itk-wasm/src/buffer-to-typed-array.ts

High-performance spatial analysis in a web browser, Node.js, and reproducible execution across programming languages and hardware architectures.

import IntTypes from './interface-types/int-types.js'
import FloatTypes from './interface-types/float-types.js'
import type TypedArray from './typed-array.js'

function bufferToTypedArray (
  wasmType:
  | (typeof IntTypes)[keyof typeof IntTypes]
  | (typeof FloatTypes)[keyof typeof FloatTypes]
  | 'null'
  | null,
  buffer: ArrayBuffer | SharedArrayBuffer
): null | TypedArray {
  let typedArray: null | TypedArray = null
  switch (wasmType) {
    case IntTypes.UInt8: {
      typedArray = new Uint8Array(buffer)
      break
    }
    case IntTypes.Int8: {
      typedArray = new Int8Array(buffer)
      break
    }
    case IntTypes.UInt16: {
      typedArray = new Uint16Array(buffer)
      break
    }
    case IntTypes.Int16: {
      typedArray = new Int16Array(buffer)
      break
    }
    case IntTypes.UInt32: {
      typedArray = new Uint32Array(buffer)
      break
    }
    case IntTypes.Int32: {
      typedArray = new Int32Array(buffer)
      break
    }
    case IntTypes.UInt64: {
      if (typeof globalThis.BigUint64Array === 'function') {
        typedArray = new BigUint64Array(buffer)
      } else {
        // Sub with reasonable default. Will get cast to Uint8Array when
        // transferred to WebAssembly.
        typedArray = new Uint8Array(buffer)
      }
      break
    }
    case IntTypes.Int64: {
      if (typeof globalThis.BigInt64Array === 'function') {
        typedArray = new BigInt64Array(buffer)
      } else {
        // Sub with reasonable default. Will get cast to Uint8Array when
        // transferred to WebAssembly.
        typedArray = new Uint8Array(buffer)
      }
      break
    }
    case FloatTypes.Float32: {
      typedArray = new Float32Array(buffer)
      break
    }
    case FloatTypes.Float64: {
      typedArray = new Float64Array(buffer)
      break
    }
    case 'null': {
      typedArray = null
      break
    }
    case null: {
      typedArray = null
      break
    }
    default:
      throw new Error('Type is not supported as a TypedArray')
  }

  return typedArray
}

export default bufferToTypedArray