core/datatype-1.0.0¶

An description of array element data format.

Description

The data format of array elements. May be a single scalar datatype, or may be a nested list of datatypes. When a list, each field may have a name.

Outline

Schema Definitions
Internal Definitions
Original Schema

Schema Definitions ¶

This node must validate against any of the following:

array
No length restriction
Items in the array must be any of the following types:

#/definitions/scalar-datatype
This type is an object with the following properties:

name
string
The name of the field

No length restriction
Must match the following pattern:

[A-Za-z_][A-Za-z0-9_]*

datatype
# Required
byteorder
string
The byteorder for the field. If not provided, the byteorder of the datatype as a whole will be used.

No length restriction

Only the following values are valid for this node:

big

little

shape
array
No length restriction

Items in the array are restricted to the following types:

integer
Minimum value: 0

Internal Definitions ¶

scalar-datatype

object

Describes the type of a single element.

There is a set of numeric types, each with a single identifier:

int8, int16, int32, int64: Signed integer types, with the given bit size.
uint8, uint16, uint32, uint64: Unsigned integer types, with the given bit size.
float16: Half-precision floating-point type or “binary16”, as defined in IEEE 754.
float32: Single-precision floating-point type or “binary32”, as defined in IEEE 754.
float64: Double-precision floating-point type or “binary64”, as defined in IEEE 754.
complex64: Complex number where the real and imaginary parts are each single-precision floating-point (“binary32”) numbers, as defined in IEEE 754.
complex128: Complex number where the real and imaginary parts are each double-precision floating-point (“binary64”) numbers, as defined in IEEE 754.

There are two distinct fixed-length string types, which must be indicated with a 2-element array where the first element is an identifier for the string type, and the second is a length:

ascii: A string containing ASCII text (all codepoints < 128), where each character is 1 byte.
ucs4: A string containing unicode text in the UCS-4 encoding, where each character is always 4 bytes long. Here the number of bytes used is 4 times the given length.

This node must validate against any of the following:

string
No length restriction
Only the following values are valid for this node:

int8

uint8

int16

uint16

int32

uint32

int64

uint64

float16

float32

float64

complex64

complex128

bool8
array
No length restriction
The first 2 items in the list must be the following types:

string
No length restriction

Only the following values are valid for this node:

ascii

ucs4

integer
Minimum value: 0

Original Schema ¶

%YAML 1.1
---
$schema: "http://stsci.edu/schemas/yaml-schema/draft-01"
id: "http://stsci.edu/schemas/asdf/core/datatype-1.0.0"

title: >
  An description of array element data format.

description: |
  The data format of array elements. May be a single scalar
  datatype, or may be a nested list of datatypes. When a list, each field
  may have a name.

definitions:
  scalar-datatype:
    description: |
      Describes the type of a single element.

      There is a set of numeric types, each with a single identifier:

      - `int8`, `int16`, `int32`, `int64`: Signed integer types, with
        the given bit size.

      - `uint8`, `uint16`, `uint32`, `uint64`: Unsigned integer types,
        with the given bit size.

      - `float16`: Half-precision floating-point type or "binary16",
        as defined in IEEE 754.

      - `float32`: Single-precision floating-point type or "binary32",
        as defined in IEEE 754.

      - `float64`: Double-precision floating-point type or "binary64",
        as defined in IEEE 754.

      - `complex64`: Complex number where the real and imaginary parts
        are each single-precision floating-point ("binary32") numbers,
        as defined in IEEE 754.

      - `complex128`: Complex number where the real and imaginary
        parts are each double-precision floating-point ("binary64")
        numbers, as defined in IEEE 754.

      There are two distinct fixed-length string types, which must
      be indicated with a 2-element array where the first element is an
      identifier for the string type, and the second is a length:

      - `ascii`: A string containing ASCII text (all codepoints <
        128), where each character is 1 byte.

      - `ucs4`: A string containing unicode text in the UCS-4
        encoding, where each character is always 4 bytes long.  Here
        the number of bytes used is 4 times the given length.

    anyOf:
      - type: string
        enum: [int8, uint8, int16, uint16, int32, uint32, int64, uint64,
               float16, float32, float64, complex64, complex128, bool8]
      - type: array
        items:
          - type: string
            enum: [ascii, ucs4]
          - type: integer
            minimum: 0
        minLength: 2
        maxLength: 2

anyOf:
  - $ref: "#/definitions/scalar-datatype"
  - type: array
    items:
      anyOf:
        - $ref: "#/definitions/scalar-datatype"
        - type: object
          properties:
            name:
              type: string
              pattern: "[A-Za-z_][A-Za-z0-9_]*"
              description: The name of the field
            datatype:
              $ref: "#"
            byteorder:
              type: string
              enum: [big, little]
              description: |
                The byteorder for the field. If not provided, the
                byteorder of the datatype as a whole will be used.
            shape:
              type: array
              items:
                type: integer
                minimum: 0
          required: [datatype]
...