Description
Align two equal-total encoded sequences at every source boundary, with paired values and exact logical spans.
Run-length records represent repeated observations without expanding them. Each record pairs a literal string value with a positive exact integer length; neighboring equal values can be valid but noncompact. Expanded offsets count observations rather than run records, and half-open ranges include their start while excluding their end.
Align two equal-total encoded sequences at every source boundary, with paired values and exact logical spans.
When to use this tool
Use this tool to align two equal-total encoded sequences at every source boundary, with paired values and exact logical spans.
How to use the tool and how it works
- Enter leftJson, rightJson 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.
Require equal expanded totals and advance through both run streams by the smaller remaining length. Emit each half-open [start,end) span with its current left/right values, retaining both streams’ boundaries.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| leftJson | Left run sequence using string values and positive decimal-string lengths. | Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply. |
| rightJson | Right run sequence in the same format; pair-alignment/equality operations require equal expanded totals. | Text, at most 8,192 UTF-16 code units; narrower grammar/range rules also apply. |
These decoded structures show the examples inside JSON text fields. Supply their serialized JSON strings as input.
{
"leftJson": [
{
"value": "a",
"length": "3"
},
{
"value": "a",
"length": "2"
},
{
"value": "b",
"length": "4"
}
],
"rightJson": [
{
"value": "a",
"length": "4"
},
{
"value": "c",
"length": "5"
}
]
}| Output field | Interpretation |
|---|---|
| result | Object containing the fields below. |
| result.spans | Aligned half-open exact decimal intervals with simultaneous left/right values. |
{
"input": {
"leftJson": "[{\"value\": \"a\", \"length\": \"3\"}, {\"value\": \"a\", \"length\": \"2\"}, {\"value\": \"b\", \"length\": \"4\"}]",
"rightJson": "[{\"value\":\"a\",\"length\":\"4\"},{\"value\":\"c\",\"length\":\"5\"}]"
},
"output": {
"result": {
"spans": [
{
"start": "0",
"end": "3",
"left": "a",
"right": "a"
},
{
"start": "3",
"end": "4",
"left": "a",
"right": "a"
},
{
"start": "4",
"end": "5",
"left": "a",
"right": "c"
},
{
"start": "5",
"end": "9",
"left": "b",
"right": "c"
}
]
}
}
}Limitations and assumptions
- At most 255 aligned spans are allowed. Values remain literal strings and lengths/offsets are exact decimal text.
- Run records contain string value and positive length as exact decimal integer text. Lengths and offset inputs support up to 256 decimal digits before operation-specific checks; results use decimal text and do not expand the repeated observations.
- 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
Use compaction for a canonical adjacent-run layout and boundary-aware operations when provenance matters. Retain exact decimal lengths rather than converting long totals to floating-point numbers.
References
Similar or alternative tools
- Run Length Record Adjacent Compaction
Run lengths are positive exact integer decimal strings with literal string values, never expanded; compact adjacent exactly equal values by summing exact lengths, not global deduplication.
- Run Length Record Boundary Transition Table
Run lengths are positive exact integer decimal strings with literal string values, never expanded; report encoded run boundaries with exact logical offsets and equal-versus-changed neighboring values.