Faster printf in bash SI script

Part of microsoft#212090

Author: Tyriar

src/vs/workbench/contrib/terminal/browser/media/shellIntegration-bash.sh

@@ -112,56 +112,34 @@ __vsc_escape_value() {
 	fi
 
 	# Process text byte by byte, not by codepoint.
-	builtin local LC_ALL=C str="${1}" i byte token out=''
+	local -r LC_ALL=C
+	local -r str="${1}"
+	local -ir len="${#str}"
+
+	local -i i
+	local -i val
+	local byte
+	local token
+	local out=''
 
 	for (( i=0; i < "${#str}"; ++i )); do
-		byte="${str:$i:1}"
 		# Escape backslashes, semi-colons specially, then special ASCII chars below space (0x20).
-		# This is done in an unwrapped loop instead of using printf as the latter is very slow.
-		if [ "$byte" = "\\" ]; then
+		byte="${str:$i:1}"
+		builtin printf -v val '%d' "'$byte"
+		if  (( val < 31 )); then
+			builtin printf -v token '\\x%02x' "'$byte"
+		elif (( val == 92 )); then
 			token="\\\\"
-		elif [ "$byte" = ";" ]; then
+		elif (( val == 59 )); then
 			token="\\x3b"
-		elif [ "$byte" = $'\x00' ]; then token="\\x00"
-		elif [ "$byte" = $'\x01' ]; then token="\\x01"
-		elif [ "$byte" = $'\x02' ]; then token="\\x02"
-		elif [ "$byte" = $'\x03' ]; then token="\\x03"
-		elif [ "$byte" = $'\x04' ]; then token="\\x04"
-		elif [ "$byte" = $'\x05' ]; then token="\\x05"
-		elif [ "$byte" = $'\x06' ]; then token="\\x06"
-		elif [ "$byte" = $'\x07' ]; then token="\\x07"
-		elif [ "$byte" = $'\x08' ]; then token="\\x08"
-		elif [ "$byte" = $'\x09' ]; then token="\\x09"
-		elif [ "$byte" = $'\x0a' ]; then token="\\x0a"
-		elif [ "$byte" = $'\x0b' ]; then token="\\x0b"
-		elif [ "$byte" = $'\x0c' ]; then token="\\x0c"
-		elif [ "$byte" = $'\x0d' ]; then token="\\x0d"
-		elif [ "$byte" = $'\x0e' ]; then token="\\x0e"
-		elif [ "$byte" = $'\x0f' ]; then token="\\x0f"
-		elif [ "$byte" = $'\x10' ]; then token="\\x10"
-		elif [ "$byte" = $'\x11' ]; then token="\\x11"
-		elif [ "$byte" = $'\x12' ]; then token="\\x12"
-		elif [ "$byte" = $'\x13' ]; then token="\\x13"
-		elif [ "$byte" = $'\x14' ]; then token="\\x14"
-		elif [ "$byte" = $'\x15' ]; then token="\\x15"
-		elif [ "$byte" = $'\x16' ]; then token="\\x16"
-		elif [ "$byte" = $'\x17' ]; then token="\\x17"
-		elif [ "$byte" = $'\x18' ]; then token="\\x18"
-		elif [ "$byte" = $'\x19' ]; then token="\\x19"
-		elif [ "$byte" = $'\x1a' ]; then token="\\x1a"
-		elif [ "$byte" = $'\x1b' ]; then token="\\x1b"
-		elif [ "$byte" = $'\x1c' ]; then token="\\x1c"
-		elif [ "$byte" = $'\x1d' ]; then token="\\x1d"
-		elif [ "$byte" = $'\x1e' ]; then token="\\x1e"
-		elif [ "$byte" = $'\x1f' ]; then token="\\x1f"
 		else
 			token="$byte"
 		fi
 
 		out+="$token"
 	done
 
-	builtin printf '%s\n' "${out}"
+	builtin printf '%s\n' "$out"
 }
 
 # Send the IsWindows property if the environment looks like Windows
@@ -196,11 +174,6 @@ unset VSCODE_NONCE
 builtin printf "\e]633;P;ContinuationPrompt=$(echo "$PS2" | sed 's/\x1b/\\\\x1b/g')\a"
 
 __vsc_report_prompt() {
-	# HACK: Git bash is too slow at reporting the prompt, so skip for now
-	if [ "$__vsc_is_windows" = "1" ]; then
-		return
-	fi
-
 	# Expand the original PS1 similarly to how bash would normally
 	# See https://stackoverflow.com/a/37137981 for technique
 	if ((BASH_VERSINFO[0] >= 5 || (BASH_VERSINFO[0] == 4 && BASH_VERSINFO[1] >= 4))); then