Description
Return header = 128+entries for one fixmap key-value-pair count.
MessagePack uses compact tag families for small integers, short strings and small containers. A header can carry a count directly, but that count must agree with the following encoded items or UTF-8 bytes.
Return header = 128+entries for one fixmap key-value-pair count.
When to use this tool
Use MessagePack Fixmap Count Header when constructing one compact MessagePack header or scalar byte.
How to use the tool and how it works
- Enter entries. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read header. Use the output convention below.
Require whole entries in [0,15]. Return header = 128+entries for one fixmap key-value-pair count.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| entries | Entries | Required. Safe integer; minimum 0; maximum 15. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| header | Header | Required. Safe integer. |
{
"input": {
"entries": 2
},
"output": {
"header": 130
}
}Limitations and assumptions
- entries counts pairs rather than total keys plus values. This emits only the header, not map contents or key validation.
- 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 complete MessagePack serializer for payload encoding, nested structure and interoperable validation.
References
Similar or alternative tools
- Msgpack Fixarray Count Header
Return octet = 144+count for the fixed-array item-count header.
- Msgpack Fixstr Length Prefix
Return octet = 160+utf8Bytes, combining the fixstr tag with its five-bit byte length.