@tensorflow/tfjs-data
Version:
TensorFlow Data API in JavaScript
115 lines • 13.6 kB
JavaScript
/**
* @license
* Copyright 2018 Google LLC. All Rights Reserved.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* =============================================================================
*/
import { env } from '@tensorflow/tfjs-core';
import { LazyIterator, OneToManyIterator } from './lazy_iterator';
import { StringIterator } from './string_iterator';
export class ByteChunkIterator extends LazyIterator {
/**
* Decode a stream of UTF8-encoded byte arrays to a stream of strings.
*
* The byte arrays producetd from the ByteChunkIterator on which this is
* called will be interpreted as concatenated. No assumptions are made about
* the boundaries of the incoming chunks, so a multi-byte UTF8 encoding of a
* character may span the boundary between chunks. This naturally happens,
* for instance, when reading fixed-size byte arrays from a file.
*/
decodeUTF8() {
return new Utf8Iterator(this);
}
}
// ============================================================================
// The following private classes serve to implement the chainable methods
// on ByteChunkIterator. Unfortunately they can't be placed in separate files,
// due to resulting trouble with circular imports.
// ============================================================================
// We wanted multiple inheritance, e.g.
// class Utf8Iterator extends QueueIterator<string>, StringIterator
// but the TypeScript mixin approach is a bit hacky, so we take this adapter
// approach instead.
class Utf8Iterator extends StringIterator {
constructor(upstream) {
super();
this.upstream = upstream;
this.impl = new Utf8IteratorImpl(upstream);
}
summary() {
return this.impl.summary();
}
async next() {
return this.impl.next();
}
}
/**
* Decode a stream of UTF8-encoded byte arrays to a stream of strings.
*
* This is tricky because the incoming byte array boundaries may disrupt a
* multi-byte UTF8 character. Thus any incomplete character data at the end of
* a chunk must be carried over and prepended to the next chunk before
* decoding. Luckily with native decoder, TextDecoder in browser and
* string_decoder in node, byte array boundaries are handled automatically.
*
* In the context of an input pipeline for machine learning, UTF8 decoding is
* needed to parse text files containing training examples or prediction
* requests (e.g., formatted as CSV or JSON). We cannot use the built-in
* decoding provided by FileReader.readAsText() because here we are in a
* streaming context, which FileReader does not support.
*
* @param upstream A `LazyIterator` of `Uint8Arrays` containing UTF8-encoded
* text, which should be interpreted as concatenated. No assumptions are
* made about the boundaries of the incoming chunks, so a multi-byte UTF8
* encoding of a character may span the boundary between chunks. This
* naturally happens, for instance, when reading fixed-size byte arrays from a
* file.
*/
class Utf8IteratorImpl extends OneToManyIterator {
constructor(upstream) {
super();
this.upstream = upstream;
if (env().get('IS_BROWSER')) {
this.decoder = new TextDecoder('utf-8');
}
else {
// tslint:disable-next-line:no-require-imports
const { StringDecoder } = require('string_decoder');
this.decoder = new StringDecoder('utf8');
}
}
summary() {
return `${this.upstream.summary()} -> Utf8`;
}
async pump() {
const chunkResult = await this.upstream.next();
let chunk;
if (chunkResult.done) {
return false;
}
else {
chunk = chunkResult.value;
}
let text;
if (env().get('IS_BROWSER')) {
text = this.decoder.decode(chunk, { stream: true });
}
else {
text = this.decoder.write(Buffer.from(chunk.buffer));
}
this.outputQueue.push(text);
return true;
}
}
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All Rights Reserved.\n * Licensed under the Apache License, Version 2.0 (the \"License\");\n * you may not use this file except in compliance with the License.\n * You may obtain a copy of the License at\n *\n * http://www.apache.org/licenses/LICENSE-2.0\n *\n * Unless required by applicable law or agreed to in writing, software\n * distributed under the License is distributed on an \"AS IS\" BASIS,\n * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n * See the License for the specific language governing permissions and\n * limitations under the License.\n *\n * =============================================================================\n */\n\nimport {env} from '@tensorflow/tfjs-core';\nimport {LazyIterator, OneToManyIterator} from './lazy_iterator';\nimport {StringIterator} from './string_iterator';\n\nexport abstract class ByteChunkIterator extends LazyIterator<Uint8Array> {\n  /**\n   * Decode a stream of UTF8-encoded byte arrays to a stream of strings.\n   *\n   * The byte arrays producetd from the ByteChunkIterator on which this is\n   * called will be interpreted as concatenated.  No assumptions are made about\n   * the boundaries of the incoming chunks, so a multi-byte UTF8 encoding of a\n   * character may span the boundary between chunks.  This naturally happens,\n   * for instance, when reading fixed-size byte arrays from a file.\n   */\n  decodeUTF8(): StringIterator {\n    return new Utf8Iterator(this);\n  }\n}\n\n// ============================================================================\n// The following private classes serve to implement the chainable methods\n// on ByteChunkIterator.  Unfortunately they can't be placed in separate files,\n// due to resulting trouble with circular imports.\n// ============================================================================\n\n// We wanted multiple inheritance, e.g.\n//   class Utf8Iterator extends QueueIterator<string>, StringIterator\n// but the TypeScript mixin approach is a bit hacky, so we take this adapter\n// approach instead.\n\nclass Utf8Iterator extends StringIterator {\n  private impl: Utf8IteratorImpl;\n\n  constructor(protected upstream: LazyIterator<Uint8Array>) {\n    super();\n    this.impl = new Utf8IteratorImpl(upstream);\n  }\n\n  summary() {\n    return this.impl.summary();\n  }\n\n  async next() {\n    return this.impl.next();\n  }\n}\n\n/**\n * Decode a stream of UTF8-encoded byte arrays to a stream of strings.\n *\n * This is tricky because the incoming byte array boundaries may disrupt a\n * multi-byte UTF8 character. Thus any incomplete character data at the end of\n * a chunk must be carried over and prepended to the next chunk before\n * decoding. Luckily with native decoder, TextDecoder in browser and\n * string_decoder in node, byte array boundaries are handled automatically.\n *\n * In the context of an input pipeline for machine learning, UTF8 decoding is\n * needed to parse text files containing training examples or prediction\n * requests (e.g., formatted as CSV or JSON). We cannot use the built-in\n * decoding provided by FileReader.readAsText() because here we are in a\n * streaming context, which FileReader does not support.\n *\n * @param upstream A `LazyIterator` of `Uint8Arrays` containing UTF8-encoded\n *   text, which should be interpreted as concatenated.  No assumptions are\n *   made about the boundaries of the incoming chunks, so a multi-byte UTF8\n *   encoding of a character may span the boundary between chunks.  This\n *   naturally happens, for instance, when reading fixed-size byte arrays from a\n *   file.\n */\nclass Utf8IteratorImpl extends OneToManyIterator<string> {\n  // `decoder` as `any` here to dynamically assign value based on the\n  // environment.\n  // tslint:disable-next-line:no-any\n  decoder: any;\n\n  constructor(protected readonly upstream: LazyIterator<Uint8Array>) {\n    super();\n    if (env().get('IS_BROWSER')) {\n      this.decoder = new TextDecoder('utf-8');\n    } else {\n      // tslint:disable-next-line:no-require-imports\n      const {StringDecoder} = require('string_decoder');\n      this.decoder = new StringDecoder('utf8');\n    }\n  }\n  summary() {\n    return `${this.upstream.summary()} -> Utf8`;\n  }\n\n  async pump(): Promise<boolean> {\n    const chunkResult = await this.upstream.next();\n    let chunk;\n    if (chunkResult.done) {\n      return false;\n    } else {\n      chunk = chunkResult.value;\n    }\n\n    let text: string;\n    if (env().get('IS_BROWSER')) {\n      text = this.decoder.decode(chunk, {stream: true});\n    } else {\n      text = this.decoder.write(Buffer.from(chunk.buffer));\n    }\n    this.outputQueue.push(text);\n    return true;\n  }\n}\n"]}