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ethdebug/format/pointer/scheme/fragment

$schema: "https://json-schema.org/draft/2020-12/schema"
$id: "schema:ethdebug/format/pointer/scheme/fragment"

title: ethdebug/format/pointer/scheme/fragment
description: |
  An addressing scheme for pointing to a range of bytes inside the value of
  an expression.

  The other addressing schemes address bytes in a byte space that the data
  location already has. This scheme supplies the byte space itself: the
  bytes of the value that `expression` evaluates to. It then addresses a
  range of bytes in that value by `offset` and `length`, as the slice
  scheme does.

  A fragment that extends outside the value's bytes (i.e., where `offset`
  plus `length` exceeds the value's width) is invalid.

type: object

properties:
  expression:
    description: |
      The expression whose value supplies the bytes for this fragment.

      This expression **must** be width-bearing (bytes), the same rule as
      for the operands of `~concat` and `~keccak256`. A bare integer (a JSON
      number, an odd-digit hex literal, `~wordsize`, an arithmetic result,
      or a lookup) is **not** valid here: give it a width first with
      `~sizedN` or `~wordsized`.

      This expression is evaluated against the same machine state as the
      other regions of the pointer. It may refer only to regions that come
      before this region.
    $ref: "schema:ethdebug/format/pointer/expression"
  offset:
    description: |
      The index of the byte (starting from zero) in the value's bytes where
      the fragment begins.

      This field is **optional**. If unspecified, it has the default value
      of `0`, indicating that the fragment begins at the first byte of the
      value.
    $ref: "schema:ethdebug/format/pointer/expression"
    default: 0
  length:
    description: |
      The length of the fragment in number of bytes.

      This field is **optional**. If unspecified, its default value
      indicates that the fragment ends at the end of the value: the value's
      width minus `offset`.
    $ref: "schema:ethdebug/format/pointer/expression"

required:
  - expression

examples:
  - expression:
      ~wordsized: 1
  - expression:
      ~keccak256:
        - ~wordsized: 0
    length: 4
  - expression: "0xdeadbeef"
    offset: 2
    length: 2

JSON

ethdebug/format/pointer/scheme/fragment

{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id": "schema:ethdebug/format/pointer/scheme/fragment",
  "title": "ethdebug/format/pointer/scheme/fragment",
  "description": "An addressing scheme for pointing to a range of bytes inside the value of\nan expression.\n\nThe other addressing schemes address bytes in a byte space that the data\nlocation already has. This scheme supplies the byte space itself: the\nbytes of the value that `expression` evaluates to. It then addresses a\nrange of bytes in that value by `offset` and `length`, as the slice\nscheme does.\n\nA fragment that extends outside the value's bytes (i.e., where `offset`\nplus `length` exceeds the value's width) is invalid.\n",
  "type": "object",
  "properties": {
    "expression": {
      "description": "The expression whose value supplies the bytes for this fragment.\n\nThis expression **must** be width-bearing (bytes), the same rule as\nfor the operands of `~concat` and `~keccak256`. A bare integer (a JSON\nnumber, an odd-digit hex literal, `~wordsize`, an arithmetic result,\nor a lookup) is **not** valid here: give it a width first with\n`~sizedN` or `~wordsized`.\n\nThis expression is evaluated against the same machine state as the\nother regions of the pointer. It may refer only to regions that come\nbefore this region.\n",
      "$ref": "schema:ethdebug/format/pointer/expression"
    },
    "offset": {
      "description": "The index of the byte (starting from zero) in the value's bytes where\nthe fragment begins.\n\nThis field is **optional**. If unspecified, it has the default value\nof `0`, indicating that the fragment begins at the first byte of the\nvalue.\n",
      "$ref": "schema:ethdebug/format/pointer/expression",
      "default": 0
    },
    "length": {
      "description": "The length of the fragment in number of bytes.\n\nThis field is **optional**. If unspecified, its default value\nindicates that the fragment ends at the end of the value: the value's\nwidth minus `offset`.\n",
      "$ref": "schema:ethdebug/format/pointer/expression"
    }
  },
  "required": [
    "expression"
  ],
  "examples": [
    {
      "expression": {
        "~wordsized": 1
      }
    },
    {
      "expression": {
        "~keccak256": [
          {
            "~wordsized": 0
          }
        ]
      },
      "length": 4
    },
    {
      "expression": "0xdeadbeef",
      "offset": 2,
      "length": 2
    }
  ]
}

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