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Encoding: UTF-8 Continuation Byte From Payload Tool

Encode one six-bit payload into a UTF-8 continuation octet without claiming that it forms a valid whole code point.

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Description

Return byte = 128+payload, setting the UTF-8 continuation prefix bits to 10.

Unicode scalar values are distinct from UTF-8 bytes and UTF-16 code units. One scalar can require several units, and printable escape text is a representation of those values rather than execution or normalization of a string.

Return byte = 128+payload, setting the UTF-8 continuation prefix bits to 10.

When to use this tool

Use Encoding: UTF-8 Continuation Byte From Payload when inspecting one scalar, code-unit layout or literal escape representation.

How to use the tool and how it works

  1. Enter payload. Use the units and conventions below.
  2. Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
  3. Read result. Expand result to inspect the returned fields.

Require whole payload in [0,63]. Return byte = 128+payload, setting the UTF-8 continuation prefix bits to 10.1

UTF-8 encodes Unicode scalars using constrained one-to-four-octet sequences; an isolated field is not a complete stream validation.2

Input fieldMeaning and unitsAccepted input
payloadPayloadRequired. Safe integer.
Output fieldInterpretationReturned shape
resultObject containing the named calculated members below.Required. Object.
result.byteByteCalculated result member: number.
json
{
  "input": {
    "payload": 44
  },
  "output": {
    "result": {
      "byte": 172
    }
  }
}

Limitations and assumptions

  • One syntactically valid continuation byte does not establish a valid UTF-8 sequence. Position, scalar range and overlong-sequence constraints require the surrounding bytes.
  • Outputs are nested inside result. Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
  • Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.

Alternative or Complementary methods

Use a full Unicode encoder or parser when processing strings, and handle normalization, graphemes and context-specific escaping separately.

References

  1. Calculation and input contract: encode/utf8-continuation-byte-from-payload — tool.io

  2. UTF-8: RFC 3629 — Internet Engineering Task Force

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