Bit Range Byte Envelope
Find the smallest half-open byte envelope of a bit range; empty bit ranges return an empty envelope.
Description
Find the smallest half-open byte envelope of a bit range; empty bit ranges return an empty envelope.
A half-open bit range may touch partial first and last bytes. Its envelope counts every touched byte.
When to use this tool
Find the smallest half-open byte envelope of a bit range; empty bit ranges return an empty envelope.
- Prepare the supplied startBit, bitLength fields for this operation.
- Compare the complete example with the representation used by your own input before carrying the result into another step.
How to use the tool and how it works
- Enter startBit, bitLength. Use the exact text syntax, units and index conventions explained below.
- Run the tool. If input validation fails, correct the supplied fields before interpreting any result.
- Read result.startByte, result.endByte, result.bytes. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.
For nonnegative integer startBit and bitLength, startByte is floor(startBit/8). For positive length endByte is ceil((startBit+bitLength)/8), otherwise endByte equals startByte. Return their difference as bytes.1
| Input field | Meaning and representation | Accepted input |
|---|---|---|
| startBit | start bit. | Integer from 0 to 1e9 inclusive |
| bitLength | bit length. | Integer from 0 to 1e9 inclusive |
| Output field | Interpretation |
|---|---|
| result | Object containing the named outputs below. |
| result.startByte | The start byte value under the stated formula or text convention. |
| result.endByte | The end byte value under the stated formula or text convention. |
| result.bytes | The bytes value under the stated formula or text convention. |
{
"input": {
"startBit": 7,
"bitLength": 2
},
"output": {
"result": {
"startByte": 0,
"endByte": 2,
"bytes": 2
}
}
}Limitations and assumptions
- The zero-length special case touches no byte. No bit significance order, value extraction or buffer-size check is implied.
- Every declared top-level field is required and unexpected fields are rejected. Numeric inputs must be finite; ordinary text fields are bounded to 8,192 UTF-16 code units, with tighter operation-specific limits where stated.
- Lists are limited to 128 entries. JSON text must meet bounded size and depth checks, and numeric outputs beyond the safe finite magnitude are rejected. Exact large integers use decimal strings.
- Indexes are zero-based and spans have an exclusive end unless explicitly stated otherwise. A valid false, null or empty-list result is distinct from malformed input.
Alternative or Complementary methods
Retain the field-width, bit-index and byte-order conventions when combining operations. Slicing, escaping, permutation and alignment are separate transforms; none supplies a complete framing or cryptographic protocol.
References
Similar or alternative tools
- Byte Range Bit Offset
Map a nonnegative half-open byte range to bit offsets; empty ranges stay empty.
- Bit String Byte Grouping
Group a complete MSB-first binary string into eight-bit bytes; partial final bytes are rejected.