Bit String Shift with Fill

Shift bit positions with explicit zero/one fill and fixed output width; positive shifts move toward higher string indexes, not numeric bit significance.

Description

Shift bit positions with explicit zero/one fill and fixed output width; positive shifts move toward higher string indexes, not numeric bit significance.

A fixed-length bitstring shift needs a direction and an explicit fill bit. Positions are measured left to right in this tool.

When to use this tool

Shift bit positions with explicit zero/one fill and fixed output width; positive shifts move toward higher string indexes, not numeric bit significance.

Prepare the supplied bits, shift, fill 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 bits, shift, fill. 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.bits. Interpret false, null and empty lists using the distinctions below; they can be valid outputs.

For shift from -128 to 128, output position j reads input j minus shift, using fill when outside the input. Positive shift moves content toward larger indexes; fill must be zero or one.^[1]

Input field	Meaning and representation	Accepted input
bits	bits.	Binary text containing only 0 and 1; at most 128 characters
shift	shift.	Integer from -128 to 128 inclusive
fill	fill.	Text; at most 8,192 UTF-16 code units, subject to the grammar above

Output field	Interpretation
result	Object containing the named outputs below.
result.bits	The bits value under the stated formula or text convention.

json

{
  "input": {
    "bits": "1011",
    "shift": 2,
    "fill": "0"
  },
  "output": {
    "result": {
      "bits": "0010"
    }
  }
}

Limitations and assumptions

Length is preserved and discarded bits do not wrap. This is not an arithmetic signed-integer shift.
Every bitstring is at most 128 characters and contains only literal zero and one.
All declared input fields are required and unexpected top-level fields are rejected. Numbers must be finite; lists are limited to 128 entries and ordinary text fields to 8,192 UTF-16 code units, with tighter limits where stated.
JSON text inputs must parse within bounded nesting and size limits. Numeric outputs outside the safe finite range are rejected; large exact integer results use decimal strings. Indexes and half-open spans are zero-based unless a rank is explicitly described as one-based.

Alternative or Complementary methods

Choose a packed-integer or textual-bit representation deliberately before combining operations. Preserve the documented index direction, width and exclusive boundaries; do not substitute a rank query for select.

References

Tool behavior and example: Bit String Shift with Fill — tool.io

Similar or alternative tools

Bit String Circular One Runs
Inventory circular one-bit runs with modular starting positions and lengths; all-ones has one full-cycle run and empty/all-zero strings have none.
Bit String Contained Mask Check
Check exact equal-width bit-mask left containment in right at each string position; no implicit padding or integer coercion.