Lesson plan

Variable-length integer

A variable-length integer is a variable-length encoded representation of an integer value using a sequence of bytes. The number of bytes that is needed depends on the value being represented, with larger magnitudes using more bytes than smaller ones. A variable-length integer has no inherent bound on the range of values that can be expressed, unless such a bound is imposed in a particular application. Such schemes have been in use in applications at least since the 1983 specification of the MIDI file format. Variations exist for representing signed and unsigned integers. Variable-length integers are used in applications where it is important to be able to support a large range of integer values and in which smaller numbers are more common than larger ones. Several variations of such formats exist. Early versions used in the MIDI file format and Abstract Syntax Notation One (ASN.1) used big-endian representation. A later-developed little-endian variation is called LEB128. Most variable-length integer representation methods have some built-in redundancy, such that values can be represented using more bytes than necessary, unless the longer representations are prohibited in a particular application (e.g., by prohibiting certain leading or trailing byte values).

Back to article

Article summary

A variable-length integer is a variable-length encoded representation of an integer value using a sequence of bytes. The number of bytes that is needed depends on the value being represented, with larger magnitudes using more bytes than smaller ones. A variable-length integer has no inherent bound on the range of values that can be expressed, unless such a bound is imposed in a particular application. Such schemes have been in use in applications at least since the 1983 specification of the MIDI file format. Variations exist for representing signed and unsigned integers. Variable-length integers are used in applications where it is important to be able to support a large range of integer values and in which smaller numbers are more common than larger ones. Several variations of such formats exist. Early versions used in the MIDI file format and Abstract Syntax Notation One (ASN.1) used big-endian representation. A later-developed little-endian variation is called LEB128. Most variable-length integer representation methods have some built-in redundancy, such that values can be represented using more bytes than necessary, unless the longer representations are prohibited in a particular application (e.g., by prohibiting certain leading or trailing byte values).

Key claims

  1. publication date: 1983 — source: Wikipedia · confidence 0.95
  2. publication date: 2001 — source: Wikipedia · confidence 0.95
  3. publication date: 1984 — source: Wikipedia · confidence 0.95

Discussion questions

  1. Summarise the article in your own words. Which single claim would you verify first, and why?
  2. The record states that the publication date is "1983". What evidence would count against this claim?
  3. The record states that the publication date is "2001". What evidence would count against this claim?
  4. The record states that the publication date is "1984". What evidence would count against this claim?
  5. Which claim in this article is most likely to be revised as the sources update? How would you check its current status?
  6. If two sources disagreed about one of these facts, what would you need in order to trust one over the other?

Bibliography

  1. Wikipedia https://en.wikipedia.org/w/index.php?oldid=1367364674

Key claims and bibliography are generated from the same tracked claims and sources as the article page.