2 files changed, 147 insertions, 0 deletions

diff --git a/src/read-tty b/src/read-tty
new file mode 100755
index 0000000..306a69d
--- /dev/null
+++ b/src/read-tty
@@ -0,0 +1,5 @@
+#!/bin/bash
+: "${BASH_LOADABLES_PATH:=/lib/bash:/usr/lib/bash:/usr/local/lib/bash:$HOME/.local/lib/bash}"
+enable -f sleep sleep
+source read_chars.bash
+(read_chars)
diff --git a/src/read_chars.bash b/src/read_chars.bash
new file mode 100644
index 0000000..f34dcc4
--- /dev/null
+++ b/src/read_chars.bash
@@ -0,0 +1,142 @@
+# =================
+#  read_chars.bash
+# =================
+#
+# Bash library for reading from tty and writing to standard out.
+# Can be suspended and resumed from bash (or with unix job control in
+# any shell).
+#
+# exporting for users:
+#
+# read_chars()    <-- calls readchar in a loop
+#
+# readchar()      <-- reads one character
+#
+# readchar_init() <-- must be called before readchar() in the same subshell
+#
+# The function read_chars is also available as the executable read-tty
+
+cfmakeraw()
+{
+        cmd=(stty -ignbrk -brkint -parmrk -istrip -inlcr -igncr -icrnl
+        -ixon -opost -echo -echonl -icanon -isig -iexten -parenb cs8)
+        "${cmd[@]}" "$@" >/dev/null
+}
+
+i()
+{
+        if [ "$DEBUG" ]
+        then
+                printf 'I: %s\n' "$*" >&2
+        fi
+}
+
+x()
+{
+        if [ "$DEBUG" ]
+        then
+                printf '+ %s\n' "${*@Q}" >&2
+        fi
+        "$@"
+}
+
+readchar_init()
+{
+        declare -g SOCAT= SOCAT_PID=
+        declare -g t
+        declare -g -a readchar_termopts
+
+        [ -t 1 ] && t=y || t=
+        readchar_termopts=(
+                opost onlcr isig
+                intr undef
+                quit undef
+        )
+
+        trap "kill $SOCAT_PID 2>/dev/null" EXIT
+        trap "i CONT; readchar_SIGCONT" CONT
+        for sig in TSTP TTIN TTOU
+        do
+                trap "i $sig; x kill -STOP \$BASHPID \$SOCAT_PID 2>/dev/null" $sig
+        done
+}
+
+readchar_SIGCONT()
+{
+        if check_foreground
+        then
+                if [ -t 0 ]
+                then
+                        x cfmakeraw "${readchar_termopts[@]}"
+                fi
+                x kill -CONT $SOCAT_PID 2>/dev/null
+        else
+                x kill -STOP $BASHPID $SOCAT_PID 2>/dev/null
+        fi
+}
+
+check_foreground()
+{
+        read _pid _comm _state _ppid pgrp _session _tty_nr tpgid _rest < /proc/self/stat
+        [ "$tpgid" = "$pgrp" ]
+}
+
+readchar()
+{
+        declare -n REPLY="${1:-CHARACTER}"
+
+        if [ -t 0 ]
+        then
+                if check_foreground
+                then
+                        if ! [ "$SOCAT_PID" ]
+                        then
+                                x cfmakeraw "${readchar_termopts[@]}"
+                        fi
+                else
+                        sleep .25
+                        return
+                fi
+        fi
+
+        if ! [ "$SOCAT_PID" ]
+        then
+                exec {SOCAT}< <(trap 'sleep .25' SIGTSTP; socat - -)
+                SOCAT_PID=$!
+        fi
+
+        if read -n 1 -d '' -r -s -u "$SOCAT"
+        then
+                if [ "$t" ]
+                then
+                        printf -v quoted_reply "%s" "${REPLY@Q}"
+                        if (( (count += 1 + ${#quoted_reply}) < ${COLUMNS:-80} - 10 ))
+                        then
+                                seperate=' '
+                        else
+                                seperate=$'\n'
+                                count=0
+                        fi
+                        printf "%s" "$seperate" "$quoted_reply"
+                else
+                        if [ "$REPLY" ]
+                        then
+                                printf "%s" "$REPLY"
+                        else
+                                printf "\0"
+                        fi
+                fi
+        else
+                [ $? -gt 128 ]
+        fi
+}
+
+read_chars()
+{
+        readchar_init
+        while readchar
+        do
+                continue
+        done
+}
+