Description
Decode an ordered UTF-16 surrogate pair to a scalar.
Unicode code points, UTF-16 units and UTF-8 octets are different representations. A local escape or byte check can report useful structure without establishing that an entire encoded string is well formed.
Decode an ordered UTF-16 surrogate pair to a scalar.
When to use this tool
Use Decoding: Utf16 Surrogate Pair Scalar when inspecting the stated scalar, escape or byte-layout component.
How to use the tool and how it works
- Enter highSurrogate, lowSurrogate. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read result. Expand result to inspect the returned fields.
Decode an ordered UTF-16 surrogate pair to a scalar. Require highSurrogate in D800-DBFF and lowSurrogate in DC00-DFFF; combine offsets as 65536+(high-D800)*1024+(low-DC00).1
Unicode scalar values exclude surrogate code points. Code units, scalar values and encoded byte sequences are distinct representations.2
| Input field | Meaning and units | Accepted input |
|---|---|---|
| highSurrogate | High Surrogate | Required. Safe integer. |
| lowSurrogate | Low Surrogate | Required. Safe integer. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| result | Returned object; expand its named members below. | Required. Object. |
| result.codepoint | Numeric Unicode code point; distinguish code points from UTF-16 code units. | Calculated result member: number. |
{
"input": {
"highSurrogate": 55357,
"lowSurrogate": 56832
},
"output": {
"result": {
"codepoint": 128512
}
}
}Limitations and assumptions
- Inputs are numeric code units, not endian-specific bytes or literal escape strings.
- 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 conforming complete decoder for strings and distinguish Unicode scalar validity from source-language or HTML error recovery.
References
-
Calculation and input contract: decode/utf16-surrogate-pair-scalar — tool.io
-
Unicode 17.0: conformance and encoding forms — Unicode Consortium
Similar or alternative tools
- Utf16 Lone Surrogate Token Label
Classify a numeric UTF-16 code unit.
- Decoding: UTF-8 Continuation Payload Bits
Extract one UTF-8 continuation octet's six payload bits.