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hex_bytes/2

Module​

This predicate is provided by crypto.pl.

Load this module before using the predicate:

:- consult('/v1/lib/crypto.pl').

Description​

Relates a hexadecimal text representation to a list of bytes.

  • Hex may be an atom, a list of characters, or a list of character codes.
  • Bytes is a proper list of integers in [0,255].
  • At least one argument must be instantiated.
  • When converting Bytes to Hex, Hex is returned as a lowercase atom.

Signature​

hex_bytes(?Hex, ?Bytes) is det

Examples​

Decode a hexadecimal atom into bytes​

This scenario demonstrates how to decode a hexadecimal atom into a list of bytes.

Here are the steps of the scenario:

  • Given the query:
consult('/v1/lib/crypto.pl'),
hex_bytes('501ACE', Bytes).
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 5016
answer:
  has_more: false
  variables: ["Bytes"]
  results:
  - substitutions:
    - variable: Bytes
      expression: "[80,26,206]"

Encode bytes into a hexadecimal atom​

This scenario demonstrates how to encode a list of bytes into a lowercase hexadecimal atom.

Here are the steps of the scenario:

  • Given the query:
consult('/v1/lib/crypto.pl'),
hex_bytes(Hex, [80,26,206]).
  • When the query is run
  • Then the answer we get is:
height: 42
gas_used: 7861
answer:
  has_more: false
  variables: ["Hex"]
  results:
  - substitutions:
    - variable: Hex
      expression: "'501ace'"