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timvandermeijtimvandermeij
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Merge pull request #13303 from Snuffleupagus/BaseStream
Add an abstract base-class, which all the various Stream implementations inherit from
2 parents af4dc55 + 2ac4ad3 commit f6f3351

23 files changed

+1481
-1425
lines changed

‎src/core/ascii_85_stream.js

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/* Copyright 2012 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { DecodeStream } from "./decode_stream.js";
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import { isWhiteSpace } from "./core_utils.js";
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class Ascii85Stream extends DecodeStream {
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constructor(str, maybeLength) {
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// Most streams increase in size when decoded, but Ascii85 streams
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// typically shrink by ~20%.
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if (maybeLength) {
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maybeLength = 0.8 * maybeLength;
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}
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super(maybeLength);
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this.str = str;
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this.dict = str.dict;
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this.input = new Uint8Array(5);
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}
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readBlock() {
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const TILDA_CHAR = 0x7e; // '~'
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const Z_LOWER_CHAR = 0x7a; // 'z'
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const EOF = -1;
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const str = this.str;
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let c = str.getByte();
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while (isWhiteSpace(c)) {
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c = str.getByte();
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}
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if (c === EOF || c === TILDA_CHAR) {
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this.eof = true;
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return;
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}
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const bufferLength = this.bufferLength;
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let buffer, i;
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// special code for z
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if (c === Z_LOWER_CHAR) {
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buffer = this.ensureBuffer(bufferLength + 4);
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for (i = 0; i < 4; ++i) {
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buffer[bufferLength + i] = 0;
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}
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this.bufferLength += 4;
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} else {
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const input = this.input;
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input[0] = c;
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for (i = 1; i < 5; ++i) {
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c = str.getByte();
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while (isWhiteSpace(c)) {
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c = str.getByte();
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}
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input[i] = c;
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if (c === EOF || c === TILDA_CHAR) {
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break;
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}
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}
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buffer = this.ensureBuffer(bufferLength + i - 1);
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this.bufferLength += i - 1;
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// partial ending;
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if (i < 5) {
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for (; i < 5; ++i) {
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input[i] = 0x21 + 84;
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}
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this.eof = true;
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}
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let t = 0;
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for (i = 0; i < 5; ++i) {
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t = t * 85 + (input[i] - 0x21);
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}
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for (i = 3; i >= 0; --i) {
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buffer[bufferLength + i] = t & 0xff;
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t >>= 8;
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}
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}
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}
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}
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export { Ascii85Stream };

‎src/core/ascii_hex_stream.js

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/* Copyright 2012 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { DecodeStream } from "./decode_stream.js";
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class AsciiHexStream extends DecodeStream {
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constructor(str, maybeLength) {
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// Most streams increase in size when decoded, but AsciiHex streams shrink
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// by 50%.
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if (maybeLength) {
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maybeLength = 0.5 * maybeLength;
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}
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super(maybeLength);
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this.str = str;
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this.dict = str.dict;
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this.firstDigit = -1;
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}
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readBlock() {
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const UPSTREAM_BLOCK_SIZE = 8000;
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const bytes = this.str.getBytes(UPSTREAM_BLOCK_SIZE);
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if (!bytes.length) {
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this.eof = true;
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return;
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}
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const maxDecodeLength = (bytes.length + 1) >> 1;
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const buffer = this.ensureBuffer(this.bufferLength + maxDecodeLength);
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let bufferLength = this.bufferLength;
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let firstDigit = this.firstDigit;
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for (const ch of bytes) {
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let digit;
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if (ch >= /* '0' = */ 0x30 && ch <= /* '9' = */ 0x39) {
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digit = ch & 0x0f;
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} else if (
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(ch >= /* 'A' = */ 0x41 && ch <= /* 'Z' = */ 0x46) ||
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(ch >= /* 'a' = */ 0x61 && ch <= /* 'z' = */ 0x66)
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) {
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digit = (ch & 0x0f) + 9;
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} else if (ch === /* '>' = */ 0x3e) {
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this.eof = true;
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break;
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} else {
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// Probably whitespace, ignoring.
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continue;
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}
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if (firstDigit < 0) {
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firstDigit = digit;
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} else {
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buffer[bufferLength++] = (firstDigit << 4) | digit;
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firstDigit = -1;
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}
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}
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if (firstDigit >= 0 && this.eof) {
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// incomplete byte
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buffer[bufferLength++] = firstDigit << 4;
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firstDigit = -1;
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}
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this.firstDigit = firstDigit;
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this.bufferLength = bufferLength;
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}
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}
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export { AsciiHexStream };

‎src/core/base_stream.js

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/* Copyright 2021 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { shadow, unreachable } from "../shared/util.js";
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class BaseStream {
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constructor() {
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if (this.constructor === BaseStream) {
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unreachable("Cannot initialize BaseStream.");
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}
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}
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// eslint-disable-next-line getter-return
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get length() {
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unreachable("Abstract getter `length` accessed");
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}
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// eslint-disable-next-line getter-return
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get isEmpty() {
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unreachable("Abstract getter `isEmpty` accessed");
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}
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get isDataLoaded() {
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return shadow(this, "isDataLoaded", true);
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}
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getByte() {
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unreachable("Abstract method `getByte` called");
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}
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getBytes(length, forceClamped = false) {
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unreachable("Abstract method `getBytes` called");
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}
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peekByte() {
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const peekedByte = this.getByte();
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if (peekedByte !== -1) {
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this.pos--;
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}
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return peekedByte;
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}
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peekBytes(length, forceClamped = false) {
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const bytes = this.getBytes(length, forceClamped);
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this.pos -= bytes.length;
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return bytes;
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}
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getUint16() {
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const b0 = this.getByte();
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const b1 = this.getByte();
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if (b0 === -1 || b1 === -1) {
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return -1;
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}
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return (b0 << 8) + b1;
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}
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getInt32() {
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const b0 = this.getByte();
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const b1 = this.getByte();
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const b2 = this.getByte();
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const b3 = this.getByte();
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return (b0 << 24) + (b1 << 16) + (b2 << 8) + b3;
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}
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getByteRange(begin, end) {
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unreachable("Abstract method `getByteRange` called");
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}
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skip(n) {
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this.pos += n || 1;
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}
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reset() {
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unreachable("Abstract method `reset` called");
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}
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moveStart() {
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unreachable("Abstract method `moveStart` called");
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}
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makeSubStream(start, length, dict = null) {
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unreachable("Abstract method `makeSubStream` called");
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}
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/**
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* @returns {Array | null}
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*/
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getBaseStreams() {
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return null;
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}
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}
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export { BaseStream };

‎src/core/ccitt_stream.js

+1-1
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@@ -15,7 +15,7 @@
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import { Dict, isDict } from "./primitives.js";
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import { CCITTFaxDecoder } from "./ccitt.js";
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import { DecodeStream } from "./stream.js";
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import { DecodeStream } from "./decode_stream.js";
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class CCITTFaxStream extends DecodeStream {
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constructor(str, maybeLength, params) {

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