Terminal CSI Final Byte Classifier

Description

Classify one raw byte under the ECMA CSI final-byte range 0x40–0x7e; does not imply a valid or supported escape sequence.

Terminal escape sequences can encode cursor commands, text styles and other controls inside ordinary text. SGR changes selected graphic attributes; CSI and OSC tokens have different framing. These tools operate on explicit strings and records, with a deliberately limited parser or style model rather than an emulated screen.^[1]

Classify one raw byte under the ECMA CSI final-byte range 0x40–0x7e; does not imply a valid or supported escape sequence.

When to use this tool

Use this tool to classify one raw byte under the ECMA CSI final-byte range 0x40–0x7e; does not imply a valid or supported escape sequence.

How to use the tool and how it works

Enter byte using the field definitions below.
Run the operation. Correct input errors before interpreting an output.
Read result.isFinal. Use the ordering, boundary rules and absence conditions described below.

Validate one byte and return isFinal when its value lies from 64 through 126 inclusive.^[2]

Input field	Meaning and units	Accepted input
byte	Byte value as an integer 0–255.	A finite safe integer within the operation’s stated bounds.

Output field	Interpretation
result	Object containing the named fields below.
result.isFinal	Whether the supplied byte is in the CSI final-byte range 64–126.

json

{
  "input": {
    "byte": 109
  },
  "output": {
    "result": {
      "isFinal": true
    }
  }
}

Limitations and assumptions

A valid final byte alone does not make a complete or supported CSI sequence.
Source spans use zero-based UTF-16 offsets with exclusive ends; byte totals, where returned, use UTF-8. Escape tokens are represented as JSON escapes in the example and are not executed by this description.
Every declared top-level input field is required and unexpected fields are rejected. Ordinary strings are limited to 8,192 UTF-16 code units and lists to 128 entries, with tighter operation-specific bounds where stated. JSON text has bounded nesting and node counts.
Numeric outputs must be finite and no larger in absolute magnitude than the safe-integer limit; operations returning exact large integers use decimal text. Positions are zero-based and spans end exclusively unless the operation explicitly states a different convention.

Alternative or Complementary methods

Use token inspection for source offsets and style replay for the supported attributes. A real terminal emulator is needed to determine screen contents, terminal-specific rendering or device behavior.

References

ECMA-48: Control Functions for Coded Character Sets — Ecma International
Tool behavior and example: Terminal CSI Final Byte Classifier — tool.io

Similar or alternative tools

Terminal CSI Cursor Move Formatter
Format a supported relative CSI cursor movement token with positive explicit count; directions are up/down/right/left only, no terminal execution.
Terminal CSI Cursor Position Formatter
Format an explicit one-based CSI CUP row/column position token; does not move a cursor or inspect screen dimensions.