Description
Derive bounded half-open UTC effective spans from a complete ordered transition chain, clipping to explicit UTC endpoints.
An offset maps a supplied UTC coordinate to local civil coordinates by local = UTC + offset. Half-open spans include their start and exclude their end. A forward offset jump can leave local coordinates uncovered; a backward jump can give several UTC interpretations of one local value. These tools use explicit synthetic civil-second observations rather than a named-zone database.
Derive bounded half-open UTC effective spans from a complete ordered transition chain, clipping to explicit UTC endpoints.
When to use this tool
Use this tool to derive bounded half-open UTC effective spans from a complete ordered transition chain, clipping to explicit UTC endpoints.
How to use the tool and how it works
- Enter transitionsJson, initialOffset, start, end using the definitions below. Serialize JSON text fields in the decoded shape shown below.
- Run the operation. Resolve input-format errors before interpreting an output.
- Read result.spans, using the stated boundary, ordering, sign and absence conventions.
Validate a strictly ordered continuous transition chain and start<end. Apply all transitions at or before start to establish the initial in-window offset, then split at transitions strictly inside the window and return half-open UTC spans.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| transitionsJson | JSON array of {at,before,after} second-valued observations; at is UTC and before/after are signed offsets. | Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply. |
| initialOffset | Offset before the first supplied transition, in seconds within ±86,400. | Finite numeric value satisfying the stated comparisons. |
| start | Inclusive UTC or local window start in seconds, as explicitly stated by this operation. | Finite numeric value satisfying the stated comparisons. |
| end | Exclusive window end in seconds, on the same coordinate scale as start. | Finite numeric value satisfying the stated comparisons. |
These decoded structures show the examples inside JSON text fields. Supply their serialized JSON strings as input.
{
"transitionsJson": [
{
"at": 10,
"before": 0,
"after": 2
},
{
"at": 20,
"before": 2,
"after": 0
}
]
}| Output field | Interpretation |
|---|---|
| result | Object containing the fields below. |
| result.spans | Resulting half-open UTC {start,end,offset} records. |
{
"input": {
"transitionsJson": "[{\"at\": 10, \"before\": 0, \"after\": 2}, {\"at\": 20, \"before\": 2, \"after\": 0}]",
"initialOffset": 0,
"start": 0,
"end": 30
},
"output": {
"result": {
"spans": [
{
"start": 0,
"end": 10,
"offset": 0
},
{
"start": 10,
"end": 20,
"offset": 2
},
{
"start": 20,
"end": 30,
"offset": 0
}
]
}
}
}Limitations and assumptions
- initialOffset describes the state before the first supplied transition, not necessarily at the requested window’s start.
- Span/transition coordinates are finite seconds within ±10¹² and offsets within ±86,400 seconds. Spans require start<end. No IANA database, calendar parsing, daylight-saving inference or leap seconds are included.
- Every declared outer field is required and unknown outer fields are rejected. Strings and JSON text have size limits, lists are bounded to 128 entries, and JSON nesting/node counts are bounded. Tighter operation-specific bounds stated above take precedence.
- Ordinary numeric outputs must be finite and within safe-integer magnitude. Exact large lengths/counts use decimal strings. Original record indexes and code-unit positions are zero-based; span ends are exclusive unless stated otherwise.
Alternative or Complementary methods
Keep all timestamps on one origin and in seconds, and retain gaps or competing observations. Use a maintained time-zone library when real dates, named zones or historical rules are required.
References
Similar or alternative tools
- Time Zone Local Window UTC Span List
Invert a local half-open window against every observed offset span, preserving multiple UTC solutions and source span indexes.
- Time Zone Transition Calendar Marker Table
Produce numeric transition calendar marker coordinates on both sides of each jump; no actual Gregorian dates or formatting implied.