pdfjs-dist/lib/core/stream.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2022 Mozilla Foundation
 *
 * 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.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.StringStream = exports.Stream = exports.NullStream = void 0;

var _base_stream = require("./base_stream.js");

var _util = require("../shared/util.js");

class Stream extends _base_stream.BaseStream {
  constructor(arrayBuffer, start, length, dict) {
    super();
    this.bytes = arrayBuffer instanceof Uint8Array ? arrayBuffer : new Uint8Array(arrayBuffer);
    this.start = start || 0;
    this.pos = this.start;
    this.end = start + length || this.bytes.length;
    this.dict = dict;
  }

  get length() {
    return this.end - this.start;
  }

  get isEmpty() {
    return this.length === 0;
  }

  getByte() {
    if (this.pos >= this.end) {
      return -1;
    }

    return this.bytes[this.pos++];
  }

  getBytes(length, forceClamped = false) {
    const bytes = this.bytes;
    const pos = this.pos;
    const strEnd = this.end;

    if (!length) {
      const subarray = bytes.subarray(pos, strEnd);
      return forceClamped ? new Uint8ClampedArray(subarray) : subarray;
    }

    let end = pos + length;

    if (end > strEnd) {
      end = strEnd;
    }

    this.pos = end;
    const subarray = bytes.subarray(pos, end);
    return forceClamped ? new Uint8ClampedArray(subarray) : subarray;
  }

  getByteRange(begin, end) {
    if (begin < 0) {
      begin = 0;
    }

    if (end > this.end) {
      end = this.end;
    }

    return this.bytes.subarray(begin, end);
  }

  reset() {
    this.pos = this.start;
  }

  moveStart() {
    this.start = this.pos;
  }

  makeSubStream(start, length, dict = null) {
    return new Stream(this.bytes.buffer, start, length, dict);
  }

}

exports.Stream = Stream;

class StringStream extends Stream {
  constructor(str) {
    super((0, _util.stringToBytes)(str));
  }

}

exports.StringStream = StringStream;

class NullStream extends Stream {
  constructor() {
    super(new Uint8Array(0));
  }

}

exports.NullStream = NullStream;