Description
Add signed index and offset using exact integers, then use floor division by positive length to return a nonnegative wrappedIndex and signed turns.
An index map tracks where one item lands after a structural list operation. Zero-based element positions differ from boundary cursors, and missing destinations need a sentinel.
Add signed index and offset using exact integers, then use floor division by positive length to return a nonnegative wrappedIndex and signed turns.
When to use this tool
Use List Offset Wrap Index when you need one item's position under an explicit list transformation.
How to use the tool and how it works
- Enter index, offset, length. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read wrappedIndex, turns. Use the output convention below.
Add signed index and offset using exact integers, then use floor division by positive length to return a nonnegative wrappedIndex and signed turns.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| index | Zero-based position or diagnostic index under the calculation above; inspect any sentinel policy. | Required. Safe integer. |
| offset | Offset | Required. Safe integer. |
| length | Length, count, or code length under the stated domain and unit convention. | Required. Safe integer; minimum 1. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| wrappedIndex | Wrapped Index | Required. Safe integer. |
| turns | Turns | Required. Safe integer. |
{
"input": {
"index": 8,
"offset": 5,
"length": 10
},
"output": {
"wrappedIndex": 3,
"turns": 1
}
}Limitations and assumptions
- The returned numeric fields must fit their output contract; turns counts complete cycles relative to zero rather than observed traversals.
- 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
Apply the operation to a small representative list when checking a consuming language's indexing and slicing semantics.
References
Similar or alternative tools
- List Rotation Selected Index Preimage
Subtract shift from the valid selected destination and reduce modulo positive length for source.
- Cyclic List Phase Remainder
Subtract origin from index using exact integers and reduce modulo positive length into phase in [0, length).