null 2>&1 ; then
 			CONFIG_CURSES=1
 			printf "yes\n"
 			break
+		else
+			CFLAGS_CURSES=""
+			LDFLAGS_CURSES=""
+			printf "no\n"
 		fi
-	fi
-
-	CFLAGS_CURSES=""
-	LDFLAGS_CURSES="-l$curses"
-
-	if $CC $CFLAGS $CFLAGS_CURSES "$tmpc" \
-		$LDFLAGS $LDFLAGS_CURSES -o "$tmpo" >/dev/null 2>&1 ; then
-		CONFIG_CURSES=1
-		printf "yes\n"
-		break
-	else
-		printf "no\n"
-	fi
-done
+	done
 
-test $CONFIG_CURSES -ne 1 && fail "$0: cannot find libcurses"
+	test "$curses" = "yes" -a $CONFIG_CURSES -ne 1 && fail "$0: cannot find libcurses"
+fi
 
 # libtermkey is a mandatory dependency
 
@@ -356,7 +364,7 @@ fi
 
 if test -z "$LDFLAGS_TERMKEY"; then
 	CFLAGS_TERMKEY=""
-	LDFLAGS_TERMKEY="-ltermkey"
+	LDFLAGS_TERMKEY="-ltermkey -lncursesw"
 fi
 
 if $CC $CFLAGS $CFLAGS_TERMKEY "$tmpc" $LDFLAGS $LDFLAGS_TERMKEY $LDFLAGS_CURSES \
@@ -591,11 +599,12 @@ printf "completing config.mk... "
 exec 3>&1 1>>config.mk
 
 cat << EOF
-CFLAGS_CURSES = $CFLAGS_CURSES
-LDFLAGS_CURSES = $LDFLAGS_CURSES
+CONFIG_HELP = $CONFIG_HELP
 CFLAGS_TERMKEY = $CFLAGS_TERMKEY
 LDFLAGS_TERMKEY = $LDFLAGS_TERMKEY
-CONFIG_HELP = $CONFIG_HELP
+CONFIG_CURSES = $CONFIG_CURSES
+CFLAGS_CURSES = $CFLAGS_CURSES
+LDFLAGS_CURSES = $LDFLAGS_CURSES
 REGEX_SRC = $REGEX_SRC
 CONFIG_TRE = $CONFIG_TRE
 CFLAGS_TRE = $CFLAGS_TRE